Re: Bgp update source loopback

When, *Neighbor update-source* command is used, the source of BGP TCP
connections for that is the IP address of the loopback interface instead of
the IP address of a physical interface....

Means that for so and so neighbor...i am updating my source..i.e
loopback...means i want to establish my BGP TCP peering with the neighbor
using my loopback address

i BGP will come up...but reason for using loopbacks are is that..Loopbacks
interfaces are always up....it only goes down incase the whole router is
down... as u said IBGP will come up....with physical interface .... and if
your physical interface gets down...your peering is down..and you can reach
the the neighbor...

so its better to do peering in IBGP using loopbacks..rather than physical ip
interface..

Raghava Rao TV

On Sun, May 16, 2010 at 9:10 AM, Joe Astorino <jastorino_at_ipexpert.com>wrote:

> Peering using loopbacks is almost always what you want between PE routers.
> If you use physical addresses you can run into issues with PHP causing a
> no-label to next hop situation
>
>
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> -----Original Message-----
> From: Mustafa Yadav <mustafa.yadav_at_gmail.com>
> Date: Sun, 16 May 2010 06:29:19
> To: Cisco certification<ccielab_at_groupstudy.com>
> Subject: Bgp update source loopback
>
> Hi All,
>
> I see i-bgp configuration in all mpls labs done by using update-source
> loopback.Why do we have to use loopback as a source?If we do not use I
> think
> ibgp also come up.Is not that right?
>
>
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-- 
Regards,
Raghava Rao T.V
Mumbai
Blogs and organic groups at http://www.ccie.net