Subject: Two signalling protocols (LDP & RSVP)

From: "Anil Gunturu" <[email-masked]>
Date: Fri, 20 Apr 2001 11:12:21 -0700

Hi,
Is it possible to run both LDP and RSVP on the same interface? If it is
possible can they be using the same label space?
-Anil

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From: Eric Osborne <[email-masked]>
Date: Fri, 20 Apr 2001 16:01:16 -0400

> possible can they be using the same label space?

Yes, and yes.

eric

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From: Soumen Sarkar <[email-masked]>
Date: Mon, 23 Apr 2001 10:01:17 +0530 (IST)

> possible can they be using the same label space?

I didn't understand this. I thought standard LDP does not use LSP. Where is
label space coming into picture for LDP to use ?

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From: Ajay Simha <[email-masked]>
Date: Mon, 23 Apr 2001 01:14:50 -0400 (Eastern Daylight Time)

> label space coming into picture for LDP to use ?

Both LDP and RSVP *are* Label Distribution Protocols.  They both would be
responsible for assigning a label to a FEC and distributing it to their
neighbors.  If they are both running on the same LSR.  They could be
coming from either the same Label Space OR different Label Spaces.  The
answer to this like someone pointed out is "yes" and "yes".

-ajay

-- 
Ajay Simha
MPLS Deployment Engineer
IOS Technology Division
(919) 392-3141

"Study as if you were to live forever
 Live as if you were to die tomorrow"

 - Mahatma Gandhi

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From: David Charlap <[email-masked]>
Date: Mon, 23 Apr 2001 10:06:19 -0400

Soumen Sarkar wrote:
>> Is it possible to run both LDP and RSVP on the same interface? If
>> it is possible can they be using the same label space?
> 
> I didn't understand this. I thought standard LDP does not use LSP.
> Where is label space coming into picture for LDP to use ?

LDP, RSVP-TE and CR-LDP all distribute labels.  As such, if multiple
protocols are enabled on a single interface, they must share label
spaces - the data plane doesn't know which signaling protocol was used
to create the LSPs for each packet, so they must remain synchronized.

While LDP doesn't explicitly request the setup of LSPs, LSPs are
established as a natural consequence of distributing labels from one
side of the MPLS cloud to the other.

-- David