From: Brant I. Stevens (branto@branto.com)
Date: Sat Sep 09 2006 - 16:18:40 ART
IIRC, when speaking to another iBGP peer, a router running iBGP will not
modify the next-hop attribute of an advertised prefix. The knob "neighbor
a.b.c.d next-hop-self" is used to override that behavior.
The non-BGP router will see packets sourced-from/destined-to the
tunnel-source addresses of routers R1 and R2.
On 9/9/06 3:10 PM, "Mohamed Saeed" <mohamed_saeed2@rayacorp.com> wrote:
> Hi Briant,
>
> You have given me the point, when I set the next hop to the tunnel
> interface (using next-hop-self on R1 and R2), every thing went fine.
>
> I have tried to test why it does work now after setting the next hop to
> the tunnel interface.
>
> I have enabled "debug ip packet" on the intermediate router that is not
> running bgp (R3) and I have issued ping from one of the IBGP peers (R2)
> to a BGP destination behind the other IBGP neighbor (R1).
>
> What should be the packets source and destination as seen by the
> intermediate router (R3)?
>
>
> Could someone help with this?
>
> Regards
> Mohamed ...
>
>
> -----Original Message-----
> From: Brant I. Stevens [mailto:branto@branto.com]
> Sent: Saturday, September 09, 2006 6:17 AM
> To: Mohamed Saeed; ccielab@groupstudy.com
> Subject: Re: Transiting Non BGP Speaking Devices using Tunnels
>
> What is the next-hop address set to?
>
>
> On 9/7/06 4:03 PM, "Mohamed Saeed" <mohamed_saeed2@rayacorp.com> wrote:
>
>> Hi,
>>
>>
>>
>> How could I use GRE tunnels to transit non-BGP speaking routers
> without
>> redistributing the EBGP routes into the AS IGP?
>>
>>
>>
>> Assume that the AS consists of three routers; R1, R2 and R3. Each of
> R1
>> and R2 has an EBGP session with other AS. R3 has not BGP configured.
> Is
>> there a way to use a GRE tunnel between R1 and R2 to have reachability
>> from R1 to the BGP routes learned from R2 and vice versa without
>> redistributing the BGP table into the IGP of the AS?
>>
>>
>>
>> I have configured a GRE tunnel between R1 and R2 and I have
> established
>> IBGP peering between them using the tunnel IP address.
>>
>>
>>
>> Still I could not have full reachability unless I have disabled
>> synchronization and redistributed the BGP into the AS IGP, and I have
>> concluded that the tunnel has no added value,
>>
>>
>>
>> Would someone help with this?
>>
>>
>>
>> Thanks
>>
>> Mohamed ..
>>
>>
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