[c-nsp] Monitoring CPU punted traffic

[Jeff Fitzwater]

I am running 720CXL with SXH code and am trying to monitor the punted  
traffic to the RP so that I can confirm what actually gets punted to it.

It appears to show packets but not positive I have configured it  
correctly.   Has anyone else used this tool?




The doc states that when using the RP CPU as SOURCE that the traffic  
is seen from the viewpoint of the ASIC, as shown in snippet below...


------------

Source CPUs

A source CPU is a CPU monitored for traffic analysis. With Release  
12.2(33)SXH and later releases, you can configure both the SP CPU and  
the RP CPU as SPAN sources. These are examples of what you can do with  
the data generated by CPU monitoring:

•Develop baseline information about CPU traffic.

•Develop information to use when creating CoPP policies.

•Troubleshoot CPU-related issues (for example, high CPU utilization).


Note•CPU SPAN monitors CPU traffic from the perspective of the ASICs  
that send and receive the CPU traffic, rather than from on board the  
CPUs themselves.

•Traffic to and from the CPU is tagged with VLAN IDs. You can  
configure source VLAN filtering of the CPU traffic.



-------------





This is how I configured the SPAN port....





(config) monitor ses 1 local   (This puts me in config-mon-local mode)

(config-mon-local) destination interface gi13/17  (THIS PORT HAS  
TCPDUMP HOST ATTACHED)

(config-mon-local) source cpu rp tx  (As stated in doc traffic is from  
viewpoint of ASIC, so I used TX assuming transmitted traffic to RP CPU.)

(config-mon-local)no shutdown  (This is needed to turn on monitor)

(config-mon-local) exit  (Must exit in order for no shutdown to take  
effect)





Thanks for any advise on this config.







Jeff Fitzwater

OIT Network Systems

Princeton University