Subject: Re: FE-CE data path

From: "Khosravi, Hormuzd M" <[email-masked]>
Date: Tue, 15 Mar 2005 15:23:54 -0800

Joel,

I agree in spirit with what your proposing regarding using DCCP for the
data channel and we have mentioned it in the draft as well.

Regarding implementation, here is the latest info that I got from the
DCCP WG couple of days back...

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Naadir Jeewa
Sent: Monday, March 14, 2005 12:09 PM
To: [email-masked]
Subject: Re: [dccp] Any dccp implementations compliant with the latest
specs ?

Arnaldo Mela @ Conectiva, and I have been working independently on such
an implementation. Mines not very good, so I'll probably on Arnaldo's
code base from now on.
I need to extract it out of the main BitKeeper tree into a separable
module. I'll do that by the end of the week and stick it on CVS at
www.sf.net/projects/linux-dccp once I've done some exams on Wednesday.
CCID and feature handling need to be added, and a good way of
implementing those CCIDs needs to be decided upon - perhaps something
similar to Stephen Hemminger's forthcoming patch to the TCP congestion
control mechanisms
( http://marc.theaimsgroup.com/?l=linux-net&m=110920482303293&w=2 ).

Yours,
Naadir

On Mon, 2005-03-14 at 11:51 -0800, Khosravi, Hormuzd M wrote:
> I was wondering if there are any DCCP implementations for Linux Kernel
> compliant with the latest DCCP specs going for RFC ? If no, are there
> any such efforts in play ?
> 
> 
> Thanks
> Hormuzd
> P.s. I had checked on this sometime last year, hopefully things have
> progressed on this now.

--------------------

I haven't looked at this in more detail. But the previous
implementations that I looked at were not promising at all. If you have
any thoughts on this "no running code" issue, let me know?

Thanks
Hormuzd 

-----Original Message-----
From: Forwarding and Control Element Separation
[mailto:[email-masked]] On Behalf Of Joel M. Halpern
Sent: Tuesday, March 15, 2005 2:03 PM
To: [email-masked]
Subject: Re: [FORCES] FE-CE data path

I have a basic problem with this.  We are trying to design a congestion 
controlling datagram transfer protocol.  We are not the right place to
do 
that.  Congestion control is known to be very tricky, and obvious
answers 
often have very non-obvious implications.  (Just getting the delay
bounded 
DiffServ stuff to work right took some interesting effort, and I had
some 
very good folks to work with.)

it is possible that DCCP is too complex, but there is really no
difference 
between an encapsulation driver (GRE) and a small protocol stack (DCCP I
hope.)

I will endeavor in the near future to take a good look at the DCCP 
documents to see what they really give us and what it will take to use 
it.  (The last protocol I wanted to use did not have the capabilities I
was 
looking for.)

If DCCP is not usable, we are in for a lot of very tricky work to get 
congestion control right, particularly since we need it to interact 
properly with TCP on the same link.

Yours,
Joel

---

From: Jamal Hadi Salim <[email-masked]>
Date: Tue, 15 Mar 2005 19:46:21 -0500

I should know  a little more about the subject because I got Arnaldo
started on Linux DCCP. I havent looked at the code in sometime, but:
I doubt very much i would want to deploy that code with any product i am
responsible for. Mostly because it hasnt been really tested probably by
anyone other than Arnaldo - or deployed for that matter . I am pretty
sure full of spec misconduct as a result of the above. I think in due
time it will be ready - but i wouldnt use this as a reason to say DCCP
is ready. 

cheers,
jamal