Subject: RE: help

From: Apratim Mukherjee <[email-masked]>
Date: Wed, 4 Sep 2002 11:47:59 -0500

hi harish,

normally , you would store the incoming and outgoing object separately in
the Path State since you need the incoming object to check for changes in
the incoming refresh message while you need the outgoing object while
buiding the Path Refresh message. Sometimes , the outgoing object can be
calculated every time you send a refresh , but this is implementation
dependant .
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. 

-----Original Message-----
From: Harish Kumtakar [mailto:[email-masked]]
Sent: Wednesday, September 04, 2002 11:28 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: help

hi,

    what i understood after reading RFC 2205 and 2209 is that, 
when a node receives a PATH message it will store or update the 
info. contained in the message into corresponding PATH state and 
then forwards the PATH message (the message may be modified) to 
the next hop.

   my question is will that node stores the info that is modified 
by it(in case the PATH message is modified) somewhere (i mean, in 
some state?).

---

From: David Charlap <[email-masked]>
Date: Wed, 04 Sep 2002 09:55:40 -0400

> time an outgoing object changes or it could be recalculated while sending

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