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Hello Alberto,

thank you very much for the measurement. Before making more
detailed commetents on that I have two questions:
1. Have you modified SCTP timers? The delays have a 'granularity'
of 500 ms. This is something I do not understand.
2. How do you send back the packets with the timestamps?

Best regards
Michael

Michael Tuexen Tel.: +49 89 722 47210
Siemens AG Fax: +49 89 722 48212
ICN WN CS SE 5 E-mail:
Michael.Tuexen AT icn.siemens.de

> -----Original Message-----
> From: Alberto Bellettato
> [SMTP:Alberto.Bellettato AT icn.siemens.it]
> Sent: Tuesday, January 22, 2002 12:12 PM
> To:
> discussion AT sctp.de
> Subject: [SCTP-Discussion] Path failure in multi-homing scenario
>
> Hello all,
> I am testing sctp behavior in the following multihoming configuration:
> 2 Linux PCs, each pc has got 2 NICs, and these interfaces are connected 2
> by 2
> through 2 crossed cables (a scheme is present at
> http://spazioweb.inwind.it/stazionebase/graphs.jpg). I
> established an association and I began to transmit fixed sized data chunks
> (250
> bytes), one every 2 milliseconds (for ex.). Some seconds after
> transmission's
> beginning, I physically disconnected the primary path (disconnecting one
> crossed cable). In this situation, as I had expected, I experienced
> retransmission on the secondary path and then notification of inactive
> primary
> path, and conseguent path's switching.
> My test program calculates delay time for every data message transmitted
> from
> upper layer (through echo of timestamped messages). As result I expected a
> graph
> following a "step shaping", i.e. a standard delay value at the beginning
> (both
> paths active) and at the end (secondary path has become the primary one),
> and an
> incremented delay value between primary path physically disconnecting and
> path's switching.
> Instead I obtained a decrementing graph shaping (see image at
> http://spazioweb.inwind.it/stazionebase/graphs.jpg). I would
> want to understand why the graph is decrementing and why there so many
> steps.
> Could anyone explain to me the implementation's behavior in this
> situation?
> Thank you very much in advance.
>
> Best regards,
>
>
> Alberto Bellettato
> Developing thesis on SCTP at Univ. of Parma (Italy)
> On stage at Siemens I.C.N. Italy
> _______________________________________________
> discussion mailing list
> discussion AT sctp.de
> http://www.sctp.de/mailman/listinfo/discussion

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• [SCTP-Discussion] Path failure in multi-homing scenario, Alberto Bellettato, 01/22/2002
  • Re: [SCTP-Discussion] Path failure in multi-homing scenario, Brian F. G. Bidulock, 01/22/2002
  • <Possible follow-up(s)>
  • RE: [SCTP-Discussion] Path failure in multi-homing scenario, Tuexen Michael, 01/22/2002
    • RE: [SCTP-Discussion] Path failure in multi-homing scenario, Alberto Bellettato, 01/23/2002
      • Re: [SCTP-Discussion] Path failure in multi-homing scenario, Michael Tuexen, 01/23/2002
  • RE: [SCTP-Discussion] Path failure in multi-homing scenario, Tuexen Michael, 01/25/2002

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