Hello M.Tüxen, 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=1 on T, just in case, I'm not exactly sure if it has an effect on my tests. Kind regards Aman Jassal -----Message d'origine----- De : Michael Tüxen [mailto:michael.tue...@lurchi.franken.de] Envoyé : lundi 29 décembre 2008 14:09 À : 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....@orange-ftgroup.com> <ajassal....@orange-ftgroup.com > wrote: > Hi all, > > I have been working with SCTP and more specifically with the mobility > 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 > set up both Access Points to send Router Advertisement messages > periodically (minimum of 3 seconds, maximum of 4 seconds). That way I > 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), > launch an SCTP association with T (T sends data to my PC), and then > perform a handover on Wifi2. I do make address reconfiguration during > 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 > following sysctl parameters : > > # sysctl -w net.inet.sctp.mobility_base=1 # sysctl -w > net.inet.sctp.mobility_fasthandoff=1 > # sysctl -w net.inet.sctp.debug=0x00f301f0 (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 > but I'm trying to be thorough. This is the script I use to perform > handover > : > > ifconfig rum0 inet6 <my old address> delete ifconfig rum0 ssid <the > target access point> route del -inet6 default <my old gateway> rtsol > rum0 > > If I'm not mistaken, the PC should have sent an ASCONF chunk to > perform dynamic address reconfiguration. However what I observed is > that nothing happens. No ASCONF chunks are sent, and therefore, T > doesn't ever know that it should send data on the PC's newly acquired > address. > > I tried to investigate the problem myself, by adding some debug logs > in the sctp source code (to see which functions are called during the > handover process), and it seems as if the kernel doesn't ever add an > ASCONF chunk to send in its queue... But that's just my understanding > of the problem... > > I looked up in the CVS repository for answers, and to see the various > changes that were gradually brought on the code. There, I noticed that > on the revision dating 24th July 2007, changes were made for dynamic > address reconfiguration : "Change behaviour so that when the last > address is deleted (auto-asconf on a boudall endpoint) no action is > 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 > handover scenario. But I just haven't been able to successfully > perform it because I don't seem to send any ASCONF chunk. I'm > 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 > got when performing a handover test. This is the kind of debug logs > 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-unsubscr...@freebsd.org" > _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
