Subject: RE: question: 'application adaptation for SCTP'

From: "Lei Zhang" <[email-masked]>
Date: Mon, 1 Sep 2003 20:11:26 +0200

Hi, That's the idea what I want. And it's quite reasonable and implementable based on my simulation. 

very happy!

Thanks a lot!!!

-----Original Message-----
From: Caitlin Bestler [mailto:[email-masked]]
Sent: Monday, September 01, 2003 8:03 PM
To: Lei Zhang
Cc: [email-masked]
Subject: RE: question: 'application adaptation for SCTP'

It is possible for a higher level protocol to have a concept
of "endpoints" that are connected to each other and that can
then reliably exchange messages. The underlying connection
could be a TCP connection or a pair of SCTP streams.

This is also a very useful abstraction for encouraging
migration to SCTP.

The mapping of RDMA over IP to SCTP in the rddp WG
assumes this sort of strategy.

It could apply to any upper layer protocol that reliably
exhcnages a sequence of messages. So if the exisitng TCP
adaptation has to waste time putting message delimiters
in, then the approach could easily work.

With this approach the application is not aware of the
SCTP association, just its "Connection" on a pair of
streams. It is only applicable if it makes sense to
have multiple "connections" between two hosts within
a single session.

Otherwise, you're into an application specific mapping.
If the existing TCP version of the application only
uses a single connection then it will be hard to retrofit
multiple streams into the SCTP adaptation.

-----Original Message-----
From: Lei Zhang [mailto:[email-masked]]
Sent: Monday, September 01, 2003 6:15 AM
To: [email-masked]
Cc: [email-masked]
Subject: RE: question: 'application adaptation for SCTP'

Hi, yuzhou;

Thanks for the reply, actually, there is a ULP process between Applicatio
and SCTP called "tpal" in my simulation (on OPNET). I don't know if I should
only operate the "tpal" layer or reckon the application layer as well.

Maybe I didn't explain my question clearly, sorry.

If anyone has a experience with OPNET for studying SCTP, could you give me
some instruction?

Best Regards

Lei