When a Cisco WLC's data plane crashes, it stores the last 50 packets that the controller received in flash memory. This information can be useful in troubleshooting the crash.
When a crash occurs, the controller generates a new packet capture file (*.pcap) file, and a message similar to the following appears in the controller crash file:
Last 5 packets processed at each core are stored in
"last_received_pkts.pcap" captured file.
- Frame 36,38,43,47,49, processed at core #0.
- Frame 14,27,30,42,45, processed at core #1.
- Frame 15,18,20,32,48, processed at core #2.
- Frame 11,29,34,37,46, processed at core #3.
- Frame 7,8,12,31,35, processed at core #4.
- Frame 21,25,39,41,50, processed at core #5.
- Frame 16,17,19,22,33, processed at core #6.
- Frame 6,10,13,23,26, processed at core #7.
- Frame 9,24,28,40,44, processed at core #8.
- Frame 1,2,3,4,5, processed at core #9.
You can use the controller GUI or CLI to upload the packet capture file from the controller. You can then use Wireshark or another standard packet capture tool to view and analyze the contents of the file.
Figure 2. Sample Output of Packet Capture File in Wireshark. This figure shows a sample output of the packet capture in Wireshark.