Online resources for University of Greenwich, School of Engineering

Introduction to Computer Networking 

 Labwork - CDP, Ping, TELNET, Traceroute
Download the PT file for this part of the lab and run it in Packet Tracer.

You may need to save it to the desktop before running Packet Tracer from the NAL window if the preconfigured file does not open automatically.


Use your log books to make notes for this lab.

Login to Router0 and gain access to User Exec mode.

Can you use cdp from this mode?

If not, enter Priv Exec mode and try again.

The routers have names that are unrealistic. Rename your routers from the Global Configuration prompt.

Give both routers names that will help you to differentiate between them.


Router#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#hostname London
London(config)#end

%SYS-5-CONFIG_I: Configured from console by console
London#

If you have renamed your routers, substitute your new names for Router1 and Router0 in the steps below.

Type show cdp ? at the command prompt.

Check whether cdp is running. If not, use the command cdp run to set it going.

What information is shown if you type show cdp?

What options are there for cdp?

Use the show cdp neighbors command and examine the output.

What platform are you connected to?

What interfaces are in use for the serial connection to Router1?

What is the holdtime currently?

Type show cdp neighbor detail

What is now displayed?

What is the IP address of  Router1?

If this does not work, try adding IP addressing information to the connected interfaces and repeat the steps above.

Use the show ip interface brief command to check whether your interfaces are correctly configured.

Turn the cdp protocol off. This is done in Global Configuration mode.

London(config)#no cdp run

Now examine the output from the show cdp command. What is the output now?


Using Ping

Type ping Router1

Why do you not get any responses? What are the names of your routers?

If you have renamed your routers, substitute your new name for Router1 in the steps below.

Enter Priv Exec then type configure terminal

Enter the command

Router(config)#ip host Router1 a.b.c.d  (where a.b.c.d is Router1's IP address) 

What is the IP address of Router1?

Issue the show ip interface brief command to find this.

Type ping Router1 again from Priv Exec.

Does this command work now?

Explain why or why not.

Type ping a.b.c.d where a.b.c.d is the IP address of Router1.

Does this command work now?

Now use the extended ping command to ping Router1.

Use the default values, except for the IP address by typing Enter at the prompt. Note the default values are in square brackets [ ].

Router1#ping
Protocol [ip]:
Target IP address: 192.168.1.1
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.

How many ping responses did you get?

What was the average time for a ping round trip?

Now use the extended ping command to send 20 ping requests.

What was the average time for a round trip?

If Packet Tracer  does not display a value, it may be that there is a bug in the application - don't worry.

TELNET

TELNET does not run until the server has been setup on the destination router.

This is accomplished in global configuration mode by selecting the appropriate line.

This is historically the Virtual Terminal or vty.

We select by default five input lines 0, 1, 2, 3 & 4

The syntax is:

Router(config)#
Router(config)#line vty 0 4
Router(config-line)#password cisco
Router(config-line)#login
Router(config-line)#end

%SYS-5-CONFIG_I: Configured from console by console
Router#

This has setup the TELNET server on the router.

Do this for both of your routers and try to login to each of the routers remotely.

Use the IP address of the router to login.

Router>enable
Router#telnet 2.2.2.2
Trying 2.2.2.2 ...Open


User Access Verification

Password:
Router>

Note that this command will not work if you use an IP address that is incorrect.

Now you are logged in to the remote router.

Try to suspend a session using ctrl+shift+6 (release the keys then) x

Resume the session using Return (Enter).

Disconnect using the disconnect command.
Traceroute

Now download this Packet Tracer file

You may need to save it to the desktop before opening it in Packet Tracer.

Open one of the routers and type:

Router#traceroute 200.2.3.2

How many hops did the information pass through?

What could the traceroute command be useful for?

Save your results in your logbook.

If you wish, you may download Packet Tracer 5 from the Useful Applications link on the home page.


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Written by M Clements                        
Last updated : 20/01/2009 13:13