Subject: RE: [Mip4] Revocation clarification - 3543

From: "Arun SG" <[email-masked]>
Date: Tue, 30 Jan 2007 12:56:42 +0530

Thanks for the very prompt response, Kent !

I get the picture, and maybe this then is more an editorial nit-pick.

But reading 4.2.2.2 gives the impression that the ACK is sent upon 
A) Revocation being valid - and binding existing
B) Revoking itself happening.

If ACK is to be sent regardless of the above conditions, then that para
might re-order the actions taken to emphasise that the ACK is sent on
receiving a valid revocation and then proceeding with identifying the
binding, revoking etc. This will make it more consistent with para 3.4.

Thanks again,
Arun

-----Original Message-----
From: Kent Leung (kleung) [mailto:[email-masked]] 
Sent: Tuesday, January 30, 2007 12:39 PM
To: Arun SG; [email-masked]
Subject: RE: [Mip4] Revocation clarification - 3543

Hi Arun.  My comments below in "KL>". 

-----Original Message-----
From: Arun SG [mailto:[email-masked]]
Sent: Monday, January 29, 2007 10:49 PM
To: [email-masked]
Subject: [Mip4] Revocation clarification - 3543

Hi,
I am a little unsure of the exact point in the revocation process that
the ACK is to be sent.

Assume a scenario where HA sends a Revocation, does the FA send the ACK
on simply receiving a valid revocation message as para 3.4 seems to
suggest OR after revoking the binding indentified by the revocation as
recommended by 4.2.2.2 ? 

3.4.  Registration Revocation Acknowledgment Message

   A revocation acknowledgment message is sent by mobility agents or
'direct' co-located mobile nodes to indicate the successful receipt of a
revocation message.
.
.
.

A registration revocation acknowledgment message MUST be sent in
response to a valid and authenticated registration revocation message.

4.2.2.2.  Foreign Agent Responsibilities

.....revocations are only valid for existing registrations, .... .. Upon
locating the binding, the foreign agent MUST revoke it, and MUST respond
with a revocation acknowledgment sent to the source address of the
revocation message.

My two questions hence are:
1. Does ACk signify merely receiving the revocation message, or
successful completion of revocation?

KL> ACK is sent in response to a valid and authentication registration
revocation message.  BTW, why would FA not be able to revoke the
binding?

2. What is the correct behaviour when the HA sends a revocation, but the
binding does not exist? Does the FA still send  ACK as having received a
message or keeps quiet, since it has not revoked any binding?  

KL> Yes, FA should still send ACK.  Since the point of the revocation is
to clean up resources such as the binding entry, it makes sense that FA
respond to HA that the binding is no longer around (i.e. maybe an
administrator had manually cleared the entry).

Kent

Thanks,
Arun

The nice thing about Standards is that there are so many of them to
choose from.
Andrew Tannenbaum

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