Netdr IOS

Unanswered Question

Can someone explain the difference between the two debug netdr  commands.

SUP 720


NJSE-425M-1-WAN1#debug netdr ?
  capture        Capture packets into a buffer to show later
  clear-capture  Clear the capture buffer (leaves filters as was)



NJSE-425M-1-WAN2#debug netdr ?
  all    All NetDriver debugging messages
  data   NetDriver Data Flow
  error  NetDriver Errors

Thank you

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Overall Rating: 3 (1 ratings)
Scott Bradley Tue, 08/17/2010 - 09:46
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Sup2 had a much older implementation of debug netdr.  We would typically use debug netdr data rx.  Debug netdr all and errors -never tried it.

With sup720 the implementation is much cleaner and easier to use as you have shown below. We typically use these for troubleshooting high cpu or using it to figure out unauthorized packets hitting the cpu.

John Patrick Lopez Sat, 08/28/2010 - 09:14
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Hi Sirs,

We are using hybrid 6500. We encountered several switching loops this past few months but it gets resolved prior to troubleshooting. According to Cisco TAC, they would like to run that netdr thing but I would also like to know what else it can do to locate the problem. The traffic in the network is high and I would like to know if enabling this netdr will hit the network or cpu utilization of the switch too much.

Can I use it even if I'm using hybrid? Thanks.


george.karavitis Fri, 09/10/2010 - 00:33
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Hello John

I can help you on this question. Enabling netdr is not impacting the CPU and the captures are kept on separate (special) buffers for the job. So it is safe to enable it as it will capture the packets going to CPU giving an indication of why they are special handled. Even better if you specify interface when enabling it.

I have my own question, I thought if better posting it here instead of opening a new subject:

WHere can I find a list describing the 'dest_indx' values?

Example, Cisco has identified that "dest_indx 0x7F07" means that these packets are icmp redirects. And indeed with applying a msl rate limit for icmp redirects problem solved. So the question is where can i find a list explaining all codes for 'dest_indx' ? Now we have on another part of the network identified many packets with "dest_indx 0x380" and I don't want to open a TAC Case everytime to ask what kind of packet are those... ANy help?



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