Quick Reference Guide

1106 IPv6 Routing Commands
Receiving large numbers unresolved packets spikes the CPU usage to high
levels at no benefit. For Ipv6, it also results in delayed processing of the NUD
packets (NS/NA) for the existing neighbor entries leading to NUD anomalies
and deletions of existing neighbor entries.
To avoid such an unnecessary CPU load leading to NUD anomalies when the
ARP or IPV6 neighbor table is close to full (crossing 95% of table size) or
other failures, the switch automatically reduces the rate limit to an empirical
value of 50 pps irrespective of the configured rate limit. When the table size
falls below 95% of the table size, it is restored to the configured rate limit
value.
Use this command to limit the CPU load in situations where large numbers of
unknown multicast or IPv4/IPv6 packets with an unknown multicast or
unicast IPv4/IPv6 destination are being handled in software. The symptom
can be diagnosed by high CPU usage of the ipMapForwardingTask.
Example
An example output is showing higher than normal CPU usage due to packets
copied to the software forwarding task below:
console#show process cpu
Memory Utilization Report
status bytes
------ ----------
free 1055653888
alloc 672153600
CPU Utilization:
PID Name 5 Secs 60 Secs 300 Secs
---------- ------------------- -------- -------- --------
1129 osapiTimer 0.09% 0.02% 0.01%
1137 bcmCNTR.0 0.19% 0.28% 0.30%
1142 bcmRX 18.00% 12.04% 11.10%
1155 bcmLINK.0 0.39% 0.37% 0.36%
1156 cpuUtilMonitorTask 0.09% 0.04% 0.04%
1170 nim_t 0.09% 0.07% 0.07%
1222 snoopTask 0.09% 0.02% 0.02%
1243 ipMapForwardingTask 27.30% 24.19% 29.06%
1257 tRtrDiscProcessingT 0.09% 0.01% 0.00%
1291 RMONTask 0.00% 0.02% 0.03%
2CSNXXX_SWUM200.book Page 1106 Tuesday, December 10, 2013 1:22 PM