Subject: Re: I-D ACTION:draft-khosravi-forces-tcptml-01.txt

From: "Khosravi, Hormuzd M" <[email-masked]>
Date: Fri, 25 Feb 2005 23:01:03 -0800

Regarding this shim/TML header containing the length for redirected
packets,
I believe the ForCES PL header already has a length field that can be
used for this purpose.
The redirected packets are also transported within a ForCES PL message
so the shim/TML header is really not needed if they are sent on a
different connection/channel.

As Furquan said, if we sent them on the same channel we would need a
header to distinguish between TML messages and PL messages, unless we
use a separate connection/channel as Jamal is suggesting.
The only problem that I see with using a separate channel for TML
messages would be for a TML heartbeat message, which would be
meaningless over a different connection. But if we decide not to have a
TML heartbeat and just use the PL heartbeat message then using a
separate connection for TML messages would be a viable approach.
Actually I would prefer doing away with TML messages completely as Jamal
is suggesting but I need to analyze this further.

BTW, Jamal, I agree very much with your design philosophy regarding
doing away with TML messages/ header and keeping it simple. Just need to
analyze further if this is viable.

Regards
Hormuzd

-----Original Message-----
From: Forwarding and Control Element Separation
[mailto:[email-masked]] On Behalf Of Joel M. Halpern
Sent: Friday, February 25, 2005 12:32 PM
To: [email-masked]
Subject: Re: [FORCES] I-D ACTION:draft-khosravi-forces-tcptml-01.txt

At least for the redirected packets (which folks are arguing should not 
have a shim header) I can not see how to avoid such a header.   Although

the IP Header has a total length field, one of the reasons for sending
the 
packet to CE may be that the amount of data received and the total
length 
actually received may not match.
We can argue that in such a case we should never send that packet to the

CE, but that seems an odd restriction.

Yours,
Joel

PS: This also mandates that the PL header have a total length field.  Is
it 
really the job of the TML to tell the PL how to do its job?

---

From: "Joel M. Halpern" <[email-masked]>
Date: Sat, 26 Feb 2005 11:49:13 -0500

If the assumption is that redirected packets are carried within a PL 
header, and that PL header carries packet type and redirect reason 
information, then I would agree that there ought to be no need for an 
additional TML shim.

Yours,
Joel

---

From: Furquan Ansari <[email-masked]>
Date: Mon, 28 Feb 2005 11:47:47 -0500

Joel,
    Sorry, didn't see all this activity over the weekend..just catching 
up on my emails.

Yes, the assumption is in fact that all redirected packets are indeed 
carried within a PL header - which will carry the
type and length fields within it. That's the reason why we mention in 
the draft that if the TML shim header exists,
the length field there only corresponds to the length of the TML message 
and not the entire payload length.

Thanks,

-- 
Furquan Ansari
Bell Labs Research			Ph : 732-949-5249
Holmdel, NJ				Fax: 732-949-4556