From: ZZ (zurabz@gmail.com)
Date: Wed Dec 03 2008 - 13:15:26 ARST
this is excellent explanation!
Thank you
On Wed, Dec 3, 2008 at 2:17 AM, Cristea, Bogdan, VF-RO <
Bogdan.Cristea@vodafone.com> wrote:
> 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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