4.0 Introduction
4.0.1 IntroductionPage 1:
As the size of the network for a small- or medium-sized business grows, the management involved in maintaining the network grows. In the previous chapter, you learned how to create and manage VLANs and trunks using Cisco IOS commands. The focus was on managing VLAN information on a single switch. But what if you have many switches to manage? How will you manage the VLAN database across many switches? In this chapter, you will explore how you can use the VLAN Trunking Protocol (VTP) of Cisco Catalyst switches to simplify management of the VLAN database across multiple switches.
4.0.1 - Chapter Introduction
The diagram depicts the chapter objectives.
-Explain the role of VTP in a converged switched network.
-Describe VTP operation, including domains, modes, advertisements, and pruning.
-Configure VTP on the switches in a converged network.
The diagram depicts the chapter objectives.
-Explain the role of VTP in a converged switched network.
-Describe VTP operation, including domains, modes, advertisements, and pruning.
-Configure VTP on the switches in a converged network.
4.1 VTP Concepts
4.1.1 What is VTP?Page 1:
The VLAN Management Challenge
As the number of switches increases on a small- or medium-sized business network, the overall administration required to manage VLANs and trunks in a network becomes a challenge.
Click Play to view an animation of the VLAN management challenge.
Small Network VLAN Management
In the animation, the figure shows a network manager adding a new VLAN, VLAN30. The network manager needs to update the three trunks to allow VLANs 10, 20, 30, and 99. Recall that a common error is forgetting to update the allowed list of VLANs on trunks.
Click the Larger Network button in the figure.
Larger Network VLAN Management
When you consider the larger network in the figure, the VLAN management challenge becomes clear. After you have manually updated this network a few times, you may want to know if there is a way for the switches to learn what the VLANs and trunks are so that you do not have to manually configure them. You are ready to learn about VLAN trunking protocol (VTP).
4.1.1 - What Is VTP?
The diagram depicts the V LAN management challenge as the number of switches increases on a small- or medium-sized business network.
Small Network
There are three switches, S1, S2, and S3. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S3 port F0/3 is connected to S1 port F0/3 using a crossover cable.
Existing V LAN's:
- V LAN 10 - faculty/staff
- V LAN 20 - students
- V LAN 99 - management V LAN
V LAN Management Task:
- Add V LAN 30 - guest
With a small network, the new V LAN can be added to each switch.
Larger Network
The larger network has many more switches. There are six Access Layer switches connected to four Distribution Layer switches, which are connected to two Core Layer switches. Each Core Layer switch is connected to a router.
Existing V LAN's: 10, 20, and 99
V LAN Management Task: Add V LAN 30
With a larger network, it is very time consuming to add a new V LAN to each switch.
The diagram depicts the V LAN management challenge as the number of switches increases on a small- or medium-sized business network.
Small Network
There are three switches, S1, S2, and S3. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S3 port F0/3 is connected to S1 port F0/3 using a crossover cable.
Existing V LAN's:
- V LAN 10 - faculty/staff
- V LAN 20 - students
- V LAN 99 - management V LAN
V LAN Management Task:
- Add V LAN 30 - guest
With a small network, the new V LAN can be added to each switch.
Larger Network
The larger network has many more switches. There are six Access Layer switches connected to four Distribution Layer switches, which are connected to two Core Layer switches. Each Core Layer switch is connected to a router.
Existing V LAN's: 10, 20, and 99
V LAN Management Task: Add V LAN 30
With a larger network, it is very time consuming to add a new V LAN to each switch.
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What is VTP?
VTP allows a network manager to configure a switch so that it will propagate VLAN configurations to other switches in the network. The switch can be configured in the role of a VTP server or a VTP client. VTP only learns about normal-range VLANs (VLAN IDs 1 to 1005). Extended-range VLANs (IDs greater than 1005) are not supported by VTP.
Click Play in the figure to view an animation of an overview of how VTP works.
VTP Overview
VTP allows a network manager to makes changes on a switch that is configured as a VTP server. Basically, the VTP server distributes and synchronizes VLAN information to VTP-enabled switches throughout the switched network, which minimizes the problems caused by incorrect configurations and configuration inconsistencies. VTP stores VLAN configurations in the VLAN database called vlan.dat.
Click the Two Switches button in the figure.
Two Switches
Click Play in the figure to view an animation on the basic VTP interaction between a VTP server and a VTP client.
In the figure, a trunk link is added between switch S1, a VTP server, and S2, a VTP client. After a trunk is established between the two switches, VTP advertisements are exchanged between the switches. Both the server and client leverage advertisements from one another to ensure each has an accurate record of VLAN information. VTP advertisements will not be exchanged if the trunk between the switches is inactive. The details on how VTP works is explained in the rest of this chapter.
4.1.1 - What Is VTP?
The animation depicts an overview of VTP and how it functions between two switches connected by a trunk link.
VTP Overview
There are three switches, S1, S2, and S3. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S3 port F0/3 is connected to S1 port F0/3 using a crossover cable.
Switch S1 is a VTP server, and S2 and S3 are VTP-enabled switches. The network administrator configures V LAN 30 on S1. VTP automatically propagates the new V LAN 30 information to switches S2 and S3 using VTP. Switches S2 and S3 communicate with switch S1 using VTP advertisements.
Two switches
There are two switches, S1 and S2. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S1 is a VTP server, and switch S2 is a VTP client.
Animation sequence:
One. A trunk link is added between switch S1, the VTP server, and S2, the VTP client.
Two. VTP advertisements are exchanged between the switches.
Three. Port F0/1 on switch S2 is incorrectly configured.
Four. Port F0/1 on switch S1 and port F0/1 on switch S2 revert to access switch ports.
Five. The link between switches S1 and S2 becomes an access link.
Six. Communication between switches S1 and S2 is lost.
The animation depicts an overview of VTP and how it functions between two switches connected by a trunk link.
VTP Overview
There are three switches, S1, S2, and S3. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S3 port F0/3 is connected to S1 port F0/3 using a crossover cable.
Switch S1 is a VTP server, and S2 and S3 are VTP-enabled switches. The network administrator configures V LAN 30 on S1. VTP automatically propagates the new V LAN 30 information to switches S2 and S3 using VTP. Switches S2 and S3 communicate with switch S1 using VTP advertisements.
Two switches
There are two switches, S1 and S2. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S1 is a VTP server, and switch S2 is a VTP client.
Animation sequence:
One. A trunk link is added between switch S1, the VTP server, and S2, the VTP client.
Two. VTP advertisements are exchanged between the switches.
Three. Port F0/1 on switch S2 is incorrectly configured.
Four. Port F0/1 on switch S1 and port F0/1 on switch S2 revert to access switch ports.
Five. The link between switches S1 and S2 becomes an access link.
Six. Communication between switches S1 and S2 is lost.
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Benefits of VTP
You have learned that VTP maintains VLAN configuration consistency by managing the addition, deletion, and renaming of VLANs across multiple Cisco switches in a network. VTP offers a number of benefits for network managers, as shown in the figure.
4.1.1 - What Is VTP?
The diagram depicts a list of VTP benefits.
VTP benefits include:
- V LAN configuration consistency across the network.
- Accurate tracking and monitoring of V LAN's.
- Dynamic reporting of added V LAN's across a network.
- Dynamic trunk configuration when V LAN's are added to the network.
The diagram depicts a list of VTP benefits.
VTP benefits include:
- V LAN configuration consistency across the network.
- Accurate tracking and monitoring of V LAN's.
- Dynamic reporting of added V LAN's across a network.
- Dynamic trunk configuration when V LAN's are added to the network.
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VTP Components
There are number of key components that you need to be familiar with when learning about VTP. Here is a brief description of the components, which will be further explained as you go through the chapter.
- VTP Domain-Consists of one or more interconnected switches. All switches in a domain share VLAN configuration details using VTP advertisements. A router or Layer 3 switch defines the boundary of each domain.
- VTP Advertisements-VTP uses a hierarchy of advertisements to distribute and synchronize VLAN configurations across the network.
- VTP Modes- A switch can be configured in one of three modes: server, client, or transparent.
- VTP Server-VTP servers advertise the VTP domain VLAN information to other VTP-enabled switches in the same VTP domain. VTP servers store the VLAN information for the entire domain in NVRAM. The server is where VLANs can be created, deleted, or renamed for the domain.
- VTP Client-VTP clients function the same way as VTP servers, but you cannot create, change, or delete VLANs on a VTP client. A VTP client only stores the VLAN information for the entire domain while the switch is on. A switch reset deletes the VLAN information. You must configure VTP client mode on a switch.
- VTP Transparent-Transparent switches forward VTP advertisements to VTP clients and VTP servers. Transparent switches do not participate in VTP. VLANs that are created, renamed, or deleted on transparent switches are local to that switch only.
- VTP Pruning-VTP pruning increases network available bandwidth by restricting flooded traffic to those trunk links that the traffic must use to reach the destination devices. Without VTP pruning, a switch floods broadcast, multicast, and unknown unicast traffic across all trunk links within a VTP domain even though receiving switches might discard them.
Roll over the key VTP components in the figure to see where they are in the network.
4.1.1 - What Is VTP?
The diagram depicts VTP components and terminology, including VTP domain, VTP advertisements, VTP modes, VTP server, VTP client, VTP transparent, and VTP pruning.
Network Topology:
There are six Access Layer switches, S1, S2, S3, S4, S5, and S6, which are connected to four Distribution Layer switches, D1, D2, D3, and D4. The Distribution Layer switches are connected to two Core Layer switches, C1 and C2. The two Core Layer switches are connected to single switch at the top of the hierarchy, S0.
Switches S1, S2, and S3 are each connected to switches D1 and D2. Switches S4, S5, and S6 are each connected to D3 and D4. Switches D1 and D2 are connected to C1. Switches D3 and D4 are connected to C2. Switches C1 and C2 are connected to switch S0. All switch interconnections use crossover cables.
As the following VTP terms are rolled over, various components are highlighted in the network.
VTP Domain
Switches C1, D1, D2, S1, S2, and S3 make up VTP Domain 1. Switches C2, D3, D4, S4, S5, and S5 make up VTP Domain 2.
VTP Advertisements
Examples of VTP advertisement packets are shown being sent between C1, D1, and D2 and between S6 and D4.
VTP Modes
Switches C1 and C2 are highlighted as VTP servers. Switches S1, S2, S3, S4, S5, S6, D1, and D3 are highlighted as VTP clients. Switches D2 and D4 are highlighted as VTP transparent.
VTP Server
Switches C1 and C2 are highlighted as VTP servers.
VTP Client
Switches S1, S2, S3, S4, S5, S6, D1, and D3 are highlighted as VTP clients.
VTP Transparent
Switches D2 and D4 are highlighted as VTP transparent.
VTP Pruning
Trunk links between switches D3 and S6, D4 and S4, and D4 and C2 are shown as blocked, indicating that flooded traffic is restricted.
The diagram depicts VTP components and terminology, including VTP domain, VTP advertisements, VTP modes, VTP server, VTP client, VTP transparent, and VTP pruning.
Network Topology:
There are six Access Layer switches, S1, S2, S3, S4, S5, and S6, which are connected to four Distribution Layer switches, D1, D2, D3, and D4. The Distribution Layer switches are connected to two Core Layer switches, C1 and C2. The two Core Layer switches are connected to single switch at the top of the hierarchy, S0.
Switches S1, S2, and S3 are each connected to switches D1 and D2. Switches S4, S5, and S6 are each connected to D3 and D4. Switches D1 and D2 are connected to C1. Switches D3 and D4 are connected to C2. Switches C1 and C2 are connected to switch S0. All switch interconnections use crossover cables.
As the following VTP terms are rolled over, various components are highlighted in the network.
VTP Domain
Switches C1, D1, D2, S1, S2, and S3 make up VTP Domain 1. Switches C2, D3, D4, S4, S5, and S5 make up VTP Domain 2.
VTP Advertisements
Examples of VTP advertisement packets are shown being sent between C1, D1, and D2 and between S6 and D4.
VTP Modes
Switches C1 and C2 are highlighted as VTP servers. Switches S1, S2, S3, S4, S5, S6, D1, and D3 are highlighted as VTP clients. Switches D2 and D4 are highlighted as VTP transparent.
VTP Server
Switches C1 and C2 are highlighted as VTP servers.
VTP Client
Switches S1, S2, S3, S4, S5, S6, D1, and D3 are highlighted as VTP clients.
VTP Transparent
Switches D2 and D4 are highlighted as VTP transparent.
VTP Pruning
Trunk links between switches D3 and S6, D4 and S4, and D4 and C2 are shown as blocked, indicating that flooded traffic is restricted.
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4.1.1 - What Is VTP?
The diagram depicts an activity where you must replace the blank within a statement using the proper VTP term. Not all terms are used.
Statements:
A. VTP is an acronym for BLANK.
B. VTP is a BLANK messaging protocol that maintains V LAN configuration consistency by managing the addition, deletion, and renaming of V LAN's across multiple Cisco switches in a network.
C. VTP is a BLANK protocol available only on Cisco switches.
D. In VTP BLANK mode, you can create, modify, and delete V LAN's for the entire VTP domain.
E. In VTP BLANK mode, the switch does not participate in VTP. However, the switch does forward VTP advertisements through trunk interfaces.
F. In VTP BLANK mode, you cannot create, change, or delete V LAN's.
G. In VTP BLANK mode, V LAN configurations are not saved in NV RAM.
H. VTP BLANK mode allows you to create, modify, and delete V LAN's on the single switch without affecting the rest of the switches in your network.
I. VTP BLANK mode is the default mode for a Cisco switch.
Terms:
One. Layer 2.
Two. Server.
Three. Open-source.
Four. V LAN trunking protocol.
Five. Transparent.
Six. Virtual trunking protocol.
Seven. Translation.
Eight. Proprietary.
Nine. Client.
Ten. Layer 3.
The diagram depicts an activity where you must replace the blank within a statement using the proper VTP term. Not all terms are used.
Statements:
A. VTP is an acronym for BLANK.
B. VTP is a BLANK messaging protocol that maintains V LAN configuration consistency by managing the addition, deletion, and renaming of V LAN's across multiple Cisco switches in a network.
C. VTP is a BLANK protocol available only on Cisco switches.
D. In VTP BLANK mode, you can create, modify, and delete V LAN's for the entire VTP domain.
E. In VTP BLANK mode, the switch does not participate in VTP. However, the switch does forward VTP advertisements through trunk interfaces.
F. In VTP BLANK mode, you cannot create, change, or delete V LAN's.
G. In VTP BLANK mode, V LAN configurations are not saved in NV RAM.
H. VTP BLANK mode allows you to create, modify, and delete V LAN's on the single switch without affecting the rest of the switches in your network.
I. VTP BLANK mode is the default mode for a Cisco switch.
Terms:
One. Layer 2.
Two. Server.
Three. Open-source.
Four. V LAN trunking protocol.
Five. Transparent.
Six. Virtual trunking protocol.
Seven. Translation.
Eight. Proprietary.
Nine. Client.
Ten. Layer 3.
4.2 VTP Operation
4.2.1 Default VTP ConfigurationPage 1:
In CCNA Exploration: Network Fundamentals, you learned that a Cisco switch comes from the factory with default settings. The default VTP settings are shown in the figure. The benefit of VTP is that it automatically distributes and synchronizes domain and VLAN configurations across the network. However, this benefit comes with a cost, you can only add switches that are in their default VTP configuration. If you add a VTP-enabled switch that is configured with settings that supersede existing network VTP configurations, changes that are difficult to fix are automatically propagated throughout the network. So make sure that you only add switches that are in their default VTP configuration. You will learn how to add switches to a VTP network later in this chapter.
VTP Versions
VTP has three versions, 1, 2, and 3. Only one VTP version is allowed in a VTP domain. The default is VTP version 1. A Cisco 2960 switch supports VTP version 2, but it is disabled. A discussion of VTP versions is beyond the scope of this course.
Click the Switch Output button in the figure to see the default VTP settings on switch S1.
Displaying the VTP Status
The figure shows how to view the VTP settings for a Cisco 2960 switch, S1. The Cisco IOS command show VTP status displays the VTP status. The output shows that switch S1 is in VTP server mode by default and that there is no VTP domain name assigned. The output also shows that the maximum VTP version available for the switch is version 2, and that VTP version 2 is disabled. You will use the show VTP status command frequently as you configure and manage VTP on a network. The following briefly describes the show VTP status parameters:
- VTP Version-Displays the VTP version the switch is capable of running. By default, the switch implements version 1, but can be set to version 2.
- Configuration Revision-Current configuration revision number on this switch. You will learn more about revisions numbers in this chapter.
- Maximum VLANs Supported Locally-Maximum number of VLANs supported locally.
- Number of Existing VLANs-Number of existing VLANs.
- VTP Operating Mode-Can be server, client, or transparent.
- VTP Domain Name-Name that identifies the administrative domain for the switch.
- VTP Pruning Mode-Displays whether pruning is enabled or disabled.
- VTP V2 Mode-Displays if VTP version 2 mode is enabled. VTP version 2 is disabled by default.
- VTP Traps Generation-Displays whether VTP traps are sent to a network management station.
- MD5 Digest-A 16-byte checksum of the VTP configuration.
- Configuration Last Modified-Date and time of the last configuration modification. Displays the IP address of the switch that caused the configuration change to the database.
4.2.1 - Default VTP Configuration
The diagram depicts the default VTP settings and switch output from the show vtp status command.
Network Topology:
Switches S2 and S3 are connected to switch S1. Switch S1 is connected to router R1, which is connected to router C1. Router C1 is connected to a network cloud with a WAN link.
Default VTP Configuration:
VTP Version = 1
VTP Domain Name = null
VTP Mode = Server
Config Revision = 0
V LAN's = 1
Switch Output Example:
S1#show vtp status
VTP Version : 2
Configuration Revision : 0
Maximum V LAN's supported : 255
Number of existing V LAN's : 5
VTP Operating Mode : Server
VTP Domain Name :
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x3F 0x37 0x45 0x9A 0x37 0x53 0xA6 0xDE
Configuration last modified by 0.0.0.0 at 3-1-93 00:14:07
S1#
The diagram depicts the default VTP settings and switch output from the show vtp status command.
Network Topology:
Switches S2 and S3 are connected to switch S1. Switch S1 is connected to router R1, which is connected to router C1. Router C1 is connected to a network cloud with a WAN link.
Default VTP Configuration:
VTP Version = 1
VTP Domain Name = null
VTP Mode = Server
Config Revision = 0
V LAN's = 1
Switch Output Example:
S1#show vtp status
VTP Version : 2
Configuration Revision : 0
Maximum V LAN's supported : 255
Number of existing V LAN's : 5
VTP Operating Mode : Server
VTP Domain Name :
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x3F 0x37 0x45 0x9A 0x37 0x53 0xA6 0xDE
Configuration last modified by 0.0.0.0 at 3-1-93 00:14:07
S1#
4.2.2 VTP Domains
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VTP Domains
VTP allows you to separate your network into smaller management domains to help reduce VLAN management. An additional benefit of configuring VTP domains is that it limits the extent to which configuration changes are propagated in the network if an error occurs. The figure shows a network with two VTP domains, cisco2 and cisco3. In this chapter, the three switches, S1, S2, and S3, will be configured for VTP.
A VTP domain consists of one switch or several interconnected switches sharing the same VTP domain name. Later in this chapter, you will learn how VTP-enabled switches acquire a common domain name. A switch can be a member of only one VTP domain at a time. Until the VTP domain name is specified you cannot create or modify VLANs on a VTP server, and VLAN information is not propagated over the network.
Click the Switch Output button in the figure to see switch S4 output.
4.2.2 - VTP Domains
The diagram depicts VTP domains and switch output from the show vtp status command.
Network Topology:
Nine switches are shown. Switches S2 and S3 are connected to switch S1. Switch S1 is connected to router R1, which is connected to router C1. Router C1 is connected to a network cloud with a WAN link.
Switches S5 and S6 are connected to switch S4. Switch S4 is connected to router R2, which is connected to routers C1 and C2. Router C1 and C2 are connected to a network cloud with WAN links.
Switches S8 and S9 are connected to switch S7. Switch S7 is connected to router R3, which is connected to router C2. Router C2 is connected to a network cloud with a WAN link.
VTP Domains:
A line is drawn around switches S4, S5, and S6 and labeled as domain cisco2. A line is drawn around switches S7, S8, and S9 and labeled as domain cisco3.
Switch S4 Output (configured):
S4#show vtp status
VTP Version : 1
Configuration Revision : 3
Maximum V LAN's supported locally : 255
Number of existing V LAN's : 8
VTP Operating Mode : Server
VTP Domain Name : cisco2
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x3 F0X37 0X45 0X9A 0X37 0X53 0XA6 0XDE
Configuration last modified by 192.168.0.99 at 3-9-39 05:20:38
S4#
Configuration Revision, VTP Operating Mode, and VTP Domain Name are highlighted in the output.
The diagram depicts VTP domains and switch output from the show vtp status command.
Network Topology:
Nine switches are shown. Switches S2 and S3 are connected to switch S1. Switch S1 is connected to router R1, which is connected to router C1. Router C1 is connected to a network cloud with a WAN link.
Switches S5 and S6 are connected to switch S4. Switch S4 is connected to router R2, which is connected to routers C1 and C2. Router C1 and C2 are connected to a network cloud with WAN links.
Switches S8 and S9 are connected to switch S7. Switch S7 is connected to router R3, which is connected to router C2. Router C2 is connected to a network cloud with a WAN link.
VTP Domains:
A line is drawn around switches S4, S5, and S6 and labeled as domain cisco2. A line is drawn around switches S7, S8, and S9 and labeled as domain cisco3.
Switch S4 Output (configured):
S4#show vtp status
VTP Version : 1
Configuration Revision : 3
Maximum V LAN's supported locally : 255
Number of existing V LAN's : 8
VTP Operating Mode : Server
VTP Domain Name : cisco2
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x3 F0X37 0X45 0X9A 0X37 0X53 0XA6 0XDE
Configuration last modified by 192.168.0.99 at 3-9-39 05:20:38
S4#
Configuration Revision, VTP Operating Mode, and VTP Domain Name are highlighted in the output.
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VTP Domain Name Propagation
For a VTP server or client switch to participate in a VTP-enabled network, it must be a part of the same domain. When switches are in different VTP domains, they do not exchange VTP messages. A VTP server propagates the VTP domain name to all switches for you. Domain name propagation uses three VTP components: servers, clients, and advertisements.
Click Play in the figure to see how a VTP server propagates the VTP domain name in a network.
The network in the figure shows three switches, S1, S2, and S3, in their default VTP configuration. They are configured as VTP servers. VTP domain names have not been configured on any of the switches.
The network manager configures the VTP domain name as cisco1 on the VTP server switch S1. The VTP server sends out a VTP advertisement with the new domain name embedded inside. The S2 and S3 VTP server switches update their VTP configuration to the new domain name.
Note: Cisco recommends that access to the domain name configuration functions be protected by a password. The details of password configuration will be presented later in the course.
How does the domain name get placed into a VTP advertisement? What information is exchanged between VTP-enabled switches? In the next topic, you will learn about the details of VTP advertisements and find answers to these questions.
4.2.2 - VTP Domains
The diagram depicts VTP domain name propagation.
Network Topology:
There are three switches, S1, S2, and S3. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S3 port F0/3 is connected to S1 port F0/3 using a crossover cable.
Switch S1, S2, and S3 are VTP servers by default. The network administrator configures the VTP domain name cisco1 on S1. S1 sends the new domain name to S2 and S3. It does this as a result of VTP automatically propagating the domain name to switches S2 and S3 using VTP advertisements. Now all VTP-enabled switches are configured with the cisco1 domain name.
The diagram depicts VTP domain name propagation.
Network Topology:
There are three switches, S1, S2, and S3. Switch S2 port F0/1 is connected to S1 port F0/1 using a crossover cable. Switch S3 port F0/3 is connected to S1 port F0/3 using a crossover cable.
Switch S1, S2, and S3 are VTP servers by default. The network administrator configures the VTP domain name cisco1 on S1. S1 sends the new domain name to S2 and S3. It does this as a result of VTP automatically propagating the domain name to switches S2 and S3 using VTP advertisements. Now all VTP-enabled switches are configured with the cisco1 domain name.
4.2.3 VTP Advertising
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VTP Frame Structure
VTP advertisements (or messages) distribute VTP domain name and VLAN configuration changes to VTP-enabled switches. In this topic, you will learn about the VTP frame structure and how the three types of advertisements enable VTP to distribute and synchronize VLAN configurations throughout the network.
Click the Overview button in the figure and then click Play to view an animation on the structure of a VTP frame.
VTP Frame Encapsulation
A VTP frame consists of a header field and a message field. The VTP information is inserted into the data field of an Ethernet frame. The Ethernet frame is then encapsulated as a 802.1Q trunk frame (or ISL frame). Each switch in the domain sends periodic advertisements out each trunk port to a reserved multicast address. These advertisements are received by neighboring switches, which update their VTP and VLAN configurations as necessary.
Click the VTP Frame Details button in the figure.
VTP Frame Details
In the figure, you can see the VTP frame structure in more detail. Keep in mind that a VTP frame encapsulated as an 802.1Q frame is not static. The contents of the VTP message determines which fields are present. The receiving VTP-enabled switch looks for specific fields and values in the 802.1Q frame to know what to process. The following key fields are present when a VTP frame is encapsulated as an 802.1Q frame:
Destination MAC address- This address is set to 01-00-0C-CC-CC-CC, which is the reserved multicast address for all VTP messages.
LLC field- Logical link control (LLC) field contains a destination service access point (DSAP) and a source service access point (SSAP) set to the value of AA.
SNAP field- Subnetwork Access Protocol (SNAP) field has an OUI set to AAAA and type set to 2003.
VTP header field- The contents vary depending on the VTP message type-summary, subset, or request, but it always contains these VTP fields:
- Domain name- Identifies the administrative domain for the switch.
- Domain name length- Length of the domain name.
- Version- Set to either VTP 1, VTP 2, or VTP 3. The Cisco 2960 switch only supports VTP 1 and VTP 2.
- Configuration revision number- The current configuration revision number on this switch.
VTP message field- Varies depending on the message type.
Click the VTP Message Contents button in the figure.
VTP Message Contents
VTP frames contain the following fixed-length global domain information:
- VTP domain name
- Identity of the switch sending the message, and the time it was sent
- MD5 digest VLAN configuration, including maximum transmission unit (MTU) size for each VLAN
- Frame format: ISL or 802.1Q
VTP frames contain the following information for each configured VLAN:
- VLAN IDs (IEEE 802.1Q)
- VLAN name
- VLAN type
- VLAN state
- Additional VLAN configuration information specific to the VLAN type
Note: A VTP frame is encapsulated in an 802.1Q Ethernet frame. The entire 802.1Q Ethernet frame is the VTP advertisement often called a VTP message. Often the terms frame, advertisement, and message are used interchangeably.
4.2.3 - VTP Advertising
The diagram depicts an animation overview of the structure of a VTP frame as well as images of VTP frame details and message contents.
Overview:
Shown is VTP information that consists of a header field and a message field inserted into the data field of an Ethernet frame. The Ethernet frame is then encapsulated as an 8 0 2 dot 1Q trunk frame. The 8 0 2 dot 1Q frame also contains a tag with V LAN information and the FCS is recalculated. The 8 0 2 dot 1Q frames are sent between VTP Server, switch S1 and VTP Client, switch S2.
VTP Frame Details:
Shown are the key fields of an 8 0 2 dot 1Q VTP frame:
Destination MAC address: 01-00-0C-CC-CC-CC
LLC field: The logical link control (LLC) field contains a destination service access point (D SAP) and a source service access point (S SAP) set to the value of A A.
SNAP field: The Subnetwork Access Protocol (SNAP) field has an O U I set to A A A A and a type set to 2003.
VTP header field: Fields and size varies, but it always contains these VTP fields:
- Domain name.
- Domain name length.
- Version.
- Message type.
- Revision number.
VTP message field: Varies depending on the message type.
VTP Message Contents:
VTP advertisements send this global domain information:
- VTP domain name.
- Updater identity and update timestamp.
- MD5 digest.
- Frame format.
VTP advertisements send this V LAN information:
- V LAN ID.
- V LAN name.
- V LAN type.
- V LAN state.
- Additional V LAN configuration information specific to the V LAN type.
The diagram depicts an animation overview of the structure of a VTP frame as well as images of VTP frame details and message contents.
Overview:
Shown is VTP information that consists of a header field and a message field inserted into the data field of an Ethernet frame. The Ethernet frame is then encapsulated as an 8 0 2 dot 1Q trunk frame. The 8 0 2 dot 1Q frame also contains a tag with V LAN information and the FCS is recalculated. The 8 0 2 dot 1Q frames are sent between VTP Server, switch S1 and VTP Client, switch S2.
VTP Frame Details:
Shown are the key fields of an 8 0 2 dot 1Q VTP frame:
Destination MAC address: 01-00-0C-CC-CC-CC
LLC field: The logical link control (LLC) field contains a destination service access point (D SAP) and a source service access point (S SAP) set to the value of A A.
SNAP field: The Subnetwork Access Protocol (SNAP) field has an O U I set to A A A A and a type set to 2003.
VTP header field: Fields and size varies, but it always contains these VTP fields:
- Domain name.
- Domain name length.
- Version.
- Message type.
- Revision number.
VTP message field: Varies depending on the message type.
VTP Message Contents:
VTP advertisements send this global domain information:
- VTP domain name.
- Updater identity and update timestamp.
- MD5 digest.
- Frame format.
VTP advertisements send this V LAN information:
- V LAN ID.
- V LAN name.
- V LAN type.
- V LAN state.
- Additional V LAN configuration information specific to the V LAN type.
Page 2:
VTP Revision Number
The configuration revision number is a 32-bit number that indicates the level of revision for a VTP frame. The default configuration number for a switch is zero. Each time a VLAN is added or removed, the configuration revision number is incremented. Each VTP device tracks the VTP configuration revision number that is assigned to it.
Note: A VTP domain name change does not increment the revision number. Instead, it resets the revision number to zero.
The configuration revision number determines whether the configuration information received from another VTP-enabled switch is more recent than the version stored on the switch. The figure shows a network manager adding three VLANs to switch S1.
Click the Switch Output button in the figure to see how the revision number has been changed.
The highlighted area shows that the revision number on switch S1 is 3, the number of VLANs is up to eight, because three VLANs have been added to the five default VLANs.
The revision number plays an important and complex role in enabling VTP to distribute and synchronize VTP domain and VLAN configuration information. To comprehend what the revision number does, you first need to learn about the three types of VTP advertisements and the three VTP modes.
4.2.3 - VTP Advertising
The diagram depicts the use of the VTP revision number to track changes to V LAN definitions. Also shown is switch output from the show vtp status command.
Network Topology:
Switches S2 and S3 are connected to switch S1. Switch S1 is connected to router R1.
Switch S1 text: V LAN's added on S1: 10, 20, and 30.
Switch Output:
S1#show vtp status
VTP Version : 2
Configuration Revision : 3
Maximum V LAN's supported locally : 255
Number of existing V LAN's : 8
VTP Operating Mode : Server
VTP Domain Name : cisco1
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x3F0X37 0X45 0X9A 0X37 0X53 0XA6 0XDE
Configuration last modified by 192.168.0.99 at 3-9-39 05:20:38
S1#
Configuration Revision and Number of existing V LAN's are highlighted in the output.
The diagram depicts the use of the VTP revision number to track changes to V LAN definitions. Also shown is switch output from the show vtp status command.
Network Topology:
Switches S2 and S3 are connected to switch S1. Switch S1 is connected to router R1.
Switch S1 text: V LAN's added on S1: 10, 20, and 30.
Switch Output:
S1#show vtp status
VTP Version : 2
Configuration Revision : 3
Maximum V LAN's supported locally : 255
Number of existing V LAN's : 8
VTP Operating Mode : Server
VTP Domain Name : cisco1
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x3F0X37 0X45 0X9A 0X37 0X53 0XA6 0XDE
Configuration last modified by 192.168.0.99 at 3-9-39 05:20:38
S1#
Configuration Revision and Number of existing V LAN's are highlighted in the output.
Page 3:
VTP Advertisements
Summary Advertisements
The summary advertisement contains the VTP domain name, the current revision number, and other VTP configuration details.
Summary advertisements are sent:
- Every 5 minutes by a VTP server or client to inform neighboring VTP-enabled switches of the current VTP configuration revision number for its VTP domain
- Immediately after a configuration has been made
Click the Summary button in the figure and then click Play to view an animation on the summary VTP advertisements.
Subset Advertisements
A subset advertisement contains VLAN information. Changes that trigger the subset advertisement include:
- Creating or deleting a VLAN
- Suspending or activating a VLAN
- Changing the name of a VLAN
- Changing the MTU of a VLAN
It may take multiple subset advertisements to fully update the VLAN information.
Click the Subset button in the figure and then click Play to view an animation on the subset VTP advertisements.
Request Advertisements
When a request advertisement is sent to a VTP server in the same VTP domain, the VTP server responds by sending a summary advertisement and then a subset advertisement.
Request advertisements are sent if:
- The VTP domain name has been changed
- The switch receives a summary advertisement with a higher configuration revision number than its own
- A subset advertisement message is missed for some reason
- The switch has been reset
Click the Request button in the figure and then click Play to view an animation on the request VTP advertisements.
4.2.3 - VTP Advertising
The animation depicts the three types of VTP advertisements used to communicate between VTP-enabled switches: summary, subset, and request advertisements.
Summary Advertisements:
- Sent every five minutes by a VTP server.
- Inform VTP-enabled switches of the current VTP configuration revision number.
- Sent immediately after a configuration change.
The animation shows two envelopes representing a summary advertisement being passed back and forth between server and client switches.
Subset Advertisements:
Changes that trigger the subset advertisement include:
- Creating or deleting a V LAN.
- Suspending or activating a V LAN.
- Changing the name of a V LAN.
- Changing the MTU of a V LAN.
The animation shows a subset advertisement being sent from the server switch S1 to the client switch S2.
Request Advertisements:
When a request advertisement is sent to the VTP server:
- The VTP server sends a summary advertisement.
- Then the VTP server sends a subset advertisement.
Request advertisements are sent if:
- The VTP domain name has changed.
- A summary advertisement arrives with a higher configuration revision - number.
- A subset advertisement message is missed.
- The switch has been reset.
The animation shows the client switch S2 sending a request advertisement to the server switch S1. The server switch S1 then sends a summary advertisement and a subset advertisement to S2.
The animation depicts the three types of VTP advertisements used to communicate between VTP-enabled switches: summary, subset, and request advertisements.
Summary Advertisements:
- Sent every five minutes by a VTP server.
- Inform VTP-enabled switches of the current VTP configuration revision number.
- Sent immediately after a configuration change.
The animation shows two envelopes representing a summary advertisement being passed back and forth between server and client switches.
Subset Advertisements:
Changes that trigger the subset advertisement include:
- Creating or deleting a V LAN.
- Suspending or activating a V LAN.
- Changing the name of a V LAN.
- Changing the MTU of a V LAN.
The animation shows a subset advertisement being sent from the server switch S1 to the client switch S2.
Request Advertisements:
When a request advertisement is sent to the VTP server:
- The VTP server sends a summary advertisement.
- Then the VTP server sends a subset advertisement.
Request advertisements are sent if:
- The VTP domain name has changed.
- A summary advertisement arrives with a higher configuration revision - number.
- A subset advertisement message is missed.
- The switch has been reset.
The animation shows the client switch S2 sending a request advertisement to the server switch S1. The server switch S1 then sends a summary advertisement and a subset advertisement to S2.
Page 4:
VTP Advertisements Details
VTP uses advertisements to distribute and synchronize information about domains and VLAN configurations. There are three main VTP advertisements.
Each type of VTP advertisement sends information about several parameters used by VTP. A description of the fields in each of the VTP advertisements are presented.
Click the Summary Details button in the figure.
Summary Advertisements
Summary advertisements comprise the majority of VTP advertisement traffic. Roll over the fields in the summary advertisement to view the descriptions.
Roll over the fields in the summary advertisement to view the descriptions.
Click the Subset Details button in the figure.
Subset Advertisements
The fields found in a subset advertisement are briefly described. The fields in the VLAN-info are not described.
Roll over the fields in the subset advertisement to view the descriptions.
Click the Request Details button in the figure.
Request Advertisements
The fields found in a request advertisement are briefly described.
Roll over the fields in the request advertisement to view the descriptions.
4.2.3 - VTP Advertising
The diagram depicts the details for the three types of VTP advertisements used to communicate between VTP-enabled switches.
Summary Advertisement Details:
Version - This field displays the VTP version used. On Cisco 2960 switches, the version is either VTP V1 or VTP V2.
Code - A code that identifies the type of advertisement.
Followers - This field indicates that the packet is followed by a subset advertisement packet.
MgmtD Len - Indicates the length of the management domain name.
Management Domain Name (zero-padded to 32 bytes) - The name of the VTP domain.
Configuration Revision Number - The revision number of the VTP server sending the message.
Updater Identity - The IP address of the switch that last incremented the configuration revision.
Update Timestamp (12 bytes) - The date and time of the last increment of the configuration revision.
MD5 Digest (16 bytes) - Message Digest 5 (MD5) carries the VTP password, if MD5 is configured and used to authenticate the validation of a VTP update.
Subset Advertisement Details:
Version - This field displays the VTP version used. On Cisco 2960 switches, the version is either VTP V1 or VTP V2.
Code - The format is 0x02 for a subset advertisement.
Seq-Number - Sequence of the packet in the stream of packets that follow a summary advertisement. The sequence starts with 1.
MgmtD Len - Indicates the length of the management domain name.
Management Domain Name (zero-padded to 32 bytes) - The name of the VTP domain.
Configuration Revision Number - The revision number of the VTP server sending the message.
V LAN-info Field 1 through V LAN-info Field N
V LAN-Info contains information for each V LAN and is formatted as follows:
- Info Length
- Status
- V LAN-Type
- V LAN-name Len
- ISL V LAN-id
- MTU Size
- 802 dot 10 Index
- V LAN name (Padded with zeroes to multiples of 4 bytes)
Request Advertisement Details:
Version - This field displays the VTP version used. On Cisco 2960 switches, the version is either VTP V1 or VTP V2.
Code - The format is 0x03 for an advertisement request.
Rsvd - Reserved field.
MgmtD Len - Indicates the length of the management domain name.
Management Domain Name (zero-padded to 32 bytes) - The name of the VTP domain.
Start Value - This field is used when there are several subset advertisements. If the first (n) subset advertisement has been received and the subsequent advertisement (n+1) has not been received, the VTP-enabled switch only requests advertisements from the (n+1) one.
The diagram depicts the details for the three types of VTP advertisements used to communicate between VTP-enabled switches.
Summary Advertisement Details:
Version - This field displays the VTP version used. On Cisco 2960 switches, the version is either VTP V1 or VTP V2.
Code - A code that identifies the type of advertisement.
Followers - This field indicates that the packet is followed by a subset advertisement packet.
MgmtD Len - Indicates the length of the management domain name.
Management Domain Name (zero-padded to 32 bytes) - The name of the VTP domain.
Configuration Revision Number - The revision number of the VTP server sending the message.
Updater Identity - The IP address of the switch that last incremented the configuration revision.
Update Timestamp (12 bytes) - The date and time of the last increment of the configuration revision.
MD5 Digest (16 bytes) - Message Digest 5 (MD5) carries the VTP password, if MD5 is configured and used to authenticate the validation of a VTP update.
Subset Advertisement Details:
Version - This field displays the VTP version used. On Cisco 2960 switches, the version is either VTP V1 or VTP V2.
Code - The format is 0x02 for a subset advertisement.
Seq-Number - Sequence of the packet in the stream of packets that follow a summary advertisement. The sequence starts with 1.
MgmtD Len - Indicates the length of the management domain name.
Management Domain Name (zero-padded to 32 bytes) - The name of the VTP domain.
Configuration Revision Number - The revision number of the VTP server sending the message.
V LAN-info Field 1 through V LAN-info Field N
V LAN-Info contains information for each V LAN and is formatted as follows:
- Info Length
- Status
- V LAN-Type
- V LAN-name Len
- ISL V LAN-id
- MTU Size
- 802 dot 10 Index
- V LAN name (Padded with zeroes to multiples of 4 bytes)
Request Advertisement Details:
Version - This field displays the VTP version used. On Cisco 2960 switches, the version is either VTP V1 or VTP V2.
Code - The format is 0x03 for an advertisement request.
Rsvd - Reserved field.
MgmtD Len - Indicates the length of the management domain name.
Management Domain Name (zero-padded to 32 bytes) - The name of the VTP domain.
Start Value - This field is used when there are several subset advertisements. If the first (n) subset advertisement has been received and the subsequent advertisement (n+1) has not been received, the VTP-enabled switch only requests advertisements from the (n+1) one.
4.2.4 VTP Modes
Page 1:
VTP Modes Overview
A Cisco switch, configured with Cisco IOS software, can be configured in either server, client, or transparent mode. These modes differ in how they are used to manage and advertise VTP domains and VLANs.
Server Mode
In server mode, you can create, modify, and delete VLANs for the entire VTP domain. VTP server mode is the default mode for a Cisco switch. VTP servers advertise their VLAN configurations to other switches in the same VTP domain and synchronize their VLAN configurations with other switches based on advertisements received over trunk links. VTP servers keep track of updates through a configuration revision number. Other switches in the same VTP domain compare their configuration revision number with the revision number received from a VTP server to see if they need to synchronize their VLAN database.
Client Mode
If a switch is in client mode, you cannot create, change, or delete VLANs. In addition, the VLAN configuration information that a VTP client switch receives from a VTP server switch is stored in a VLAN database, not in NVRAM. Consequently, VTP clients require less memory than VTP servers. When a VTP client is shut down and restarted, it sends a request advertisement to a VTP server for updated VLAN configuration information.
Switches configured as VTP clients are more typically found in larger networks, because in a network consisting of many hundreds of switches, it is harder to coordinate network upgrades. Often there are many network administrators working at different times of the day. Having only a few switches that are physically able to maintain VLAN configurations makes it easier to control VLAN upgrades and to track which network administrators performed them.
For large networks, having client switches is also more cost-effective. By default, all switches are configured to be VTP servers. This configuration is suitable for small scale networks in which the size of the VLAN information is small and the information is easily stored in NVRAM on the switches. In a large network of many hundreds of switches, the network administrator must decide if the cost of purchasing switches with enough NVRAM to store the duplicate VLAN information is too much. A cost-conscious network administrator could choose to configure a few well-equipped switches as VTP servers, and then use switches with less memory as VTP clients. Although a discussion of network redundancy is beyond the scope of this course, know that the number of VTP servers should be chosen to provide the degree of redundancy that is desired in the network.
Transparent Mode
Switches configured in transparent mode forward VTP advertisements that they receive on trunk ports to other switches in the network. VTP transparent mode switches do not advertise their VLAN configuration and do not synchronize their VLAN configuration with any other switch. Configure a switch in VTP transparent mode when you have VLAN configurations that have local significance and should not be shared with the rest of the network.
In transparent mode, VLAN configurations are saved in NVRAM (but not advertised to other switches), so the configuration is available after a switch reload. This means that when a VTP transparent mode switch reboots, it does not revert to a default VTP server mode, but remains in VTP transparent mode.
4.2.4 - VTP Modes
The diagram depicts a table describing the three VTP modes: server, client, and transparent.
VTP Server:
- Description: Manages domain and V LAN configurations.
- Respond to VTP advertisements? Participates fully.
- Global V LAN configuration preserved on restart? Yes, global configurations are stored in NV RAM.
- Update other VTP-enabled switches? Yes.
VTP Client:
- Description: Updates its VTP configuration with information from a VTP server but a VTP client switch cannot change V LAN configurations.
- Respond to VTP advertisements? Participates fully.
- Global V LAN configuration preserved on restart? No, global configurations are stored in RAM, not in NV RAM.
- Update other VTP-enabled switches? Yes.
VTP Transparent:
- Description: Able to manage local V LAN configurations. Local V LAN configurations not shared with VTP network.
- Respond to VTP advertisements? Only forwards VTP advertisements.
- Global V LAN configuration preserved on restart? No, only local configuration is stored in NV RAM.
- Update other VTP-enabled switches? No.
The diagram depicts a table describing the three VTP modes: server, client, and transparent.
VTP Server:
- Description: Manages domain and V LAN configurations.
- Respond to VTP advertisements? Participates fully.
- Global V LAN configuration preserved on restart? Yes, global configurations are stored in NV RAM.
- Update other VTP-enabled switches? Yes.
VTP Client:
- Description: Updates its VTP configuration with information from a VTP server but a VTP client switch cannot change V LAN configurations.
- Respond to VTP advertisements? Participates fully.
- Global V LAN configuration preserved on restart? No, global configurations are stored in RAM, not in NV RAM.
- Update other VTP-enabled switches? Yes.
VTP Transparent:
- Description: Able to manage local V LAN configurations. Local V LAN configurations not shared with VTP network.
- Respond to VTP advertisements? Only forwards VTP advertisements.
- Global V LAN configuration preserved on restart? No, only local configuration is stored in NV RAM.
- Update other VTP-enabled switches? No.
Page 2:
VTP in Action
You will now see how the various VTP features come together to distribute and synchronize domain and VLAN configurations in a VTP-enabled network. The animation starts with three new switches, S1, S2, and S3, configured with their factory default settings, and finishes with all three switches configured and participating in a VTP-enabled network.
You can pause and rewind the animation to reflect and review this process.
4.2.4 - VTP Modes
The animation depicts VTP in action.
Network Topology:
Switches S1, S2, and S3 are not connected initially. All switches have default settings.
VTP Domain Name - null
VTP Mode - server
Config Revision - 0
V LAN's - 1
Animation Sequence:
All switches have default settings.
S1 VTP mode set to server.
S2 VTP mode set to client.
S3 VTP mode set to transparent.
Switch S1 is configured as a VTP server, switch S2 is configured as a VTP client, and switch S3 as VTP transparent. After V LAN's are configured on S1, the switches are connected so that VTP advertisements can pass between them.
The S1 VTP domain name is set to cisco1.
S1 V LAN 2 is added.
S1 Revision = 1.
S1 V LAN 3 is added.
S1 Revision = 2.
Switch S1 is now configured and ready to be trunked to the other VTP-enabled switches.
Switch S1 sends the following summary advertisement to S2 and S3:
Domain Name - cisco1.
Configuration Revision Number - 2.
Switch S2 updates its VTP domain name to cisco1.
Switch S3 does not respond to the summary advertisement.
Switch S2 sends a request advertisement for V LAN configuration details to S1.
Switch S1 sends a summary advertisement to S2.
Switch S1 sends the following subset advertisement to S2 with V LAN configuration details:
V LAN's - 1, 2, 3.
Switch S2 updates its V LAN configuration.
Switch S3 in VTP transparent mode remains configured the same. In this example, it does not participate in VTP.
After VTP has sent all the advertisements, the VTP information in the switches is as follows:
Switch S1:
VTP Domain Name = Cisco1
VTP Mode = Server
Config Revision = 2
V LAN's = 1, 2, 3
Switch S2:
VTP Domain Name = Cisco1
VTP Mode = Client
Config Revision = 2
V LAN's = 1, 2, 3
Switch S3:
VTP Domain Name = null
VTP Mode = Transparent
Config Revision = 0
V LAN's = 1
The animation depicts VTP in action.
Network Topology:
Switches S1, S2, and S3 are not connected initially. All switches have default settings.
VTP Domain Name - null
VTP Mode - server
Config Revision - 0
V LAN's - 1
Animation Sequence:
All switches have default settings.
S1 VTP mode set to server.
S2 VTP mode set to client.
S3 VTP mode set to transparent.
Switch S1 is configured as a VTP server, switch S2 is configured as a VTP client, and switch S3 as VTP transparent. After V LAN's are configured on S1, the switches are connected so that VTP advertisements can pass between them.
The S1 VTP domain name is set to cisco1.
S1 V LAN 2 is added.
S1 Revision = 1.
S1 V LAN 3 is added.
S1 Revision = 2.
Switch S1 is now configured and ready to be trunked to the other VTP-enabled switches.
Switch S1 sends the following summary advertisement to S2 and S3:
Domain Name - cisco1.
Configuration Revision Number - 2.
Switch S2 updates its VTP domain name to cisco1.
Switch S3 does not respond to the summary advertisement.
Switch S2 sends a request advertisement for V LAN configuration details to S1.
Switch S1 sends a summary advertisement to S2.
Switch S1 sends the following subset advertisement to S2 with V LAN configuration details:
V LAN's - 1, 2, 3.
Switch S2 updates its V LAN configuration.
Switch S3 in VTP transparent mode remains configured the same. In this example, it does not participate in VTP.
After VTP has sent all the advertisements, the VTP information in the switches is as follows:
Switch S1:
VTP Domain Name = Cisco1
VTP Mode = Server
Config Revision = 2
V LAN's = 1, 2, 3
Switch S2:
VTP Domain Name = Cisco1
VTP Mode = Client
Config Revision = 2
V LAN's = 1, 2, 3
Switch S3:
VTP Domain Name = null
VTP Mode = Transparent
Config Revision = 0
V LAN's = 1
Page 3:
You have seen how VTP works with three switches. This animation examines in more detail how a switch configured in VTP transparent mode supports the functionality of VTP.
Click the Play button in the figure.
You can pause and rewind the animation to reflect and review this process.
4.2.4 - VTP Modes
The animation depicts VTP transparent mode in action.
Network Topology:
There are four switches, S1, S2, S3, and S4 . Switch S1 is connected to S2 and S3. Switch S3 is connected to S4.
Animation Sequence:
Switch S3 in VTP transparent mode has been configured with V LAN's.
Switch S4 has been added to the network.
Switch S1 sends out a periodic summary advertisement to S3 and S4.
Switch S4 requests V LAN configuration information from S1.
Switch S1 responds to S4 with a summary advertisement.
Switch S1 also responds to S4 with subset advertisement containing V LAN configurations.
Throughout this sequence, switch S3 only forwards VTP advertisements.
The revision number and V LAN configurations are unchanged.
After VTP has sent all the advertisements, the VTP information in the switches is as follows:
Switch S1:
VTP Domain Name = cisco1
VTP Mode = Server
Config Revision = 2
V LAN's = 1, 2, 3
Switch S2:
VTP Domain Name = cisco1
VTP Mode = Client
Config Revision = 2
V LAN's = 1, 2, 3
Switch S3:
VTP Domain Name = cisco1
VTP Mode = Transparent
Config Revision = 0
V LAN's = 1, 2, 3, 4, 5, 6
Switch S4:
VTP Domain Name = cisco1
VTP Mode = Client
Config Revision = 2
V LAN's = 1, 2, 3
The animation depicts VTP transparent mode in action.
Network Topology:
There are four switches, S1, S2, S3, and S4 . Switch S1 is connected to S2 and S3. Switch S3 is connected to S4.
Animation Sequence:
Switch S3 in VTP transparent mode has been configured with V LAN's.
Switch S4 has been added to the network.
Switch S1 sends out a periodic summary advertisement to S3 and S4.
Switch S4 requests V LAN configuration information from S1.
Switch S1 responds to S4 with a summary advertisement.
Switch S1 also responds to S4 with subset advertisement containing V LAN configurations.
Throughout this sequence, switch S3 only forwards VTP advertisements.
The revision number and V LAN configurations are unchanged.
After VTP has sent all the advertisements, the VTP information in the switches is as follows:
Switch S1:
VTP Domain Name = cisco1
VTP Mode = Server
Config Revision = 2
V LAN's = 1, 2, 3
Switch S2:
VTP Domain Name = cisco1
VTP Mode = Client
Config Revision = 2
V LAN's = 1, 2, 3
Switch S3:
VTP Domain Name = cisco1
VTP Mode = Transparent
Config Revision = 0
V LAN's = 1, 2, 3, 4, 5, 6
Switch S4:
VTP Domain Name = cisco1
VTP Mode = Client
Config Revision = 2
V LAN's = 1, 2, 3
4.2.5 VTP Pruning
Page 1:
VTP pruning prevents unnecessary flooding of broadcast information from one VLAN across all trunks in a VTP domain. VTP pruning permits switches to negotiate which VLANs are assigned to ports at the other end of a trunk and, hence, prune the VLANs that are not assigned to ports on the remote switch. Pruning is disabled by default. VTP pruning is enabled using the vtp pruning global configuration command. You need to enable pruning on only one VTP server switch in the domain. In the figure, you would enable VTP pruning on switch S1. The figure shows a network with VLAN 10 and VLAN 20 configured. Switch S3 has VLAN 20 configured, and switch S2 has VLAN 10 and VLAN 20 configured. Examine the topology in the figure and then click to see the switch configurations.
4.2.5 - VTP Pruning
The diagram depicts a switched network without VTP pruning enabled and includes switch output from the show interfaces trunk command.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 port F0/1 is connected to S2 port F0/1, and switch S1 port F0/3 is connected to S3 port F0/3. Three PC's, PC1, PC2 and PC3, are connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Three PC's, PC4, PC5, and PC6, are connected to switch S3 on ports F0/11, F0/18, and F0/6, respectively.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.10.23
V LAN 10
PC4:
IP address 172.17.20.24
V LAN 20
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.20.26
V LAN 20
Switch output from the show interfaces trunk command:
Switch S1:
S1#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1 on 8 0 2 dot 1q trunking1
FA0/3 on 8 0 2 dot 1q trunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
FA0/3 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
S1#
Switch S2:
S2#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1 on 8 0 2 dot 1q trunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
S2#
Switch S3:
S3#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/3 on 8 0 2 dot 1q trunking1
Port V lan's allowed on trunk.
FA0/3 1-1005
Port V lan's allowed and active in management domain.
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
S3#
The diagram depicts a switched network without VTP pruning enabled and includes switch output from the show interfaces trunk command.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 port F0/1 is connected to S2 port F0/1, and switch S1 port F0/3 is connected to S3 port F0/3. Three PC's, PC1, PC2 and PC3, are connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Three PC's, PC4, PC5, and PC6, are connected to switch S3 on ports F0/11, F0/18, and F0/6, respectively.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.10.23
V LAN 10
PC4:
IP address 172.17.20.24
V LAN 20
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.20.26
V LAN 20
Switch output from the show interfaces trunk command:
Switch S1:
S1#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1 on 8 0 2 dot 1q trunking1
FA0/3 on 8 0 2 dot 1q trunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
FA0/3 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
S1#
Switch S2:
S2#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1 on 8 0 2 dot 1q trunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
S2#
Switch S3:
S3#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/3 on 8 0 2 dot 1q trunking1
Port V lan's allowed on trunk.
FA0/3 1-1005
Port V lan's allowed and active in management domain.
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
S3#
Page 2:
VTP Pruning in Action
Recall that a VLAN creates an isolated broadcast domain. A switch floods broadcast, multicast, and unknown unicast traffic across all trunk links within a VTP domain. When a computer or device broadcasts on a VLAN, for example, VLAN 10 in the figure, the broadcast traffic travels across all trunk links throughout the network to all ports on all switches in VLAN 10. In the figure, switches S1, S2, and S3 all receive broadcast frames from computer PC1. The broadcast traffic from PC1 consumes bandwidth on the trunk link between all 3 switches and consumes processor time on all 3 switches. The link between switches S1 and S3 does not carry any VLAN 10 traffic, so it is a candidate for VTP pruning.
Click the Play button in the figure to see the how VLAN flood traffic is handled on a network with no VTP pruning.
VTP Pruning
Click the VTP Pruning button and then click Play to see an animation on how VLAN flood traffic is handled on a network with VTP pruning.
The flood traffic is stopped from entering the trunk connecting switches S1 and S2. VTP pruning only prunes the egress port F0/1 on switch S2.
4.2.5 - VTP Pruning
The diagram depicts the operation of a switched network with VTP pruning and without VTP pruning enabled.
Network Topology:
Same as Diagram 4.2.5.1.
No VTP Pruning:
Animation Sequence.
PC1 sends out flood traffic on V LAN 10.
Switch S2 forwards the flood traffic out all of its static access ports configured on V LAN 10, as well as out the trunk link to switch S1.
Switch S1 continues to forward the flood traffic over its trunk link to S3, even though there are no static access ports configured on V LAN 10.
Switch S3 discards the flood traffic, but only after it has consumed bandwidth on the trunk link and processing time on the switch.
VTP Pruning:
Animation Sequence.
PC1 sends out flood traffic on V LAN 10.
Switch S2 forwards the flood traffic out all of its static access ports configured on V LAN 10, but does not forward the traffic out the trunk link to switch S1 because it knows that there are no other switch ports configured for V LAN 10 on any of the remote switches.
The diagram depicts the operation of a switched network with VTP pruning and without VTP pruning enabled.
Network Topology:
Same as Diagram 4.2.5.1.
No VTP Pruning:
Animation Sequence.
PC1 sends out flood traffic on V LAN 10.
Switch S2 forwards the flood traffic out all of its static access ports configured on V LAN 10, as well as out the trunk link to switch S1.
Switch S1 continues to forward the flood traffic over its trunk link to S3, even though there are no static access ports configured on V LAN 10.
Switch S3 discards the flood traffic, but only after it has consumed bandwidth on the trunk link and processing time on the switch.
VTP Pruning:
Animation Sequence.
PC1 sends out flood traffic on V LAN 10.
Switch S2 forwards the flood traffic out all of its static access ports configured on V LAN 10, but does not forward the traffic out the trunk link to switch S1 because it knows that there are no other switch ports configured for V LAN 10 on any of the remote switches.
Page 3:
VTP Pruning Enabled
The figure shows a network topology that has switches S1, S2, and S3 configured with VTP pruning. When VTP pruning is enabled on a network, it reconfigures the trunk links based on which ports are configured with which VLANs.
Click the Switch S1 button in the figure.
The highlighted area shows that the trunk on port F0/1 allows VLAN 10 traffic. VTP pruning only prunes the egress port.
Click the Switch S2 button in the figure.
The highlighted area shows that the trunk on port F0/1 does not allow VLAN 10 traffic. VLAN 10 is not listed. For more details on VTP pruning, visit: http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/rel_4_2/config/vlans.htm#xtocid798016.
4.2.5 - VTP Pruning
The diagram depicts a switched network with VTP pruning enabled and includes switch output from the show interfaces trunk command.
Network Topology:
Same as Diagram 4.2.5.1.
Switch S1:
S1#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1on8 0 2 dot 1qtrunking1
FA0/3on8 0 2 dot 1qtrunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
FA0/3 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
The following line is highlighted:
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
S1#
Switch S2:
S2#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1on8 0 2 dot 1qtrunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
The following line is highlighted :
FA0/1 1, 20, 1002, 1003, 1004, 1005
S2#
The diagram depicts a switched network with VTP pruning enabled and includes switch output from the show interfaces trunk command.
Network Topology:
Same as Diagram 4.2.5.1.
Switch S1:
S1#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1on8 0 2 dot 1qtrunking1
FA0/3on8 0 2 dot 1qtrunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
FA0/3 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
The following line is highlighted:
FA0/3 1, 10, 20, 1002, 1003, 1004, 1005
S1#
Switch S2:
S2#show interfaces trunk
PortModeEncapsulationStatusNative v lan
FA0/1on8 0 2 dot 1qtrunking1
Port V lan's allowed on trunk.
FA0/1 1-1005
Port V lan's allowed and active in management domain.
FA0/1 1, 10, 20, 1002, 1003, 1004, 1005
Port V lan's in spanning tree forwarding state and not pruned.
The following line is highlighted :
FA0/1 1, 20, 1002, 1003, 1004, 1005
S2#
Page 4:
4.2.5 - VTP Pruning
The diagram depicts an activity in which you must perform a VTP operation testlet.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 port F0/1 is connected to S2 port F0/1. Switch S3 is not currently connected. Three PC's, PC1, PC2, and PC3, are connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Switch S2 has failed and is being replaced with switch S3.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.30.23
V LAN 30
Switch S1:
VTP Domain Name = CCNA
VTP Mode = Server
Config Revision = 4
V LAN's = 1, 10, 20, 30, 99
Switch S2:
VTP Domain Name = CCNA
VTP Mode = Client
Config Revision = 4
V LAN's = 1, 10, 20, 30, 99
Switch S3:
VTP Domain Name = CCNA
VTP Mode = Client
Config Revision = 6
V LAN's = 1, 99-104
Scenario:
In the topology, S2 failed and is being replaced. The network administrator acquired the S3 switch from another area of the network where it was no longer in use. The administrator erased the configuration of the S3 device and applied the configuration from the old S2 device so that V LAN port assignments would be reapplied. The administrator also added the VTP domain name and set the VTP mode to client. However, when the S3 device was connected to S1 and trunking was restored, all the ports in V LAN's 10, 20, and 30 transitioned to the inactive state.
Question One.
After the S2 device was replaced with the S3 device and the trunk links were established, which represents the configuration revision number and V LAN information for switches S1 and S3?
A. Config Revision = 4, V LAN's = 1, 10, 20, 30, 99 to 104
B. Config Revision = 6, V LAN's = 1, 10, 20, 30, 99 to 104
C. Config Revision = 4, V LAN's = 1, 10, 20, 30, 99
D. Config Revision = 6, V LAN's = 1, 10, 20, 30, 99
E. Config Revision = 6, V LAN's = 1, 99 to 104
Question Two.
Which two of the following is true about the configuration revision number? (Choose two.)
A. Only subset advertisements contain the configuration revision number.
B. Only summary advertisements contain the configuration revision number.
C. All VTP messages contain the configuration revision number.
D. Higher configuration revision numbers take precedence over lower configuration revision numbers.
E. Lower configuration revision numbers take precedence over higher configuration revision numbers.
Question Three.
Which solution is appropriate to resolve the V LAN configuration discrepancies for the VTP domain and connectivity for the PC1, PC2, and PC3 devices?
A. Add the missing V LAN's to the VTP server S1.
B. Delete the V LAN's from the new S3.
C. Delete all possible V LAN's from the VTP server S1.
D. Add the missing V LAN's to switches S1 and S3.
Question Four.
Which two methods avoid unintentional V LAN database corruption when adding a new switch? (Choose two.)
A. Reset the configuration revision number on the new switch by temporarily changing the VTP domain name.
B. Increase the configuration revision number on an existing VTP server so that it is lower than the switch being added.
C. Temporarily change the mode of the new switch to transparent.
D. Delete the V LAN database of the VTP server before connecting the new device to the network.
E. Change the configuration register number on the new switch using the config-reg command.
The diagram depicts an activity in which you must perform a VTP operation testlet.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 port F0/1 is connected to S2 port F0/1. Switch S3 is not currently connected. Three PC's, PC1, PC2, and PC3, are connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Switch S2 has failed and is being replaced with switch S3.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.30.23
V LAN 30
Switch S1:
VTP Domain Name = CCNA
VTP Mode = Server
Config Revision = 4
V LAN's = 1, 10, 20, 30, 99
Switch S2:
VTP Domain Name = CCNA
VTP Mode = Client
Config Revision = 4
V LAN's = 1, 10, 20, 30, 99
Switch S3:
VTP Domain Name = CCNA
VTP Mode = Client
Config Revision = 6
V LAN's = 1, 99-104
Scenario:
In the topology, S2 failed and is being replaced. The network administrator acquired the S3 switch from another area of the network where it was no longer in use. The administrator erased the configuration of the S3 device and applied the configuration from the old S2 device so that V LAN port assignments would be reapplied. The administrator also added the VTP domain name and set the VTP mode to client. However, when the S3 device was connected to S1 and trunking was restored, all the ports in V LAN's 10, 20, and 30 transitioned to the inactive state.
Question One.
After the S2 device was replaced with the S3 device and the trunk links were established, which represents the configuration revision number and V LAN information for switches S1 and S3?
A. Config Revision = 4, V LAN's = 1, 10, 20, 30, 99 to 104
B. Config Revision = 6, V LAN's = 1, 10, 20, 30, 99 to 104
C. Config Revision = 4, V LAN's = 1, 10, 20, 30, 99
D. Config Revision = 6, V LAN's = 1, 10, 20, 30, 99
E. Config Revision = 6, V LAN's = 1, 99 to 104
Question Two.
Which two of the following is true about the configuration revision number? (Choose two.)
A. Only subset advertisements contain the configuration revision number.
B. Only summary advertisements contain the configuration revision number.
C. All VTP messages contain the configuration revision number.
D. Higher configuration revision numbers take precedence over lower configuration revision numbers.
E. Lower configuration revision numbers take precedence over higher configuration revision numbers.
Question Three.
Which solution is appropriate to resolve the V LAN configuration discrepancies for the VTP domain and connectivity for the PC1, PC2, and PC3 devices?
A. Add the missing V LAN's to the VTP server S1.
B. Delete the V LAN's from the new S3.
C. Delete all possible V LAN's from the VTP server S1.
D. Add the missing V LAN's to switches S1 and S3.
Question Four.
Which two methods avoid unintentional V LAN database corruption when adding a new switch? (Choose two.)
A. Reset the configuration revision number on the new switch by temporarily changing the VTP domain name.
B. Increase the configuration revision number on an existing VTP server so that it is lower than the switch being added.
C. Temporarily change the mode of the new switch to transparent.
D. Delete the V LAN database of the VTP server before connecting the new device to the network.
E. Change the configuration register number on the new switch using the config-reg command.
4.3 Configure VTP
4.3.1 Configuring VTPPage 1:
VTP Configuration Guidelines
Now that you are familiar with the functionality of VTP, you are ready to learn how to configure a Cisco Catalyst switch to use VTP. The topology shows the reference topology for this chapter. VTP will be configured on this topology.
Click the Table button in the figure.
VTP Server Switches
Follow these steps and associated guidelines to ensure that you configure VTP successfully:
- Confirm that all of the switches you are going to configure have been set to their default settings.
- Always reset the configuration revision number before installing a previously configured switch into a VTP domain. Not resetting the configuration revision number allows for potential disruption in the VLAN configuration across the rest of the switches in the VTP domain.
- Configure at least two VTP server switches in your network. Because only server switches can create, delete, and modify VLANs, you should make sure that you have one backup VTP server in case the primary VTP server becomes disabled. If all the switches in the network are configured in VTP client mode, you cannot create new VLANs on the network.
- Configure a VTP domain on the VTP server. Configuring the VTP domain on the first switch enables VTP to start advertising VLAN information. Other switches connected through trunk links receive the VTP domain information automatically through VTP advertisements.
- If there is an existing VTP domain, make sure that you match the name exactly. VTP domain names are case-sensitive.
- If you are configuring a VTP password, ensure that the same password is set on all switches in the domain that need to be able to exchange VTP information. Switches without a password or with the wrong password reject VTP advertisements.
- Ensure that all switches are configured to use the same VTP protocol version. VTP version 1 is not compatible with VTP version 2. By default, Cisco Catalyst 2960 switches run version 1 but are capable of running version 2. When the VTP version is set to version 2, all version 2 capable switches in the domain autoconfigure to use version 2 through the VTP announcement process. Any version 1-only switches cannot participate in the VTP domain after that point.
- Create the VLAN after you have enabled VTP on the VTP server. VLANs created before you enable VTP are removed. Always ensure that trunk ports are configured to interconnect switches in a VTP domain. VTP information is only exchanged on trunk ports.
VTP Client Switches
- As on the VTP server switch, confirm that the default settings are present.
- Configure VTP client mode. Recall that the switch is not in VTP client mode by default. You have to configure this mode.
- Configure trunks. VTP works over trunk links.
- Connect to a VTP server. When you connect to a VTP server or another VTP-enabled switch, it takes a few moments for the various advertisements to make their way back and forth to the VTP server.
- Verify VTP status. Before you begin configuring the access ports, confirm that the revision mode and number of VLANs have been updated.
- Configure access ports. When a switch is in VTP client mode, you cannot add new VLANs. You can only assign access ports to existing VLANs.
4.3.1 - Configuring VTP
The diagram depicts a switched network with VTP enabled and includes VTP configuration guidelines.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 port F0/1 is connected to S2 port F0/1, and switch S1 port F0/3 is connected to S3 port F0/3. Three PC's, PC1, PC2, and PC3, are connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Three PC's, PC4, PC5, and PC6, are connected to switch S3 on ports F0/11, F0/18, and F0/6, respectively.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.30.23
V LAN 30
PC4:
IP address 172.17.10.24
V LAN 10
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.30.26
V LAN 30
VTP Configuration Guidelines.
On the VTP server:
- Confirm default settings.
- Configure two switches as VTP servers.
- Configure the VTP domain on the first switch in the network.
- Ensure that all switches are in the same VTP protocol version mode.
- Configure V LAN's and trunk ports.
On the VTP client:
- Confirm default settings.
- Configure VTP client mode.
- Configure trunks.
- Connect to the VTP server.
- Verify VTP status.
- Configure access ports.
The diagram depicts a switched network with VTP enabled and includes VTP configuration guidelines.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 port F0/1 is connected to S2 port F0/1, and switch S1 port F0/3 is connected to S3 port F0/3. Three PC's, PC1, PC2, and PC3, are connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Three PC's, PC4, PC5, and PC6, are connected to switch S3 on ports F0/11, F0/18, and F0/6, respectively.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.30.23
V LAN 30
PC4:
IP address 172.17.10.24
V LAN 10
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.30.26
V LAN 30
VTP Configuration Guidelines.
On the VTP server:
- Confirm default settings.
- Configure two switches as VTP servers.
- Configure the VTP domain on the first switch in the network.
- Ensure that all switches are in the same VTP protocol version mode.
- Configure V LAN's and trunk ports.
On the VTP client:
- Confirm default settings.
- Configure VTP client mode.
- Configure trunks.
- Connect to the VTP server.
- Verify VTP status.
- Configure access ports.
Page 2:
Configuring VTP Step 1 - Configure the VTP Server
The next three topics will show you how to configure a VTP server and two VTP clients. Initially none of the devices are connected.
The topology highlights switch S1. You will configure this switch to be a VTP server. The commands to configure the trunk ports are provided for interface F0/1.
Click the Confirm Details button in the figure.
The output of the show vtp status command confirms that the switch is by default a VTP server. Since no VLANs have yet been configured, the revision number is still set to 0 and the switch does not belong to VTP domain.
If the switch was not already configured as a VTP server, you could configure it using the the vtp mode {server} command.
Click the Configure Domain Name button in the figure.
The domain name is configured using the the vtp domain domain-name command. In the figure, switch S1 has been configured with the domain name cisco1.
For security reasons, a password could be configured using the vtp password password command.
Click the Configure Version button in the figure.
Most switches can support VTP version 1 and 2. However, the default setting for Catalyst 2960 switches is version 1. When the vtp version 1 command is entered on the switch, it informs us that the switch is already configured to be in version 1.
Click the Add VLANs and Trunks button in the figure.
Assume that three VLANs have been configured and have been assigned VLANs names. The output in the figure is displaying the result of these changes.
You can use the no version of the commands.
4.3.1 - Configuring VTP
The diagram depicts configuring the VTP server. Cisco I O S C L I commands are used to configure and verify the VTP server switch, including confirming defaults, configuring the domain name and version, and adding V LAN's and trunks.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is a VTP server, and switches S2 and S3 are VTP clients. The switches are not currently connected. Three PC's, PC1, PC2, and PC3, are to be connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Three PC's, PC4 , PC5, and PC6, are to be connected to switch S3 on ports F0/11, F0/18, and F0/6, respectively.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.30.23
V LAN 30
PC4:
IP address 172.17.10.24
V LAN 10
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.30.26
V LAN 30
Confirm Defaults:
The highlighted areas in the following output are Configuration Revision and VTP Domain Name.
S1#show vtp status
VTP Version: 1
Configuration Revision: 0
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 5
VTP Operating Mode: Server
VTP Domain Name:
VTP Pruning Mode: Disabled
VTP V2 Mode: Disabled
VTP Traps Generation: Disabled
MD5 digest: 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 3-1-93 00:41:42
S1#
Configure Domain Name:
The highlighted areas in the following output are the lines referencing the new domain name of cisco1.
S1#configure terminal
S1(config)#vtp domain cisco1
Changing VTP domain name from NULL to cisco1
S1(config)#exit
S1#show vtp status
VTP Version: 1
Configuration Revision: 0
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 5
VTP Operating Mode: Server
VTP Domain Name: cisco1
output omitted
S1#
Configure Version:
Confirm that VTP version 1 is configured.
The highlighted area is VTP mode already in V1.
S1(config)#vtp version 1
VTP mode already in V1.
S1(config)#exit
S1#
Add V LAN's and Trunks:
S1#show v lan brief
Output omitted
V LANNameStatusPorts
10facultyactive
20studentactive
30guestactive
Output omitted
S1#show interfaces 0/1 switchport
Name: FA0/1
Switchport: Enabled
Administrative Mode: trunk
Output omitted
S1#show vtp status
VTP Version: 1
Configuration Revision: 6
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 8
VTP Operating Mode: Server
VTP Domain Name: cisco1
Note: Adding a name to a V LAN is considered a revision. Three V LAN's plus three names equals 6.
The diagram depicts configuring the VTP server. Cisco I O S C L I commands are used to configure and verify the VTP server switch, including confirming defaults, configuring the domain name and version, and adding V LAN's and trunks.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is a VTP server, and switches S2 and S3 are VTP clients. The switches are not currently connected. Three PC's, PC1, PC2, and PC3, are to be connected to switch S2 on ports F0/11, F0/18, and F0/6, respectively. Three PC's, PC4 , PC5, and PC6, are to be connected to switch S3 on ports F0/11, F0/18, and F0/6, respectively.
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.30.23
V LAN 30
PC4:
IP address 172.17.10.24
V LAN 10
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.30.26
V LAN 30
Confirm Defaults:
The highlighted areas in the following output are Configuration Revision and VTP Domain Name.
S1#show vtp status
VTP Version: 1
Configuration Revision: 0
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 5
VTP Operating Mode: Server
VTP Domain Name:
VTP Pruning Mode: Disabled
VTP V2 Mode: Disabled
VTP Traps Generation: Disabled
MD5 digest: 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 3-1-93 00:41:42
S1#
Configure Domain Name:
The highlighted areas in the following output are the lines referencing the new domain name of cisco1.
S1#configure terminal
S1(config)#vtp domain cisco1
Changing VTP domain name from NULL to cisco1
S1(config)#exit
S1#show vtp status
VTP Version: 1
Configuration Revision: 0
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 5
VTP Operating Mode: Server
VTP Domain Name: cisco1
output omitted
S1#
Configure Version:
Confirm that VTP version 1 is configured.
The highlighted area is VTP mode already in V1.
S1(config)#vtp version 1
VTP mode already in V1.
S1(config)#exit
S1#
Add V LAN's and Trunks:
S1#show v lan brief
Output omitted
V LANNameStatusPorts
10facultyactive
20studentactive
30guestactive
Output omitted
S1#show interfaces 0/1 switchport
Name: FA0/1
Switchport: Enabled
Administrative Mode: trunk
Output omitted
S1#show vtp status
VTP Version: 1
Configuration Revision: 6
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 8
VTP Operating Mode: Server
VTP Domain Name: cisco1
Note: Adding a name to a V LAN is considered a revision. Three V LAN's plus three names equals 6.
Page 3:
The topology highlights switches S2 and S3. You will be shown the VTP client configuration for S2. To configure S3 as a VTP client, you will follow the same procedure.
Click the Confirm Defaults button to verify the switch status.
Before configuring a switch as a VTP client, verify its current VTP status. Once you've confirmed status, you will configure the switch to operate in VTP client mode.
Click the Enable VTP Client Mode button to see how to configure a switch for VTP client mode.
Configure VTP client mode using the following Cisco IOS command syntax:
Enter global configuration mode with the configure terminal command.
Configure the switch in client mode with the vtp mode {client} command.
If you need to reset the VTP configuration to the default values, you can use the no version of the commands.
Click the Verify VTP Status button to see the rest of VTP client configuration.
4.3.1 - Configuring VTP
The diagram depicts configuring VTP clients. Cisco I O S C L I commands are used to configure and verify the VTP client switches, including confirming defaults, enabling VTP client mode, and verifying VTP status.
Network Topology:
Same as Diagram 4.3.1.2, except that VTP client switches S2 and S3 are highlighted.
Confirm Defaults:
The highlighted areas are Configuration Revision and VTP Domain Name.
S2#show vtp status
VTP Version : 1
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Server
VTP Domain Name :
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
S2#
Enable VTP Client Mode:
The highlighted areas in the following are the lines referencing client mode.
S2#configure terminal
S2(config)#vtp mode client
Setting device to VTP CLIENT mode.
S2(config)#exit
S2#show vtp status
VTP Version : 1
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Client
Output omitted
S2#
Verify VTP Status:
The highlighted areas are all the output from the show interfaces 0/1 switchport command and Client in the show vtp status command.
S2 #show interfaces 0/1 switchport
Name: FA 0/1
Switchport: Enabled
Administrative Mode: trunk
S2#show vtp status
VTP Version : 1
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Client
VTP Domain Name :
VTP Pruning Mode : Disabled
The diagram depicts configuring VTP clients. Cisco I O S C L I commands are used to configure and verify the VTP client switches, including confirming defaults, enabling VTP client mode, and verifying VTP status.
Network Topology:
Same as Diagram 4.3.1.2, except that VTP client switches S2 and S3 are highlighted.
Confirm Defaults:
The highlighted areas are Configuration Revision and VTP Domain Name.
S2#show vtp status
VTP Version : 1
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Server
VTP Domain Name :
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
S2#
Enable VTP Client Mode:
The highlighted areas in the following are the lines referencing client mode.
S2#configure terminal
S2(config)#vtp mode client
Setting device to VTP CLIENT mode.
S2(config)#exit
S2#show vtp status
VTP Version : 1
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Client
Output omitted
S2#
Verify VTP Status:
The highlighted areas are all the output from the show interfaces 0/1 switchport command and Client in the show vtp status command.
S2 #show interfaces 0/1 switchport
Name: FA 0/1
Switchport: Enabled
Administrative Mode: trunk
S2#show vtp status
VTP Version : 1
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Client
VTP Domain Name :
VTP Pruning Mode : Disabled
Page 4:
Configuring VTP Step 3 - Confirm and Connect
After configuring the main VTP server and the VTP clients, you will connect the VTP client switch S2 to the switch S1 VTP server.
The topology highlights the trunks that will be added to this topology. In the figure, switch S2 will be connected to switch S1. Then switch S2 will be configured to support the computers, PC1 to PC3. The same procedure will be applied to switch S3, although the commands for S3 are not shown.
Confirm VTP Operation
Click the Confirm VTP Operation button in the figure.
There are two Cisco IOS commands for confirming that VTP domain and VLAN configurations have been transferred to switch S2. Use the show VTP status command to verify the following:
- Configuration revision number has been incremented to 6.
- There are now three new VLANs indicated by the existing number of VLANs showing 8.
- Domain name has been changed to cisco1.
Use the show vtp counters command to confirm that the advertisements took place.
Configure Access Ports
Click the Configure Access Ports button in the figure.
The top highlight in the screen output confirms that the switch S2 is in VTP client mode. The task now is to configure the port F0/18 on switch S2 to be in VLAN 20. The bottom highlighted area shows the Cisco IOS command used to configure port F0/18 on switch S2 to be in VLAN 20.
4.3.1 - Configuring VTP
The diagram depicts configuring the VTP server. Cisco I O S C L I commands are used to configure and verify the VTP client switch S2, including confirming VTP operation and configuring access ports.
Network Topology:
Same as Diagram 4.3.1.2, except that cables are now connected from switch S1 to switches S2 and S3, and PC's are connected to S2 and S3. The connections from switch S2 F0/1 to switch S1 F0/1 and from switch S3 F0/3 to S1 FA0/3 are trunks.
Confirm VTP Operation:
The show vtp status output confirms that switch S2 has been updated and now has three new V LAN's.
S2#show vtp status
VTP Version: 1
Configuration Revision: 6
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 8
VTP Operating Mode: Client
VTP Domain Name: cisco1
output omitted
S2#show vtp counters
VTP statistics:
Summary advertisements received: 1
Subset advertisements received: 1
Request advertisements received: 0
Summary advertisements transmitted: 1
Subset advertisements transmitted: 1
output omitted
S2#
Configure Access Ports:
The message displayed confirms that VTP client mode is in effect. V LAN creation is not allowed; only V LAN assignment is allowed.
S2 # configure terminal
Enter configuration commands, one per line. End with CTRL Z.
S2(config)#v lan 20
%VTP V LAN configuration not allowed when device is in CLIENT mode.
S2(config)#interface fast Ethernet 0/18
S2(config-i f)#switchport access v lan 20
S2(config-i f)#exit
S2(config)#exit
S2#
The diagram depicts configuring the VTP server. Cisco I O S C L I commands are used to configure and verify the VTP client switch S2, including confirming VTP operation and configuring access ports.
Network Topology:
Same as Diagram 4.3.1.2, except that cables are now connected from switch S1 to switches S2 and S3, and PC's are connected to S2 and S3. The connections from switch S2 F0/1 to switch S1 F0/1 and from switch S3 F0/3 to S1 FA0/3 are trunks.
Confirm VTP Operation:
The show vtp status output confirms that switch S2 has been updated and now has three new V LAN's.
S2#show vtp status
VTP Version: 1
Configuration Revision: 6
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 8
VTP Operating Mode: Client
VTP Domain Name: cisco1
output omitted
S2#show vtp counters
VTP statistics:
Summary advertisements received: 1
Subset advertisements received: 1
Request advertisements received: 0
Summary advertisements transmitted: 1
Subset advertisements transmitted: 1
output omitted
S2#
Configure Access Ports:
The message displayed confirms that VTP client mode is in effect. V LAN creation is not allowed; only V LAN assignment is allowed.
S2 # configure terminal
Enter configuration commands, one per line. End with CTRL Z.
S2(config)#v lan 20
%VTP V LAN configuration not allowed when device is in CLIENT mode.
S2(config)#interface fast Ethernet 0/18
S2(config-i f)#switchport access v lan 20
S2(config-i f)#exit
S2(config)#exit
S2#
4.3.2 Troubleshooting VTP Configurations
Page 1:
Troubleshooting VTP Connections
You have learned how VTP can be used to simplify managing a VLAN database across multiple switches. In this topic, you will learn about common VTP configuration problems. This information, combined with your VTP configuration skills, will help you when troubleshooting VTP configuration problems.
The figure lists the common VTP configuration issues that will be explored in this topic.
4.3.2 - Troubleshooting VTP Configurations
The diagram depicts common VTP configuration issues.
Common VTP configuration issues are:
- Incompatible VTP versions.
- VTP password issues.
- Incorrect VTP mode name.
- All switches set to VTP client mode.
The diagram depicts common VTP configuration issues.
Common VTP configuration issues are:
- Incompatible VTP versions.
- VTP password issues.
- Incorrect VTP mode name.
- All switches set to VTP client mode.
Page 2:
Incompatible VTP Versions
VTP versions 1 and 2 are incompatible with each other. Modern Cisco Catalyst switches, such as the 2960, are configured to use VTP version 1 by default. However, older switches may only support VTP version 1. Switches that only support version 1 cannot participate in the VTP domain along with version 2 switches. If your network contains switches that support only version 1, you need to manually configure the version 2 switches to operate in version 1 mode.
Click the VTP Version Solution button in the figure.
VTP Password Issues
When using a VTP password to control participation in the VTP domain, ensure that the password is set correctly on all switches in the VTP domain. Forgetting to set a VTP password is a very common problem. If a password is used, it must be configured on each switch in the domain. By default, a Cisco switch does not use a VTP password. The switch does not automatically set the password parameter, unlike other parameters that are set automatically when a VTP advertisement is received.
Click the VTP Password Solution button in the figure.
4.3.2 - Troubleshooting VTP Configurations
The diagram depicts VTP version and password issues.
Incompatible VTP Versions:
- VTP versions 1 and 2 are incompatible with each other.
- Make sure that all switches are running the same VTP version.
VTP Version Solution:
Reset the VTP version to the lowest VTP version supported by all the switches using the following commands:
Enter global configuration mode.
#configure terminal
Configure the VTP version.
(config)#vtp version number
Here is an example showing how to reset the VTP version for switch S3:
S3(config)#vtp version 2
VTP Password Issues:
- Ensure that passwords are all the same on all VTP-enabled switches in the VTP domain.
- By default, a Cisco switch does not use a VTP password.
- When a VTP advertisement is received, Cisco switches do not automatically set the VTP password parameter.
VTP Password Solution:
Enter global configuration mode.
#configure terminal
Configure the VTP password.
(config)#vtp password password
Here is an example showing how to configure the VTP password for switch S3:
S3(config)#vtp password cisco
The diagram depicts VTP version and password issues.
Incompatible VTP Versions:
- VTP versions 1 and 2 are incompatible with each other.
- Make sure that all switches are running the same VTP version.
VTP Version Solution:
Reset the VTP version to the lowest VTP version supported by all the switches using the following commands:
Enter global configuration mode.
#configure terminal
Configure the VTP version.
(config)#vtp version number
Here is an example showing how to reset the VTP version for switch S3:
S3(config)#vtp version 2
VTP Password Issues:
- Ensure that passwords are all the same on all VTP-enabled switches in the VTP domain.
- By default, a Cisco switch does not use a VTP password.
- When a VTP advertisement is received, Cisco switches do not automatically set the VTP password parameter.
VTP Password Solution:
Enter global configuration mode.
#configure terminal
Configure the VTP password.
(config)#vtp password password
Here is an example showing how to configure the VTP password for switch S3:
S3(config)#vtp password cisco
Page 3:
Incorrect VTP Domain Name
The VTP domain name is a key parameter that is set on a switch. An improperly configured VTP domain affects VLAN synchronization between switches. As you learned earlier, if a switch receives the wrong VTP advertisement, the switch discards the message. If the discarded message contains legitimate configuration information, the switch does not synchronize its VLAN database as expected.
Click Play in the figure to see an animation of this issue.
Click the VTP Domain Solution button in the figure.
Solution
To avoid incorrectly configuring a VTP domain name, only set the VTP domain name on one VTP server switch. All other switches in the same VTP domain will accept and automatically configure their VTP domain name when they receive the first VTP summary advertisement.
4.3.2 - Troubleshooting VTP Configurations
The diagram depicts incorrect VTP domain name issues.
Network Topology:
There are four switches, S1, S2, S3, and S4. Switch S1 is connected to S2 and S3. Switch S3 is connected to S4. Switch S1 is a VTP server, and switches S2, S3, and S4 are VTP clients. The domain name for S1, S2, and S4 is set to cisco1. The domain name for S3 is set to Not Cisco.
Incorrect VTP Domain Name:
Animation Sequence.
A new V LAN is created on the VTP server.
The VTP server S1 sends a summary advertisement to the adjacent switches.
Switch S2 accepts the summary VTP advertisement and synchronizes its V LAN database with S1.
Switch S3 discards the VTP summary advertisement.
Switch S4 does not add V LAN 10 to its database.
VTP Domain Solution:
Change the VTP domain name for a VTP-enabled switch using these commands:
Enter global configuration mode.
#configure terminal
Configure the VTP domain name.
(config)#vtp domain domain-name
Here is an example showing how to change the VTP domain name for switch S3:
S3 (config)#vtp domain cisco1
The diagram depicts incorrect VTP domain name issues.
Network Topology:
There are four switches, S1, S2, S3, and S4. Switch S1 is connected to S2 and S3. Switch S3 is connected to S4. Switch S1 is a VTP server, and switches S2, S3, and S4 are VTP clients. The domain name for S1, S2, and S4 is set to cisco1. The domain name for S3 is set to Not Cisco.
Incorrect VTP Domain Name:
Animation Sequence.
A new V LAN is created on the VTP server.
The VTP server S1 sends a summary advertisement to the adjacent switches.
Switch S2 accepts the summary VTP advertisement and synchronizes its V LAN database with S1.
Switch S3 discards the VTP summary advertisement.
Switch S4 does not add V LAN 10 to its database.
VTP Domain Solution:
Change the VTP domain name for a VTP-enabled switch using these commands:
Enter global configuration mode.
#configure terminal
Configure the VTP domain name.
(config)#vtp domain domain-name
Here is an example showing how to change the VTP domain name for switch S3:
S3 (config)#vtp domain cisco1
Page 4:
Switches Set to VTP Client Mode
It is possible to change the operating mode of all switches to VTP client. By doing so, you lose all ability to create, delete, and manage VLANs within your network environment. Because the VTP client switches do not store the VLAN information in NVRAM, they need to refresh the VLAN information after a reload.
Click Play in the figure to see an animation of this issue.
Click the Solution button in the figure.
Solution
To avoid losing all VLAN configurations in a VTP domain by accidentally reconfiguring the only VTP server in the domain as a VTP client, you can configure a second switch in the same domain as a VTP server. It is not uncommon for small networks that use VTP to have all the switches in VTP server mode. If the network is being managed by a couple of network administrators, it is unlikely that conflicting VLAN configurations will arise.
4.3.2 - Troubleshooting VTP Configurations
The diagram depicts issues associated with switches set to VTP client mode and no VTP server switch is present.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. S1 is a VTP server. S2 and S3 are VTP clients.
Switches Set to VTP Client Mode:
The network has been configured with these V LAN's:
- V LAN 10 - faculty/staff
- V LAN 20 - students
- V LAN 30 - guest
- V LAN 99 - management
Animation Sequence.
The network manager mistakenly reconfigures switch S1:
S1#configure terminal
S1(configure)#VTP mode client
S1(config)#end
S1#
If the network manager then reboots, each switch network V LAN configuration is lost. No V LAN's will be configured on any of the switches.
Solution:
Reset two switches in the same VTP domain to be in VTP server mode using these commands:
Enter global configuration mode.
#configure terminal
Configure the VTP mode.
(config)#vtp mode server
Here is an example showing how to change the VTP mode for switch S3 to VTP server:
S3#(config)#VTP mode server
The diagram depicts issues associated with switches set to VTP client mode and no VTP server switch is present.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. S1 is a VTP server. S2 and S3 are VTP clients.
Switches Set to VTP Client Mode:
The network has been configured with these V LAN's:
- V LAN 10 - faculty/staff
- V LAN 20 - students
- V LAN 30 - guest
- V LAN 99 - management
Animation Sequence.
The network manager mistakenly reconfigures switch S1:
S1#configure terminal
S1(configure)#VTP mode client
S1(config)#end
S1#
If the network manager then reboots, each switch network V LAN configuration is lost. No V LAN's will be configured on any of the switches.
Solution:
Reset two switches in the same VTP domain to be in VTP server mode using these commands:
Enter global configuration mode.
#configure terminal
Configure the VTP mode.
(config)#vtp mode server
Here is an example showing how to change the VTP mode for switch S3 to VTP server:
S3#(config)#VTP mode server
Page 5:
Incorrect Revision Number
Even after you have configured the switches in your VTP domain correctly, there are other factors that can adversely affect the functionality of VTP.
Configuration Revision Number Issues
The topology in the figure is configured with VTP. There is one VTP server switch, S1, and two VTP client switches, S2 and S3.
Click the Incorrect Revision Number button in the figure to play an animation showing how the addition of a switch with a higher configuration revision number affects the rest of the switches in the VTP domain.
S4, which has been previously configured as a VTP client, is added to the network. The revision number of the switch S4 is 35, which is higher than the revision number of 17 in the existing network. S4 comes preconfigured with two VLANs, 30 and 40, that are not configured in the existing network. The existing network has VLANs 10 and 20.
When switch S4 is connected to switch S3, VTP summary advertisements announce the arrival of a VTP-enabled switch with the highest revision number in the network. The animation shows how switch S3, switch S1, and finally switch S2 all reconfigure themselves to the configuration found in switch S4. As each switch reconfigures itself with VLANs that are not supported in the network, the ports no longer forward traffic from the computers because they are configured with VLANs that no longer exist on the newly reconfigured switches.
Click the Reset Revision Number button in the figure.
Solution
The solution to the problem is to reset each switch back to an earlier configuration and then reconfigure the correct VLANs, 10 and 20, on switch S1. To prevent this problem in the first place, reset the configuration revision number on previously configured switches being added to a VTP-enabled network. The figure shows the commands needed to reset switch S4 back to the default revision number.
Click Verify Revision Number button in the figure to see that switch S4 has had its revision number reset.
4.3.2 - Troubleshooting VTP Configurations
The diagram depicts issues associated with an incorrect revision number. Cisco I O S C L I commands are provided to reset and verify the revision number.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. Switch S1 is a VTP server, and switches S2 and S3 are VTP clients. The VTP server switch S4, which has a higher revision number, is added to the topology by attaching it to S3.
PC1, PC2, and PC3 are connected to switch S2. PC4, PC5, and PC6 are connected to switch S3.
Switch S1:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
Switch S2:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
Switch S3:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.10.23
V LAN 10
PC4:
IP address 172.17.20.24
V LAN 20
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.20.26
V LAN 20
Incorrect Revision Number:
Animation Sequence.
When the animation starts, switches S1, S2, and S3 are synchronized with a VTP domain of cisco1, a revision number of 17, and V LAN's 10 and 20 defined.
VTP server switch S4 with a VTP domain of cisco1, a revision number of 35, and V LAN's 30 and 40 defined, is connected to switch S3.
VTP summary advertisements announce the arrival of a VTP-enabled switch with the highest revision number in the network.
The animation shows how switch S3, switch S1, and finally switch S2 all reconfigure themselves to the incorrect configuration found in switch S4. The new configuration consists of a VTP domain of cisco1, a revision number of 35, and V LAN's 30 and 40 defined.
The incorrect V LAN's are not supported, and the ports no longer forward traffic from the computers.
Reset Revision Number:
Before adding a switch to a VTP-enabled network, reset the revision number on the switch using these commands:
Enter global configuration mode.
#configure terminal
Configure the VTP domain name.
(config)#vtp domain domain-name
Here is an example showing how to reset the revision number on switch S4:
S4(config)#vtp domain test
S4(config)#vtp domain cisco1
Verify the Revision Number:
S4#show vtp status
VTP Version : 2
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Server
VTP Domain Name : cisco1
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
S4#
The diagram depicts issues associated with an incorrect revision number. Cisco I O S C L I commands are provided to reset and verify the revision number.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. Switch S1 is a VTP server, and switches S2 and S3 are VTP clients. The VTP server switch S4, which has a higher revision number, is added to the topology by attaching it to S3.
PC1, PC2, and PC3 are connected to switch S2. PC4, PC5, and PC6 are connected to switch S3.
Switch S1:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
Switch S2:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
Switch S3:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
PC1:
IP address 172.17.10.21
V LAN 10
PC2:
IP address 172.17.20.22
V LAN 20
PC3:
IP address 172.17.10.23
V LAN 10
PC4:
IP address 172.17.20.24
V LAN 20
PC5:
IP address 172.17.20.25
V LAN 20
PC6:
IP address 172.17.20.26
V LAN 20
Incorrect Revision Number:
Animation Sequence.
When the animation starts, switches S1, S2, and S3 are synchronized with a VTP domain of cisco1, a revision number of 17, and V LAN's 10 and 20 defined.
VTP server switch S4 with a VTP domain of cisco1, a revision number of 35, and V LAN's 30 and 40 defined, is connected to switch S3.
VTP summary advertisements announce the arrival of a VTP-enabled switch with the highest revision number in the network.
The animation shows how switch S3, switch S1, and finally switch S2 all reconfigure themselves to the incorrect configuration found in switch S4. The new configuration consists of a VTP domain of cisco1, a revision number of 35, and V LAN's 30 and 40 defined.
The incorrect V LAN's are not supported, and the ports no longer forward traffic from the computers.
Reset Revision Number:
Before adding a switch to a VTP-enabled network, reset the revision number on the switch using these commands:
Enter global configuration mode.
#configure terminal
Configure the VTP domain name.
(config)#vtp domain domain-name
Here is an example showing how to reset the revision number on switch S4:
S4(config)#vtp domain test
S4(config)#vtp domain cisco1
Verify the Revision Number:
S4#show vtp status
VTP Version : 2
Configuration Revision : 0
Maximum V LAN's supported locally : 64
Number of existing V LAN's : 5
VTP Operating Mode : Server
VTP Domain Name : cisco1
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
S4#
4.3.3 Managing VLANs on a VTP Server
Page 1:
Managing VLANs on a VTP Server
You have learned about VTP and how it can be used to simplify managing VLANs in a VTP-enabled network. Consider the topology in the figure. When a new VLAN, for example, VLAN 10, is added to the network, the network manager adds the VLAN to the VTP server, switch S1 in the figure. As you know, VTP takes care of propagating the VLAN configuration details to the rest of the network. It does not have any effect on which ports are configured in VLAN 10 on switches S1, S2, and S3.
Click the Configure New VLANs and Ports button in the figure.
The figure displays the commands used to configure VLAN 10 and the port F0/11 on switch S1. The commands to configure the correct ports for switches S2 and S3 are not shown.
After you have configured the new VLAN on switch S1 and configured the ports on switches S1, S2, and S3 to support the new VLAN, confirm that VTP updated the VLAN database on switches S2 and S3.
Click the show vtp status button in the figure.
The output of the command is used to verify the configuration on switch S2. The verification for S3 is not shown.
Click the show interfaces trunk button in the figure.
The output confirms that the new VLAN has been added to F0/1 on switch S2. The highlighted area shows that VLAN 10 is now active in the VTP management domain.
4.3.3 - Managing V LAN's on a VTP Server
The diagram depicts managing V LAN's on a VTP server, including configuring new V LAN's and ports and using the show vtp status and show interfaces trunk commands.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. Switch S1 is a VTP server, and switches S2 and S3 are VTP clients.
Configure New V LAN's and Ports:
S1>enable
Password:
S1#configure terminal
Enter configuration commands, one per line. End with CTRL Z.
S1(config)#v lan 10
S1(config-v lan)#name faculty
S1(config-v lan)#exit
S1(config)#interface FastEthernet 0/11
S1(config-i f)# switchport access v lan 10
S1(config-i f)#exit
S1(config)#exit
S1#
The show vtp status command:
S2#show vtp status
VTP Version: 1
Configuration Revision: 4
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 8
VTP Operating Mode: Client
VTP Domain Name: cisco1
VTP Pruning Mode: Disabled
VTP V2 Mode: Disabled
VTP Traps Generation: Disabled
MD5 digest: 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 3-1-93 00:41:42
S2#
Configuration Revision, VTP Operating Mode, and VTP Domain Name are highlighted in the output.
The show interfaces trunk command:
S2#show interfaces trunk
PortModeEncapsulationStatusNative v lan:
FA0/1 on 8 0 2 dot 1q trunking1
Port: FA0/1
V lan's allowed on trunk: 1-1005
Port: FA0/1
V lan's allowed and active in management domain:
1, 10, 20, 30, 1002, 1003, 1004, 1005
S2#
FA0/1 : 1, 10, 20, 30, 1002, 1003, 1004, 1005 is highlighted in the output.
The diagram depicts managing V LAN's on a VTP server, including configuring new V LAN's and ports and using the show vtp status and show interfaces trunk commands.
Network Topology:
There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. Switch S1 is a VTP server, and switches S2 and S3 are VTP clients.
Configure New V LAN's and Ports:
S1>enable
Password:
S1#configure terminal
Enter configuration commands, one per line. End with CTRL Z.
S1(config)#v lan 10
S1(config-v lan)#name faculty
S1(config-v lan)#exit
S1(config)#interface FastEthernet 0/11
S1(config-i f)# switchport access v lan 10
S1(config-i f)#exit
S1(config)#exit
S1#
The show vtp status command:
S2#show vtp status
VTP Version: 1
Configuration Revision: 4
Maximum V LAN's supported locally: 64
Number of existing V LAN's: 8
VTP Operating Mode: Client
VTP Domain Name: cisco1
VTP Pruning Mode: Disabled
VTP V2 Mode: Disabled
VTP Traps Generation: Disabled
MD5 digest: 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 3-1-93 00:41:42
S2#
Configuration Revision, VTP Operating Mode, and VTP Domain Name are highlighted in the output.
The show interfaces trunk command:
S2#show interfaces trunk
PortModeEncapsulationStatusNative v lan:
FA0/1 on 8 0 2 dot 1q trunking1
Port: FA0/1
V lan's allowed on trunk: 1-1005
Port: FA0/1
V lan's allowed and active in management domain:
1, 10, 20, 30, 1002, 1003, 1004, 1005
S2#
FA0/1 : 1, 10, 20, 30, 1002, 1003, 1004, 1005 is highlighted in the output.
Page 2:
In this activity, you will practice configuring VTP. When Packet Tracer first opens, the switches already contain a partial configuration.
Detailed instructions are provided within the activity as well as in the PDF link below.
Activity Instructions (PDF)
Click the Packet Tracer icon for more details.
4.3.3 - Managing V LAN's on a VTP Server
Link to Packet Tracer Exploration: Configure VTP
Link to Packet Tracer Exploration: Configure VTP
4.4 Chapter Labs
4.4.1 Basic VTP ConfigurationPage 1:
Imagine a network with 50 switches with a total of 12 identical VLANs each. If you had to manually type in the commands to each switch, it would be a huge undertaking. It would be so much easier if you could configure those 12 VLANs once, and then allow those VLANs to be propagated automatically to the other 49 switches. VTP configuration makes this possible.
4.4.1 - Basic VTP Configuration
Link to Hands-on Lab: Basic VTP Configuration
Link to Hands-on Lab: Basic VTP Configuration
Page 2:
This activity is a variation of Lab 4.4.1. Packet Tracer may not support all the tasks specified in the hands-on lab. This activity should not be considered equivalent to completing the hands-on lab. Packet Tracer is not a substitute for a hands-on lab experience with real equipment.
Detailed instructions are provided within the activity as well as in the PDF link below.
Activity Instructions (PDF)
Click the Packet Tracer icon for more details.
4.4.1 - Basic VTP Configuration
Link to Packet Tracer Exploration: Basic VTP Configuration
Link to Packet Tracer Exploration: Basic VTP Configuration
4.4.2 VTP Configuration Challenge
Page 1:
How much of the basics of VTP configuration do you remember? Let's see how much you can configure from memory having completed the Basic VTP lab. Be sure to check your work with the answer key that your instructor will provide.
4.4.2 - Challenge VTP Configuration
Link to Hands-on Lab: VTP Configuration Challenge
Link to Hands-on Lab: VTP Configuration Challenge
Page 2:
This activity is a variation of Lab 4.4.2. Packet Tracer may not support all the tasks specified in the hands-on lab. This activity should not be considered equivalent to completing the hands-on lab. Packet Tracer is not a substitute for a hands-on lab experience with real equipment.
Detailed instructions are provided within the activity as well as in the PDF link below.
Activity Instructions (PDF)
Click the Packet Tracer icon for more details.
4.4.2 - Challenge VTP Configuration
Link to Packet Tracer Exploration: Challenge VTP Configuration
Link to Packet Tracer Exploration: Challenge VTP Configuration
4.4.3 Troubleshooting VTP Configuration
Page 1:
In this lab, you will use the supplied scripts to configure S1 as a VTP server, and S2 and S3 as VTP clients. However, there are a number of errors in this configuration that you must troubleshoot and correct before end-to-end connectivity within the VLAN is restored.
You will have successfully resolved all errors when the same VLANs are configured on all three switches, and you can ping between any two hosts in the same VLAN or between any two switches.
4.4.3 - Troubleshooting the VTP Configuration
Link to Hands-on Lab: Troubleshooting VTP Configuration
Link to Hands-on Lab: Troubleshooting VTP Configuration
Page 2:
This activity is a variation of Lab 4.4.3. Packet Tracer may not support all the tasks specified in the hands-on lab. This activity should not be considered equivalent to completing the hands-on lab. Packet Tracer is not a substitute for a hands-on lab experience with real equipment.
Detailed instructions are provided within the activity as well as in the PDF link below.
Activity Instructions (PDF)
Click the Packet Tracer icon for more details.
4.4.3 - Troubleshooting the VTP Configuration
Link to Packet Tracer Exploration: Troubleshooting the VTP Configuration
Link to Packet Tracer Exploration: Troubleshooting the VTP Configuration
4.5 Chapter Summary
4.5.1 SummaryPage 1:
In this chapter, we discussed the VLAN trunking protocol. VTP is a Cisco-proprietary protocol used to exchange VLAN information across trunk links, reducing VLAN administration and configuration errors. VTP allows you to create a VLAN once within a VTP domain and have that VLAN propagated to all other switches in the VTP domain.
There are three VTP operating modes: server, client, and transparent. VTP client mode switches are more prevalent in large networks, where there definition reduces the administration of VLAN information. In small networks, network managers can more easily keep track of network changes, so switches are often left in the default VTP server mode.
VTP pruning limits the unnecessary propagation of VLAN traffic across a LAN. VTP determines which trunk ports forward which VLAN traffic. VTP pruning improves overall network performance by restricting the unnecessary flooding of traffic across trunk links. Pruning only permits VLAN traffic for VLANs that are assigned to some switch port of a switch on the other end of a trunk link. By reducing the total amount of flooded traffic on the network, bandwidth is freed up for other network traffic.
We discussed VTP configuration and preventative measures to take to avoid common problematic VTP issues.
4.5.1 - Summary and Review
In this chapter, you have learned:
- VTP simplifies V LAN administration across multiple Cisco Catalyst switches by replicating V LAN configurations between switches.
- A VTP domain defines which switches in a network are to be configured similarly with respect to the V LAN configuration.
- A Cisco Catalyst switch can be configured for one of three VTP operational modes: server, client, or transparent.
- VTP server mode allows for the creation, deletion, and modification of V LAN's.
- VTP client mode prevents modification of the V LAN's and can only receive V LAN information through VTP advertisements.
- VTP transparent mode allows for the creation, deletion, and modification of local V LAN's, including extended-range V LAN's. V LAN information is not synchronized with other switches.
- VTP passwords can be used to limit synchronization between switches configured with the same VTP domain.
- VTP pruning can improve the overall bandwidth over trunk links by limiting flood traffic to switches that contain active V LAN's specific for the flood traffic.
- Always verify your configuration to limit the possibility of VTP errors.
In this chapter, you have learned:
- VTP simplifies V LAN administration across multiple Cisco Catalyst switches by replicating V LAN configurations between switches.
- A VTP domain defines which switches in a network are to be configured similarly with respect to the V LAN configuration.
- A Cisco Catalyst switch can be configured for one of three VTP operational modes: server, client, or transparent.
- VTP server mode allows for the creation, deletion, and modification of V LAN's.
- VTP client mode prevents modification of the V LAN's and can only receive V LAN information through VTP advertisements.
- VTP transparent mode allows for the creation, deletion, and modification of local V LAN's, including extended-range V LAN's. V LAN information is not synchronized with other switches.
- VTP passwords can be used to limit synchronization between switches configured with the same VTP domain.
- VTP pruning can improve the overall bandwidth over trunk links by limiting flood traffic to switches that contain active V LAN's specific for the flood traffic.
- Always verify your configuration to limit the possibility of VTP errors.
Page 2:
4.5.1 - Summary and Review
This is a review and is not a quiz. Questions and answers are provided.
Question One. Match each term with the correct description.
A. VTP Domain.
B. VTP Advertisements.
C. VTP Modes.
D. VTP Server.
E. VTP Client.
F. VTP Transparent.
G. VTP Pruning.
One. One IP subnet to many V LAN's.
Two. One V LAN to many IP subnets.
Three. Two IP subnets to one V LAN.
Four. Two V LAN's to one IP subnet.
Five. One IP subnet to one V LAN.
Six. Varies with the model of Cisco Catalyst switch.
Seven. Default for a Catalyst switch; advertises V LAN configurations to other VTP-enabled switches.
Answers:
A = Five.
B = Six.
C = One.
D = Seven.
E = Four.
F = Two.
G = Three.
Question Two. List the default VTP configuration on a Catalyst switch for VTP version, VTP domain name, VTP mode, configuration revision number, and number of V LAN's.
Answer:
VTP Version = 1
VTP Domain Name = null
VTP Mode = Server
Config Revision = 0
V LAN's = 1
Question Three.
Refer to the diagram descriptions for Figures 1 and 2 provided here.
Diagram descriptions:
Figure 1 - There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. PC1, PC2, and PC3 are connected to switch S2. PC4, PC5, and PC6 are connected to switch S3. Switch S1 is a VTP server. Switches S2 and S3 are VTP clients.
S1 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S2 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S3 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
Figure 2 - There are four switches, S1, S2, S3, and S4. Switch S1 is connected to S2 and S3. Switch S3 is connected to S4, a VTP client. PC1, PC2, and PC3 are connected to switch S2. PC4, PC5, and PC6 are connected to switch S3.
S1 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S2 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S3 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S4 text:
VTP Domain = cisco1
Revision number = 35
V LAN's: 30, 40
Figure 1 shows a converged VTP domain. In Figure 2, switch S4 is trunked to switch S3. The VTP information residing in switch S4 is displayed. Which conclusions can be made after VTP has converged when switch S4 is added?
A. PC1 cannot communicate with PC2.
B. PC2 cannot communicate with PC4.
C. PC4 cannot communicate with PC5.
D. The names of V LAN's can be determined.
Answer: A, B, C
This is a review and is not a quiz. Questions and answers are provided.
Question One. Match each term with the correct description.
A. VTP Domain.
B. VTP Advertisements.
C. VTP Modes.
D. VTP Server.
E. VTP Client.
F. VTP Transparent.
G. VTP Pruning.
One. One IP subnet to many V LAN's.
Two. One V LAN to many IP subnets.
Three. Two IP subnets to one V LAN.
Four. Two V LAN's to one IP subnet.
Five. One IP subnet to one V LAN.
Six. Varies with the model of Cisco Catalyst switch.
Seven. Default for a Catalyst switch; advertises V LAN configurations to other VTP-enabled switches.
Answers:
A = Five.
B = Six.
C = One.
D = Seven.
E = Four.
F = Two.
G = Three.
Question Two. List the default VTP configuration on a Catalyst switch for VTP version, VTP domain name, VTP mode, configuration revision number, and number of V LAN's.
Answer:
VTP Version = 1
VTP Domain Name = null
VTP Mode = Server
Config Revision = 0
V LAN's = 1
Question Three.
Refer to the diagram descriptions for Figures 1 and 2 provided here.
Diagram descriptions:
Figure 1 - There are three switches, S1, S2, and S3. Switch S1 is connected to S2 and S3. PC1, PC2, and PC3 are connected to switch S2. PC4, PC5, and PC6 are connected to switch S3. Switch S1 is a VTP server. Switches S2 and S3 are VTP clients.
S1 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S2 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S3 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
Figure 2 - There are four switches, S1, S2, S3, and S4. Switch S1 is connected to S2 and S3. Switch S3 is connected to S4, a VTP client. PC1, PC2, and PC3 are connected to switch S2. PC4, PC5, and PC6 are connected to switch S3.
S1 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S2 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S3 text:
VTP Domain = cisco1
Revision number = 17
V LAN's: 10, 20
S4 text:
VTP Domain = cisco1
Revision number = 35
V LAN's: 30, 40
Figure 1 shows a converged VTP domain. In Figure 2, switch S4 is trunked to switch S3. The VTP information residing in switch S4 is displayed. Which conclusions can be made after VTP has converged when switch S4 is added?
A. PC1 cannot communicate with PC2.
B. PC2 cannot communicate with PC4.
C. PC4 cannot communicate with PC5.
D. The names of V LAN's can be determined.
Answer: A, B, C
Page 3:
In this activity, you will configure switches including basic configuration, port security, trunking and VLANs. You will use VTP to advertise the VLAN configurations to other switches.
Activity Instructions (PDF)
Click the Packet Tracer icon for more details.
4.5.1 - Summary and Review
Link to Packet Tracer Exploration: Packet Tracer Skills Integration Challenge
Link to Packet Tracer Exploration: Packet Tracer Skills Integration Challenge
4.6 Chapter Quiz
4.6.1 Chapter QuizPage 1:
4.6.1 - Chapter Quiz
1.How does VTP affect V LAN administration?
A.Port to V LAN assignments for an entire VTP domain can all be done on a single switch.
B.V LAN's are only visible on switches that have ports assigned to them.
C.VTP propagates V LAN numbers, but not names, to all switches in a VTP domain.
D.VTP is required to allow V LAN naming across switches.
E.VTP propagates V LAN names to all switches in a VTP domain.
2.A Catalyst switch must be in which VTP mode to delete or add V LAN's to a management domain?
A.client.
B.server.
C.domain.
D.transparent.
E.designated.
3.What is the purpose of VTP transparent mode?
A.Permits V LAN creation on a single transparent switch and subsequent propagation to all other VTP switches.
B.Allows propagation of extended-range V LAN's.
C.Makes VTP traffic transparent to other devices by allowing V LAN's other than V LAN 1 to act as the management V LAN.
D.Enables VTP advertisements to pass through a non-participating switch.
4.Refer to the following diagram description to answer the question. Switches A and B connect via a trunk and are running VTP. However, switch B is not getting V LAN update information. What could cause this problem?
A.FastEthernet cannot be used for trunking.
B.The switches are not set to the same VTP mode.
C.The VTP domain name is not the same on both switches.
D.The configuration revision number does not match on both switches.
5.A switch in a VTP domain sends an advertisement request. What is the response?
A.A configuration status reply is issued from the closest client switch.
B.A three-way handshake establishes a configuration session with the VTP server.
C.Summary and subset advertisements are sent by the VTP server.
D.The configuration version number is set to zero, and all switches in the domain issue advertisements regarding the state of their V LAN's.
6.Which function, when enabled on a switches network, prevents broadcast, multicast, and unknown unicast traffic to a V LAN from being flooded to switches that do not have that particular V LAN assigned to them?
A.Trunking.
B.VTP domain.
C.VTP pruning.
D.VTP transparent mode.
7.Which three conditions are required to add a new switch to an existing VTP domain? (Choose three.)
A.All VTP switches must use the same version of VTP.
B.Token ring switches must run VTP version 3 or higher.
C.The VTP pruning settings must be identical.
D.The VTP domain passwords must be unique.
E.The VTP domain names must be identical.
F.The connection to the VTP domain must be a trunked link.
8.Match the command to the associated description. (Not all options are used.)
Commands:
A.VTP mode client
B.VTP mode server
C.VTP version 2
D.VTP pruning
E.VTP domain LABS
Descriptions:
One. Specifies that the switch cannot create or delete V LAN's shared in VTP advertisements.
Two. Configures the name used to determine which switches belong to the same management group.
Three. Restricts flooded traffic to trunk links that the traffic must use to reach destination devices.
9.What is the purpose of the V LAN Trunking Protocol?
A.Maintaining consistency of V LAN configurations across the network.
B.Routing frames from one V LAN to another.
C.Routing frames along the best path between switches.
D.Tagging user data frames with V LAN membership information.
E.Distributing BPDU's to maintain loop-free switched paths.
10.Refer to the following diagram description to answer this question.
Network Topology:
Two switches, SW1 and SW2, are connected with a single trunk link. Switch SW1 has two V LAN's defined, V LAN 20 and V LAN 30. Switch SW2 has three V LAN's defined, V LAN 10, V LAN 20, and V LAN 30.
Switch SW1 has three PC's attached, PC1, PC2, and PC3. PC1 is not in a V LAN. PC2 is in V LAN 20, and PC3 is in V LAN 30.
Switch SW2 has three PC's attached, PC4, PC5, and PC6. PC4 is in V LAN 10. PC5 is in V LAN 20, and PC6 is in V LAN 30.
Switch commands issued:
Switch SW1:
SW1#config terminal
SW1(config )#VTP mode server
SW1(config )#VTP domain Lab
SW1(config )#VTP password admin
SW1(config )#VTP version 2
SW1(config)#VTP pruning
SW1(config)#end
Switch SW2:
SW1#config terminal
SW1(config )#VTP mode client
SW1(config )#VTP domain Lab
SW1(config )#VTP password Admin
SW1(config )#VTP version 2
SW1(config)#VTP pruning
SW1(config )#end
Switches SW1 and SW2 are configured in the same VTP domain but failed to exchange V LAN information. What could be done to fix the problem?
A.Configure the same V LAN's on the VTP client and VTP server.
B.Configure the same VTP mode on the VTP client and VTP server.
C.Configure the same password on the VTP client and VTP server.
D.Configure different VTP domain names on the VTP client and VTP server.
E.Configure the VTP client in VTP transparent mode.
F.Configure the trunk link as an access link.
11.A network engineer is implementing a new V LAN design on an existing structure. The plan is to rename the VTP domain and implement 25 V LAN's. The engineer takes an existing production switch to the lab, enters the proposed V LAN's, and changes the VTP domain name. All new V LAN's are verified present with the show v lan command. The network administrator subsequently decides to retain the original domain name, so the name is changed back, and the switch is reconnected to the production network. The show v lan command shows that none of the new V LAN's are synchronizing on the other network switches. All switches can ping each other and trunking is correct. What is the likely problem?
A.No ports are assigned to the new V LAN's yet, so VTP pruning is disabling them.
B.The switch rejoined the network with the revision number set to zero.
C.The engineer failed to save the new V LAN configuration to NV RAM.
D.The other switches are all in server mode by default and do not accept VTP updates.
12.Match the description to the correct VTP mode. (Not all options are used.)
Descriptions:
A.Create, modify, and delete V LAN's and specify other configuration parameters, such as VTP version and VTP pruning, for the entire VTP domain.
B.Advertise VTP configuration parameters, such as VTP version and VTP pruning, for the entire VTP domain, but cannot create, modify, and delete V LAN's.
C.Advertise and synchronize V LAN configuration to other switches in the same VTP domain, but cannot create, change, or delete V LAN's.
D.Forward VTP advertisements that are received out the trunk ports, but cannot advertise and synchronize the V LAN configuration based on received advertisements.
E.Cannot forward VTP advertisements nor advertise and synchronize the V LAN configuration based on received advertisements.
VTP Modes:
One. VTP Transparent Mode.
Two. VTP Client Mode.
Three. VTP Server Mode.
13.Refer to the following diagram description to answer this question. There are four switches, Switch1, Switch2, Switch3, and Switch4, interconnected by trunked links and are configured for VTP.
Switch1 is connected to Switch2, Switch2 is connected to Switch3, and Switch3 is connected to Switch4. Switch1 is in server mode, Switch2 is in client mode, Switch3 is in transparent mode, and Switch4 is in server mode.
A new V LAN is added to Switch1. Which three actions occur? (Choose three.)
A.Switch1 sends a VTP update to Switch2.
B.Switch2 adds the V LAN to its database and passes the update to Switch3.
C.Switch3 passes the VTP update to Switch4.
D.Switch3 adds the V LAN to its database.
E.Switch4 does not add the V LAN to its database.
F.Switch4 does not receive the update.
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