SCTP Discussions

Text archives Help


Re: [SCTP-Discussion] Retransmission when congestion window is full


Chronological Thread 
  • From: Andreas Jungmaier <ajung AT exp-math.uni-essen.de>
  • To: Guo Marc-YGUO1 <YGUO1 AT motorola.com>, "'discussion AT sctp.de'" <discussion AT sctp.de>
  • Subject: Re: [SCTP-Discussion] Retransmission when congestion window is full
  • Date: Thu Sep 11 13:42:01 2003
  • List-id: SCTP Discussions <discussion.sctp.de>
  • Organization: University Duisburg-Essen

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi Marc,

as Michael already mentioned, the Siemens SCTP release/product
is probably an entirely different thing.
SCTPLIB is released under the lesser/library GNU public license
and is currently maintained mainly by Michael Tüxen, Thomas Dreibholz
and myself (and all of us are working in networking research at
German universities, now).

Since the version you appear to be using (pre19) is quite old, you
might want to try a more recent one (which never actually made it
to a formal release). I had that version on our webserver, which is
currently down due to a harddrive crash.

You might want to try and reproduce the errors with this new
SCTPLIB version that can, in the meantime, be downloaded from
http://www.exp-math.uni-essen.de/~ajung/links.html
(look for "Latest SCTPLIB snapshot").
This version (rc1) was tested at the last bakeoff, and has already
some features of the SCTP Implementor's Guide, most notably
support for Fast Recovery.

Best regards,
Andreas

P.S.: Please let us know if you find any more bugs. Thanks.


On Friday 05 September 2003 16:56, Guo Marc-YGUO1 wrote:
> Hi,
>
> I have a question about retransmission. In our system, we see that Siemens
> SCTP stops retransmission after a network congestion. The network traffic
> is heavy. End 1 with Siemens SCTP sends many packets to end 2 with other
> SCTP implementation. End 2 sends SACK back with some delay and end 1
> receives these SACK's all together. The SACK reports that some data is
> lost. But end 1 only retransmit once or doesn't retransmit at all. End 1
> can still send SACK back after receiving DATA from end 2. Eventually, our
> application resets the link.
>
> I find that the fast retransmission does be kicked off after 4 gaps in the
> SACK. However, the stack doesn't finish retransmission, since we don't see
> the retransmitted data on the sniffer. There are no major errors on the
> log. The other SCTP implementation on end 2 had similar problem before. It
> was found that the stack was holding up retransmissions when congestion
> window is full. Do you find the same flaw in Siemens SCTP? We are using
> version pre19. Thanks for the help.
>
> Marc Guo
> Motorola, Inc

- --
Dipl.-Ing. Andreas Jungmaier
Computer Networking Technology Group
University of Duisburg-Essen
http://www.exp-math.uni-essen.de/~ajung
My PGP Key-ID: D3824AC0

My PGP Key-Fingerprint: 228C 7C2C 3381 2DD4 9998 2812 5C0B 0B04 D382 4AC0
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.2 (GNU/Linux)

iD8DBQE/YF8XXAsLBNOCSsARAsYsAKDLKtOMzvaV1iMH/TQdaQgIPArcjACgyvyy
q5hj//8MjANhi42NiOOnJeo=
=K+lF
-----END PGP SIGNATURE-----





Archive powered by MHonArc 2.6.19+.

Top of page