How can you monitor(SPAN) traffic on a only the primary port or a secondary port of a LACP trunk on a Brocade Fastiron?

I can put the monitor command on the primary port e15 and it will allow me to monitor the traffic of the whole LAG. There seems to be no way to monitor a single link in the bundle.

LAG config:

interface ethernet 15
 spanning-tree 802-1w admin-edge-port
 no flow-control
 link-aggregate active
interface ethernet 17
 link-aggregate active

Error message when I try to configure secondary port:

telnet@s1(config)#int e 17
Error - cannot configure secondary ports of a trunk
  • @MikePennington We are trying to figure out if the the hashing algorithm is using all the variables it says that it uses in the documentation. – Adam Loveless May 26 '13 at 22:14

According to the FastIron config guide:

  If the primary interface of a trunk is enabled for monitoring, the entire trunk will be monitored. 
You can also enable an individual trunk port for monitoring using the config-trunk-ind command

Trunk in this sense being the FastIron term for an aggregated interface.

If this didn't work you could use a TAP, or push a link through another switch, tunnel LACP through that switch, then mirror the switch port


To add completeness to mellowd answer, the commands below allowed for capture of packets on individual links in a LAG bunldle.

switch(config)#mirror-port e 9 
switch(config)#trunk e 15 e 17 
!Monitor only primary port
switch(config-trunk-15,17)#monitor e 15 e 9 both
!Monitor only secondary port
switch(config-trunk-15,17)#monitor e 17 e 9 both

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