First login?
Lost password?
 
 
sctp-discussion AT lists.franken.de 
SCTP Discussions

Text archives Help


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


Chronological Thread 
  • From: Michael Tüxen <Michael.Tuexen AT micmac.franken.de>
  • To: Guo Marc-YGUO1 <YGUO1 AT motorola.com>
  • Cc: "'discussion AT sctp.de'" <discussion AT sctp.de>
  • Subject: Re: [SCTP-Discussion] Retransmission when congestion window is full
  • Date: Thu Sep 11 00:17:01 2003
  • List-id: SCTP Discussions <discussion.sctp.de>
Hi Marc,

1. I'm not with Siemens anymore, I changed to the University of Applied Sciences, Münster.
2. I do continue to work on the sctplib.
3. The sctplib you are using was never and is not 'Siemens SCTP' It is a prototype
implementation which is a product of a cooperation between Siemens, the University
of Essen and the University of Applied Sciences Münster.
4. We know that the retransmission stuff in pre19 has some bugs.
5. I got (just a day ago) a detailed bug report regarding retransmissions of a
packet dropped multiple times in the network. I will test this with the upcoming
1.0.0 version.
6. Can you send a (small) tracefile (.pcap) to tuexen AT fh-muenster.de to see what the exact
problem is?
7. 1.0.0 will be released at the end of september (I have a two week vacation before that...)
8. Thank you very much for the report.

Best regards
Michael

On Friday, Sep 5, 2003, at 16:56 Europe/Berlin, 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



Archive powered by MHonArc 2.6.19+.

Top of page