The MPLS WG Archive

[David Charlap <David.Charlap@marconi.com>]

Apratim Mukherjee wrote:
> 
> e.g OutAdspec could be stored as a separate field or recalculated every time
> u send a refresh . 
> OutIntegrity could be stored as a separate field which is recalculated evry
> time an outgoing object changes or it could be recalculated while sending
> each refresh message. 

Note that you can not store an INTEGRITY object.  The INTEGRITY sequence 
number must increment for each message sent.  If it doesn't, the 
neighbor is supposed to drop the message.  And that sequence number is 
computed as part of the digest.  Which means you must reconstruct the 
INTEGRITY object for every message sent.

It also means that incoming INTEGRITY objects should not be stored, 
since refresh messages won't have the same INTEGRITY object anyway. 
Once a message is authenticated, there is no further use for the 
INTEGRITY object.

ADSPEC is a good example of an object that may be retained or 
recomputed.  Other good examples include HOP objects, FLOWSPEC objects 
(in Resv messages), and RECORD_ROUTE objects.

-- David