Subject: Re: Label Space

From: "Andrew G. Malis" <[email-masked]>
Date: Mon, 23 Aug 1999 22:13:02 -0400

Makarand,

As the person who originally suggested per-interface labels (back at the 
Cisco tag switching meeting at MIT in 11/96), I suppose it's incumbent on 
me to explain this.  Originally, labels were per-platform only (all 
incoming interfaces to an LSR shared a common set of incoming 
labels).  However, when label space is small (such as with 10-bit Frame 
Relay DLCIs), it is useful to be able to have independent label spaces on 
each incoming interface.  There are some limits on using per-interface 
labels: the LSR has to be able to distinguish which interface packets 
arrived on, so that they can be properly switched, and the upstream and 
downstream LSRs need to be directly connected.

This is discussed somewhat more formally in section 2.14 of 
draft-ietf-mpls-arch-05.txt.

Cheers,
Andy

--------

At 12:53 AM 8/24/99 +0530, Makarand Kulkarni (98307005) wrote:

>The mpls-ldp-05 draft (section 2.2.1) talks about 2 types of label spaces
>- per platform and per interface. But the difference isn't much clear to
>me. Can anyone please explain ?
>
>Regards
>Makarand

________________________________________________________________________
Andrew G. Malis  [email-masked]  phone:978 952-7414  fax:978 392-2074
Lucent Technologies                 1 Robbins Road    Westford, MA 01886