Ash,

Reading RFC 3036 one can see the need for a separate protocol for carrying
labels. It has additional things such as:

1. neighbor discovery
2. non-adjacent neighbors

I guess someone on the list can argue that all these things could be
incorporated into OSPF/ISIS or any other routing protocol. Based on the
sheer quantity of new things in RFC 3036 it seems like adding all these new
capabilities to something like OSPF would not be appropriate.

BGP on the other hand is not a link state protocol. It has proved to be a
robust protocol to carry:

1st - unicast ip routes
2nd - mcast routes

BGP also seemed to the favorite protocol folks are looking at to carry
voice routing tables etc..

Again BGP does not replace LDP. It only serves for exchanging label
bindings for external routes - again BGP has been the choice of protocols
for carrying external routes.

In short -- BGP is an exterior gateway protocol, whereas OSPF is not and
MPLS does not have any bounds with respect to the autonomous system. Hence
if you need to send your labels spanning multiple AS, then BGP is the ONLY
choice!

Hope it helps.

Regards,
Manav Bhatia

----- Original Message -----
From: "Ash he" <ash_heYAHOO.COM>
To: <OSPFDISCUSS.MICROSOFT.COM>
Sent: Tuesday, April 09, 2002 3:35 AM
Subject: Link State Protocols with Label distr.

| Why are Link State Protocols not suited for Label
| Distribution (for MPLS)?
|
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