Hi Burak,

I've got some issues doing tests on the same configuration you have.
I'm using Dave Miller's tree instead of 2.6.20 patched with Ian's patches.

When I run iperf client (DCCP patched) with :
# iperf -c serverIP -Xdccp -l8 -t60
my client machine freezes completely after sending a few data.
This issue appears only when I limit the rate on the netembox. (1024kbits/sec)

Did you ever have this problem ?

Patrick.



On 24/05/07, Ian McDonald <[EMAIL PROTECTED]> wrote:
On 5/25/07, Burak Gorkemli <[EMAIL PROTECTED]> wrote:
> Hi Ian,

Hi Burak,

Adding DCCP @ vger as I think you mistakenly added DCCP @ ietf to the mailing...

> Last but not the least, I have discovered that I am having some trouble with 
the sizes of the packets sent. When the packet sizes are equal to each other - 
which is not the actual case in my tests - everything goes fine. However, when 
they are not, DCCP behaves strangely, it halts for some period of time during the 
stream - I think due to the mismatch between the sizes of the packets sent and the 
average packet size used in the TCP equation. I must confess that I am not 
aggregating smaller packets into larger ones - which is the next thing that I will 
do - but I was not expecting such a big effect. I will post the test results 
later, as I implement packet aggregation.

CCID3 in Linux keeps a moving average of the packet size. If you look
at the TFRC equation  the rate = some numbers / packet size. In effect
CCID3 therefore becomes rate limited by packets per second as it does
not perform packet aggregation within the protocol (unlike TCP). This
would explain your results in this regard.

Ian
--
Web: http://wand.net.nz/~iam4/
Blog: http://iansblog.jandi.co.nz
WAND Network Research Group


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