Re: Next HOP on IBGP

I tried to respond to your question the other day and had browser issues. My
understanding is you are asking why in a MPLS VRF is the next hop the PE
routers and not the source CE routers? If this is your question the reason
why this is required is because MPLS routers use a dual stack (outer and
inner) label in LDP/TDP. The outer label is source PE router advertising the
prefix and the inner label is the prefix within the VRF. This is not the
same scenario for non-mpls BGP networks such as a EBGP connection to an ISP
for internet and then IBGP connections to an internal LAN.

Steve Lyons

On Wed, Aug 19, 2009 at 11:24 PM, Narbik Kocharians <narbikk_at_gmail.com>wrote:

> May be the link is advertised in the IGP that you are running between R1
> and R2. Some times its recommended to do that with a passive-interface to
> provide reachability.
>
>
> On Wed, Aug 19, 2009 at 8:12 PM, Steve Lyons <charter21p5_at_gmail.com>wrote:
>
>> On Tue, Aug 18, 2009 at 5:12 AM, Mark Stephanus Chandra <
>> mark.chandra_at_gmail.com> wrote:
>>
>> > Dear GS,
>> >
>> >
>> >
>> > I have something weird going on,
>> >
>> >
>> >
>> > This is my network topology
>> >
>> >
>> >
>> > R1(AS 65000)-------R2(AS65001) ------R3(AS65001)
>> >
>> >
>> >
>> > So R1 have eBgp connection to R2 and R2 and R3 have iBGP connection.
>> >
>> >
>> >
>> > The Theory is, if R2 have routing update from R1, then the nexthop is R1
>> > and
>> > the update continue to R3 but cause of this iBGP Connection, the next
>> hop
>> > will not change and still to R1.
>> >
>> >
>> >
>> > But Now, in one of my customer network, I can see route update that come
>> > form R1, from R3 perspective the nexthop is change to R2, and in R2 I'm
>> not
>> > configured Next-hop-Self.
>> >
>> >
>> >
>> > Have anyone experiencing the same like I do ?
>> >
>> >
>> >
>> > IOS bug ?
>> >
>> >
>> >
>> > FYI, this is all inside the same VRF
>> >
>> >
>> >
>> >
>> >
>> > Regards
>> >
>> > Mark Stephanus Chandra - CCIE#23887
>> >
>> >
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>> >
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>>
>>
>>
>>
>
>
> --
> Narbik Kocharians
> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com <http://www.micronicstraining.com/>
> Sr. Technical Instructor

Blogs and organic groups at http://www.ccie.net
Received on Thu Aug 20 2009 - 23:22:15 ART