Subject: Re: 6MAN WG Last Call: <draft-ietf-6man-flow-update-04.txt>

From: Thomas Narten <[email-masked]>
Date: Tue, 05 Apr 2011 14:09:04 -0400

Here are my comments on this document.

My main issue is that it continues to assert that flow labels are
required to be pseudo random. I am not convinced that is necessary and
I think it makes things more complex than necessary.

Detailed comments:

Review of -04

       Also, it could be used as a covert data channel, since apparently
       pseudo-random flow label values could in fact consist of covert data.

drop "pseudo-random" as that is not relevant to the point.

   As a result, some security
   specialists believe that flow labels should be cleared for safety.

If you don't have a reference to this, please delete.

   However, it is recommended that sources should set a pseudo-random
   flow label value in all flows, replacing the less precise
   recommendation made in Section 3 of RFC 3697.  Both stateful and

Again, I don't think we have agreement on this "recommendation".

   mathematically on immutable flow labels.  The new rules require that
   flow labels exported to the Internet should always be either zero or
   pseudo-random, but even this cannot be relied on mathematically.  Use

Pseudo random requirement again...

Thomas