The MPLS WG Archive

[Shahram Davari <Shahram_Davari@pmc-sierra.com>]

Hi Eric,
 
There are two scenarios that a single label may correspond to multiple
NHLFEs:
 
1) Some part of an LSP is E-LSP and another part is L-LSP
2) In case of Multicast.
 
Regards,
Shahram Davari 
Product Research 
PMC-Sierra Inc. 
555 Legget drive, 
Suit 834, Tower B, 
Ottawa, ON K2K 2X3, Canada 
Phone: +1 (613) 271-4018 
Fax  : +1 (613) 271-7007 
    

-----Original Message-----
From: Eric Gray [mailto:EGray@zaffire.com]
Sent: Monday, May 08, 2000 12:51 PM
To: 'Trilok Chand'
Cc: mpls@UU.NET
Subject: RE: ILM mappings


TrilokChand,
 
    An interesting question.  How did there get to be multiple
NHLFEs for a single incoming label?  Suspending disbelief
on this for a moment, however, and supposing there was a
reason for this to happen - the implementer must have had
some plan for demultiplexing the single label to determine
which NHLFE would be used.  One way might be to pop the
label and look at what comes after it - but a pop instruction
should be a single NHLFE (with - in this case - a next hop 
of "self").  Is there a useful application for this scenario?
 
    It seems to me that there would not be multiple NHLFE
entries for a single label as this will defeat the purpose for 
having a label.  But, even if there was a reason to do this,
the implementation that causes this to happen is the same
implementation that has to deal with the outcome.
 
    If you shoot yourself in the foot, it will hurt. :-)
 
--
Eric Gray

-----Original Message-----
From: Trilok Chand [mailto:trilok@chiplogic.com]
Sent: Monday, May 08, 2000 3:25 AM
To: mpls@UU.NET
Subject: ILM mappings


Hi,
        Can anybody tell where can i get information about choosing an ILM
mapping when there are multiple NHLFEs existing for an incoming label? 
 
Thanks in advance,
TrilokChand