From: Cristea, Bogdan, VF-RO (Bogdan.Cristea@vodafone.com)
Date: Wed Dec 03 2008 - 05:17:51 ARST
Hi all,
Hope the bellow explication helps:
Because the 7600 uses FIB downloaded in the PFC there is the following
scenario:
If you inject in RIB a number of routes larger then the maximum routes
for the supervisor you own then you will reach the case when the desired
FIB for download into PFC is larger that the maximum defined and you
will get that message.
show mls cef maximum-routes
FIB TCAM maximum routes :
=======================
Current :-
-------
IPv4 + MPLS - 192k (default)
IPv6 + IP Multicast - 32k (default)
The event will trigger an exception leading to exception state set to
TRUE for the type of routes for which you reached the maximum routes
The normal output would be:
show mls cef exception status
Current IPv4 FIB exception state = FALSE
Current IPv6 FIB exception state = FALSE
Current MPLS FIB exception state = FALSE
You can also check that you hit the exception looking in the output of
show mls cef at the start.
There are 2 solutions:
1. power cycle the router
2. if you have a redundant supervisor:
Power cycle the standby supervisor (this will enforce the
download of the current FIB in the PFC
Check that after the reload the command "remote command
standby-sp show mls cef exception status" shows you false for each
exception state
Then perform a switchover. If the old active supervisor does not
reboot you will need also to power cycle it manually.
I had the same problem on a 7600 box and resolved via solution number 2.
The behaviour before resolving the problem was random packet drops.
Also if I was transforming to process switching the packet forwarding
was ok
The solution with new ios works because you actually need to power cycle
the box/supervisors but not because the ios version is the root cause.
Take care when you perform the steps in order to not disrupt your live
services :)
Bogdan Cristea
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Marko Milivojevic
Sent: 02 December 2008 21:43
To: ZZ
Cc: Pavel Bykov; Cisco certification
Subject: Re: Hardware CEF entry usage is at 95% capacity on 7600
On Tue, Dec 2, 2008 at 16:09, ZZ <zurabz@gmail.com> wrote:
> I totally agree, it shouldn't crash, maximum it should it is to
disable CEF.
>
> I'm running 12.2(33)SRB2
Well, it can't disable CEF as it has no other forwarding mechanism
available. It should drop flows that it has no space for. Now that I
see what IOS you are running -- run from it and run fast :-). That one
is trouble. I believe they are up to SRB5 now.
-- Marko CCIE #18427 (SP) My network blog: http://cisco.markom.info/Blogs and organic groups at http://www.ccie.net
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