Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 720)

Using debug commands
You can perform the following operations related to debugging features:
• To enable debugging on a feature, use the debug command.
debug feature required-keywords
• To check whether debugging is enabled on a feature, use the show debug command.
show debug feature
• To disable debugging, use the no debug command.
no debug feature required-keywords
Use caution when debugging in real time on a production switch, because real-time debugging is
CPU-intensive. Brocade recommends checking the debug output on a lab switch first, and then if the
output looks acceptable, enable it on the production switch to get more data. In addition, to reduce
CPU load, Brocade recommends using keywords such as events and summary that limit the extent
of debugging rather than more comprehensive options such as detail and all.
Debugging operations are used mainly for debugging control plane protocols such as LACP and
LLDP. For example, to view received LLDP packets on the console, use the following command.
switch# debug lldp packets all rx
If the switch is accessed through Telnet, enable logging using a terminal monitor.
The following are the most often used debug commands:
• debug lldp packets interface [rx | tx | both ]
• debug lacp pdu [rx | tx]
• debug spanning-tree bpdu [rx | tx] (Standalone mode only)
• debug dot1x packet (Standalone mode only)
Using SPAN port and traffic mirroring
In certain instances, you may need to examine packets in transit across links to understand the traffic
pattern on a specific port. In such situations, Switched Port Analyzer (SPAN) can be configured to
copy the traffic (with the desired direction) on the specific Ethernet port to a mirror port where a sniffing
device is connected. You can then analyze the packets captured by the sniffing device.
switch(config)# monitor session 1
switch(conf-mon-sess-1)# source tengigabitethernet 1/0/10 destination
tengigabitethernet 1/0/15 direction both
switch# show monitor 1
Session :1
Description :Test SPAN Session
State :Enabled
Source interface : 1/0/10 (Up)
Destination interface : 1/0/15 (Up)
Direction :Both
The source and destination ports must belong to the same ASIC. The Brocade VDX 6720-24 and
Brocade VDX 6730-32 switches have just one ASIC, so source and destination can be any 10-GbE
port. Other Brocade VDX switches have multiple ASICs; The table below shows the mapping of ports
to these ASICs.
Using debug commands
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