The MPLS WG Archive

Cell Relay Retreat>MPLS WG Archive>month:2002-Feb> msg00161



[Date Prev][Date Next][Thread Prev][Thread Next]  
  [Date Index][Thread Index][Author Index][Subject Index]

penultimate hop popping!!!

  • From: Mohammed <ipswitching@yahoo.com>
  • Date: Tue, 19 Feb 2002 14:37:51 -0800 (PST)
  • Cc: ahussain@eng.utoledo.edu

Hi all,

  I have a query regarding penultimate hop popping.
Please refer to the following figure ..

  
      0 --- 1 --- 2 --- 3 ---- 4 --- 5
            ---------- ----------
                MPLS DOMAIN.

 Lets assume that nodes 1,2,3 and 4 form the MPLS
domain. Lets say node 0 and node 5 are ip nodes.

 For traffic generated by node 0 and destined to node
5 the path would be 0->1->2->3->4->5 where 1-2-3-4 is
an LSP.

 LSR 4 knows that it is the egress because its
adjacent is not LSR. But LSR 3 ( penultimate node for
that LSP)has to do penultimate hop popping .. but it
has no way to know about this unless informed by LSR
4.

QUERY : How does LSR 4 inform LSR 3 that it has to do
penultimate hop popping ... DOES it gives LSR 3 an
IMPLICIT NULL LABEL.

 Any pointers in this area are welcome. PLease also
suggest other points that i may be missing. 

 Thanks to one and all!
 
 Sincerely,
 Abrar.


=====
Abrar Hussain.
Graduate Student/Network Designer.
The University of Toledo.
Toledo,OH.

__________________________________________________
Do You Yahoo!?
Yahoo! Sports - Coverage of the 2002 Olympic Games
http://sports.yahoo.com