Cisco Activity

Only available on StudyMode
  • Topic: Routing, IP address, MAC address
  • Pages : 22 (6281 words )
  • Download(s) : 444
  • Published : August 21, 2012
Open Document
Text Preview
Task 3: Interpreting Debug Output.
Note: If you already configured IP addressing on R1, please remove all the interface commands now before proceeding. Furthermore, R2 and R3 should be configured through the end of “Task 2: Basic Router Configuration”. Step 1 – On R1 from privileged EXEC mode, enter the debug ip routing command. R1# debug ip routing. 

IP routing debugging is on. 

The debug ip routing command will show when routes are added, modified and deleted from the routing table. For example, every time you successfully configure and activate an interface, Cisco IOS adds a route to the routing table. We can verify this by observing output from the debug ip routing command. Step 2 – Enter interface configuration mode for R1’s LAN interface. R1#configure terminal. 

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)# interface fastethernet 0/0 

Configure the ip address as specified in the Topology Diagram. 

R1(config-if)# ip address 172.16.3.1 255.255.255.0. 
is_up: 0 state: 6 sub state: 1 line: 1 has_route: False 

As soon as you press the enter key, Cisco IOS debug output informs you that there is now a route, but its state is “False”. In other words, the route has not yet been added to the routing table. Why did this occur and what steps should be taken to insure the route is entered into the routing table?  No shut down to int

Step 3 Enter the command necessary to install the route in the routing table.

If you are not sure what the command is, review the discussion in Section 2.2: Directly Connected Networks. 

After you enter the correct command, you should see debug output. Your output may be slightly different.  is_up: 1 state: 4 sub state: 1 line: 1 has_route: False 
RT: add 172.16.3.0/24 via 0.0.0.0, connected metric [0/0] 
RT: NET-RED 172.16.3.0/24 
RT: NET-RED queued, Queue size 1 
RT: interface FastEthernet0/0 added to routing table 
%LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up  is_up: 1 state: 4 sub state: 1 line: 1 has_route: True 
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, chan  ged state to up 
is_up: 1 state: 4 sub state: 1 line: 1 has_route: True 
is_up: 1 state: 4 sub state: 1 line: 1 has_route: True 

The new network you configured on the LAN interface is now added to the routing table as shown in the output. 

If you do not see the route added to the routing table, then the interface did not come up. Use the following systematic process to troubleshoot your connection. 

1. Check your physical connections to the LAN interface. 
Is the correct interface attached? For example, your router may have more than one LAN interface. Did you connect the correct LAN interface? Yes An interface will not come up unless it detects a link beat a carrier detect signal at the physical layer from another device. Is the interface connected to another device such as a hub, switch or PC? yes 2. Check link lights. Are all link lights blinkingyes

3. Check the cabling. Are the correct cables connected to the devices? yes 4. Has the interface been activated or enabled? yes

If you can answer ‘yes’ to all the proceeding questions, then the interface should come up.  Step 4 Enter the command to verify that the new route is now in the routing table.

Your output should look similar to the following output. There should now be one route in the table for R1. What command did you use? 

R1#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP  D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route

Gateway of last resort is not set

172.16.0.0/24 is subnetted, 1 subnets 
C 172.16.3.0 is...
tracking img