From: Andrew Lissitz \(alissitz\) (alissitz@cisco.com)
Date: Wed Oct 05 2005 - 17:30:55 GMT-3
Hello,
Multicast would have problems if the Unicast table is not right. RPFs
etc... Incoming and outgoing interface problems...
The reason I asked about redist is because OSPF, by itself, is pretty
good about keeping loops from occurring. If you saw packets expiring
and looping, then I would check your routing sources. Loops occur when
routing data is not consistent / correct and up to date.
The devices that bounced the packets around thought they had the correct
route for the destinations. Why and where did they learn their routing
information....
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Mike O
Sent: Wednesday, October 05, 2005 3:38 PM
To: mandingo2073@yahoo.com
Cc: ccielab@groupstudy.com
Subject: Re: OSPF routing loop
Well we run mulitcast and it reported a unicast routing loop and when
you did a traceroute it kept bouncing back till the TTL expired.
>From: Carl Willias <mandingo2073@yahoo.com>
>Reply-To: Carl Willias <mandingo2073@yahoo.com>
>To: Mike O <mikeeo@msn.com>, alissitz@cisco.com, ccielab@groupstudy.com
>Subject: Re: OSPF routing loop
>Date: Wed, 5 Oct 2005 12:29:21 -0700 (PDT)
>
>Why do you think it was a routing loop? I have seen issues with a
flood of
>LSA's causing high CPU utilization on routers causing it to drop
packets,
>routing and otherwise.
>
>----- Original Message ----
>From: Mike O <mikeeo@msn.com>
>To: alissitz@cisco.com; ccielab@groupstudy.com
>Sent: Wednesday, October 05, 2005 1:59:30 PM
>Subject: RE: OSPF routing loop
>
>
>Yes we redistbute OSPF into BGP for iBGP.
>
>We also use the command "timers throttle spf 400 400 4000" and I think
it
>was trying to flood out LSA's while the link was flapping and caused a
loop
>in the Area
>
>
> >From: "Andrew Lissitz (alissitz)" <alissitz@cisco.com>
> >Reply-To: "Andrew Lissitz (alissitz)" <alissitz@cisco.com>
> >To: "Mike O" <mikeeo@msn.com>, <ccielab@groupstudy.com>
> >Subject: RE: OSPF routing loop
> >Date: Wed, 5 Oct 2005 14:34:22 -0400
> >
> >Mike, are you all performing any redistribution?
> >
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> >Mike O
> >Sent: Wednesday, October 05, 2005 12:09 PM
> >To: ccielab@groupstudy.com
> >Subject: OSPF routing loop
> >
> >Can a rapidly flapping interface cause a routing loop with OSPF?
> >yesterday we had an interface bounce every 90 seconds and caused a
> >routing loop within the network until we shut it down. Shouldn't the
> >hold-down timers prevent this?
> >
> >
> >Thanks,
> >
> >Mike
> >
>
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