Cisco Debug

Troubleshooting

Let's make the assumption that as the network administrator you only have access to the CaptureRouter and you need to prove if the packet loss is on that device. The first step is to determine if the packets are actually coming in to the CaptureRouter. Previously one could use things such as an ingress ACL and watch hit counters or configure netflow on the ingress interface. This exercise is to show how to use the Packet Capture feature to isolate the loss.

   All of the commands are done at the EXEC prompt so configuration access isn't required unless you need to define an access-list (ACL) to make the capture more granular.
   The following steps are needed to capture the frames: 

• Define a capture buffer -> This is where the frames are stored once captured

• Define a capture point -> This gives the user the ability to be more granular on what interface, switching path the frames are captured

• Associate the capture point with the capture buffer -> You can associate multiple points to the same buffer

• Start the capture

• View the capture and/or export it to a PCAP file for offline analysis