Subject: [tcpm] Please review RFC 1323bis

From: Pasi Sarolahti <[email-masked]>
Date: Thu, 18 Oct 2012 17:40:26 +0300

Hi,

We should make progress with RFC 1323bis, and therefore need people to review it, so that we can assess how close the draft is to being ready. Because RFC 1323 one of the key specs implemented in most stacks, it is important that this draft goes through a careful review before it is published.

The latest version of the draft is at http://tools.ietf.org/html/draft-ietf-tcpm-1323bis-04

So please read the draft and send comments, preferably to the mailing list.

- Pasi

---

From: David Malone <[email-masked]>
Date: Thu, 18 Oct 2012 16:36:16 +0100

I wonder if the text in Section 4.3 needs modification:

   It is vitally important to use the RTTM mechanism with big windows;
   otherwise, the door is opened to some dangerous instabilities due to
   aliasing.  Furthermore, the option is probably useful for all TCP's,
   since it simplifies the sender.

I believe that Linux hasn't used the echoed timestamp to calculate
RTTs for some years (though I haven't looked at the code recently,
Matt Mathis could probably say). I believe the book-keeping is just
done internally, as much as possible.

I also wonder if it is worth mentioning the issue of a reciever who
echos modified timestamps? If the timestamps are used without sanity
checking, then the timeout can be controlled by the reciever (without
changing the actual RTT).

The security section has some comments on middle boxes that remove
timestamp options. I don't know if we need to offer any advice on
scrubbing timestamp options? I haven't heard any problems being caused
by this, so maybe there is nothing to be said.

	David.