Computer Communication and Networks

Lab Manual

Department of Telecommunication Engineering,Government College University,

Faisalabad.

List of Experiments

Exp. No. Experiment Name

1. How to wire Ethernet cables?

2. Understanding network devices.

3. Basic router configuration.

4. Extended basic configuration

(a) Setting up Passwords

(b) Understanding the copy command.

(c) Configuring interfaces

5. Understanding the Cisco Discovery Protocol.

6. Assignment of IP addresses and the use of PING.

7. Viewing an ARP table.

8. Understanding the Routing Information Protocol.

9. How to make a Virtual LAN?

EXPERIMENT NO. 01

OBJECTIVE:

How to wire Ethernet Cables?

APPARATUS:

CAT 5 Cable - bulk Category 5, cable, RJ45 Ends, Crimper for RJ45, Wire Cutters - to cut and strip the cable if necessary, Cable Tester.

THEORY:

Twisted Pair Cables:Twisted pair cables are the most common transmission medium for subscriber loop. These are readily installed in buildings during construction and the most ubiquitous application is local area network. Amplifiers are required after every 2 or 3 kilometers. Twisted pair cables are used where the distance, bandwidth and data rate requirements are limited.

Fig. 1.1: Twisted Pair Cable

RJ-45 Connectors:The RJ45 end is a 8-position modular connector.

Fig. 1.2: RJ-45 Ends

Color Coding for cables:

The twisted pair is arranged in such a way so as to make it straight-through or cross-over in accordance with the coding provided by the Electronic Industries Association (EIA).

Table 1.1: Color coding for straight through cable.

RJ45 Pin #

Wire Color 10Base-T Signal100Base-TX Signal

1000Base-T Signal

1 White/Green Transmit+ BI_DA+

2 Green Transmit- BI_DA-

3 White/Orange Receive+ BI_DB+

4 Blue Unused BI_DC+

5 White/Blue Unused BI_DC-

6 Orange Receive- BI_DB-

7 White/Brown Unused BI_DD+

8 Brown Unused BI_DD-

Table 1.2: Color coding for a crossover cable.

RJ45 Pin #(End 1)

Wire Color RJ45 Pin# (End 2)

Wire Color

1 White/Orange 1 White/Green

2 Orange 2 Green

3 White/Green 3 White/Orange

4 Blue 4 White/Brown

5 White/Blue 5 Brown

6 Green 6 Orange

7 White/Brown 7 Blue

8 Brown 8 White/Blue

PROCEDURE:

1. Strip off about 2 inches of the cable sheath.

2. Untwist the pairs - don't untwist them beyond what you have exposed

3. Align the colored wires according to the diagrams above.

4. Trim all the wires to the same length, about 1/2" to 3/4" left exposed from the sheath.

5. Insert the wires into the RJ45 end - make sure each wire is fully inserted to the front of the RJ45 end and in the correct order.

6. Verify the wires ended up the right order and that the wires extend to the front of the RJ45 end and make good contact with the metal contacts in the RJ45 end.

7. Crimp the RJ45 end with the crimper tool 8. Cut the cable to length - make sure it is more than long enough for your needs

9. Repeat the above steps for the second RJ45 end.

RESULTS:

The cable tester verified that the wire was absolutely right.

EXPERIMENT NO. 02

OBJECTIVE:

Understanding network devices.

APPARATUS:

Modem, hub, switch, Ethernet, repeater, router, RJ-45 connector.

THEORY:

Modem:

It is a computer peripheral that allows you to connect and communicate with other computer via telephone line. Modem changes the digital data from your computer into analog data, a format that can be carried over telephone lines. In the same way the modem receiving the call then changes the analog signal back into digital data that the computer can understand.

Fig. 2.1: Modem.

Ethernet card:

The type of Ethernet card given below is developed by Xerox Corp. along with DEC and Intel. It uses a Bus or Star topology. Supports data transfer rates of up to 10 Mbps. It is also called a LAN card. The address assigned to it is called a physical address. It is in a 48 bit address format. e.g. 0F.38.6E.55.4A.AE.

Fig. 2.2: Ethernet Card.

RJ-45 Connector:

The Registered Jack-45 connector is commonly used for network cabling and for telephony applications. It is an eight wire connector which is commonly used to connect

computers on the local area networks, especially Ethernets. It is similar to telephone connector RJ-11 except that it has eight wires as compared to 4 in RJ-11.

Fig. 2.3: RJ-45 Connector.Hub:

It is used to connect several computers together. In this network device the information flow is accumulated and then distributed to various groups and users. It can be between users on the same LAN and users on different LANs. It is often used in Star or Ring topology. All the devices connected to a hub are said to be in the same collision domain.

Collision domain:

Two devices are said to be in the same collision domain if simultaneous transmission from them results in a collision. In other words, being in the same collision domain, they cannot transmit simultaneously.

Fig. 2.4: Hub.

Switch:

A network switch is a computer networking device that connects network segments. Network switches appear nearly identical to network hubs, but a switch contains more "intelligence" (and comes with a correspondingly slightly higher price tag) than a network hub. Network switches are capable of inspecting data packets as they are received, determining the source and destination device of that packet, and forwarding it appropriately. By delivering each message only to the connected device it was intended for, a network switch conserves network bandwidth and offers generally better performance than a hub. Switches differ from hubs in that they can have ports of different speed.

Fig. 2.5: Switch

Bridges:

Bridges provide the ability to expand beyond a single LAN. Further they provide interconnection to other LANs/WANs. Bridges are a simpler choice than routers to connect similar LANs and are used with identical protocols for physical and link layers.

Fig. 2.5: Functionality of a bridge.

Repeater:

It is a device that amplifies and restores the power of a signal being transmitted on the network. It is used in long network lines.

Router:

A router is a computer whose software and hardware are usually tailored to the tasks of routing and forwarding. This device routes the information packet between two or more physically or logically connected networks. It is different from Bridge as this uses logical address while bridge uses physical address.

Fig. 2.6: Router

Broadcast Domain:

All devices on a network segment that hear all broadcasts sent on that segment are said to be in the same broadcast domain. Routers break broadcast domains by default.

Router Advantages:

There are four basic advantages of routers: Packet switching Packet Filtering Internetwork communication Path Selection

Gateway:

This device usually a server is used to communicate between dissimilar networks i.e. networks with different protocols. e.g. to connect a LAN with Novell Netware with another LAN with Microsoft NT. In enterprises, the gateway is the computer that routes the traffic from the workstation to the outside world. In homes, the gateway is the ISP that connects the user to the Internet.

RESULTS:

I learned from this experiment about different network devices.

EXPERIMENT NO. 03

OBJECTIVE:

To learn basic router operating commands.

APPARATUS:

Boson simulator, (Router 1 and Router 2).

DIAGRAM:

PROCEDURE AND COMMANDS:

Firstly, I launched boson simulator and designed a net-map consisting of two routers and made a serial connection between them keeping router 1 as DCE. Then, I loaded the net-map in to the simulator. After that I logged on to router 1 and pressed enter to get in to user prompt:

Router>

The symbol (>) indicates that we are in the user mode. Now type (?) to see the list of commands in the user mode:

Router>?

Type “enable” to get in to the privileged mode. The symbol (#) indicates that we are in the privileged mode:

Router>enableRouter#

Now type (?) to see the list of commands in the user mode. Notice that there are more commands in the privileged mode than the user mode.

Router#?

Now, go in to the configure mode by the “configure terminal” command.

Router# configure terminalRouter (config)#

Here, you can change the name of your of your router through the “hostname” command:

Router (config)# hostname R1R1(config)#

Type (?) to see the list of commands in the configuration mode.To exit from configuration mode to privilege mode type “ctrl ^ z”.

R1 (config)# ctrl ^ zR1#

To exit from privileged mode to user mode type “disable”.

R1# disableR1>

RESULTS:

The basic router configuration commands were successfully run.

EXPERIMENT NO. 04

OBJECTIVE:

Extended basic configuration. APPARATUS:

Boson simulator, (Router 1 and Router 2).

DIAGRAM:

(a) Setting up passwords

THEORY:

An enable password is required to prevent unauthorized to the privileged mode. The enable secret command is used to encrypt the password. PROCEDURE AND COMMANDS:

Firstly, I launched boson simulator and designed a net-map consisting of two routers and made a serial connection between them keeping router 1 as DCE. Then, I loaded the net-map in to the simulator. After that I logged on to router1 typed the following commands:

Router> enableRouter# configRouter (config)# hostname R1R1 (config)# enable password bosonR1 (config)# enable secret cisco

(b) Setting up the banner motd

THEORY:

The “banner – message of the day” displays a message when logging in to a router.

PROCEDURE AND COMMANDS:

Repeat the steps as in 4 (a), and then type the following command to set the banner.

R1 (config)# banner motd zThis is r1 z

R1 (config)#

The command followed by the z is displayed as message and end the message using the letter z again.

(c) Using the copy command

THEORY:

The copy command is used to copy the running configuration to the start-up configuration. Running configuration is where the configuration is being done and start-up configuration is where the configuration would be in case of a power failure. The former configuration is in the volatile RAM whereas the later configuration is in the Non-volatile RAM.

PROCEDURE AND COMMANDS:

Use the following commands to copy running configuration to the start-up configuration.

R1# copy running-config start-up config

Then use the following show commands to view the configurations:

R1# show running-configR1# show start-up config

(d) Basic Interface Configuration

THEORY:

In a serial connection one router is selected at Data Circuit-Terminating Equipment (DCE), and the other side turns out to be Data Terminating Equipment (DTE). The basic difference in configurations is that the clock rate is provided at the DCE.

PROCEDURE AND COMMANDS:

Repeat the steps as in 4 (a), and then type the following commands to configure the interfaces:

R1:

R1 (config)# interface s0R1 (config-if)# clock rate 64000R1 (config-if)# no shut

No shut command is used to turn the link up.

Then, log on to R2:

Router> enableRouter# configRouter (config)# hostname R2R2 (config)# interface s0R2 (config-if)# no shut

RESULTS:

After this lab, I could successfully set enable passwords, set the banner motd, use the copy command and configure interface as beginner level.

EXPERIMENT NO. 05

OBJECTIVE:

Understanding the Cisco Discovery Protocol (CDP). APPARATUS:

Boson simulator, (Router 1 and Router 2).

DIAGRAM:

THEORY:

Cisco Discovery Protocol (CDP) is a Data Link Layer Protocol and is used in Cisco devices for neighbor discovery and knowing neighbor parameters. Two terms need to be defined here:

Holdtime:

The time for which a router has to keep the update from a specific neighbor saved with it.

Timer:

The interval defined by the timer is the time after which the CDP packets should be sent to keep CDP running.

PROCEDURE AND COMMANDS:

Repeat the steps as in 4 (d), log onto R1 and type the following commands:

R1# show cdp interface

The above command shows the interfaces that broadcasting and receiving updates to and from the neighbors respectively.

R1# show cdp neighbors

The above command shows details of neighbors such as device ID, local interface, hold time and some other details.

R1# show cdp neighbors detail

The above command gives a more detailed analysis of the neighbors.

R1# show cdp entry R2

The above command gives detailed information of a specific router in case of multiple routers connected to R1.

R1# show cdp

The above command shows the cdp holdtime and the timer settings for R1.

R1 (config)# cdp timer 45

The above command changes the timer interval to 45 seconds.

R1 (config)# cdp holdtime 60

The above command changes the holdtime of R1 to 60 seconds.

R1# show cdp

The above command shows the changed cdp settings of R1.

R1 (config)# no cdp run

The above command shuts cdp protocol down.

R1# cdp run

The above command turns back cdp on.

RESULTS:

I was able to learn what CDP is and all the commands were successfully run.

EXPERIMENT NO. 06OBJECTIVE:

Assignment of IP addresses and the use of PING.

APPARATUS:

Boson simulator, (Router 1 and Router 2).

DIAGRAM:

THEORY:

An IP address is a numeric identifier assigned to each machine on an IP network. PING is a command use to check connectivity with another machine. PROCEDURE AND COMMANDS:

Repeat the same steps at both routers until entrance in to the configuration mode. Then, use the following commands:

At R1:

R1 (config)# interface s0 R1 (config-if)# ip address 172.16.1.3 255.255.0.0R1 (config-if)# clock rate 64000R1 (config-if)# no shut

At R2:

R2 (config)# interface s0 R2 (config-if)# ip address 172.16.1.4 255.255.0.0R2 (config-if)# no shut

Now go to R1 and PING R2 using its IP address:

R1 # ping 172.16.1.4

Similarly you may go to R2 and PING R1 using its IP address:R2 # ping 172.16.1.3

RESULTS:

I successfully assigned the IP addresses to the routers and was able to PING them successfully from the other router.

EXPERIMENT NO. 07

OBJECTIVE:

Viewing an ARP table. APPARATUS:

Boson simulator, (Router 1, Router 2 and Router 4).

DIAGRAM:

THEORY:

ARP is the Address Resolution Protocol which works as follows: When a packet arrives at router, the router views the IP address and maps it to a specific MAC address. If the routing table does not contain the MAC address of the destination machine, it broadcasts an ARP query over the network. The addressed machine receives the ARP query and responds with its MAC address back to the router so that it can send the packet to that MAC address. PROCEDURE AND COMMANDS:

Connect Router 1 with Router 4 serially keeping Router 1as DCE and with Router 2 through Fast Ethernet. Repeat configuration steps as in the previous experiments till the entrance in to configuration mode. Then go to all routers and type the following commands:

At R1:Configuring s0:

Router1 (config)# interface s0 Router1 (config-if)# ip address 172.16.10.1 255.255.255.0Router1 (config-if)# clock rate 64000Router1 (config-if)# no shut

Configuring f0/0:

Router1 (config)# interface f0/0Router1 (config-if)# ip address 10.1.1..1 255.255.255.0Router1 (config-if)# no shut

At R2:

Router2 (config)# interface f0/0Router2 (config-if)# ip address 10.1.1.2 255.255.255.0Router2 (config-if)# no shut

At R4:

Router4 (config)# interface s0 Router4 (config-if)# ip address 172.16.10.2 255.255.255.0Router4 (config-if)# clock rate 64000Router4 (config-if)# no shut

Now, go to R1 and check its connectivity with R2 and R4.

Router1# ping 10.1.1.2 Router1# ping 172.16.10.2

If the links are running, continue with the following command to view the ARP table:

Router1# show arp

Running this command will show the local IP and MAC address and the IP and MAC addresses of the routers connected through the fast Ethernet port. Now, type “clear arp” to delete the neighbor’s information from the ARP table.

Router1# clear arp

RESULTS:

The links in the network were successfully enabled and ARP table was successfully viewed and cleared.

EXPERIMENT NO. 08

OBJECTIVE:

Understanding the Routing Information Protocol (RIP). APPARATUS:

Boson simulator, (Router 1, Router 2 and Router 4).

DIAGRAM:

THEORY:

RIP is a distance-vector routing protocol in which the nodes learn about their directly connected networks and using this information they are able to establish connectivity with indirectly connected routers.

PROCEDURE AND COMMANDS:

Repeat the procedure as in experiment no. 7, and then use the following commands to make the routers about their directly connected networks.

At Router1:

Router1 (config)# router ripRouter1 (config-router)# network 10.0.0.0Router1 (config-router)# network 172.16.0.0

At Router2:

Router2 (config)# router ripRouter2 (config-router)# network 10.0.0.0

At Router4:

Router4 (config)# router ripRouter4 (config-router)# network 172.16.0.0

Now go to Router2 and Router4 and check connectivity with Router4 and Router2 respectively.

Router2# ping 172.16.10.2Router4# ping 10.1.1.2

RESULTS:

After making the routers learn about their directly connected networks, I was able to ping indirectly connected routers.

EXPERIMENT NO. 09

OBJECTIVE:

How to make a Virtual LAN (VLAN)? APPARATUS:

Boson simulator, (Router, Switch, PC-1 and PC-2).

DIAGRAM:

THEORY:

A VLAN is a LAN with in a LAN. These are required in large scale networks where separating some of the nodes to create a separate domain with in a LAN is desired. PROCEDURE AND COMMANDS:

Configure the router as follows:

Router> enableRouter#Router# configRouter (config)# hostname R1R1 (config)# interface f0/0R1 (config-if)# ip address 24.17.2.1 255.255.255.0R1 (config-if)# no shut

Connect to PC-1 and set the IP address to 24.17.2.3/24 with router as the default gateway. i.e. ip address 24.17.2.1.

C:>winipcfg

Connect to PC-2 and set the IP address to 24.17.2.4/24 with router as the default gateway. i.e. ip address 24.17.2.1.

C:>winipcfg

Now, ping router and PC-1 from PC-2. The pings will be successful.

C:> ping 24.17.2.1C:> ping 24.17.2.3

Now, connect to switch and set the VLAN up. Start by creating the VLAN.

>enable#config t(config)# VLAN 22 name pcs

Now, assign port e0/1 for PC-1 to the new VLAN.

(config)# interface e0/1(config-if)# vlan membership-static 22

C:> ping 24.17.2.1

Now, ping router and PC-1 from PC-2. The ping to router will be successful and the one to PC-1 will be unsuccessful.

C:> ping 24.17.2.1C:> ping 24.17.2.3

Connect back to switch and assign port e0/2 for PC-2 to the new VLAN.

(config)# interface e0/2(config-if)# vlan membership-static 22

Again, ping router and PC-1 from PC-2. The ping to router will be unsuccessful and the one to PC-1 will be successful.

C:> ping 24.17.2.1C:> ping 24.17.2.3

Finally, connect back to switch and assign port f0/26 for the router to the new VLAN.

(config)# interface f0/26(config-if)# vlan membership-static 22

Now, ping the router and PC-1 from PC-2.Both pings will be successful showing that all nodes have been successfully shifted to a new VLAN.

Connect to switch and try some new show commands:

(config)# end# show VLAN# show VLAN membership

RESULTS:

The VLAN was successfully created.