The MPLS WG Archive

[Curtis Villamizar <curtis@workhorse.fictitious.org>]

Eric,

In message <4611AD058694D4118FD5009027B0A6625D8AA5@ICARIAN>, Eric Gray writes:
> Curtis,
> 
> 	Please see below.
> 
> Curtis Villamizar wrote:
>  ... <snip> ...
> > 
> > For example, optical switches will definitely NOT run IBGP with the
> > Internet routers.  They run an IGP and MPLS (plus LMP) but not BGP.
> > (In any reasonably sane network).
> > 
[...]
> 
> So, I seem to have missed your point.  Can you elucidate?


Within an AS there is no strict need for any interior MPLS capable
device to run IBGP if there are MPLS LSPs between any two non-interior
(border) devices.  An interior device is one which has no EBGP peers.
A non-interior does have EBGP peers and is usually called a border
router.

Stating the obvious: You only run IBGP wtih peers in your own AS.  You
only run EBGP with peers outside your own AS.

The only potential reason to run IBGP is so that the interior routers
have full Internet routes and can handle ICMP and traffic to the local
device without resorting to a default route to a border.

Optical switches are not known for the robustness of their BGP
implementations if they have BGP implementations at all.  They may
also have more important things to do with their CPU cycles given that
they do no externalrouting at all.  It would seem to be a relly bad
idea to run IBGP to the optical switches.

I hope that was more clear.

Curtis