Subject: Re: [pcp] Last Call: <draft-ietf-pcp-base-23.txt> (Port Control Protocol (PCP)) to Proposed Standard

From: Masataka Ohta <[email-masked]>
Date: Sun, 26 Feb 2012 22:50:26 +0900

The IESG wrote:

> The IESG has received a request from the Port Control Protocol WG (pcp)
> to consider the following document:
> - 'Port Control Protocol (PCP)'
>    <draft-ietf-pcp-base-23.txt>  as a Proposed Standard
>
> The IESG plans to make a decision in the next few weeks, and solicits
> final comments on this action. Please send substantive comments to the
> [email-masked] mailing lists by 2012-02-27.

The protocol lacks transaction IDs and is fatally broken.

That is, the protocol is expected to generate refresh request
packets and expect response packets.

However, as all the request packets are expected to be
identical, it is impossible to have correspondences between
request and response packets.

So, if requests are sent at 0, 5, 240, 245, 480 and 485 seconds
and responses with lifetime of 300 are received at 10, 250 and
490 seconds, it is impossible to know which request corresponds
to the response at 490 seconds.

If the response is generated against request at 485 second,
remaining lifetime of the response is 295 seconds.

However, if the response is generated against request at 0
second, lifetime of the response has expired 190 seconds ago.

But, without transaction ID to distinguish requests and
responses, the worst case must be assumed, which means
the response must be interpreted that lifetime expired
190 seconds ago, which means all the subsequent responses
are meaningless because their lifetime must be interpreted
to have expired.

					Masataka Ohta