Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

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Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

Packet tracing

Updated: April 10, 2026

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Introduces packet tracing for Cisco Catalyst 9800 Series Wireless Controller for Cloud, detailing how to enable and use conditional debugging, apply per-AP and per-Client tracing, and explaining limitations of filtering with MAC or IP headers in CAPWAP-encapsulated packets.

A packet tracing is a network diagnostic tool that

  • tracks the flow and processing of individual data packets through a network device

  • provides detailed per-packet information based on user-defined conditions for troubleshooting purposes, and

  • helps identify network issues such as misconfiguration, capacity overload, and software bugs.

The packet tracing feature explains how to perform data plane packet tracing for Cisco Catalyst 9800 Series Wireless Controller for Cloud software.

To trace packets on the controller:

  1. Enable conditional debugging on selected packets or traffic to trace.

  2. Enable packet tracing (per-AP or per-Client).

Note

Use per-AP conditional debugging with a MAC address filter when the AP and controllers are in the same VLAN. If they are in different VLANs, per-AP packet tracing with a MAC address does not capture packets because the MAC address varies.

Limitation of Conditional Debugging Packet Tracing

The MAC or IP filter applies only to the outer Ethernet or IP header. If a packet is CAPWAP encapsulated, the MAC or IP filter does not affect the inner 802.11 MAC or IP header.

Configure conditional debugging packet tracing (CLI)

Enable and manage in-depth packet tracing for troubleshooting and diagnostics while minimizing resource usage using commands.

Procedure

1.

Enable the privileged EXEC mode.

Example:

Device# enable

Enter your password, if prompted.
2.

Configure packet tracing to capture the last set of packets.

Example:

Device# debug platform packet-trace packet 8192 circular fia-trace data-size 2048

packet-count: Here, the valid range is from 16 to 8192.

data-size: Here, the valid range is from 2048 to 16384 bytes.
3.

Configure packet tracing for a copy of packet data.

Example:

Device# debug platform packet-trace copy packet both size 2048

packet-size: Here, the valid range is from 16 to 2048 bytes.
4.

Enable conditional debugging for an interface, MAC, or IP filter.

Example:

Enable conditional debugging for TenGigabitEthernet 0/0/0 and match packets whose source and destination MAC is 192.0.2.1:

Device# debug platform condition interface {interface-name TenGigabitEthernet | cpp} 0/0/0 {mac | ipv4 | match} 192.0.2.1 {both | ingress | egress}

An interface refers to any physical port, port channel, internal vlan, SVI, or wireless client.
5.

Start conditional debugging packet tracing.

Example:

Device# debug platform condition start
6.

Stop conditional debugging packet tracing.

Example:

Device# debug platform condition stop
7.

Redirect all traced packets to bootflash.

Example:

Device# show platform hardware chassis active qfp feature packet-trace packet all | redirect bootflash:packet_trace.txt

Convert the packet_trace.txt to pcap and download the pcap files. You can do so using this link:

http://wwwin-dharton-dev.cisco.com/pactrac2pcap.html

Configure conditional debugging packet tracing per AP (CLI)

Enable conditional debugging to trace CAPWAP packets for a specific AP by filtering with MAC or IP address using commands.

Procedure

1.

Enable privileged EXEC mode.

Example:

Device# enable

Enter your password, if prompted.
2.

Enable conditional debugging with MAC filter.

Example:

Device# debug platform condition interface {interface-name TenGigabitEthernet | cpp} 0/0/0 {mac 192.0.2.1 | access-list acl-name | ipv4 | match} {both | ingress | egress}

Here, the CLI matches the packets whose source or destination MAC address is 192.0.2.1
3.

Enable conditional debugging with inline MAC ACL.

Example:

Device# debug platform condition interface TenGigabitEthernet 0/0/0 match mac { H.H.H. | any | host} 192.0.2.1 {both | ingress | egress}
4.

Enable conditional debugging with IP filter.

Example:

Device# debug platform condition interface TenGigabitEthernet 0/0/0 ipv4 {192.0.2.1 | access-list ip-acl-name| both | egress | ingress} {both | egress | ingress}

0/0/0: is the GigabitEthernet interface number. The valid range is from 1 to 32.

Configure conditional debugging packet tracing per client (GUI)

Enable targeted packet tracing for individual clients to facilitate in-depth troubleshooting and analysis using GUI.

Procedure

1.

Choose Troubleshooting > Radioactive Trace.
2.

Click Add.
3.

In the Add MAC/IP Address window, enter the MAC/IP Address.
4.

Click Apply to Device.

Configure conditional debugging packet tracing per client (CLI)

Enable conditional debugging to trace packets for a specific wireless client, helping to diagnose network issues more efficiently using commands.

Procedure

1.

Enable privileged EXEC mode.

Example:

Device# enable

Enter your password, if prompted.
2.

Enable conditional debugging for a wireless client interface.

Example:

Device# debug platform condition interface {intf-name | cpp 0xa0000001} { mac | ipv4 | match [ipv4 | ipv6 | mac]} protocol icmp host 192.0.2.1 host 192.0.2.1 {both | ingress | egress}

cpp-handle-index: The valid range is from 1 to 4294967295.

Verify conditional debugging packet tracing configuration

To view the summary of the traced packet, use this command:

Device# show platform packet-trace summary

To view a specific traced packet, use this command:

Device# show platform packet-trace packet <packet number>

To view the wireless client interface handle, use this command:

Device# show platform hardware chassis active qfp feature wireless wlclient cpp-client mac-address client-mac details
Device# show platform hardware chassis active qfp feature wireless wlclient cpp-client mac-address 8825.93b0.b51f details 
Client Details for client cpp_if_handle: 0x34
Name : WLCLIENT-IF-0x00a0000001
Mac Addr : 8825.93b0.b51f
pal_if_handle : 0xa0000001
Mobility State : LOCAL
Multicast Action : FORWARD
Auth State : RUN