Subject: RE: Regarding Label Mapping Advertisements and Label Mapping Rele ase in maritini-trans-10

From: "Gray, Eric" <[email-masked]>
Date: Mon, 30 Sep 2002 08:55:17 -0400

There is no reason to specify a timer since the implementation

may use one of several approaches to ensure that a reasonable

delay occurs before the label is re-used.  Not all such approaches

are directly timer related.  If an implementation uses a timer, a

reasonable delay can be anything from tens of milliseconds to 

tens of seconds.  The actual time that it takes for all labeled 

packets to clear the LSP depends on the type of LSP, the 

conditions prevailing in the networks along which the LSP exists

and whether or not it is possible for the label release message 

to arrive prior to the last labeled packet from the imposition LSR.

Eric W. Gray

Systems Architect

Celox Networks, Inc.

[email-masked]

508 305 7214

-----Original Message-----
From: Manchanda, Monika [mailto:[email-masked]] 
Sent: Monday, September 30, 2002 6:39 AM
To: Mpls (E-mail)
Subject: Regarding Label Mapping Advertisements and Label Mapping Release in
maritini-trans-10

Hi,

 1. The maritini draft section 5.4.1. Label Mapping Advertisements says that

"   After a label has been withdrawn by the disposition router and/or
   released by the imposition router, care must be taken to not re-
   advertise (re-use) the released label until the disposition router
   can be reasonably certain that old packets containing the released
   label no longer persist in the MPLS network."

According to this the implementation should no re issue the same label for
some time period t, which should ideally be the time till all the packets
containing the released label reach the disposition router. But how do we
determine that what will be the value of t?

2. Also the section 5.4.2. Label Mapping Release says that 

   "In situations where the imposition router wants to restart forwarding
   of packets with sequence number 1, the router shall 1) Send to
   disposition router a label mapping release, and 2) Send to
   disposition router a label mapping request."

Here what do we exactly mean by label mapping release and label mapping
request? 

TIA and Regards,

-Monika