[ns] R: two equal UDP CBR flows in droptail queue get different bandwidths?

[Marco Fiore]

Eduardo,

it could be a synchronization issue.
Try to avoid 
synchronization between flows
by setting the random flag of the cbr 
flows
to true: "$cbr_name set random_ 1".

Regards,

Marco Fiore

>----
Messaggio originale----
>Da: ejortegau at cable.net.co
>Data: 7-giu-2006 
3.00 PM
>A: <ns-users at ISI.EDU>
>Ogg: [ns] two equal UDP CBR flows in 
droptail queue get different	bandwidths?
>
>
>Hi there:
>
>I've set up 
this experiment. I have two source nodes S1 and S2 directly 
>connected 
to a node R1 and two destination nodes D1 and D2 also directly 
>connected to a node R2. Nodes R1 and R2 are connected. All links are 1 
Mb/s 
>Full duplex with DropTail. Now, here's the thing. I set up two 
flows, one 
>going from S1 to D1 and the other one form S2 to D2. Both 
flows are UDP CBR 1 
>Mb/s. Flow 1 starts at t=0 and finishes at t=20.  
flow 2 starts at t=10 and 
>stops at t=15. Sim runs from t=0 to t=25.
>
>I'd expect that at t=10 (when flow 2 starts), both flows would 
experience the 
>same amount of packet losses, so that each one would 
use about 0.5Mb/s of the 
>link between R1 and R2. But what really 
happens is that from t=10 to t=15, 
>flow 2 uses all bandwidth while 
flow 1 loses all packets. Since both flows 
>have the same parameters, 
shouldn't they receive the same share of bandwidth 
>during that 
period? Or am i missing something here?
>
>Thanks in advance.
>
>-- 
>Eduardo J. Ortega - Linux user #222873 
>"No fake - I'm a big fan of 
konqueror, and I use it for everything." -- Linus 
>Torvalds
>
>