Trunking Misconfiguration (Troubleshooting LAN Switches)

1-3 Semester 8 Internetwork Troubleshooting v1.0 - Lab 6.2.2 Copyright  2001, Cisco Systems, Inc. Lab 6.2.2 Trunking Misconfiguration (Troubleshooting LAN Switches) Fast 2/3 Fast0/1 Fa 0/2 Trunk Crossover Connection ALSwitch 2900XL-Ent VLAN 10 Client Objective Trunking changes the formatting of the packet. The ports need to be in agree- ment as to what format they are using on the link or they will not understand each other. If you turn the trunking mode to on (as opposed to auto or desir- able) for one port and the other port has the trunking mode set to off, they will not be able to communicate. Scenario This is not part of the International Travel Agency network. As the Enterprise Network Administrator, you add a new access layer switch to the network. You establish trunking using the command “switchport mode trunk” on interface FastEthernet 0/1 for the access layer switch and establish the necessary VLAN trunking parameters for VTP. The message “02:18:24: %LINK-4-ERROR: FastEthernet0/1 is experiencing errors” appears on ALSwitch. Lab Tasks Clear the DLRouter configuration using the following commands: Router#erase start Erasing the nvram filesystem will remove all files! Continue? [confirm]y[OK] Erase of nvram: complete Router#reload Proceed with reload? [confirm]y Clear the DLSwitch configuration using the following commands: Console> (enable) clear config all This command will clear all configuration in NVRAM. This command will cause ifIndex to be reassigned on the next system startup. Do you want to continue (y/n) [n]? y . 2001 Jun 16 12:29:45 %PAGP-5-PORTFROMSTP:Port 2/1 left bridge port 2/1 .2001 Jun 16 12:29:45 %PAGP-5-PORTFROMSTP:Port 2/2 left bridge port 2/2 2001 Jun 16 12:29:45 %PAGP-5-PORTFROMSTP:Port 2/3 left bridge port 2/3 . 2-3 Semester 8 Internetwork Troubleshooting v1.0 - Lab 6.2.2 Copyright  2001, Cisco Systems, Inc. Console> (enable) reset This command will reset the system. Do you want to continue (y/n) [n]? y Clear the ALSwitch configuration and VLAN database using the following com- mands: ALSwitch#clear start Erasing the nvram filesystem will remove all files! Continue? [confirm]y[OK] Erase of nvram: complete ALSwitch#delete vlan.dat Delete filename [vlan.dat]? Delete flash:vlan.dat? [confirm]y ALSwitch#reload Proceed with reload? [confirm]y Load the file called Lab6-2-2-DLSwitchBrokenConfig.txt into the DLSwitch. Load the file called Lab6-2-2-ALSwitchBrokenConfig.txt into the ALSwitch. Step 1 Define your problem. Step 2 Gather the Facts. On the DLSwitch: DLSwitch> (enable) show trunk 2/3 * - indicates vtp domain mismatch Port Mode Encapsulation Status Native vlan -------- ----------- ------------- ------------ ----------- 2/3 on dot1q trunking 1 Port Vlans allowed on trunk -------- --------------------------------------------------------------------- 2/3 1-1005 Port Vlans allowed and active in management domain -------- --------------------------------------------------------------------- 2/3 1,10,20,30 Port Vlans in spanning tree forwarding state and not pruned -------- --------------------------------------------------------------------- 2/3 1,10,20,30 On the ALSwitch: 00:15:01: %LINK-4-ERROR: FastEthernet0/1 is experiencing errors ALSwitch#show vlan VLAN Name Status Ports 3-3 Semester 8 Internetwork Troubleshooting v1.0 - Lab 6.2.2 Copyright  2001, Cisco Systems, Inc. ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/2, Fa0/3, Fa0/4, Fa0/5, Fa0/6, Fa0/7, Fa0/8, Fa0/9, Fa0/10, Fa0/11, Fa0/12 1002 fddi-default active 1003 token-ring-default active 1004 fddinet-default active 1005 trnet-default active VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 1002 1003 1002 fddi 101002 1500 - - - - - 1 1003 1003 tr 101003 1500 1005 0 - - srb 1 1002 1004 fdnet 101004 1500 - - 1 ibm - 0 0 1005 trnet 101005 1500 - - 1 ibm - 0 0 Step 3 Write down your observations for the ALSwitch and the DLSwitch. Step 4 List the possible causes of this problem. Step 5 Create an action plan to fix the problem. Step 6 Implement the action plan. Step 7 Observe the results of the action plan. Step 8 Document your work. . Inc. Lab 6.2.2 Trunking Misconfiguration (Troubleshooting LAN Switches) Fast 2/3 Fast0/1 Fa 0/2 Trunk Crossover Connection ALSwitch 2900XL-Ent VLAN 10 Client. establish trunking using the command “switchport mode trunk” on interface FastEthernet 0/1 for the access layer switch and establish the necessary VLAN trunking