From: Mohamed M Moustafa (mmma@gawab.com)
Date: Sun Aug 26 2007 - 16:07:10 ART
Hi,
Totally agree with Lim, " r>" on an iBGP route means that the route is the
best (in the BGP path selection), but still there was a better route to be
installed in the routing table and thats why the name RIB failure (failed
to enter the routing table due to a better routing protocol route), while
it will still be sent to other BGP neighbors (since it is selected as best
by the BGP path selection), while if there wasn't a better route, then the
route would have been "*>" meaning that it is best and inserted into the
routing table.
HTH,
Mohammed Mahmoud.
Toh Soon, Lim <tohsoon28@gmail.com> wrote on 26 Aug 2007, 09:44 PM:
Subject: Re: bgp rib failure problem or not?
>Hi Alex,
>
>IMHO RIB failure means the router has learned the route via a better AD
>source, in your case it's OSPF (AD 110) compared to iBGP (AD 200).
>
>If you configure R1 to advertise the R1-R2 network in BGP, you'll see R2
>receives the route in BGP table but its status code is r>.
>
>R2 will still advertise the route in BGP because it's selected as the
>best path (the > sign).
>
>HTH. I hope I understood it correctly.
>
>
>Thank you.
>
>B.Rgds,
>Lim TS
>
>
>On 8/26/07, Alex Steer <alex.steer@eison.co.uk> wrote:
>>
>> Hello everyone,
>>
>>
>>
>> Just got a quick question with regard to BGP RIB failures on internally
>> known routes installed into BGP via the network command. I've noticed
>> quite a few scenarios where this seems to happen and not sure if I'm
>> missing a trick. I was hoping somebody would like to enlighten me
>> slightly as to if it causes some sort of problem I'm not noticing.
>>
>>
>>
>> Here is the topology/masterpiece of modern art:-
>>
>>
>>
>> Network1==R1======R2======R3
>>
>>
>>
>> AS numbers
>>
>>
>>
>> R1, R2 = 100
>>
>> R3 = 300
>>
>>
>>
>> Network1 is known to R1 and R2 via an IGP (say ospf) and via the network
>> command on R1.
>>
>>
>>
>> R1s routing table Network1 is known via connected
>>
>> R2s routing table Network1 is known via ospf
>>
>> R3s routing table Network1 is known via eBGP (ad20) next hop R2
>>
>>
>>
>> Network1 is participating in the OSPF process
>>
>> Network1 is placed in the BGP table on R1 via "network" command
>>
>>
>>
>>
>>
>> Great so it all works fine. So my question is, why does BGP on R2
>> advertise the route to R3 when it doesn't like the route itself? Is
>> there a problem that the RIB failure is causing and I'm not seeing? It
>> looks to be working fine, is there another purpose to informing me of
>> the r?
>>
>>
>>
>> R2#show ip bgp
>>
>> Network Next Hop Metric LocPrf Weight
>> Path
>>
>> r>i Network1/24 Router1 0 100
>> 0 i
>>
>>
>>
>> R3#show ip bgp
>>
>> Network Next Hop Metric LocPrf Weight
>> Path
>>
>> *>i Network1/24 Router2 0 100
>> 0 100 i
>>
>>
>>
>> By the way I made all of the output up as my lab is off so forgive any
>> slight mistakes. It's only to aid in posing my question.
>>
>> Many thanks for any info on this.
>>
>>
>>
>> Kind regards
>>
>>
>>
>> Alex
>>
>>
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