A query regarding SCTP congestion control

[Randall Stewart]

Rahman, Md Sazzadur wrote:
> Hi, I would like to get the values of SCTP congestion control
> algorithm variables  (cwnd, ssthresh, flightsize and pba) from any
> SCTP based application in runtime for research purpose. Does any API
> exist in SCTP for that?  Do I need to dig the SCTP code in kernel to
> get the values?

There is a socket option to get the cwnd.

However, I think what you really want is some of the researchish
tracing stuff that SCTP provides.

You can actually get a real time trace of the cwnd/flight etc via the
various logging functions.

You basically must compile this as an option.. have to go look
at the options..

And then you can either use ktrace (which I don't recommend since
it turns on to much overhead in the kernel) or you can
use SCTP_LOCAL_TRACE_BUF

This will put it into a piece of memory only for SCTP and
not turn on all the other ktrace points.

After you enable the logging in your compile you must turn
on the logging level..

SCTP_CWND_LOGGING_ENABLE

woudl be my recommendation.

It gives you a real time up/down growth of the cwnd/flight/rwnd

I think I wrote a "how to" somewhere.. let me go look..

R


> 
> I will appreciate any help in this regard.
> 
> Best Regards, Md Sazzadur Rahman Graduate Student, School of Computer
> Science, University of Oklahoma, Norman, Oklahoma, USA
> 
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-- 
Randall Stewart
NSSTG - Cisco Systems Inc.
803-345-0369 <or> 803-317-4952 (cell)