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


Chronological Thread 
  • From: Andreas Jungmaier <ajung AT exp-math.uni-essen.de>
  • To: "Elangovan, Sumathi " <Sumathi.Elangovan AT thalesgroup.com>, discussion AT sctp.de
  • Subject: Re: [SCTP-Discussion] Packet dropped!!!
  • Date: Tue Feb 18 16:27:01 2003
  • List-id: SCTP Discussions <discussion.sctp.de>
  • Organization: University of Essen

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Dear Sumathi,

thanks for the detailed report. Which programs did you use on
the SCTP endpoints to test this ?

I will be working on fixing these bugs during this week.


Regards,
Andreas

On Friday 14 February 2003 11:53, Elangovan, Sumathi wrote:
> 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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