10.0 Chapter Introduction
10.0.1 Chapter IntroductionPage 1:
Before using an IP phone, accessing instant messaging, or conducting any number of other interactions over a data network, we must connect end devices and intermediary devices via cable or wireless connections to form a functioning network. It is this network that will support our communication in the human network.
Up to this point in the course, we have considered the services that a data network can provide to the human network, examined the features of each layer of the OSI model and the operations of TCP/IP protocols, and looked in detail at Ethernet, a universal LAN technology. The next step is to learn how to assemble these elements together in a functioning network.
In this chapter, we will examine various media and the distinct roles they play with the devices that they connect. You will identify the cables needed to make successful LAN and WAN connections and learn how to use device management connections.
The selection of devices and the design of a network addressing scheme will be presented and then applied in the networking labs.
Learning Objectives
Upon completion of this chapter, you will be able to:
- Identify the basic network media required to make a LAN connection.
- Identify the types of connections for intermediate and end device connections in a LAN.
- Identify the pinout configurations for straight-through and crossover cables.
- Identify the different cabling types, standards, and ports used for WAN connections.
- Define the role of device management connections when using Cisco equipment.
- Design an addressing scheme for an internetwork and assign ranges for hosts, network devices, and the router interface.
- Compare and contrast the importance of network designs.
10.0.1 - Chapter Introduction
The diagram depicts planning and cabling a network. A network topology is shown along with photographs of network equipment, racks, and cabling.
The diagram depicts planning and cabling a network. A network topology is shown along with photographs of network equipment, racks, and cabling.
10.1 LANs - Making the Physical Connection
10.1.1 Choosing the Appropriate LAN DevicePage 1:
For this course, the choice of which router to deploy is determined by the Ethernet interfaces that match the technology of the switches at the center of the LAN. It is important to note that routers offer many services and features to the LAN. These services and features are covered in the more advanced courses.
Each LAN will have a router as its gateway connecting the LAN to other networks. Inside the LAN will be one or more hubs or switches to connect the end devices to the LAN.
Internetwork Devices
Routers are the primary devices used to interconnect networks. Each port on a router connects to a different network and routes packets between the networks. Routers have the ability to break up broadcast domains and collision domains.
Routers are also used to interconnect networks that use different technologies. They can have both LAN and WAN interfaces.
The router's LAN interfaces allow routers to connect to the LAN media. This is usually UTP cabling, but modules can be added for using fiber-optics. Depending on the series or model of router, there can be multiple interface types for connection of LAN and WAN cabling.
10.1.1 - Choosing the Appropriate LAN Device
The diagram depicts internetwork connections using a router. A topology is shown with a router interconnecting two LAN's, one with a hub and one with a switch. Another topology shows a router interconnecting a LAN with a switch and a WAN represented by a cloud.
The diagram depicts internetwork connections using a router. A topology is shown with a router interconnecting two LAN's, one with a hub and one with a switch. Another topology shows a router interconnecting a LAN with a switch and a WAN represented by a cloud.
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Intranetwork Devices
To create a LAN, we need to select the appropriate devices to connect the end device to the network. The two most common devices used are hubs and switches.
Hub
A hub receives a signal, regenerates it, and sends the signal over all ports. The use of hubs creates a logical bus. This means that the LAN uses multiaccess media. The ports use a shared bandwidth approach and often have reduced performance in the LAN due to collisions and recovery. Although multiple hubs can be interconnected, they remain a single collision domain.
Hubs are less expensive than switches. A hub is typically chosen as an intermediary device within a very small LAN, in a LAN that requires low throughput requirements, or when finances are limited.
Switch
A switch receives a frame and regenerates each bit of the frame on to the appropriate destination port. This device is used to segment a network into multiple collision domains. Unlike the hub, a switch reduces the collisions on a LAN. Each port on the switch creates a separate collision domain. This creates a point-to-point logical topology to the device on each port. Additionally, a switch provides dedicated bandwidth on each port, which can increase LAN performance. A LAN switch can also be used to interconnect network segments of different speeds.
In general, switches are chosen for connecting devices to a LAN. Although a switch is more expensive than a hub, its enhanced performance and reliability make it cost effective.
There is a range of switches available with a variety of features that enable the interconnection of multiple computers in a typical enterprise LAN setting.
10.1.1 - Choosing the Appropriate LAN Device
The diagram depicts intranetwork connections. A topology is shown consisting of a small LAN using a hub with four PC's attached. Another LAN is shown using a switch with seven PC's and a server attached.
The diagram depicts intranetwork connections. A topology is shown consisting of a small LAN using a hub with four PC's attached. Another LAN is shown using a switch with seven PC's and a server attached.
10.1.2 Device Selection Factors
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To meet user requirements, a LAN needs to be planned and designed. Planning ensures that all requirements, cost factors and deployment options are given due consideration.
When selecting a device for a particular LAN, there are a number of factors that need to be considered. These factors include, but are not limited to:
- Cost
- Speed and Types of Ports/Interfaces
- Expandability
- Manageability
- Additional Features and Services
10.1.2 - Device Selection Factors
The diagram depicts factors to consider in choosing a device. Photographs representing these factors include:
- Cost
- Ports
- Speed
- Expandability / Modularity
- Manageability
The diagram depicts factors to consider in choosing a device. Photographs representing these factors include:
- Cost
- Ports
- Speed
- Expandability / Modularity
- Manageability
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Factors to Consider in Choosing a Switch
Although there are many factors that must be considered when selecting a switch, the next topic will explore two: cost and interface characteristics.
Cost
The cost of a switch is determined by its capacity and features. The switch capacity includes the number and types of ports available and the switching speed. Other factors that impact the cost are its network management capabilities, embedded security technologies, and optional advanced switching technologies.
Using a simple "cost per port" calculation, it may appear initially that the best option is to deploy one large switch at a central location. However, this apparent cost savings may be offset by the expense from the longer cable lengths required to connect every device on the LAN to one switch. This option should be compared with the cost of deploying a number of smaller switches connected by a few long cables to a central switch.
Another cost consideration is how much to invest in redundancy. The operation of the entire physical network is affected if there are problems with a single central switch.
Redundancy can be provided in a number of ways. We can provide a secondary central switch to operate concurrently with the primary central switch. We can also provide additional cabling to provide multiple interconnections between the switches. The goal of redundant systems is to allow the physical network to continue its operation even if one device fails.
10.1.2 - Device Selection Factors
The diagram depicts factors in determining LAN switch selection. Three topologies are shown.
Topology 1. One large, central switch with many PC's connected.
Topology 2. Multiple switches, connected to a central switch in an extended star topology. PC's are connected to four outer switches, which are connected to the central switch.
Topology 3. Two central switches are connected depicting redundancy. PC's are connected to four outer switches, which are connected to two central switches with redundant links. An arrow points to two of the outer switches with text explaining that a failure on any of these switches only affects the directly connected PC's. An arrow points to the two central switches with text explaining that the failure of either of these central switches does not stop network operation.
The diagram depicts factors in determining LAN switch selection. Three topologies are shown.
Topology 1. One large, central switch with many PC's connected.
Topology 2. Multiple switches, connected to a central switch in an extended star topology. PC's are connected to four outer switches, which are connected to the central switch.
Topology 3. Two central switches are connected depicting redundancy. PC's are connected to four outer switches, which are connected to two central switches with redundant links. An arrow points to two of the outer switches with text explaining that a failure on any of these switches only affects the directly connected PC's. An arrow points to the two central switches with text explaining that the failure of either of these central switches does not stop network operation.
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Speed and Types of Ports/Interfaces
The need for speed is ever-present in a LAN environment. Newer computers with built-in 10/100/1000 Mbps NICs are available. Choosing Layer 2 devices that can accommodate increased speeds allows the network to evolve without replacing the central devices.
When selecting a switch, choosing the number and type of ports is a critical decision. Ask yourself these questions: Would you purchase a switch with:
- Just enough ports for today's needs?
- A mixture of UTP speeds?
- Both UTP and fiber ports?
10.1.2 - Device Selection Factors
The diagram depicts factors determining LAN switch selection, which include port speeds, types, and expandability.
A 1000 megabits per second (1 Gigabit per second) switch is shown with two 10 megabits per second PC's and two 100 megabits per second PC's connected. The same switch demonstrates expandability and is shown with two 100 megabits per second PC's and two 1000 megabits per second servers connected.
Three switches are shown with different port configurations as follows:
1. All ports are one speed and type (UTP ports at a speed of 10 megabits per second).
2. All ports are one type and have multiple speeds (UTP ports at speeds of 10 and 100 megabits per second).
3. Two type of ports, multiple speeds (UTP ports with speeds of multiple 10 and 100 megabits per second, and one fiber port with a speed of one Gigabit per second).
Some switches can be expanded to meet new requirements with additional modules.
The diagram depicts factors determining LAN switch selection, which include port speeds, types, and expandability.
A 1000 megabits per second (1 Gigabit per second) switch is shown with two 10 megabits per second PC's and two 100 megabits per second PC's connected. The same switch demonstrates expandability and is shown with two 100 megabits per second PC's and two 1000 megabits per second servers connected.
Three switches are shown with different port configurations as follows:
1. All ports are one speed and type (UTP ports at a speed of 10 megabits per second).
2. All ports are one type and have multiple speeds (UTP ports at speeds of 10 and 100 megabits per second).
3. Two type of ports, multiple speeds (UTP ports with speeds of multiple 10 and 100 megabits per second, and one fiber port with a speed of one Gigabit per second).
Some switches can be expanded to meet new requirements with additional modules.
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Factors to Consider in Choosing a Router
When selecting a router, we need to match the characteristics of the router to its purpose. Similar to the switch, cost and interface types and speeds must be considered as well. Additional factors for choosing a router include:
- Expandability
- Media
- Operating System Features
Networking devices, such as routers and switches, come in both fixed and modular physical configurations. Fixed configurations have a specific number and type of ports or interfaces. Modular devices have expansion slots that provide the flexibility to add new modules as requirements evolve. Most modular devices come with a basic number of fixed ports as well as expansion slots. Since routers can be used for connecting different numbers and types of networks, care must be taken to select the appropriate modules and interfaces for the specific media.
Operating System Features
Depending on the version of the operating system, the router can support certain features and services such as:
- Security
- Quality of Service (QoS)
- Voice over IP (VoIP)
- Routing multiple Layer 3 protocols
- Special services such as Network Address Translation (NAT) and Dynamic Host Configuration Protocol (DHCP)
10.1.2 - Device Selection Factors
The diagram depicts a photograph of various Cisco series routers. Each series of Cisco router provides expandability, support for multiple media types, and various system features and services.
The diagram depicts a photograph of various Cisco series routers. Each series of Cisco router provides expandability, support for multiple media types, and various system features and services.
10.2 Device Interconnections
10.2.1 LAN and WAN - Getting ConnectedPage 1:
When planning the installation of LAN cabling, there are four physical areas to consider:
- Work area
- Telecommunications room, also known as the distribution facility
- Backbone cabling, also known as vertical cabling
- Distribution cabling, also known as horizontal cabling
For UTP installations, the ANSI/TIA/EIA-568-B standard specifies that the total combined length of cable spanning three of the areas listed above, excluding the backbone cable, is limited to a maximum distance of 100 meters per channel. This standard also specifies maximum backbone distances, ranging from 90m for UTP to 3000m for single mode fiber cable, based on application and media type.
Work Areas
The work areas are the locations devoted to the end devices used by individual users. Each work area has a minimum of two jacks that can be used to connect an individual device to the network. We use patch cables to connect individual devices to these wall jacks. Allowed patch cable length depends on the horizontal cable and telecommunication room cable lengths. Recall that the maximum length for these three area can not exceed 100m. The EIA/TIA standard specifies that the UTP patch cords used to connect devices to the wall jacks must meet or exceed the performance requirements in ANSI/TIA/EIA-568-B.
Straight-through cable is the most common patch cable used in the work area. This type of cable is used to connect end devices, such as computers, to a network. When a hub or switch is placed in the work area, a crossover cable is typically used to connect the device to the wall jack.
Telecommunications Room
The telecommunications room is where connections to intermediary devices take place. These rooms contain the intermediary devices - hubs, switches, routers, and data service units (DSUs) - that tie the network together. These devices provide the transitions between the backbone cabling and the horizontal cabling.
Inside the telecommunications room, patch cords make connections between the patch panels, where the horizontal cables terminate, and the intermediary devices. Patch cables also interconnect these intermediary devices.
The Electronics Industry Alliance/Telecommunications Industry Association (EIA/TIA) standards specify two different types of UTP patch cables. One type is a patch cord, with a length of up to 5 meters, which is used to interconnect equipment and patch panels in the telecommunications room. Another type of patch cable can be up to 5 meters in length and is used to connect devices to a termination point on the wall.
These rooms often serve dual purposes. In many organizations, the telecommunications room also contains the servers used by the network.
Horizontal Cabling
Horizontal cabling refers to the cables connecting the telecommunication rooms with the work areas. The maximum length for a cable from a termination point in the telecommunication room to the termination at the work area outlet must not exceed 90 meters. This 90 meter maximum horizontal cabling distance is referred to as the permanent link because it is installed in the building structure. The horizontal media runs from a patch panel in the telecommunications room to a wall jack in each work area. Connections to the devices are made with patch cables.
Backbone Cabling
Backbone cabling refers to the cabling used to connect the telecommunication rooms to the equipment rooms, where the servers are often located. Backbone cabling also interconnects multiple telecommunications rooms throughout the facility. These cables are sometimes routed outside the building to the WAN connection or ISP.
Backbones, or vertical cabling, are used for aggregated traffic, such as traffic to and from the Internet and access to corporate resources at a remote location. A large portion of the traffic from the various work areas will use the backbone cabling to access resources outside the area or facility. Therefore, backbones typically require high bandwidth media such as fiber-optic cabling.
10.2.1 - LAN and WAN - Getting Connected
The diagram depicts LAN cabling areas as follows:
Work Area: A PC connects to an RJ-45 wall jack using a patch cable.
Horizontal Cabling: Cabling is run from the RJ-45 jack to a patch panel in the telecommunications room.
Telecommunications Room: UTP cabling connects the patch panel to a switch.
Backbone Cabling: UTP or fiber cabling is run from the switch in the telecommunications room to other telecommunication rooms.
The diagram depicts LAN cabling areas as follows:
Work Area: A PC connects to an RJ-45 wall jack using a patch cable.
Horizontal Cabling: Cabling is run from the RJ-45 jack to a patch panel in the telecommunications room.
Telecommunications Room: UTP cabling connects the patch panel to a switch.
Backbone Cabling: UTP or fiber cabling is run from the switch in the telecommunications room to other telecommunication rooms.
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Types of Media
Choosing the cables necessary to make a successful LAN or WAN connection requires consideration of the different media types. As you recall, there are many different Physical layer implementations that support multiple media types:
- UTP (Category 5, 5e, 6, and 7)
- Fiber-optics
- Wireless
- Cable length - Does the cable need to span across a room or from building to building?
- Cost - Does the budget allow for using a more expensive media type?
- Bandwidth - Does the technology used with the media provide adequate bandwidth?
- Ease of installation - Does the implementation team have the ability to install the cable or is a vendor required?
- Susceptible to EMI/RFI - Is the local environment going to interfere with the signal?
10.2.1 - LAN and WAN - Getting Connected
The diagram depicts types of device interconnections. Photographs are shown with fiber cable and connectors, UTP cables connected to a patch panel, and wireless devices and NIC's.
The diagram depicts types of device interconnections. Photographs are shown with fiber cable and connectors, UTP cables connected to a patch panel, and wireless devices and NIC's.
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Cable Length
The total length of cable required to connect a device includes all cables from the end devices in the work area to the intermediary device in the telecommunication room (usually a switch). This includes cable from the devices to the wall plug, the cable through the building from wall plug to the cross-connecting point, or patch panel, and cable from patch panel to the switch. If the switch is located in a telecommunication rooms on different floors in a building or in different buildings, the cable between these points must be included in the total length.
Attenuation is reduction of the strength of a signal as it moves down a media. The longer the media, the more attenuation will affect the signal. At some point, the signal will not be detectable. Cabling distance is a significant factor in data signal performance. Signal attenuation and exposure to possible interference increase with cable length.
For example, when using UTP cabling for Ethernet, the horizontal (or fixed) cabling length needs to stay within the recommended maximum distance of 90 meters to avoid attenuation of the signal. Fiber-optic cables may provide a greater cabling distance-up to 500 meters to a few kilometers depending on the technology. However, fiber-optic cable can also suffer from attenuation when these limits are reached.
Cost
The cost associated with LAN cabling can vary from media type to media type, and the staff might not realize the impact on the budget. In a perfect setting, the budget would allow for fiber-optic cabling to every device in the LAN. Although fiber provides greater bandwidth than UTP, the material and installation costs are significantly higher. In practice, this level of performance is not usually required and is not a reasonable expectation in most environments. Network designers must match the performance needs of the users with the cost of the equipment and cabling to achieve the best cost/performance ratio.
Bandwidth
The devices in a network have different bandwidth requirements. When selecting the media for individual connections, carefully consider the bandwidth requirements.
For example, a server generally has a need for more bandwidth than a computer dedicated to a single user. For a server connection, consider media that will provide high bandwidth, and can grow to meet increased bandwidth requirements and newer technologies. A fiber cable may be a logical choice for a server connection.
Currently, the technology used in fiber-optic media offers the greatest bandwidth available among the choices for LAN media. Given the seemingly unlimited bandwidth available in fiber cables, much greater speeds for LANs are expected. Wireless is also supporting huge increases in bandwidth, but it has limitations in distance and power consumption.
10.2.1 - LAN and WAN - Getting Connected
The diagram depicts cable length and cost. Cable lengths need to be determined and matched with the technology used. A horizontal floorplan is shown with PC's and printers in various locations. A vertical floorplan of a multistory building is shown with PC's and printers on various floors.
A tabular listing of Ethernet types includes the type, bandwidth, cable type, and maximum distance.
Ethernet Type: 10Base-T
Bandwidth: 10 Megabits per second
Cable Type: Cat3 /Cat5 UTP
Maximum Distance: 100 meters
Ethernet Type: 100Base-TX
Bandwidth: 100 Megabits per second
Cable Type: Cat5 UTP
Maximum Distance: 100 meters
Ethernet Type: 100Base-TX
Bandwidth: 200 Megabits per second
Cable Type: Cat5 UTP
Maximum Distance: 100 meters
Ethernet Type: 100Base-FX
Bandwidth: 100 Megabits per second
Cable Type: Multi-mode fiber
Maximum Distance: 400 meters
Ethernet Type: 100Base-FX
Bandwidth: 200 Megabits per second
Cable Type: Multi-mode fiber
Maximum Distance: 2 kilometers
Type of Ethernet: 1000Base-T
Bandwidth: 1 Gigabit per second
Cable Type: Cat5e UTP
Maximum Distance: 100 meters
Type of Ethernet: 1000Base-TX
Bandwidth: 1 Gigabit per second
Cable Type: Cat6 UTP
Maximum Distance: 100 meters
Type of Ethernet: 1000Base-SX
Bandwidth: 1 Gigabit per second
Cable Type: Multimode fiber
Maximum Distance: 550 meters
Type of Ethernet: 1000Base-LX
Bandwidth: 1 Gigabit per second
Cable Type: Single-Mode fiber
Maximum Distance: 2 kilometers
Type of Ethernet: 10GBase-T
Bandwidth: 10 Gigabits per second
Cable Type: Cat6a /Cat7 UTP
Maximum Distance: 100 meters
Type of Ethernet: 10GBase-LX4
Bandwidth: 10 Gigabits per second
Cable Type: Multimode fiber
Maximum Distance: 300 meters
Type of Ethernet: 10GBase-LX4
Bandwidth: 10 Gigabits per second
Cable Type: Single-mode fiber
Maximum Distance: 10 kilometers
The diagram depicts cable length and cost. Cable lengths need to be determined and matched with the technology used. A horizontal floorplan is shown with PC's and printers in various locations. A vertical floorplan of a multistory building is shown with PC's and printers on various floors.
A tabular listing of Ethernet types includes the type, bandwidth, cable type, and maximum distance.
Ethernet Type: 10Base-T
Bandwidth: 10 Megabits per second
Cable Type: Cat3 /Cat5 UTP
Maximum Distance: 100 meters
Ethernet Type: 100Base-TX
Bandwidth: 100 Megabits per second
Cable Type: Cat5 UTP
Maximum Distance: 100 meters
Ethernet Type: 100Base-TX
Bandwidth: 200 Megabits per second
Cable Type: Cat5 UTP
Maximum Distance: 100 meters
Ethernet Type: 100Base-FX
Bandwidth: 100 Megabits per second
Cable Type: Multi-mode fiber
Maximum Distance: 400 meters
Ethernet Type: 100Base-FX
Bandwidth: 200 Megabits per second
Cable Type: Multi-mode fiber
Maximum Distance: 2 kilometers
Type of Ethernet: 1000Base-T
Bandwidth: 1 Gigabit per second
Cable Type: Cat5e UTP
Maximum Distance: 100 meters
Type of Ethernet: 1000Base-TX
Bandwidth: 1 Gigabit per second
Cable Type: Cat6 UTP
Maximum Distance: 100 meters
Type of Ethernet: 1000Base-SX
Bandwidth: 1 Gigabit per second
Cable Type: Multimode fiber
Maximum Distance: 550 meters
Type of Ethernet: 1000Base-LX
Bandwidth: 1 Gigabit per second
Cable Type: Single-Mode fiber
Maximum Distance: 2 kilometers
Type of Ethernet: 10GBase-T
Bandwidth: 10 Gigabits per second
Cable Type: Cat6a /Cat7 UTP
Maximum Distance: 100 meters
Type of Ethernet: 10GBase-LX4
Bandwidth: 10 Gigabits per second
Cable Type: Multimode fiber
Maximum Distance: 300 meters
Type of Ethernet: 10GBase-LX4
Bandwidth: 10 Gigabits per second
Cable Type: Single-mode fiber
Maximum Distance: 10 kilometers
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Ease of Installation
The ease of cable installation varies according to cable types and building architecture. Access to floor or roof spaces, and the physical size and properties of the cable influence how easily a cable can be installed in various buildings. Cables in buildings are typically installed in raceways.
As shown in the figure, a raceway is an enclosure or tube that encloses and protects the cable. A raceway also keeps cabling neat and easy to thread.
UTP cable is relatively lightweight and flexible and has a small diameter, which allows it to fit into small spaces. The connectors, RJ-45 plugs, are relatively easy to install and are a standard for all Ethernet devices.
Many fiber-optic cables contain a thin glass fiber. This creates issues for the bend radius of the cable. Crimps or sharp bends can break the fiber. The termination of the cable connectors (ST, SC, MT-RJ) are significantly more difficult to install and require special equipment.
Wireless networks require cabling, at some point, to connect devices, such as access points, to the wired LAN. Because there are fewer cables required in a wireless network, wireless is often easier to install than UTP or fiber cable. However, a wireless LAN requires more careful planning and testing. Also, there are many external factors, such as other radio frequency devices and building construction, that can effect its operation.
Electromagnetic Interference/Radio Frequency Interference
Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI) must be taken into consideration when choosing a media type for a LAN. EMI/RFI in an industrial environment can significantly impact data communications if the wrong cable is used.
Interference can be produced by electrical machines, lightning, and other communications devices, including computers and radio equipment.
As an example, consider an installation where devices in two separate buildings are interconnected. The media used to interconnect these buildings will be exposed to the possibility of lightning strikes. Additionally, there maybe a great distance between these two buildings. For this installation, fiber cable is the best choice.
Wireless is the medium most susceptible to RFI. Before using wireless technology, potential sources of interference must be identified and, if possible, minimized.
10.2.1 - LAN and WAN - Getting Connected
The diagram depicts ease of installation factors. UTP and fiber have different installation requirements. Photographs are shown of UTP cable raceway and fiber cable raceway.
The diagram depicts ease of installation factors. UTP and fiber have different installation requirements. Photographs are shown of UTP cable raceway and fiber cable raceway.
10.2.2 Making LAN Connections
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UTP cabling connections are specified by the Electronics Industry Alliance/Telecommunications Industry Association (EIA/TIA).
The RJ-45 connector is the male component crimped on the end of the cable. When viewed from the front, the pins are numbered from 8 to 1. When viewed from above with the opening gate facing you, the pins are numbered 1 through 8, from left to right. This orientation is important to remember when identifying a cable.
10.2.2 - Making LAN Connections
The diagram depicts two standards for terminating Ethernet straight-through cable, RJ-45 T568A and T568B.
T568A:
Pair 1 is made up of pins 4 and 5, wire colors blue and blue/white.
Pair 2 is made up of pins 3 and 6, wire colors orange/white and orange.
Pair 3 is made up of pins 1 and 2, wire colors green/white and green.
Pair 4 is made up of pins 7 and 8, wire colors brown/white and brown.
T568B:
Pair 1 is made up of pins 4 and 5, wire colors blue and blue/white.
Pair 2 is made up of pins 1 and 2, wire colors orange/white and orange.
Pair 3 is made up of pins 3 and 6, wire colors green/white and green.
Pair 4 is made up of pins 7 and 8, wire colors brown/white and brown.
A photograph of the top view of the T568A and T568B connectors is shown with the wiring color sequence.
T568A wiring sequence:
Pin1. green/white
Pin 2. green
Pin 3. orange/white
Pin 4. blue
Pin 5. blue/white
Pin 6. orange
Pin 7. brown/white
Pin 8. brown
T568B wiring sequence:
Pin1. orange/white
Pin 2. orange
Pin 3. green/white
Pin 4. blue
Pin 5. blue/white
Pin 6. green
Pin 7. brown/white
Pin 8. brown
The diagram depicts two standards for terminating Ethernet straight-through cable, RJ-45 T568A and T568B.
T568A:
Pair 1 is made up of pins 4 and 5, wire colors blue and blue/white.
Pair 2 is made up of pins 3 and 6, wire colors orange/white and orange.
Pair 3 is made up of pins 1 and 2, wire colors green/white and green.
Pair 4 is made up of pins 7 and 8, wire colors brown/white and brown.
T568B:
Pair 1 is made up of pins 4 and 5, wire colors blue and blue/white.
Pair 2 is made up of pins 1 and 2, wire colors orange/white and orange.
Pair 3 is made up of pins 3 and 6, wire colors green/white and green.
Pair 4 is made up of pins 7 and 8, wire colors brown/white and brown.
A photograph of the top view of the T568A and T568B connectors is shown with the wiring color sequence.
T568A wiring sequence:
Pin1. green/white
Pin 2. green
Pin 3. orange/white
Pin 4. blue
Pin 5. blue/white
Pin 6. orange
Pin 7. brown/white
Pin 8. brown
T568B wiring sequence:
Pin1. orange/white
Pin 2. orange
Pin 3. green/white
Pin 4. blue
Pin 5. blue/white
Pin 6. green
Pin 7. brown/white
Pin 8. brown
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Types of Interfaces
In an Ethernet LAN, devices use one of two types of UTP interfaces - MDI or MDIX.
The MDI (media-dependent interface) uses the normal Ethernet pinout. Pins 1 and 2 are used for transmitting and pins 3 and 6 are used for receiving. Devices such as computers, servers, or routers will have MDI connections.
The devices that provide LAN connectivity - usually hubs or switches - typically use MDIX (media-dependent interface, crossover) connections. The MDIX connection swaps the transmit pairs internally. This swapping allows the end devices to be connected to the hub or switch using a straight-through cable.
Typically, when connecting different types of devices, use a straight-through cable. And when connecting the same type of device, use a crossover cable.
Straight-through UTP Cables
A straight-through cable has connectors on each end that are terminated the same in accordance with either the T568A or T568B standards.
Identifying the cable standard used allows you to determine if you have the right cable for the job. More importantly, it is a common practice to use the same color codes throughout the LAN for consistency in documentation.
Use straight-through cables for the following connections:
- Switch to a router Ethernet port
- Computer to switch
- Computer to hub
10.2.2 - Making LAN Connections
The diagram depicts an Ethernet straight-through cable using both RJ-45 T568A and T568B terminations. Straight-through cables have the same termination at each end, either T568A or T568B. Refer to the previous diagram for wire colors and pin locations.
The diagram depicts an Ethernet straight-through cable using both RJ-45 T568A and T568B terminations. Straight-through cables have the same termination at each end, either T568A or T568B. Refer to the previous diagram for wire colors and pin locations.
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Crossover UTP Cables
For two devices to communicate through a cable that is directly connected between the two, the transmit terminal of one device needs to be connected to the receive terminal of the other device.
The cable must be terminated so the transmit pin, Tx, taking the signal from device A at one end, is wired to the receive pin, Rx, on device B. Similarly, device B's Tx pin must be connected to device A's Rx pin. If the Tx pin on a device is numbered 1, and the Rx pin is numbered 2, the cable connects pin 1 at one end with pin 2 at the other end. These "crossed over" pin connections give this type of cable its name, crossover.
To achieve this type of connection with a UTP cable, one end must be terminated as EIA/TIA T568A pinout, and the other end terminated with T568B pinout.
To summarize, crossover cables directly connect the following devices on a LAN:
- Switch to switch
- Switch to hub
- Hub to hub
- Router to router Ethernet port connection
- Computer to computer
- Computer to a router Ethernet port
10.2.2 - Making LAN Connections
The diagram depicts an Ethernet crossover cable. Crossover cables have a T568A termination at one end and a T568B termination at the other end. Transmit pins at each end connect to the receive pins at the other end. Pin-to-pin connections are shown for 10/100 megabits per second Ethernet and for
one Gigabit per second Ethernet. Only pins 1, 2, 3, and 6 are used with 10/100 Megabits per second Ethernet. All eight pins are used with Gigabit Ethernet.
The diagram depicts an Ethernet crossover cable. Crossover cables have a T568A termination at one end and a T568B termination at the other end. Transmit pins at each end connect to the receive pins at the other end. Pin-to-pin connections are shown for 10/100 megabits per second Ethernet and for
one Gigabit per second Ethernet. Only pins 1, 2, 3, and 6 are used with 10/100 Megabits per second Ethernet. All eight pins are used with Gigabit Ethernet.
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On the figure, identify the cable type used based on the devices being connected.
As a reminder, the common uses are listed again:
Use straight-through cables for connecting:
- Switch to router
- Computer to switch
- Computer to hub
- Switch to switch
- Switch to hub
- Hub to hub
- Router to router
- Computer to computer
- Computer to router
Many devices allow the UTP Ethernet port to be set to MDI or MDIX. This can be done in one of three ways, depending on the features of the device:
1. On some devices, ports may have a mechanism that electrically swaps the transmit and receive pairs. The port can be changed from MDI to MDIX by engaging the mechanism.
2. As part of the configuration, some devices allow for selecting whether a port functions as MDI or as MDIX.
3. Many newer devices have an automatic crossover feature. This feature allows the device to detect the required cable type and configures the interfaces accordingly. On some devices, this auto-detection is performed by default. Other devices require an interface configuration command for enabling MDIX auto-detection.
10.2.2 - Making LAN Connections
The diagram depicts various cables used to make LAN connections and identifies the correct Ethernet bandwidth, UTP cable type, and the likely category to connect different intermediate and end devices in a LAN.
Network Topology:
- PC1 and PC2 are connected to Hub1 at 10 Megabits per second using Category 5 straight-through cables.
- Hub1 is connected to Switch1 at 10 Megabits per second using a Category 5 crossover cable.
- Switch1 is connected to Router1 at 100 Megabits per second using a Category 5 straight-through cable.
- Server1 is connected to Switch2, Server2 is connected to Switch3, and Server3 is connected to Switch4. All servers are connected to a switch at 100 Megabits per second using Category 5 straight-through cables.
- Switch2, Switch3, and Switch4 are connected to Router1 at 100 Megabits per second using Category 5 straight-through cables.
- Router1 is connected to Router2 at 100 Megabits per second using a Category 5 crossover cable.
The diagram depicts various cables used to make LAN connections and identifies the correct Ethernet bandwidth, UTP cable type, and the likely category to connect different intermediate and end devices in a LAN.
Network Topology:
- PC1 and PC2 are connected to Hub1 at 10 Megabits per second using Category 5 straight-through cables.
- Hub1 is connected to Switch1 at 10 Megabits per second using a Category 5 crossover cable.
- Switch1 is connected to Router1 at 100 Megabits per second using a Category 5 straight-through cable.
- Server1 is connected to Switch2, Server2 is connected to Switch3, and Server3 is connected to Switch4. All servers are connected to a switch at 100 Megabits per second using Category 5 straight-through cables.
- Switch2, Switch3, and Switch4 are connected to Router1 at 100 Megabits per second using Category 5 straight-through cables.
- Router1 is connected to Router2 at 100 Megabits per second using a Category 5 crossover cable.
10.2.3 Making WAN Connections
Page 1:
By definition, WAN links can span extremely long distances. These distances can range across the globe as they provide the communication links that we use to manage e-mail accounts, view web pages, or conduct a teleconference session with a client.
Wide area connections between networks take a number of forms, including:
- Telephone line RJ11 connectors for dialup or Digital Subscriber Line (DSL) connections
- 60 pin Serial connections
The first cable type has a male DB-60 connector on the Cisco end and a male Winchester connector on the network end. The second type is a more compact version of this cable and has a Smart Serial connector on the Cisco device end. It is necessary to be able to identify the two different types in order to connect successfully to the router.
10.2.3 - Making WAN Connections
The diagram depicts types of WAN connections.
Cisco HDLC, PPP, and Frame Relay serial WAN links use the following connections:
- EIA /T IA-232
- EIA /T IA-449
- X dot 21 /V dot 24
- V dot 35
- High Speed Serial Interface (HSSI)
DSL modem uses the following connection:
RJ-11 (works over phone line)
Cable modem uses the following connection:
F type (works over cable TV line)
A photograph of a WAN serial cable is shown with a male smart serial connector at the router end and a male Winchester block type (v dot 35) at the network end (CSU/DSU).
A router (D T E) end-user device is shown connecting to a CSU/DSU (DCE). Photographs of a router WIC2T modular interface card with two smart serial interfaces, along with an older style router integrated DB-60 connector are shown.
Diagrams of various cables connecting a router to the CSU/DSU, which connects to the service provider, are shown. The cables include the following:
- EIA /T IA-232
- EIA /T IA-449
- V dot 35
- X dot 21
- EIA-530
A DSL type of WAN connection is shown connecting a Cisco 827-4v router to a telephone line receptacle in a wall jack.
The diagram depicts types of WAN connections.
Cisco HDLC, PPP, and Frame Relay serial WAN links use the following connections:
- EIA /T IA-232
- EIA /T IA-449
- X dot 21 /V dot 24
- V dot 35
- High Speed Serial Interface (HSSI)
DSL modem uses the following connection:
RJ-11 (works over phone line)
Cable modem uses the following connection:
F type (works over cable TV line)
A photograph of a WAN serial cable is shown with a male smart serial connector at the router end and a male Winchester block type (v dot 35) at the network end (CSU/DSU).
A router (D T E) end-user device is shown connecting to a CSU/DSU (DCE). Photographs of a router WIC2T modular interface card with two smart serial interfaces, along with an older style router integrated DB-60 connector are shown.
Diagrams of various cables connecting a router to the CSU/DSU, which connects to the service provider, are shown. The cables include the following:
- EIA /T IA-232
- EIA /T IA-449
- V dot 35
- X dot 21
- EIA-530
A DSL type of WAN connection is shown connecting a Cisco 827-4v router to a telephone line receptacle in a wall jack.
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Data Communications Equipment and Data Terminal Equipment
The following terms describe the types of devices that maintain the link between a sending and a receiving device:
- Data Communications Equipment (DCE) - A device that supplies the clocking services to another device. Typically, this device is at the WAN access provider end of the link.
- Data Terminal Equipment (DTE) - A device that receives clocking services from another device and adjusts accordingly. Typically, this device is at the WAN customer or user end of the link.
Be aware that there will be occasions, especially in our labs, when the local router is required to provide the clock rate and will therefore use a data communications equipment (DCE) cable.
DCEs and DTEs are used in WAN connections. The communication via a WAN connection is maintained by providing a clock rate that is acceptable to both the sending and the receiving device. In most cases, the telco or ISP provides the clocking service that synchronizes the transmitted signal.
For example, if a device connected via a WAN link is sending its signal at 1.544 Mbps, each receiving device must use a clock, sending out a sample signal every 1/1,544,000th of a second. The timing in this case is extremely short. The devices must be able to synchronize to the signal that is sent and received very quickly.
By assigning a clock rate to the router, the timing is set. This allows a router to adjust the speed of its communication operations, thereby synchronizing with the devices connected to it.
10.2.3 - Making WAN Connections
The diagram depicts serial DCE and D T E WAN connections.
Network Topology:
Router R1 (D T E) connects to a CSU/DSU (DCE) on one side of a network cloud. Router R2 (D T E) connects to another CSU/DSU (DCE) on the opposite side of the network cloud.
Data Terminal Equipment (D T E):
- End of the user's device on the WAN link.
Data Communications Equipment (DCE):
- End of the WAN provider's side of the communication facility.
- Responsible for providing the clocking signal.
The diagram depicts serial DCE and D T E WAN connections.
Network Topology:
Router R1 (D T E) connects to a CSU/DSU (DCE) on one side of a network cloud. Router R2 (D T E) connects to another CSU/DSU (DCE) on the opposite side of the network cloud.
Data Terminal Equipment (D T E):
- End of the user's device on the WAN link.
Data Communications Equipment (DCE):
- End of the WAN provider's side of the communication facility.
- Responsible for providing the clocking signal.
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In the Lab
When making WAN connections between two routers in a lab environment, connect two routers with a serial cable to simulate a point-to-point WAN link. In this case, decide which router is going to be the one in control of clocking. Routers are DTE devices by default, but they can be configured to act as DCE devices.
The V35 compliant cables are available in DTE and DCE versions. To create a point-to-point serial connection between two routers, join together a DTE and DCE cable. Each cable comes with a connector that mates with its complementary type. These connectors are configured so that you cannot join two DCE or two DTE cables together by mistake.
10.2.3 - Making WAN Connections
The diagram depicts serial WAN connections in the lab.
Network Topology:
A small LAN is connected to router R1 on interface FA0/0. Another small LAN is connected to router R2 on interface FA 0/0. Interface S0/0 (DCE) on R1 is connected to R2 interface S0/1 (D T E) using a V dot 35 DCE female cable on R1 and a V dot 35 DCE male cable on R2. This effectively connects the two routers with a WAN serial link and bypasses the need for CSU/DSU's in a lab environment. The connection between the two cables crosses the transmit (Tx) and receive (Rx) pins.
The diagram depicts serial WAN connections in the lab.
Network Topology:
A small LAN is connected to router R1 on interface FA0/0. Another small LAN is connected to router R2 on interface FA 0/0. Interface S0/0 (DCE) on R1 is connected to R2 interface S0/1 (D T E) using a V dot 35 DCE female cable on R1 and a V dot 35 DCE male cable on R2. This effectively connects the two routers with a WAN serial link and bypasses the need for CSU/DSU's in a lab environment. The connection between the two cables crosses the transmit (Tx) and receive (Rx) pins.
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In this activity, you will practice skills important in networking lab work by making interconnections in Packet Tracer.
Click the Packet Tracer icon for more details.
10.2.3 - Making WAN Connections
Link to Packet Tracer Exploration: Connecting Devices with Different Media Types
In this activity, you will practice skills important in networking lab work by making interconnections in Packet Tracer.
Link to Packet Tracer Exploration: Connecting Devices with Different Media Types
In this activity, you will practice skills important in networking lab work by making interconnections in Packet Tracer.
10.3 Developing an Addressing Scheme
10.3.1 How Many Hosts in the Network?Page 1:
To develop an addressing scheme for a network, start with determining the total number of hosts. Consider every device that will require an IP address, now and in the future.
The end devices requiring an IP address include:
- User computers
- Administrator computers
- Servers
- Other end devices such as printers, IP phones, and IP cameras
- Router LAN interfaces
- Router WAN (serial) interfaces
- Switches
- Wireless Access Points
Once the total number of hosts - current and future - has been determined, consider the range of addresses available and where they fit within the given network address.
Next, determine if all hosts will be part of the same network, or whether the network as a whole will be divided into separate subnets.
Recall that the number of hosts on one network or subnet is calculated using the formula 2 to the nth power minus 2 (2^n - 2), where n is the number of bits available as host bits. Recall also that we subtract two addresses - the network address and the network broadcast address - cannot be assigned to hosts.
10.3.1 - How Many Hosts in the Network?
The diagram depicts determining the number of hosts in the network. These devices should be included in the count:
- Router interfaces - Count the number of interfaces, and not the number of routers.
- Printers
- IP Phones - Count other specialty IP devices.
- Switch Management Addresses
- Administration Users
- General Users
- Servers
The diagram depicts determining the number of hosts in the network. These devices should be included in the count:
- Router interfaces - Count the number of interfaces, and not the number of routers.
- Printers
- IP Phones - Count other specialty IP devices.
- Switch Management Addresses
- Administration Users
- General Users
- Servers
10.3.2 How Many Networks?
Page 1:
There are many reasons to divide a network into subnets:
- Manage Broadcast Traffic - Broadcasts can be controlled because one large broadcast domain is divided into a number of smaller domains. Not every host in the system receives every broadcast.
- Different Network Requirements - If different groups of users require specific network or computing facilities, it is easier to manage these requirements if those users who share requirements are all together on one subnet.
- Security - Different levels of network security can be implemented based on network addresses. This enables the management of access to different network and data services.
Each subnet, as a physical network segment, requires a router interface as the gateway for that subnet.
In addition, each connection between routers is a separate subnet.
Click Play in the figure to see each of the five separate subnets in a sample network.
The number of subnets on one network is also calculated using the formula 2^n, where n is the number of bits "borrowed" from the given IP network address available to create subnets.
Subnet Masks
Having determined the required number of hosts and subnets, the next step is to apply one subnet mask for the entire network and then calculate the following values:
- A unique subnet and subnet mask for each physical segment
- A range of usable host addresses for each subnet
10.3.2 - How Many Networks?
The animation depicts the counting of subnets in a network.
Network Topology:
LAN A with two PC's and a switch is connected to router R1's Ethernet interface.
LAN B with two PC's and a switch is connected to router R2's Ethernet interface.
LAN C with two PC's and a switch is connected to router R3's Ethernet interface.
Router R1 is connected to router R2 via a WAN link. Router R3 is connected to Router R2 via a WAN link.
As the animation progresses, various areas of the network are highlighted, indicating that they are distinct subnets that must be accounted for.
Subnet 1. LAN A PC's and router R1's Ethernet interface.
Subnet 2. Router R1 to router R2 WAN link.
Subnet 3. LAN B PC's and router R2's Ethernet interface.
Subnet 4. Router R3 to router R2 WAN link.
Subnet 5. LAN C PC's and router R3's Ethernet interface.
The animation depicts the counting of subnets in a network.
Network Topology:
LAN A with two PC's and a switch is connected to router R1's Ethernet interface.
LAN B with two PC's and a switch is connected to router R2's Ethernet interface.
LAN C with two PC's and a switch is connected to router R3's Ethernet interface.
Router R1 is connected to router R2 via a WAN link. Router R3 is connected to Router R2 via a WAN link.
As the animation progresses, various areas of the network are highlighted, indicating that they are distinct subnets that must be accounted for.
Subnet 1. LAN A PC's and router R1's Ethernet interface.
Subnet 2. Router R1 to router R2 WAN link.
Subnet 3. LAN B PC's and router R2's Ethernet interface.
Subnet 4. Router R3 to router R2 WAN link.
Subnet 5. LAN C PC's and router R3's Ethernet interface.
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In this lab, you will determine the number of networks in a given topology and design an appropriate addressing scheme . After assigning subnets to the networks, you will examine the usage of the available address space.
Click the lab icon for more details.
10.3.2 - How Many Networks?
Link to Hands-on Lab: How Many Networks
In this lab, you will determine the number of networks in a given topology and design an appropriate addressing scheme. After assigning subnets to the networks, you will examine the usage of the available address space.
Link to Hands-on Lab: How Many Networks
In this lab, you will determine the number of networks in a given topology and design an appropriate addressing scheme. After assigning subnets to the networks, you will examine the usage of the available address space.
10.3.3 Designing the Address Standard for our Internetwork
Page 1:
To assist troubleshooting and expedite adding new hosts to the network, use addresses that fit a common pattern across all subnets. Each of these different device types should be allocated to a logical block of addresses within the address range of the network.
Some of the different categories for hosts are:
- General users
- Special users
- Network resources
- Router LAN interfaces
- Router WAN links
- Management access
Similarly, when assigning addresses to devices that manage other devices, using a consistent pattern within a subnet makes these addresses easily recognizable. For example, in the figure, addresses with 64 - 127 in the octets always represent the general users. A network administrator monitoring or adding security can do so for all addresses ending in these values.
Roll over the device groupings in the figure for an example of how to allocate addresses based on device categories.
In addition, remember to document your IP addressing scheme on paper. This will be an important aid in troubleshooting and evolving the network.
10.3.3 - Designing the Address Standard for our Internetwork
The diagram depicts designing an internetwork address standard. A topology is shown with three LAN's interconnected by two routers. This represents four networks as follows:
LAN A - 192.168.1.x/24
WAN link - 192.168.2.x/24
LAN B - 192.168.3.x/24
LAN C - 192.168.4.x/24
The various end-user and network devices require host addressing. Some of the different categories for hosts and a suggested addressing standard for use with the fourth octet on each network are as follows:
- General user (end-user PC's): 192.168.x.64 to 192.168.x.127.
- Special users (Network Administrators): 192.168.x.8 to 192.168.x.15.
- Network resources (servers and printers): 192.168.x.224 to 192.168.x.239.
- Router LAN interfaces: 192.168.x.250 to 192.168.x.254.
- Router WAN interfaces: 168.192.x.1 and 168.192.x.2.
- Management access (Network devices): 168.192.x.192 to 168.192.x.207.
The diagram depicts designing an internetwork address standard. A topology is shown with three LAN's interconnected by two routers. This represents four networks as follows:
LAN A - 192.168.1.x/24
WAN link - 192.168.2.x/24
LAN B - 192.168.3.x/24
LAN C - 192.168.4.x/24
The various end-user and network devices require host addressing. Some of the different categories for hosts and a suggested addressing standard for use with the fourth octet on each network are as follows:
- General user (end-user PC's): 192.168.x.64 to 192.168.x.127.
- Special users (Network Administrators): 192.168.x.8 to 192.168.x.15.
- Network resources (servers and printers): 192.168.x.224 to 192.168.x.239.
- Router LAN interfaces: 192.168.x.250 to 192.168.x.254.
- Router WAN interfaces: 168.192.x.1 and 168.192.x.2.
- Management access (Network devices): 168.192.x.192 to 168.192.x.207.
10.4 Calculating the Subnets
10.4.1 Calculating Addresses: Case 1Page 1:
In this section, we will use a sample topology to practice allocating addresses to hosts.
The figure shows the network topology for this example. By starting with a given IP address and prefix (subnet mask) assigned by the network administrator, we can begin creating our network documentation.
The number and grouping of hosts are:
Student LAN
Student Computers: 460
Router (LAN Gateway): 1
Switches (management): 20
Total for student subnetwork: 481
Instructor LAN
Instructor Computers: 64
Router (LAN Gateway): 1
Switches (management): 4
Total for instructor subnetwork: 69
Administrator LAN
Administrator Computers: 20
Server: 1
Router (LAN Gateway): 1
Switch (management): 1
Total for administration subnetwork: 23
WAN
Router - Router WAN: 2
Total for WAN: 2
Allocation Methods
There are two methods available for allocating addresses to an internetwork. We can use Variable Length Subnet Masking (VLSM), where we assign the prefix and host bits to each network based on the number of hosts in that network. Or, we can use a non-VLSM approach, where all subnets use the same prefix length and the same number of host bits.
For our network example, we will demonstrate both approaches.
10.4.1 - Calculating Addresses: Case 1
The diagram depicts a sample network topology. The given IP address and prefix (subnet mask) assigned by the network administrator is 172.16.0.0/21.
Network Topology:
- The Administrator LAN has 20 hosts, a server, and one switch connected to router RTR1's FA0/0 Ethernet interface.
- The Instructor LAN has 64 hosts and four switches connected to router RTR2's FA0/0 Ethernet interface.
- The Student LAN has 460 hosts and 20 switches connected to router RTR2's FA1/0 Ethernet interface.
- Router RTR1 S0/0 is connected to router RTR2 S0/0 via a WAN link.
The diagram depicts a sample network topology. The given IP address and prefix (subnet mask) assigned by the network administrator is 172.16.0.0/21.
Network Topology:
- The Administrator LAN has 20 hosts, a server, and one switch connected to router RTR1's FA0/0 Ethernet interface.
- The Instructor LAN has 64 hosts and four switches connected to router RTR2's FA0/0 Ethernet interface.
- The Student LAN has 460 hosts and 20 switches connected to router RTR2's FA1/0 Ethernet interface.
- Router RTR1 S0/0 is connected to router RTR2 S0/0 via a WAN link.
Page 2:
Calculating and Assigning Addresses-without VLSM
When using the non-VLSM method of assigning addresses, all subnets have the same number of addresses assigned to them. In order to provide each network with an adequate number of addresses, we base the number of addresses for all networks on the addressing requirements for the largest network.
In Case 1, the Student LAN is the largest network, requiring 481 addresses.
We will use this formula to calculate the number of hosts:
Usable hosts = 2^n - 2
We use 9 as the value for n because 9 is the first power of 2 that is over 481.
Borrowing 9 bits for the host portion yields this calculation:
2^9 = 512
512 - 2 = 510 usable host addresses
This meets the current requirement for at least 481 addresses, with a small allowance for growth. This also leaves 23 network bits (32 total bits - 9 host bits).
Because there are four networks in our internetwork, we will need four blocks of 512 addresses each, for a total of 2048 addresses. We will use the address block 172.16.0.0 /23. This provides addresses in the range from 172.16.0.0 to 172.16.7.255.
Let's examine the address calculations for the networks:
Address: 172.16.0.0
In binary:
10101100.00010000.00000000.00000000
Mask: 255.255.254.0
23 bits in binary:
11111111.11111111.11111110.00000000
This mask will provide the four address ranges shown in the figure.
Student LAN
For the Student network block, the values would be:
172.16.0.1 to 172.16.1.254 with a broadcast address of 172.16.1.255.
Instructor LAN
The Instructor network requires a total of 69 addresses. The remaining addresses in this block of 512 addresses will go unused. The values for the Instructor network are:
172.16.2.1 to 172.16.3.254 with a broadcast address of 172.16.3.255.
Administrator LAN
Assigning the 172.16.4.0 /23. block to the Administrator LAN, assigns an address range of:
172.16.4.1 to 172.16.5.254 with a broadcast address of 172.16.5.255.
Only 23 of the 512 addresses will actually be used in the Instructor LAN.
WAN
In the WAN, we have a point-to-point connection between the two routers. This network only requires two IPv4 addresses for the routers on this serial link. As shown in the figure, assigning this address block to the WAN link wastes 508 addresses.
We can use VLSM in this internetwork to save addressing space, but using VLSM requires more planning. The next section demonstrates the planning associated with the use of VLSM.
10.4.1 - Calculating Addresses: Case 1
The diagram depicts calculating addresses without VLSM by showing the address ranges for each of the four subnets.
Network: Student
Subnet Address: 172.16.0.0/23
Host Address Range: 172.16.0.1 to 172.16.1.254
Broadcast Address: 172.16.1.255
Addresses available: 510
Addresses used: 481
Network: Instructor
Subnet Address: 172.16.2.0/23
Host Address Range: 172.16.2.1 to 172.16.3.254
Broadcast Address: 172.16.3.255
Addresses available: 510
Addresses used: 69
Network: Administration
Subnet Address: 172.16.4.0/23
Host Address Range: 172.16.4.1 to 172.16.5.254
Broadcast Address: 172.16.5.255
Addresses available: 510
Addresses used: 23
Network: WAN
Subnet Address: 172.16.6.0/23
Host Address Range: 172.16.6.1 to 172.16.7.254
Broadcast Address: 172.16.7.255
Addresses available: 510
Addresses used: 2
The diagram depicts calculating addresses without VLSM by showing the address ranges for each of the four subnets.
Network: Student
Subnet Address: 172.16.0.0/23
Host Address Range: 172.16.0.1 to 172.16.1.254
Broadcast Address: 172.16.1.255
Addresses available: 510
Addresses used: 481
Network: Instructor
Subnet Address: 172.16.2.0/23
Host Address Range: 172.16.2.1 to 172.16.3.254
Broadcast Address: 172.16.3.255
Addresses available: 510
Addresses used: 69
Network: Administration
Subnet Address: 172.16.4.0/23
Host Address Range: 172.16.4.1 to 172.16.5.254
Broadcast Address: 172.16.5.255
Addresses available: 510
Addresses used: 23
Network: WAN
Subnet Address: 172.16.6.0/23
Host Address Range: 172.16.6.1 to 172.16.7.254
Broadcast Address: 172.16.7.255
Addresses available: 510
Addresses used: 2
Page 3:
Calculating and Assigning Addresses - with VLSM
For the VLSM assignment, we can allocate a much smaller block of addresses to each network, as appropriate.
The address block 172.16.0.0/22 (subnet mask 255.255.252.0) has been assigned to this internetwork as a whole. Ten bits will be used to define host addresses and sub networks. This yields a total of 1024 IPv4 local addresses in the range of 172.16.0.0 to 172.16.3.255.
Student LAN
The largest subnetwork is the Student LAN which requires 481 addresses.
Using the formula usable hosts = 2^n - 2, borrowing 9 bits for the host portion gives 512 - 2 = 510 usable host addresses. This meets the current requirement, with a small allowance for growth.
Using 9 bits for hosts leaves 1 bit that can be used locally to define the subnet address. Using the lowest available address gives us a subnet address of 172.16.0.0 /23.
The Student subnet mask calculation is:
Address: 172.16.0.0
In binary:
10101100.00010000.00000000.00000000
Mask: 255.255.254.0
23 bits in binary:
11111111.11111111.11111110.00000000
In the Student network, the IPv4 host range would be:
172.16.0.1 through 172.16.1.254 with a broadcast address of 172.16.1.255.
Because the Student LAN has been assigned these addresses, they are not available for assignment to the remaining subnets: Instructor LAN, Administrator LAN, and the WAN. The addresses still to be assigned are in the range 172.16.2.0 to 172.16.3.255.
Instructor LAN
The next largest network is the Instructor LAN. This network requires at least 69 addresses. Using 6 in the power of 2 formula, 2^6 - 2, only provides 62 usable addresses. We must use an address block using 7 host bits. The calculation 2^7 -2 will yield a block of 126 addresses. This leaves 25 bits to assign to network address. The next available block of this size is the 172.16.2.0 /25 network.
Address: 172.16.2.0
In binary:
10101100.00010000.00000010.00000000
Mask: 255.255.255.128
25 bits in binary:
11111111.11111111.11111111.10000000
This provides an IPv4 host range of:
172.16.2.1 to 172.16.2.126 with a broadcast address of 172.16.2.127.
From our original address block of 172.16.0.0 /22, we allocated addresses 172.16.0.0 to 172.16.2.127. The remaining addresses to be allocated are 172.16.2.128 to 172.16.3.255.
Administrator LAN
For the Administrator LAN, we need to accommodate 23 hosts. This will require the use of 5 host bits using the calculation: 2^5 - 2.
The next available block of addresses that can accommodate these hosts is the 172.16.2.128 /27 block.
Address: 172.16.2.128
In binary:
10101100.00010000.00000010.10000000
Mask: 255.255.255.224
26 bits in binary:
11111111.11111111.11111111.11100000
This provides an IPv4 host range of:
172.16.2.129 to 172.16.2.158 with a broadcast address of 172.16.2.159.
This yields 30 unique IPv4 addresses for the Administrator LAN.
WAN
The last segment is the WAN connection, requiring 2 host addresses. Only 2 host bits will accommodate the WAN links. 2^2 - 2 = 2.
This leaves 8 bits to define the local subnet address. The next available address block is 172.16.2.160 /30.
Address: 172.16.2.160
In binary:
10101100.00010000.00000010.10100000
Mask: 255.255.255.252
30 bits in binary:
11111111.11111111.11111111.11111100
This provides an IPv4 host range of:
172.16.2.161 to 172.16.2.162 with a broadcast address of 172.16.2.163.
This completes the allocation of addresses using VLSM for Case 1. If an adjustment is necessary to accommodate future growth, addresses in the range of 172.16.2.164 to 172.16.3.255 are still available.
10.4.1 - Calculating Addresses: Case 1
The diagram depicts calculating addresses with VLSM address ranges by showing the address ranges for each of the four subnets.
Network: Student
Subnet Address: 172.16.0.0/23
Host Address Range: 172.16.0.1 to 172.16.1.254
Broadcast Address: 172.16.1.255
Addresses available: 510
Addresses used: 481
Network: Instructor
Subnet Address: 172.16.2.0/25
Host Address Range: 172.16.2.1 to 172.16.2.126
Broadcast Address: 172.16.2.127
Addresses available: 126
Addresses used: 69
Network: Administration
Subnet Address: 172.16.2.128/27
Host Address Range: 172.16.2.129 to 172.16.2.158
Broadcast Address: 172.16.2.159
Addresses available: 30
Addresses used: 23
Network: WAN
Subnet Address: 172.16.2.160/30
Host Address Range: 172.16.2.161 to 172.16.2.162
Broadcast Address: 172.16.2.163
Addresses available: 2
Addresses used: 2
Unused addresses: 172.16.2.164 to 172.16.3.255
The diagram depicts calculating addresses with VLSM address ranges by showing the address ranges for each of the four subnets.
Network: Student
Subnet Address: 172.16.0.0/23
Host Address Range: 172.16.0.1 to 172.16.1.254
Broadcast Address: 172.16.1.255
Addresses available: 510
Addresses used: 481
Network: Instructor
Subnet Address: 172.16.2.0/25
Host Address Range: 172.16.2.1 to 172.16.2.126
Broadcast Address: 172.16.2.127
Addresses available: 126
Addresses used: 69
Network: Administration
Subnet Address: 172.16.2.128/27
Host Address Range: 172.16.2.129 to 172.16.2.158
Broadcast Address: 172.16.2.159
Addresses available: 30
Addresses used: 23
Network: WAN
Subnet Address: 172.16.2.160/30
Host Address Range: 172.16.2.161 to 172.16.2.162
Broadcast Address: 172.16.2.163
Addresses available: 2
Addresses used: 2
Unused addresses: 172.16.2.164 to 172.16.3.255
10.4.2 Calculating Addresses: Case 2
Page 1:
In Case 2, the challenge is to subnet this internetwork while limiting the number of wasted hosts and subnets.
The figure shows 5 different subnets, each with different host requirements. The given IP address is 192.168.1.0/24.
The host requirements are:
- NetworkA - 14 hosts
- NetworkB - 28 hosts
- NetworkC - 2 hosts
- NetworkD - 7 hosts
- NetworkE - 28 hosts
We apply the formula: usable hosts = 2^n - 2. For networks B and E, 5 bits are borrowed from the host portion and the calculation is 2^5 = 32 - 2. Only 30 usable host addresses are available due to the 2 reserved addresses. Borrowing 5 bits meets the requirement but gives little room for growth.
So you may consider borrowing 3 bits for subnets leaving 5 bits for the hosts. This allows 8 subnets with 30 hosts each.
We allocate addresses for networks B and E first:
Network B will use Subnet 0: 192.168.1.0/27
host address range 1 to 30
Network E will use Subnet 1: 192.168.1.32/27
host address range 33 to 62
The next largest host requirement is NetworkA, followed by NetworkD.
Borrowing another bit and subnetting the network address 192.168.1.64 yields a host range of:
Network A will use Subnet 0: 192.168.1.64/28
host address range 65 to 78
Network D will use Subnet 1: 192.168.1.80/28
host address range 81 to 94
This allocation supports 14 hosts on each subnet and satisfies the requirement.
Network C has only two hosts. Two bits are borrowed to meet this requirement.
Starting from 192.168.1.96 and borrowing 2 more bits results in subnet 192.168.1.96/30.
Network C will use Subnet 1: 192.168.1.96/30
host address range 97 to 98
In Case 2, we have met all requirements without wasting many potential subnets and available addresses.
In this case, bits were borrowed from addresses that had already been subnetted. As you will recall from a previous section, this method is known as Variable Length Subnet Masking, or VLSM.
10.4.2 - Calculating Addresses: Case 2
The diagram depicts calculating addresses for host requirements.
Network Topology:
The diagram shows five different subnets, each with different host requirements.
- Network A LAN with 14 hosts is connected to router R1's FA0/0 Ethernet interface.
- Network B LAN with 28 hosts is connected to router R1's FA0/1 Ethernet interface.
- Network D LAN with 7 hosts is connected to router R2's FA0/0 Ethernet interface.
- Network E LAN with 28 hosts is connected to router R2's FA0/1 Ethernet interface.
- Network C WAN interconnects router R1 and R2.
The diagram depicts calculating addresses for host requirements.
Network Topology:
The diagram shows five different subnets, each with different host requirements.
- Network A LAN with 14 hosts is connected to router R1's FA0/0 Ethernet interface.
- Network B LAN with 28 hosts is connected to router R1's FA0/1 Ethernet interface.
- Network D LAN with 7 hosts is connected to router R2's FA0/0 Ethernet interface.
- Network E LAN with 28 hosts is connected to router R2's FA0/1 Ethernet interface.
- Network C WAN interconnects router R1 and R2.
10.5 Device Interconnections
10.5.1 Device InterfacesPage 1:
It is important to understand that Cisco devices, routers, and switches have several types of interfaces associated with them. You have worked with these interfaces in the labs. These interfaces, also commonly called ports, are where cables are connected to the device. See the figure for some example interfaces.
LAN Interfaces - Ethernet
The Ethernet interface is used for connecting cables that terminate with LAN devices such as computers and switches. This interface can also be used to connect routers to each other. This use will be covered in more detail in future courses.
Several conventions for naming Ethernet interfaces are popular, including AUI (older Cisco devices using a transceiver), Ethernet, FastEthernet and Fa 0/0. The name used depends on the type and model of the device.
WAN Interfaces - Serial
Serial WAN interfaces are used for connecting WAN devices to the CSU/DSU. A CSU/DSU is a device used to make the physical connection between data networks and WAN provider's circuits.
Serial interfaces between routers will also be used in our labs as part of various courses. For lab purposes, we will make a back-to-back connection between two routers using serial cables, and set a clock rate on one of the interfaces.
You may also need to configure other Data Link and Physical layer parameters on a router. To establish communication with a router via a console on a remote WAN, a WAN interface is assigned a Layer 3 address (IPv4 address).
Console Interface
The console interface is the primary interface for initial configuration of a Cisco router or switch. It is also an important means of troubleshooting. It is important to note that with physical access to the router's console interface, an unauthorized person can interrupt or compromise network traffic. Physical security of network devices is extremely important.
Auxiliary (AUX) Interface
This interface is used for remote management of the router. Typically, a modem is connected to the AUX interface for dial-in access. From a security standpoint, enabling the option to connect remotely to a network device carries with it the responsibility of maintaining vigilant device management.
10.5.1 - Device Interfaces
The diagram depicts example device interfaces on the router back panel
of a Cisco 1841 router. The highlighted interfaces include:
- Console interface (one integrated)
- Serial interfaces (two smart serial interfaces on a WIC2T modular card)
- FastEthernet interfaces (two integrated)
- Auxiliary Interface (one integrated)
The diagram depicts example device interfaces on the router back panel
of a Cisco 1841 router. The highlighted interfaces include:
- Console interface (one integrated)
- Serial interfaces (two smart serial interfaces on a WIC2T modular card)
- FastEthernet interfaces (two integrated)
- Auxiliary Interface (one integrated)
10.5.2 Making the Device Management Connection
Page 1:
Typically, networking devices do not have their own displays, keyboards, or input devices such as trackballs and mice. Accessing a network device for configuration, verification, or troubleshooting is made via a connection between the device and a computer. To enable this connection, the computer runs a program called a terminal emulator.
A terminal emulator is a software program that allows one computer to access the functions on another device. It allows a person to use the display and keyboard on one computer to operate another device, as if the keyboard and display were directly connected to the other device. The cable connection between the computer running the terminal emulation program and the device is often made via the serial interface.
To connect to a router or switch for device management using terminal emulation, follow these steps:
Step 1:
Connect a computer to the console port using the console cable supplied by Cisco. The console cable, supplied with each router and switch, has a DB-9 connector on one end and an RJ-45 connector on the other end. (Older Cisco devices came supplied with an RJ-45 to DB-9 adapter. This adapter is used with a rollover cable that has an RJ-45 connector at each end.)
The connection to the console is made by plugging the DB-9 connector into an available EIA/TIA 232 serial port on the computer. It is important to remember that if there is more than one serial port, note which port number is being used for the console connection. Once the serial connection to the computer is made, connect the RJ-45 end of the cable directly into the console interface on the router.
Many newer computers do not have an EIA/TIA 232 serial interface. If your computer has only a USB interface, use a USB-to-serial conversion cable to access the console port. Connect the conversion cable to a USB port on the computer and then connect the console cable or RJ-45 to DB-9 adapter to this cable.
Step 2:
With the devices directly connected via cable, configure a terminal emulator with the proper settings. The exact instructions for configuring a terminal emulator will depend on the particular emulator. For the purpose of this course, we will usually use HyperTerminal because most varieties of Windows have it. This program can be found under All Programs > Accessories > Communications. Select HyperTerminal.
Open HyperTerminal, confirm the chosen serial port number, and then configure the port with these settings:
- Bits per second: 9600 bps
- Data bits: 8
- Parity: None
- Stop bits: 1
- Flow control: None
Log in to the router using the terminal emulator software. If all settings and cable connections are done properly, you can access the router by pressing the Enter key on the keyboard.
During the lab, you will have the opportunity to use several types of terminal emulators. Each one may be slightly different in appearance, but their uses are the same.
10.5.2 - Making the Device Management Connection
The diagram depicts a device management connection to a switch from a PC. One end of an RJ-45 to RJ-45 cable plugs into the switch. The other end plugs into an RJ-45 to DB-9 adapter labeled TERMINAL.
- PC's require an RJ-45 to DB-9 or RJ-45 to DB-25 adapter.
- COM port settings are 9600 bps, 8 data bits, no parity, 1 stop bit, no flow control. This provides out-of-band console access.
- AUX switch port may be used for a modem-connected console.
The diagram depicts a device management connection to a switch from a PC. One end of an RJ-45 to RJ-45 cable plugs into the switch. The other end plugs into an RJ-45 to DB-9 adapter labeled TERMINAL.
- PC's require an RJ-45 to DB-9 or RJ-45 to DB-25 adapter.
- COM port settings are 9600 bps, 8 data bits, no parity, 1 stop bit, no flow control. This provides out-of-band console access.
- AUX switch port may be used for a modem-connected console.
10.6 Chapter Labs
10.6.1 Lab - Creating a Small Lab TopologyPage 1:
In this lab, you will create a small network that requires connecting network devices, configuring host computers for basic network connectivity, and verifying that connectivity.
Click the lab icon to launch the activity.
10.6.1 - Creating a Small Lab Topology
Link to Hands-on Lab: Creating a Small Lab Topology
In this lab, you will create a small network that requires connecting network devices, configuring host computers for basic network connectivity, and verifying that connectivity.
Link to Hands-on Lab: Creating a Small Lab Topology
In this lab, you will create a small network that requires connecting network devices, configuring host computers for basic network connectivity, and verifying that connectivity.
Page 2:
In this activity you will create a small network that requires connecting network devices and configuring host computers for basic network connectivity. SubnetA and SubnetB are subnets that are currently needed. SubnetC and SubnetD are anticipated subnets, not yet connected to the network.
Click the Packet Tracer icon for more details.
10.6.1 - Creating a Small Lab Topology
Link to Packet Tracer Exploration: Creating a Small Lab Topology
In this lab, you will create a small network that requires connecting network devices and configuring host computers for basic network connectivity. Subnet A and Subnet B are subnets that are currently needed. Subnet C and Subnet D are anticipated subnets, not yet connected to the network.
Link to Packet Tracer Exploration: Creating a Small Lab Topology
In this lab, you will create a small network that requires connecting network devices and configuring host computers for basic network connectivity. Subnet A and Subnet B are subnets that are currently needed. Subnet C and Subnet D are anticipated subnets, not yet connected to the network.
10.6.2 Lab - Establishing a Console Session with HyperTerminal
Page 1:
Cisco routers and switches are configured using the device Internetworking Operation System (IOS). The command-line interface (CLI) of the IOS is accessed via a terminal that can be emulated on Windows computers.
This lab introduces two Windows-based terminal emulation programs, HyperTerminal and TeraTerm. These programs can be used to connect a computer's serial (COM) port to the console port of the Cisco device running IOS.
Click the Lab icon to launch the activity.
10.6.2 - Establishing a Console Session with HyperTerminal
Link to Hands-on Lab: Establishing a Console Session with HyperTerminal
Cisco routers and switches are configured using the Cisco Internetworking Operation System (I O S). The command-line interface (C L I) of the Cisco I O S software is accessed via a terminal that can be emulated on Windows computers.
This lab introduces two Windows-based terminal emulation programs, HyperTerminal and TeraTerm. These programs can be used to connect a computer's serial (COM) port to the console port of the Cisco device running Cisco I O S.
Link to Hands-on Lab: Establishing a Console Session with HyperTerminal
Cisco routers and switches are configured using the Cisco Internetworking Operation System (I O S). The command-line interface (C L I) of the Cisco I O S software is accessed via a terminal that can be emulated on Windows computers.
This lab introduces two Windows-based terminal emulation programs, HyperTerminal and TeraTerm. These programs can be used to connect a computer's serial (COM) port to the console port of the Cisco device running Cisco I O S.
Page 2:
Upon completion of this activity, you will be able to connect a router and computer using a console cable. You will also configure HyperTerminal to establish a console session with a Cisco IOS router and switch.
Click the Packet Tracer icon to launch the activity.
10.6.2 - Establishing a Console Session with HyperTerminal
Link to Packet Tracer Exploration: Establishing a Console Session with PT Terminal
Upon completion of this activity, you will be able to connect a router and computer using a console cable. You will also configure HyperTerminal to establish a console session with a Cisco I O S router and switch.
Link to Packet Tracer Exploration: Establishing a Console Session with PT Terminal
Upon completion of this activity, you will be able to connect a router and computer using a console cable. You will also configure HyperTerminal to establish a console session with a Cisco I O S router and switch.
10.6.3 Lab - Establishing a Console Session with Minicom
Page 1:
This lab introduces the Linux-based terminal emulation program, Minicom, which can be used to connect a computer's serial port to the console port of Cisco device running IOS.
Click the Lab icon to launch the activity.
10.6.3 - Establishing a Console Session with Minicom
Link to Hands-on Lab: Establishing a Console Session with Minicom
This lab introduces the Linux-based terminal emulation program, Minicom, which can be used to connect a computer's serial port to the console port of a Cisco device running Cisco I O S software.
Link to Hands-on Lab: Establishing a Console Session with Minicom
This lab introduces the Linux-based terminal emulation program, Minicom, which can be used to connect a computer's serial port to the console port of a Cisco device running Cisco I O S software.
10.7 Chapter Summary
10.7.1 Summary and ReviewPage 1:
This chapter discussed the planning and design processes that contribute to the installation of a successful, operating network.
The various LAN and WAN media types and their associated cables and connectors were considered so that the most appropriate interconnection decisions can be made.
Determining the number of hosts and subnets in a network required now - and simultaneously planning for future growth - ensures that data communications are available at the best combination of cost and performance.
Similarly, a planned and consistently implemented addressing scheme is an important factor in ensuring that networks work well with provisions to scale as needed. Such addressing schemes also facilitate easy configuration and troubleshooting.
Terminal access to routers and switches is a means to configure addresses and network features on these devices.
10.7.1 - Summary and Review
In this chapter, you learned to:
- Identify the basic network media required to make a LAN connection.
- Identify the types of connections for intermediate and end-device connections in a LAN.
- Identify the pin out configurations for straight-through and crossover cables.
- Identify the different cabling types, standards, and ports used for WAN connections.
- Define the role of device management connections when using Cisco equipment.
- Design an addressing scheme for an internetwork and assign ranges for hosts, network devices, and the router interface.
- Compare and contrast the importance of network designs.
In this chapter, you learned to:
- Identify the basic network media required to make a LAN connection.
- Identify the types of connections for intermediate and end-device connections in a LAN.
- Identify the pin out configurations for straight-through and crossover cables.
- Identify the different cabling types, standards, and ports used for WAN connections.
- Define the role of device management connections when using Cisco equipment.
- Design an addressing scheme for an internetwork and assign ranges for hosts, network devices, and the router interface.
- Compare and contrast the importance of network designs.
Page 2:
10.7.1 - Summary and Review
This is a review and is not a quiz. Questions and answers are provided.
Question 1. List the five factors to consider when selecting the type of physical media to deploy in the LAN.
Answer:
- Cable length - Does the cable need to span across a room or from building to building?
- Cost - Does the budget allow for using a more expensive media type?
- Bandwidth - Does the technology used with the media provide adequate bandwidth?
- Ease of installation - Does the implementation team have the ability to install the cable or is a vendor required?
- Susceptible to EMI/RFI - Is the environment in which the cable is being installed going to interfere with the signal?
Question 2. List where a straight-through UTP cable would be used in connecting network devices.
Answer:
- Switch to router
- PC to switch
- PC to hub (if used)
Question 3. List where a crossover UTP cable would be used in connecting network devices.
Answer:
- Switch to switch
- Switch to hub (if used)
- Hub to hub (if used)
- Router to router
- PC to PC
- PC to router
Question 4. Describe the purposes of and differences between DCE and D T E WAN serial cables.
Answer:
Data Communications Equipment (DCE) - A device that supplies the clocking to another device. Typically a device at the WAN access provider end of the link.
Data Terminal Equipment (D T E) - A device that receives clocking from another device and adjusts accordingly. Typically, this device is at the WAN customer or user end of the link.
In a lab environment, generally connect two routers with a serial cable providing a point-to-point WAN link. In this case, decide which router is going to be the one in control of the clocking. Cisco routers are D T E devices by default but can be configured to act as DCE devices.
Question 5. List criteria that should be considered when selecting a switch for a LAN.
Answer:
- Cost
- Cable or wireless
- Speed
- Ports
- Expandability
- Manageability
- Features
Question 6. Give examples of the different types of hosts and network devices that require IP addresses.
Answer:
End devices requiring IP addresses include:
- User computers
- Administrator computers
- Servers
- Other end devices such as printers, IP phones, and IP cameras
Network devices requiring IP addresses include:
- Router LAN gateway interfaces
- Router WAN (serial) interfaces
Network devices requiring IP addresses for management:
- Switches
- Wireless access points
Question 7. List three reasons for subnetting a network.
Answer:
Manage Broadcast Traffic
Broadcasts are controlled because one large broadcast domain is divided into a number of smaller domains. This means that every host in the system does not receive every broadcast.
Similar Network Requirements
If different groups of users require specific network and computing facilities or features, it is easier to manage these requirements if those users are all together on one subnet.
Security
Network security features can be implemented based on network addresses. This enables control and management of access to different network and data services.
Question 8. Describe five attributes of an effective network addressing scheme.
Answer:
- Scalability - Supports growth as more devices are attached to the network.
- Reliability - Handles messages across short or long distances.
- Flexibility - Allows for future technologies.
- Dynamic - Adjusts to changes on the network.
- Availability - Provides communications any time and anywhere.
Question 9. List four of the interfaces found on Cisco routers and switches, and give the function of each.
Answer:
Ethernet Interfaces: This interface is used for connecting the LAN devices, which include computers and switches. This interface can also be used to connect routers together.
Serial Interfaces: This interface is used for connecting the WAN devices to the CSU/DSU. Clock rate and addressing are assigned to these interfaces.
Console Interface: This is the primary interface for gaining initial access to and configuration of a Cisco router or switch and is the primary means of troubleshooting. It is important to note that through physical access to the router's console interface, an unauthorized person can interrupt or compromise network traffic. Physical security is extremely important!
Auxiliary (AUX) Interface: This interface is used for remote, out-of-band management of the router. Typically, a modem is connected to the AUX interface for dial-in access. From a security standpoint, having the ability to remotely dial in to a network device also requires vigilant management.
This is a review and is not a quiz. Questions and answers are provided.
Question 1. List the five factors to consider when selecting the type of physical media to deploy in the LAN.
Answer:
- Cable length - Does the cable need to span across a room or from building to building?
- Cost - Does the budget allow for using a more expensive media type?
- Bandwidth - Does the technology used with the media provide adequate bandwidth?
- Ease of installation - Does the implementation team have the ability to install the cable or is a vendor required?
- Susceptible to EMI/RFI - Is the environment in which the cable is being installed going to interfere with the signal?
Question 2. List where a straight-through UTP cable would be used in connecting network devices.
Answer:
- Switch to router
- PC to switch
- PC to hub (if used)
Question 3. List where a crossover UTP cable would be used in connecting network devices.
Answer:
- Switch to switch
- Switch to hub (if used)
- Hub to hub (if used)
- Router to router
- PC to PC
- PC to router
Question 4. Describe the purposes of and differences between DCE and D T E WAN serial cables.
Answer:
Data Communications Equipment (DCE) - A device that supplies the clocking to another device. Typically a device at the WAN access provider end of the link.
Data Terminal Equipment (D T E) - A device that receives clocking from another device and adjusts accordingly. Typically, this device is at the WAN customer or user end of the link.
In a lab environment, generally connect two routers with a serial cable providing a point-to-point WAN link. In this case, decide which router is going to be the one in control of the clocking. Cisco routers are D T E devices by default but can be configured to act as DCE devices.
Question 5. List criteria that should be considered when selecting a switch for a LAN.
Answer:
- Cost
- Cable or wireless
- Speed
- Ports
- Expandability
- Manageability
- Features
Question 6. Give examples of the different types of hosts and network devices that require IP addresses.
Answer:
End devices requiring IP addresses include:
- User computers
- Administrator computers
- Servers
- Other end devices such as printers, IP phones, and IP cameras
Network devices requiring IP addresses include:
- Router LAN gateway interfaces
- Router WAN (serial) interfaces
Network devices requiring IP addresses for management:
- Switches
- Wireless access points
Question 7. List three reasons for subnetting a network.
Answer:
Manage Broadcast Traffic
Broadcasts are controlled because one large broadcast domain is divided into a number of smaller domains. This means that every host in the system does not receive every broadcast.
Similar Network Requirements
If different groups of users require specific network and computing facilities or features, it is easier to manage these requirements if those users are all together on one subnet.
Security
Network security features can be implemented based on network addresses. This enables control and management of access to different network and data services.
Question 8. Describe five attributes of an effective network addressing scheme.
Answer:
- Scalability - Supports growth as more devices are attached to the network.
- Reliability - Handles messages across short or long distances.
- Flexibility - Allows for future technologies.
- Dynamic - Adjusts to changes on the network.
- Availability - Provides communications any time and anywhere.
Question 9. List four of the interfaces found on Cisco routers and switches, and give the function of each.
Answer:
Ethernet Interfaces: This interface is used for connecting the LAN devices, which include computers and switches. This interface can also be used to connect routers together.
Serial Interfaces: This interface is used for connecting the WAN devices to the CSU/DSU. Clock rate and addressing are assigned to these interfaces.
Console Interface: This is the primary interface for gaining initial access to and configuration of a Cisco router or switch and is the primary means of troubleshooting. It is important to note that through physical access to the router's console interface, an unauthorized person can interrupt or compromise network traffic. Physical security is extremely important!
Auxiliary (AUX) Interface: This interface is used for remote, out-of-band management of the router. Typically, a modem is connected to the AUX interface for dial-in access. From a security standpoint, having the ability to remotely dial in to a network device also requires vigilant management.
Page 3:
In this activity, you will devise a subnet scheme, create and interconnect networking devices in a model lab network, apply your IP addressing scheme to the network you created, and test your network.
Packet Tracer Skills Integration Instructions (PDF)
Click the Packet Tracer icon for more details.
10.7.1 - Summary and Review
Link to Packet Tracer Exploration: Skills Integration Challenge: Network Planning and Interface Configuration.
In this activity, you will devise a subnet scheme, create and interconnect networking devices in a model lab network, apply your IP addressing scheme to the network you created, and test your network.
Link to Packet Tracer Exploration: Skills Integration Challenge: Network Planning and Interface Configuration.
In this activity, you will devise a subnet scheme, create and interconnect networking devices in a model lab network, apply your IP addressing scheme to the network you created, and test your network.
Page 4:
To Learn More
Structured Cabling Supplement
Structured cabling skills are crucial for any networking professional. Structured cabling creates a physical topology where telecommunications cabling is organized into hierarchical termination and interconnection structures according to standards. The word telecommunications is used to express the necessity of dealing with electrical power wires, telephone wires, and cable television coaxial cable in addition to copper and optical networking media.
Structured cabling is an OSI Layer 1 issue. Without Layer 1 connectivity, the Layer 2 switching and Layer 3 routing process that makes data transfer across large networks possible cannot occur. Especially for people new to the networking workforce, many of the day-to-day jobs deal with structured cabling.
Many different standards are used to define the rules of structured cabling. These standards vary around the world. Three standards of central importance in structured cabling are ANSI TIA/EIA-568-B, ISO/IEC 11801, and IEEE 802.x.
This supplement provides the opportunity to complete a structured cabling case study. This can be done on paper only, or part of a hands-on structured cabling installation project.
10.7.1 - Summary and Review
The diagram depicts a collage of people using computers and networks.
The diagram depicts a collage of people using computers and networks.
10.8 Chapter Quiz
10.8.1 Chapter QuizPage 1:
10.8.1 - Chapter Quiz
1.Determine the IP addresses that are usable for hosts on the subnetworks of the 200.100.50.0/28 network.
Addresses:
200.100.50.25
200.100.50.80
200.100.50.100
200.100.50.143
200.100.50.208
200.100.50.170
200.100.50.90
200.100.50.79
Categories:
Usable for host address
Not usable for host address
2.When is a straight-through cable used in a network?
A.When connecting a router through the console port
B.When connecting one switch to another switch
C.When connecting a host to a switch
D.When connecting a router to another router
3.Refer to the topology description below to answer the question.
Topology description:
Router R1 is connected to a CSU/DSU. The CSU/DSU is connected to one side of a network cloud. Router R2 is connected to another CSU/DSU. This CSU/DSU is connected to the opposite side of the network cloud.
Which function is a unique responsibility of the DCE devices shown in the exhibit?
A.Transmission of data
B.Reception of data
C.Clocking for the synchronous link
D.Noise cancellation in transmitted data
4.A router that terminates a serial WAN link is typically a D T E device. Under which circumstance would a router be configured as a DCE device?
A.A router cannot be configured as a DCE device.
B.When connecting a router directly to an analog device.
C.When performing a back-to-back router scenario in a test environment.
D.When the clock rate from the service provider cannot be matched by the router.
5.Which of the following are private IP addresses? (Choose three.)
A.10.1.1.1
B.172.32.5.2
C.192.167.10.10
D.172.16.4.4
E.192.168.5.5
F.224.6.6.6
6.Match the slash-format prefix number with the decimal mask number to subnet the last octet.
Slash-format prefix numbers:
/24
/25
/26
/27
/28
/29
/30
Decimal mask numbers:
128
252
224
0
248
192
240
7.Refer to the topology description to answer the question.
Topology description.
Router R1 interface FA0 is connected to router R2 interface FA0.
What type of cable connects the two routers together without any intermediary device?
A.Console
B.Rollover
C.Crossover
D.Straight-through
8.When setting the COM port properties for a PC, which option defines the default port configuration settings used to establish a direct serial connection between a computer and a Cisco networking device?
A.19,200 bps, 8 data bits, no parity, 1 stop bit, no flow control
B.9600 bps, 8 data bits, even parity, 2 stop bits, hardware flow control
C.9600 bps, 16 data bits, odd parity, 1 stop bit, hardware flow control
D.19,200 bps, 8 data bits, even parity, 1 stop bit, hardware flow control
E.9600 bps, 8 data bits, no parity, 1 stop bit, no flow control
9.Which three UTP cable lengths are specified by ANSI/T IA/EIA-568-B standards? (Choose three.)
A.Total end-to-end length of up to 100 meters
B.Up to 110 meters total end-to-end length
C.Horizontal cabling maximum of 90 meters
D.Up to 10 meters for interconnecting patch panels
E.Up to 5 meters for interconnecting patch panels
F.Up to 10 meters for connecting individual devices to wall jacks
10.What primary factor should be addressed before using wireless technology?
A.FFC address assignment
B.Selecting an Auto-MDIX capable switch
C.Power supply redundancy
D.Identify and if possible minimize sources of RFI
1.Determine the IP addresses that are usable for hosts on the subnetworks of the 200.100.50.0/28 network.
Addresses:
200.100.50.25
200.100.50.80
200.100.50.100
200.100.50.143
200.100.50.208
200.100.50.170
200.100.50.90
200.100.50.79
Categories:
Usable for host address
Not usable for host address
2.When is a straight-through cable used in a network?
A.When connecting a router through the console port
B.When connecting one switch to another switch
C.When connecting a host to a switch
D.When connecting a router to another router
3.Refer to the topology description below to answer the question.
Topology description:
Router R1 is connected to a CSU/DSU. The CSU/DSU is connected to one side of a network cloud. Router R2 is connected to another CSU/DSU. This CSU/DSU is connected to the opposite side of the network cloud.
Which function is a unique responsibility of the DCE devices shown in the exhibit?
A.Transmission of data
B.Reception of data
C.Clocking for the synchronous link
D.Noise cancellation in transmitted data
4.A router that terminates a serial WAN link is typically a D T E device. Under which circumstance would a router be configured as a DCE device?
A.A router cannot be configured as a DCE device.
B.When connecting a router directly to an analog device.
C.When performing a back-to-back router scenario in a test environment.
D.When the clock rate from the service provider cannot be matched by the router.
5.Which of the following are private IP addresses? (Choose three.)
A.10.1.1.1
B.172.32.5.2
C.192.167.10.10
D.172.16.4.4
E.192.168.5.5
F.224.6.6.6
6.Match the slash-format prefix number with the decimal mask number to subnet the last octet.
Slash-format prefix numbers:
/24
/25
/26
/27
/28
/29
/30
Decimal mask numbers:
128
252
224
0
248
192
240
7.Refer to the topology description to answer the question.
Topology description.
Router R1 interface FA0 is connected to router R2 interface FA0.
What type of cable connects the two routers together without any intermediary device?
A.Console
B.Rollover
C.Crossover
D.Straight-through
8.When setting the COM port properties for a PC, which option defines the default port configuration settings used to establish a direct serial connection between a computer and a Cisco networking device?
A.19,200 bps, 8 data bits, no parity, 1 stop bit, no flow control
B.9600 bps, 8 data bits, even parity, 2 stop bits, hardware flow control
C.9600 bps, 16 data bits, odd parity, 1 stop bit, hardware flow control
D.19,200 bps, 8 data bits, even parity, 1 stop bit, hardware flow control
E.9600 bps, 8 data bits, no parity, 1 stop bit, no flow control
9.Which three UTP cable lengths are specified by ANSI/T IA/EIA-568-B standards? (Choose three.)
A.Total end-to-end length of up to 100 meters
B.Up to 110 meters total end-to-end length
C.Horizontal cabling maximum of 90 meters
D.Up to 10 meters for interconnecting patch panels
E.Up to 5 meters for interconnecting patch panels
F.Up to 10 meters for connecting individual devices to wall jacks
10.What primary factor should be addressed before using wireless technology?
A.FFC address assignment
B.Selecting an Auto-MDIX capable switch
C.Power supply redundancy
D.Identify and if possible minimize sources of RFI
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