Subject: [Pana] Some inconsistencies in PANA draft 7

From: Sasikanth Bharadwaj <[email-masked]>
Date: Wed, 09 Feb 2005 18:59:36 +0530

Hi 

Here are a few inconsistencies that we came across in draft-ietf-pana-pana-07

Section 4.2 says
   A PANA-Start-Request message in stateless PAA discovery MUST NOT be
   retransmitted as this voids the statelessness on the PAA.  Instead,
   the PaC MUST retransmit the PANA-PAA-Discover message until it
   receives a PANA-Start-Request message, and retransmit the
   PANA-Start-Answer message until it receives a PANA-Auth-Request
   message.whereas in section 5.2, it is written   If the received PANA-Start-Request message included a Cookie AVP (an
   indication of stateless PAA discovery), the PaC MUST retransmit the
   PANA-PAA-Discover message until the first PANA-Auth-Request message
   is received I think this paragraph has to be removed or modified according to whatis said in 4.2 Another one related to PANA Error Request Section 5.5 - Message Validity Check says PANA Error Request is unexpectedand invalid in discovery and handshake phase but in section 5.10 - Error    Handling, we find     If the cause of this error message was a request message (e.g., PANA-PAA-Discover ... BTW can anyone please tell why error requests are invalid in discoveryphase and what a PAA or PaC has to do in case it receives an erroneousmessage in that phase? ThanksSasikanth
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From: Yoshihiro Ohba <[email-masked]>
Date: Wed, 09 Feb 2005 09:46:22 -0500

Hi Sasi,

On Wed, Feb 09, 2005 at 06:59:36PM +0530, Sasikanth Bharadwaj wrote:
> Section 4.2 says A PANA-Start-Request message in stateless PAA
> discovery MUST NOT be retransmitted as this voids the statelessness
> on the PAA.  Instead, the PaC MUST retransmit the PANA-PAA-Discover
> message until it receives a PANA-Start-Request message, and
> retransmit the PANA-Start-Answer message until it receives a
> PANA-Auth-Request message.whereas in section 5.2, it is written If
> the received PANA-Start-Request message included a Cookie AVP (an
> is received I think this paragraph has to be removed or modified
> according to whatis said in 4.2

You are right.  The description in section 5.2 seems to be a leftover
of a previous revision.  I think we can remove the following text from
section 5.2 since section 4.2 already desribes the retransmission
behavior in stateless PAA discovery:

"
   If the received PANA-Start-Request message included a Cookie AVP
   (an indication of stateless PAA discovery), the PaC MUST retransmit
   the PANA-PAA-Discover message until the first PANA-Auth-Request
   message is received.  Otherwise, the PaC can rely on the PAA to
   retransmit the PANA-Start-Request message as soon as the PaC
   receives the first one (i.e., the PaC can stop sending the
   PANA-PAA-Discover message).
"

> Another one related to PANA Error Request Section 5.5 - Message
> Validity Check says PANA Error Request is unexpectedand invalid in
> discovery and handshake phase but in section 5.10 - Error Handling,
> we find If the cause of this error message was a request message
> (e.g., PANA-PAA-Discover ... BTW can anyone please tell why error
> requests are invalid in discoveryphase and what a PAA or PaC has to
> do in case it receives an erroneousmessage in that phase? 

I think the following text in section 5.10 should be revised:

"
   If the cause of this error message was a
   request message (e.g., PANA-PAA-Discover or *-Request), then the
   request MAY be retransmitted immediately without waiting for its
   retransmission timer to go off.
"

to:

"
   If the cause of this error message was a
   request message then the
   request MAY be retransmitted immediately without waiting for its
   retransmission timer to go off.
"

As far as I understand there are two reasons for not allowing
PANA-Error-Request in the discovery and handshake phase.  

The first reason is that a PER needs a Session-Id AVP, but a
Session-Id is not assigned yet in the discovery and handshake phase.

The second reason is related to sequence number.  Any request needs a
non-zero sequence number.  In order to use non-zero sequece numbers,
initial sequence numbers need to be known, but initial sequence
numbers are established by PSR/PSA exchange.  This means that a PER
can be sent only after completion of PSR/PSA.

Regards,

Yoshihiro Ohba

> ThanksSasikanth

---

From: Yoshihiro Ohba <[email-masked]>
Date: Wed, 09 Feb 2005 09:46:22 -0500

Hi Sasi,

"

"

to:

"

Regards,

Yoshihiro Ohba