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RE: [SCTP-Discussion] Packet dropped!!!


Chronological Thread 
  • From: Torbjörn Andersson <torbjorn.andersson AT kau.se>
  • To: "'Tuexen Michael'" <michael.tuexen AT siemens.com>
  • Cc: <discussion AT sctp.de>
  • Subject: RE: [SCTP-Discussion] Packet dropped!!!
  • Date: Fri Feb 14 15:22:01 2003
  • Importance: Normal
  • List-id: SCTP Discussions <discussion.sctp.de>

How big is the impact of this bug ? I'm am not sure if it has affected me. I
can only guess that I am in the clear if my transmissions worked fine, even
with some retransmissions.

/////////////////////////
Torbjörn Andersson
Adjunkt
Karlstads Universitet
torbjorn.andersson AT kau.se

> -----Original Message-----
> From:
> discussion-admin AT sctp.de
>
> [mailto:discussion-admin AT sctp.de]
> On Behalf
> Of Tuexen Michael
> Sent: Friday, February 14, 2003 1:47 PM
> To: 'Elangovan, Sumathi '; 'Michael Tüxen'; 'Andreas Jungmaier';
> discussion AT sctp.de
> Cc: Thomson, Iain
> Subject: RE: [SCTP-Discussion] Packet dropped!!!
>
> Hi Sumathi,
>
> we will make sure that this will work in the next release. It
> is definitly a bug in the sctplib, not in the socketapilib.
> Thank you very much for the detailed report.
>
> Best regards
> Michael
>
> Michael Tuexen Tel.: +49 89 722 47210
> Siemens AG Fax: +49 89 722 48212
> ICN CP SE C 7 e-mail:
> Michael.Tuexen AT siemens.com
>
> > -----Original Message-----
> > From: Elangovan, Sumathi
> > [mailto:Sumathi.Elangovan AT thalesgroup.com]
> > Sent: Friday, February 14, 2003 11:53 AM
> > To: 'Michael Tüxen'; 'Andreas Jungmaier';
> > discussion AT sctp.de
> > Cc: Thomson, Iain
> > Subject: [SCTP-Discussion] Packet dropped!!!
> >
> >
> > Hi!
> > I am using socketapi-1.0.1 using version sctplib-1.0.0-pre19
> > (socketapi via
> > the socketapilib). I want to test the SCTP behaviour when a packet is
> > dropped. This is achieved by introducing noise of BER
> > 1x10-7. I have listed
> > the various scenarios that it was tested below:
> >
> > 1) 8k message size of 1M of data transfer with delay of
> > 250S, noise 1x10-7
> > Results show that
> > * The transmitter is not able to recover when a packet is dropped
> > * Abort occurs when it cannot recover
> > * Which in turn does not retransmit the lost packet
> >
> > Question: Why isnt the transmitter not able to recover?
> >
> > 2) 1K message size of 1M data transfer with delay of
> > 250S,noise 1x10-7,
> > * Transmitter is able to recover
> > * and ensure Complete transmission of data
> > * No retransmission of lost packet
> > * Forward TSN occurs
> >
> > Question: Why there is no retransmission of lost packet?
> >
> > 3) Unordered delivery is set,1K message size of 1M data with delay of
> > 250S,noise 1x10-7,
> > * Forward TSN occurs
> > * Even when the a_rwnd does not decrease its size as data is
> > transferred
> > * No retransmission of lost packet
> > * Ensures complete transmission of data
> >
> > Question: Why does Forward-TSN occur and there is no
> > retransmission of data?
> >
> > 4) Unordered delivery,1k message size of 126K data tranafer with NO
> > DELAY,noise 1x10-7
> > * Forward TSN occurs
> > * a_rwnd stays the same i.e does not decrease
> > * No retransmission of lost packet.
> >
> > Question: Why there is no retransmission of lost packet even
> > with no delay
> >
> > Any help would be appreciated. I realise that that for the first two
> > questions you gave me some solutions but why even with
> > unordered delivery
> > set its not able to retransmit the lost packet? Is
> > retransmission of lost
> > packets not implemented with the present release? If yes,
> > could you please
> > let me know when the next version will be released. Thank you.
> > I would also like to extend my help for any further debugging
> > that you might
> > require.Thanks for all your help!!
> >
> >
> > Regards
> > Sumathi Elangovan
> >
> > Sumathi Elangovan
> > Design Engineer
> > Thales Research and Technology(UK) Ltd
> > Reading
> > Tel: 0118 923 8272
> > Email :
> > Sumathi.Elangovan AT thalesgroup.com
> >
> >
> > _______________________________________________
> > discussion mailing list
> > discussion AT sctp.de
> > http://www.sctp.de/mailman/listinfo/discussion
> >
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