[j-nsp] JUNOS Equivalent to CISCO IOS next-hop-self

[Niaz, Wajahat]

We are using this technique in our network without running into any problem.

How changing the next hop attribute for an EBGP learnt route will lead to
routing loops ?


-----Original Message-----
From: Daniel Roesen [mailto:dr at cluenet.de] 
Sent: Monday, October 20, 2003 5:01 PM
To: Niaz, Wajahat
Cc: 'stewells at verizon.net'; juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] JUNOS Equivalent to CISCO IOS next-hop-self

On Mon, Oct 20, 2003 at 04:25:43PM -0400, Niaz, Wajahat wrote:
> Create policy under policy options to change the next hop
> 
> policy-statement next-hop-self {
>         then {
>             next-hop self;
>         }
>     }
> 
> and then import this policy in bgp
> 
> protocols {
>     bgp {
>         group ibgp-peer {
>             type internal;
>            
>             export next-hop-self;

This will read to routing loops in many topologies. Changing the
next-hop of IBGP-received routes to self must not be done.

Cisco's next-hop-self has this intelligence, JunOS not. You have
to do that manually by tagging EBGP-received routes and setting
next-hop self for them (and static/direct/whatever routes) when
re-advertising those to the IBGP mesh.


Regards,
Daniel