Subject: RE: [mobile-ip] RFC3012bis - Comments from ADs (Protocol related) (ISSUE NO. 7)

From: "Jayshree Bharatia" <[email-masked]>
Date: Mon, 11 Nov 2002 15:24:37 -0600

Issue: 
The Foreign Agent MUST NOT accept any Challenge in the Registration Request
unless it was offered in last Registration Reply issued to the Mobile Node,
or else advertised as one of the last CHALLENGE_WINDOW (see section 9)
Challenge values inserted into the immediately preceding Agent
advertisements.  If the Challenge is...
 
This seems suboptimal. If the reply is lost between the FA and MN then the
MN can't send a new request until it has received a new agent advertisement.
Why not have the "keep N+1 challenge values"  apply to the values sent in
both advertisements and replies.
 
Proposal:
As mentioned in the proposal for issue 6, if the Registration Reply is lost,
the Mobile Node will retransmit the Registration Request as mentioned in RFC
3344. In this case, the challenge value in the retransmitted request will be
the same as sent in the original Registration Request message. Hence, there
is no need to have "keep N+1 challenge values".
 
Any comments?
 
Thanks,
Jayshree

 -----Original Message-----
From: Muhanna, Ahmad [RICH2:2Q20:EXCH] 
Sent: Thursday, September 26, 2002 10:34 AM
To: [email-masked]'; [email-masked]
Subject: RE: [mobile-ip] RFC3012bis - Comments from ADs (Protocol related)
(ISSUE NO. 7)

Please see my comments inline. 

Regards; 
Ahmad Muhanna 

Non-editorial comments associated with RFC3012bis: 

Please post your comments with the appropriate issue number in the subject
line (instead of simply replying to this email).

-Chairs. 

7. The Foreign Agent MUST NOT accept any Challenge in the Registration 
   Request unless it was offered in last Registration Reply issued 
   to the Mobile Node, or else advertised as one of the last 
   CHALLENGE_WINDOW (see section 9) Challenge values inserted into the 
   immediately preceding Agent advertisements.  If the Challenge is 

   This seems suboptimal. If the reply is lost between the FA and MN 
   then the MN can't send a new request until it has received a new 
   agent advertisement.  Why not have the "keep N+1 challege values" 
   apply to the values sent in both advertisements and replies? 

Yes, we are trying to optimize the solution. No one ever said it is perfect.

It is possible that the RRP message is getting lost and not received by the 
Mobile Node. 
The assumption that the RRP is going to be lost and why to keep track with 
the Challenge is quite a broader question and issue than MIP itself. 
The suggestion here is that UDP is not reliable at all! If so why to bother 
keeping track of anything sent in RRP message or anything using UDP. 

I am in favor of continue tracking N+1 unless a convincing argument proves
otherwise. 

Regards, 
Ahmad