Hi Michael,
Thanks for your reply. From the log, I found that the values of from field of
sctp_cwnd_log are:
/* 32 */ "No Cwnd advance from CA",
/* 61 */ "Log from a Send",
/* 64 */ "Log from SACK",
/* 68 */ "chunk output completes",
/* 69 */ "fill_out_queue_called",
I have only tried to investigate the cwnd value when the from field value is:
/* 61 */ "Log from a Send" and found that tsn never changes :( although cwnd
and flight size values change over time.
Please let me know if you have any hint to resolve this problem.
Thanks,
Sazzad.
-Original Message-
From: Michael Tüxen [mailto:michael.tue...@lurchi.franken.de]
Sent: Sunday, January 25, 2009 5:14 AM
To: Rahman, Md Sazzadur
Cc: Randy Stewart; freebsd-net; Atiquzzaman, Mohammed
Subject: Re: A query regarding SCTP congestion control
Hi Sazzad,
what is the value of the from field i the structure sctp_cwnd_log?
Best reards
Michael
On Jan 23, 2009, at 1:16 AM, Rahman, Md Sazzadur wrote:
> Hi Randall,
>
> Thanks for your suggestions. I could collect congestion window data
> from SCTP sender using SCTP_LOCAL_TRACE_BUF on FreeBSD7.1 kernel
> using the tools you provided (dump_apple_log.c, prtcwndlog.c etc.).
> Now, in the log, I found that tsn (Transmission Sequence Number)
> never changes and remains fixed which is not supposed to happen, I
> believe. Do you have any idea what could go wrong?
>
>
> For example, in the log below, tsn is always 28170ae0.
>
> //-From Log---
> 2.162922 1543161849724545 Network:0xc463aaf0 cwnd:13063 flight:
> 12762 pq:f4f72484 Log from a Send tsn:28170ae0 (sendcnt:191,strcnt:
> 191)
> 2.200947 1543161849753090 Network:0xc463aaf0 cwnd:13063 flight:
> 14180 pq:f4f72484 Log from a Send tsn:28170ae0 (sendcnt:191,strcnt:
> 191)
> ..
> .
> 2592.987776 1543168861292865 Network:0xc463aaf0 cwnd:13063 flight:
> 14180 pq:f4f72484 Log from a Send tsn:28170ae0 (sendcnt:191,strcnt:
> 191)
>
> //--
>
> Steps I have followed:
>
> //--
> 1. Recompiled FreeBSD7.1 kernel by enabling SCTP_LOCAL_TRACE_BUF
> #define SCTP_LOCAL_TRACE_BUF 1
>
> 2.Enalble desired loging using sysctl;
> Sysctl -w "net.inet.sctp.log_level=0x0004
>
> 3.Run application that sends SCTP data to the network
>
> 4../Dump_apple_log > data.txt
>
> 5../Prtcwdlog -l data.txt> cwnd.txt
> //--
>
> I have attached the log file herewith this mail.
>
> It would be great if you can give me any hint to resolve this issue.
>
>
>
> Thanks,
> Sazzad
>
> -Original Message-
> From: Randy Stewart [mailto:rand...@lakerest.net]
> Sent: Thursday, August 28, 2008 6:39 AM
> To: sazzadur rahman
> Cc: freebsd-net; Atiquzzaman, Mohammed; Rahman, Md Sazzadur
> Subject: Re: A query regarding SCTP congestion control
>
> Remember a lot has changed between the book and now.
>
> 1) The initial window is now different
> 2) labc variable may influence how the cwnd responds
>
> are just 2 off the top of my head.
>
> You also may want to use a local trace buffer (as I mentioned earlier)
> since
> turning KTR on really really skew's things time wise.. its a resource
> pig.
>
> We added the local trace buffer for this very reason.
>
> Contact me directly if you need guidance on this. Also you may want
> to pick up the latest update that I just put up on www.sctp.org
>
> It gets the 7.0 stack current to 8.0's code.. .and there have
> been at least 1 CC fix in the last few months..
>
> R
> On Jul 2, 2008, at 2:37 PM, sazzadur rahman wrote:
>
>> Hello,
>> I need to get SCTP congestion window data for research purpose. I
>> collected
>> cwnd data from SCTP sender running on FreeBSD 7.0 machine by using
>> KTR
>> kernel log. After that, I tried to plot cwnd vs. time and generated
>> graph.
>> But I am unable to explain the graph and it is very different
>> compared to
>> the graph as shown in the book "Stream Control Transmission Protocol
>> (SCTP)", a reference guide by Randall R. Stewart, page 187 and TCP
>> congestion window. An typical entry from the log looks like:
>>
>> 749199232185105 Net:0xc7703000 at cwnd_event (SACK) cwnd:25140
>> flight:0 pq:0
>> atpc:72 needpc:235 (tsn:0,sendcnt:191,strcnt:191)
>>
>> I have used 749199232185105 in x axis as time and cwnd:25140 in y
>> axis. I
>> have attached the image file of the graph herewith this mail.
>>
>>> From the log, I found
