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Hi,
for a project, we're interested in using DCCP. As such, I did some performance measurements with the latest version of the DCCP implementation. To my opinion, they are not really what I expected. Could you give some ideas or maybe some information about the current status of the implementation (e.g. is packet loss detection planned for implementation, when ?) ?
Results of similar tests are also interesting to see if they compare. For the tests, I used an impairment node (based on linux, which introduced some packet loss).
Measurements where performed with the patched iperf on linux-2.6.16.20 and I came to the following table:
TCP DCCP-CCID3 (Send/Recv)
No drop 94 Mbps 93.3 Mbps 93.2 Mbps
Drop 1% 83.4 Mbps 93.3 Mbps 92.3 Mbps Drop 5% 16.6 Mbps 93.3 Mbps 88.6 Mbps
Drop 10% 3.25 Mbps 93.3 Mbps 83.9 Mbps
The transmitter does not detect the packet loss and doesnt slow down, instead it keeps sending <CCID option 192 4294967295>.
As CCID3 is TFRC, I expected similar results for TCP and DCCP-CCID3.
When i tried out linux-2.6.17.1 (no packet drop) the receiver seems to stop sending feedback packets after a while and the transmitter slows down. The receiving process doesnt receive any data (recv doesnt return).
[ 3] local 10.0.1.3 port 3743 connected with 10.0.1.1 port 5001 [ 3] 0.0- 1.0 sec 11.0 MBytes 92.5 Mbits/sec [ 3] 1.0- 2.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 2.0- 3.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 3.0- 4.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 4.0- 5.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 5.0- 6.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 6.0- 7.0 sec 6.86 MBytes 57.5 Mbits/sec [ 3] 7.0- 8.0 sec 194 KBytes 1.59 Mbits/sec [ 3] 8.0- 9.0 sec 100 KBytes 819 Kbits/sec [ 3] 9.0-10.0 sec 100 KBytes 819 Kbits/sec [ 3] 10.0-11.0 sec 100 KBytes 819 Kbits/sec [ 3] 11.0-12.0 sec 100 KBytes 819 Kbits/sec [ 3] 12.0-13.0 sec 100 KBytes 819 Kbits/sec
best regards,
Johannes
Quoted 9 lines · Johannes Deleu
Hi,
for a project, we're interested in using DCCP. As such, I did some performance measurements with the latest version of the DCCP implementation. To my opinion, they are not really what I expected. Could you give some ideas or maybe some information about the current status of the implementation (e.g. is packet loss detection planned for implementation, when ?) ?
Packet loss has been implemented and is working for me. What is your test environment? I am using netem on a router between two boxes.
Quoted 22 lines
Results of similar tests are also interesting to see if they compare. For the tests, I used an impairment node (based on linux, which introduced some packet loss).
Measurements where performed with the patched iperf on linux-2.6.16.20 and I came to the following table:
TCP DCCP-CCID3 (Send/Recv)
No drop 94 Mbps 93.3 Mbps 93.2 MbpsDrop 1% 83.4 Mbps 93.3 Mbps 92.3 Mbps Drop 5% 16.6 Mbps 93.3 Mbps 88.6 MbpsDrop 10% 3.25 Mbps 93.3 Mbps 83.9 Mbps
The transmitter does not detect the packet loss and doesnt slow down, instead it keeps sending <CCID option 192 4294967295>.
As CCID3 is TFRC, I expected similar results for TCP and DCCP-CCID3.When i tried out linux-2.6.17.1 (no packet drop) the receiver seems to stop sending feedback packets after a while and the transmitter slows down. The receiving process doesnt receive any data (recv doesnt return).
Quoted 15 lines
[ 3] local 10.0.1.3 port 3743 connected with 10.0.1.1 port 5001 [ 3] 0.0- 1.0 sec 11.0 MBytes 92.5 Mbits/sec [ 3] 1.0- 2.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 2.0- 3.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 3.0- 4.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 4.0- 5.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 5.0- 6.0 sec 10.9 MBytes 91.6 Mbits/sec [ 3] 6.0- 7.0 sec 6.86 MBytes 57.5 Mbits/sec [ 3] 7.0- 8.0 sec 194 KBytes 1.59 Mbits/sec [ 3] 8.0- 9.0 sec 100 KBytes 819 Kbits/sec [ 3] 9.0-10.0 sec 100 KBytes 819 Kbits/sec [ 3] 10.0-11.0 sec 100 KBytes 819 Kbits/sec [ 3] 11.0-12.0 sec 100 KBytes 819 Kbits/sec [ 3] 12.0-13.0 sec 100 KBytes 819 Kbits/sec
There are a few issues still with DCCP at the moment (which is why it is marked experimental). Keep supplying us data/info and we will see what we will do. Nobody is working fulltime on this code so it can take a while to fix - feel free to help though!
One note - when using CCID3 have you turned off ackvecs via the sysctl as that is really for CCID2... It's probably something we should do in the code actually.
Ian
Signature · 7 lines
Ian McDonald Web: http://wand.net.nz/~iam4 Blog: http://imcdnzl.blogspot.com WAND Network Research Group Department of Computer Science University of Waikato New Zealand