Dear Tai, I have not been working on CCID 2..So I am not sure about your questions..But I am not sure whether DCCP would have better throughput compared to SACK - since it depends on how u calculate ur throughput..As throughput is the total no of bytes transmitted in unit time, this includes the retransmitted bytes as well (in SACK)..So I presume that SACK should give better throughput that DCCP..I may be wrong..Did u try calculating the goodput? Yes, pl do put ur results :).. Regards, Arjuna On 4/25/06, Tai-hua Ma <0209853ai011033@xxxxxxxxxxxxxxxxxxx> wrote: > Dear all, > > I am a beginner of DCCP. At the moment I am writing my undergraduate thesis > about DCCP. > I tried some simulations on ns2 with DCCP module by Nils-Erik Mattsson. > There are some questions that I hope I could get some helps. > > 1. I am focusing on DCCP CCID2. The TCP-Like Congestion Control. And the > DCCP TCP-Like Agent is referenced from draft-ietf-dccp-ccid2-04. And up to > now, the latest profile for CCID2 is draft-ietf-dccp-ccid2-10 (since March > 2005). And I tried to do some simulations, I found out that the Sack > TCP(Also Newreno TCP) is always more aggressive than DCCP in many > conditions. And I notices the changes log noted that the version 05 of the > profile is changed according to Nils-Erik Mattsson's feedback. > Finally in version 10, the byte-counting is disabled for making DCCP more > aggressive. > > So is it an expected result that the Sack/Newreno TCP is more aggressive > than DCCP? DCCP is unreliable transfer protocol, so DCCP should have better > throughput than TCP. > > I have read a ref paper: Performance Evaluations of DCCP for Bursty Traffic > The paper concludes a different result shows that Sack TCP is less > aggressive than DCCP in some condition. > > 2. Is there a updated DCCP -CCID2's module in ns2? > > If someone is interested in my work, I am happy to put some plots and > scripts on the net. > > Thanks in advanced, > > Tai-hua Ma > Student of IT Faculty > Macao University of Science and Technology > EMAIL: 0209853ai011033@xxxxxxxxxxxxxxxxxxx > -- Regards, Arjuna Postdoctoral Researcher Engineering Research Lab, Department of Engineering, University of Aberdeen
