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Cisco Bug: CSCtg95381 - Traffic may punt to CPU because uRIB is not installed

Last Modified

Oct 04, 2016

Product

Cisco Nexus 7000 Series Switches

Known Affected Releases

5.0(2)

Description (partial)

Symptom:
Nexus 7000 may punt traffic to CPU; so that the traffic may experience random delay or drop.

Further looking, ARP is learned and FIB adjacency is in FIB adjacency table.

Conditions:
The problem is caused by race condition. Some hosts have not responded to the ARP refresh sent by 
N7k which in turn  trigger to delete  ARP entry  due to expiry. As a result   the route delete notification is 
sent to URIB from the process. However there is still traffic coming to given IP address as a result  the next packet that hit glean resulting in triggering ARP and  hope ARP is learnt from the host this time. 

Workaround(s):
Clear ip route <host>.
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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
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