From owner-freebsd-net@FreeBSD.ORG Wed Jul 2 18:37:12 2008 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5FAD51065671 for ; Wed, 2 Jul 2008 18:37:12 +0000 (UTC) (envelope-from rahman.sazzadur@gmail.com) Received: from yx-out-2324.google.com (yx-out-2324.google.com [74.125.44.30]) by mx1.freebsd.org (Postfix) with ESMTP id 6D0A28FC1F for ; Wed, 2 Jul 2008 18:37:11 +0000 (UTC) (envelope-from rahman.sazzadur@gmail.com) Received: by yx-out-2324.google.com with SMTP id 8so137273yxb.13 for ; Wed, 02 Jul 2008 11:37:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type:references; bh=l01/Pck+V7odk7ZGQy89fQwzeCDfZGfM6i2gvydlI4c=; b=kkxm/BD1XddAcAtUcBcW7ehORhXWsZ35W1QB1Ujtbg0UtIaz3fjFzFeaGHoz/6L8DM I/wR54c1vkdgK7pA9+H9OiD7cuiJxpfO8szydTVQSPFltuLs+L+E48FDpgb95FgjD3st uANK0rS+PRn3FdP7/qtjfw4y4sL7JdemDs6hQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:references; b=LGcmMSMqEDv/Wz7uTM3Zk04p9kVhKHxpwU6xXBjOdn81NQ5iYcZI6xQe6eOd1CwzJ2 Qvt9U5jFSilBnGz7ueaLJzQP5aZRjFXGBXxqcaXvVt5+n4KnmEdCw8AAKLchoyJCjlyX mlgGiUCLP8ScnvI2lpLnMsM+x+EDxtSJTxUao= Received: by 10.142.252.11 with SMTP id z11mr3178166wfh.232.1215023829401; Wed, 02 Jul 2008 11:37:09 -0700 (PDT) Received: by 10.143.173.10 with HTTP; Wed, 2 Jul 2008 11:37:09 -0700 (PDT) Message-ID: <82bdb5ec0807021137m7819153rbc0631ab6f310d0e@mail.gmail.com> Date: Wed, 2 Jul 2008 13:37:09 -0500 From: "sazzadur rahman" To: "Randall Stewart" , freebsd-net@freebsd.org In-Reply-To: <48060748.1090807@cisco.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_6989_27538040.1215023829381" References: <7059EA19D7837E44A3BA7DAB464944B37FDA715193@XMAIL5.sooner.net.ou.edu> <48060748.1090807@cisco.com> X-Mailman-Approved-At: Wed, 02 Jul 2008 19:30:35 +0000 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: atiq@ou.edu, "Rahman, Md Sazzadur" Subject: Re: A query regarding SCTP congestion control X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Jul 2008 18:37:12 -0000 ------=_Part_6989_27538040.1215023829381 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline 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 that cwnd varies very frequently accross time. Does anyone have any idea regarding this issue? Please let me know if you have any questions further. Thanks in advance. Best regards, Md Sazzadur Rahman Graduate Student, School of Computer Science, University of Oklahoma, Norman, Oklahoma, USA Steps for getting kernel log ------------------------------------------ 1. Add options: options KTR options KTR_ENTRIES=3D65536 options KTR_MASK=3DKTR_SUBSYS 2. Recompile kernel config CUSTOM_KERNEL_9_6 cd ../compile/ CUSTOM_KERNEL_9_6 make cleandepend;make depend; make all install 3. Tried to enable trace point by: Sysctl -w "net.inet.sctp.log_level=3D0x00000004" 4. run SCTP sender. 5. pull out data: Ktrdump =96q =96t =96o file_name Prtcwndlog =96l filename > cwnd.txt --------------------------------------------------- On Wed, Apr 16, 2008 at 9:03 AM, Randall Stewart wrote: > 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 >> >> _______________________________________________ freebsd-net@freebsd.orgm= ailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, >> send any mail to "freebsd-net-unsubscribe@freebsd.org" >> >> > > -- > Randall Stewart > NSSTG - Cisco Systems Inc. > 803-345-0369 803-317-4952 (cell) > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > ------=_Part_6989_27538040.1215023829381--