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

Text archives Help


[SCTP-Discussion] Packet dropped!!!


Chronological Thread 
  • From: "Elangovan, Sumathi " <Sumathi.Elangovan AT thalesgroup.com>
  • To: 'Michael Tüxen' <Michael.Tuexen AT micmac.franken.de>, 'Andreas Jungmaier' <ajung AT exp-math.uni-essen.de>, discussion AT sctp.de
  • Cc: "Thomson, Iain" <Iain.Thomson AT thalesgroup.com>
  • Subject: [SCTP-Discussion] Packet dropped!!!
  • Date: Fri Feb 14 11:57:00 2003
  • List-id: SCTP Discussions <discussion.sctp.de>
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




Archive powered by MHonArc 2.6.19+.

Top of page