mls cef rate limit auto defense

tporembski · ‎05-20-2008

I have upgraded 68 6509s with sup 720s from 12.2.18SXF7 to 12.2.18SXF13 and on the 2 6509s facing the Internet I received the following log messages during the reboot:

May 18 03:54:12 UTC: %MLSCEF-SP-4-FIB_EXCEPTION_THRESHOLD: Hardware CEF entry usage is at 95% capacity for IPv4 unicast protocol.

May 18 03:54:15 UTC: %MLSCEF-SP-4-FIB_EXCEPTION: FIB TCAM exception for IPv4 unicast, Some routes will be software switched.

Use "mls cef maximum-routes" to modify FIB TCAM partition.

When I went back into the configuration I noticed this command was put in by the IOS:

mls rate-limit unicast cef receive 10000 100

I assume that the IOS does this as some type of self defense. The effect it had was it slowed Internet access to a crawl.

I am trying to find any documentation that speaks to this situation and couldn't find anything on Cisco and currently have TAC case open but they are currently telling me the IOS doesn't put commands in by itself, however I have proof that it does.

has anyone experienced this or know of any documentation that addresses this possibility?

Thank You

Tony.

didyap · ‎05-26-2008

The following message is logged continuously even though all traffic was stopped.

%MLSCEF-SP-4-FIB_EXCEPTION: FIB TCAM exception for IPv4 unicast,

Some routes will be software switched.

Use "mls cef maximum-routes" to modify FIB TCAM partition.

For the further details follow the bug CSCsm27567 which will help you.