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


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  • From: Tuexen Michael <michael.tuexen AT siemens.com>
  • To: 'Torbjörn Andersson' <torbjorn.andersson AT kau.se>, Tuexen Michael <michael.tuexen AT siemens.com>
  • Cc: discussion AT sctp.de
  • Subject: RE: [SCTP-Discussion] Packet dropped!!!
  • Date: Fri Feb 14 15:33:36 2003
  • List-id: SCTP Discussions <discussion.sctp.de>

Hi,

Andreas (who is currently on vacation) has to look
into this. But if you see FORWARD_TSN chunks on the
wire, you were affected. My guess is, if you do not
see them, you are not.

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: Torbjörn Andersson
> [mailto:torbjorn.andersson AT kau.se]
> Sent: Friday, February 14, 2003 3:20 PM
> To: 'Tuexen Michael'
> Cc:
> discussion AT sctp.de
> Subject: RE: [SCTP-Discussion] Packet dropped!!!
>
>
> 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
> > >
> > _______________________________________________
> > discussion mailing list
> > discussion AT sctp.de
> > http://www.sctp.de/mailman/listinfo/discussion
>




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