Date: Mon, 29 Dec 2008 14:36:26 +0100 From: <ajassal.ext@orange-ftgroup.com> To: <Michael.Tuexen@lurchi.franken.de> Cc: freebsd-net@freebsd.org, khadija.daoud@orange-ftgroup.com Subject: RE: SCTP : problems in sending ASCONF chunks Message-ID: <3418F3471F1CA4409901547349FFAE2E091067B8@ftrdmel2> In-Reply-To: <2C67145C-C26B-4666-B7A5-6EC1C4ABA1E5@lurchi.franken.de> References: <3418F3471F1CA4409901547349FFAE2E0910679F@ftrdmel2> <2C67145C-C26B-4666-B7A5-6EC1C4ABA1E5@lurchi.franken.de>
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Hello M.T=FCxen, No, only the PC is running under FreeBSD 7.0. T is running under Linux = (kernel version is 2.6.21 and the distribution used is Fedora Core 7). = SCTP is running on T thanks to the lksctp implementation, we loaded the = sctp module on it and made the necessary configurations so that it is = loaded at boot time. Also, I enable net.sctp.addip_enable=3D1 on T, just in case, I'm not = exactly sure if it has an effect on my tests. Kind regards Aman Jassal=20 -----Message d'origine----- De : Michael T=FCxen [mailto:Michael.Tuexen@lurchi.franken.de]=20 Envoy=E9 : lundi 29 d=E9cembre 2008 14:09 =C0 : zze-Abac JASSAL A ext RD-RESA-ISS Cc : freebsd-net@freebsd.org; DAOUD TRIKI Khadija RD-RESA-ISS Objet : Re: SCTP : problems in sending ASCONF chunks Hi, are both machines (T and you PC) running FreeBSD? Best regards Michael On Dec 29, 2008, at 12:33 PM, <ajassal.ext@orange-ftgroup.com> = <ajassal.ext@orange-ftgroup.com > wrote: > Hi all, > > I have been working with SCTP and more specifically with the mobility=20 > features of SCTP at my work. Basically, I have been trying to use SCTP = > to perform handover tests between 2 separate Wifi networks. I use IPv6 = > for all my tests. > > I have a local LAN (wired-network), on which I have 3 machines, one of = > them is the machine I use to communicate with for the tests (I'll call = > it T to make things simple), and the other two are used as Wifi Access = > Points (say Wifi1 and Wifi2 respectively). Since I work with IPv6, I=20 > set up both Access Points to send Router Advertisement messages=20 > periodically (minimum of 3 seconds, maximum of 4 seconds). That way I=20 > can have automatic address reconfiguration when I connect to either of = > the access points. > > The aim of my tests is to use a PC, connect to Wifi1 (for example),=20 > launch an SCTP association with T (T sends data to my PC), and then=20 > perform a handover on Wifi2. I do make address reconfiguration during=20 > the handover process. The important point is that I work with only ONE = > address on my network interface. Before I start my tests, I set the=20 > following sysctl parameters : > > # sysctl -w net.inet.sctp.mobility_base=3D1 # sysctl -w=20 > net.inet.sctp.mobility_fasthandoff=3D1 > # sysctl -w net.inet.sctp.debug=3D0x00f301f0 (that is to dump > messages in /var/log/messages) > > net.inet.sctp.auto_asconf is set to 1 by default. > > I use FreeBSD 7.0 on my PC, I don't know if that is extremely useful=20 > but I'm trying to be thorough. This is the script I use to perform=20 > handover > : > > ifconfig rum0 inet6 <my old address> delete ifconfig rum0 ssid <the=20 > target access point> route del -inet6 default <my old gateway> rtsol=20 > rum0 > > If I'm not mistaken, the PC should have sent an ASCONF chunk to=20 > perform dynamic address reconfiguration. However what I observed is=20 > that nothing happens. No ASCONF chunks are sent, and therefore, T=20 > doesn't ever know that it should send data on the PC's newly acquired=20 > address. > > I tried to investigate the problem myself, by adding some debug logs=20 > in the sctp source code (to see which functions are called during the=20 > handover process), and it seems as if the kernel doesn't ever add an=20 > ASCONF chunk to send in its queue... But that's just my understanding=20 > of the problem... > > I looked up in the CVS repository for answers, and to see the various=20 > changes that were gradually brought on the code. There, I noticed that = > on the revision dating 24th July 2007, changes were made for dynamic=20 > address reconfiguration : "Change behaviour so that when the last=20 > address is deleted (auto-asconf on a boudall endpoint) no action is=20 > taken until an address is added ; at that time an ASCONF add+delete is = > sent (if the asoc is still up)" > > In my humble opinion, this is exactly the case that corresponds to my=20 > handover scenario. But I just haven't been able to successfully=20 > perform it because I don't seem to send any ASCONF chunk. I'm=20 > struggling to understand why I do not see any ASCONF chunk sent. > > If it can help, I'm also attaching links to the kind of debug logs I=20 > got when performing a handover test. This is the kind of debug logs=20 > that I got : > > http://www.divshare.com/download/6200509-560 > > This is another debug logfile, but with my own debug logs added in the = > sctp source code : > > http://www.divshare.com/download/6200504-2e9 > > > Many thanks for your work, and I hope someone will be able to help and = > shed some light on this problem :-) > > > Aman Jassal > > _______________________________________________ > 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" >
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