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SONiC hands-on training - Module 7 - Lab 1 - Interface Troubleshooting

You are a network engineer tasked with troubleshooting interfaces between R1 and R2. You need to check what’s wrong on the R2 and you need to make changes there to match the settings from R1.

Topology

 Instruction 

Step 1: Verify the interface status

  1. Verify the interface status to check the status of three connected interface to see what’s wrong with every pair.


    Show interface status

Step 2: Verify the LLDP Table

  1. Check the LLDP table to see

      show lldp table

Step 3: Check first connection (R1 Ethernet0 – R2 Ethernet0) – what’s wrong there? Compare both sides.

  1. As you can see, the ports are shut down. Enter configuration mode and bring up the interfaces.

Step 4: Check second connection(R1 Ethernet1 – R2 Ethernet1) – what’s wrong there? Compare both sides.

  1. As you can see in the interface configuration, there’s an FEC mismatch. To check that, use command:

Show interface Ethernet 1

In the R2 you have “none” when on the R1 you have RS. Change the FEC in the Ethernet1 on R2 to RS using this command in interface config:

        fec RS

Step 5: Check third connection(R1 Ethernet2 – R2 Ethernet2) – what’s wrong there? Compare both sides and try to ping after solving an issue.

  1. As you can see, there’s VLAN mismatch there. To check that, use command:

         Show vlan

      After changing vlan in the R2 to match the R1, try the ping again. Ping should be executed successfully.

–  Default Credentials: admin / YourPaSsWoRd

 – Compare settings on both devices to spot mismatches.

 – Use LLDP info to verify physical connections.

 – After fixing configuration issues, recheck interface status and test connectivity.

 – Don’t forget to save your changes.