Subject: L2TP Diffserv Draft

From: Evan Caves <[email-masked]>
Date: Fri, 25 Aug 2000 10:15:22 -0700

I have a number of question regarding this draft which I hope one
of the authors can comment on.

1. Is the DSCP AVP a six or eight bit value?

2. What DSCP value is used for tunnel control messages? If the
   session DSCP has a 'higher priority' than the tunnels then
   payload packets may arrive before session setup completion.

3. Why is this AVP restricted to just sessions? One could conceive
   bringing up a tunnel for each PHB and forwarding all tunnel
   traffic (control and payload) with one of the PHB class DSCPs.

4. This draft makes a big assumption that the tunnel traverses a
   single DS domain. If the tunnel traverses multiple DS domains
   the DSCP to PHB mappings could be different (this may mean
   that each tunnel endpoint uses different DSCP marks that get
   translated at some DS boundary). How is this resolved?

5. Related to 4 it would seem that it may be more appropriate that
   the tunnel initiator ask for a PHB rather than a DSCP and then
   let each endpoint decide how that PHB maps to a DSCP.

evan
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