From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Mon Apr 14 2003 - 23:27:55 GMT-3
At 8:58 PM -0400 4/14/03, OhioHondo wrote:
>Hello
>>
> I thought I'd try resending this because the orginal thread
>got somewhat
>off track. Someone suggested that, when using confederations, each sub-AS
>should be its' own IGP domain (i.e. with OSPF, have it's own area 0) Does
>everyone else agree with this??
Emphatically agree. The whole point of confederations is to bound a
community of interest, with the reduction of iBGP loads in comparison
with non-confederation a desirable side effect. If you are trying to
bound BGP information, what would be the point of leaking IGP
information outside the community of interest?
*sigh* I suppose I can't preclude something like this on a lab, given
Cisco's propensity for wanting to explore knowledge of knobs with
configurations which, if anybody did in the real world, should be
grounds for firing. But from my perspective, it really makes sense
to master the plausible configurations first, and learn the protocols
in the way they were intended to be used. If you get sufficient
understanding of this and then get a weird case in the lab, your
in-depth understanding should dig you out. It's simply not possible
to practice every conceivable permutation of protocol options,
especially those that don't make sense.
>
>Thge original question was....
>I have a question for someone with a grasp on BGP Confederations and how>
>synchronization affects it. My scenario
>>
>> AS301/R7 --- AS501/sub-AS65001/R3 --- AS501/sub-AS65002/R1 --- AS101/R9
>> |
>> |
>> AS501/subAS65001/R2
>>
>> Routers R1, R2 and R3 are in a single OSPF domain. The BGP router-id's and
>> OSPF router-ids are the same on all routers.
>>
>> My problem --- an advertisement comes in from AS101/R9, let say
>49.0.0.0/8.
>> That advertisement is propagated via OSPF to router R2 with R1's OSPF
>> router-id.
>>
>> When that advertisement crosses the sub-AS border between R1 and R3, the
>BGP
>> router-id is changed to that of R3, therefor when the iBGP route gets to
>R2,
>> the BGP router-id is from R3 while the OSPF router-id is from R1. The
>result
>> is no sync. Any advice????
>
>Jerry Haverkos
>jhaverkos@columbus.rr.com
>614-351-8617
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