Re: [ns] how to compute TCP's throughput

["Aashish Patil" <aashishp@usc.edu>]

Hello,

Well i think even the receiver received bytes would work well because they
finally represent the number of bytes received. However, I am not sure as to
how you obtain that param. As for UDP, you can use the agent LossMonitor at
the sink.

All the agent params are given in the ns manual. You might have to do a
little searching. I think the TCP agent is pretty well documented in a
seperate chapter.

Thanks and bye.

Aashish Patil.

----- Original Message -----
From: "Susan Tsao" <SusanTsao@WoodsideNet.Com>
To: "Aashish Patil" <aashishp@usc.edu>
Cc: "jie zhang" <skyws_hn@yahoo.com>
Sent: Sunday, December 16, 2001 2:35 PM
Subject: RE: [ns] how to compute TCP's throughput


> Hi Aashish,
>
> I have 2 question.
>
> Would it also be correct to calculate TCP throughput
> as (number of bytes received at receiver node / time)?
> If so, how do we get the total bytes received
> parameter in TCL script?
>
> In a CBR/UDP traffic, there's no retransmission and
> therefore we cannot calculate throughput as:
> (num of packet send - num of retransmitted packet) / time.
> So I'm assuming the only way to calculate throughput
> would again be:
>   throughput = total bytes recevied at receiver / time
> Again, I'm not sure extract this parameter from my
> simulation tcl script.
>
> I'm a little unfamiliar with TCL/C++ binding and therefore
> having a hard time extracting paramters of intereste in
> a simulation script.  I would appreciate any of your
> suggestion or pointers.
>
> Thank you!
>
> Susan
>
>
> -----Original Message-----
> From: Aashish Patil [mailto:aashishp@usc.edu]
> Sent: Sunday, December 16, 2001 8:25 AM
> To: jie zhang
> Cc: ns-users@ISI.EDU
> Subject: Re: [ns] how to compute TCP's throughput
>
>
> Hello,
>
> You can calculate the tcp thruput at the source in the following manner,
> #the following gets the total bytes sent by the tcp source
>  set total_sent_tcp_src_1 [$tcp_src_1 set ndatabytes_]
> #the followig gets the total bytes retransmitted by the source
>         set total_ret_tcp_src_1 [$tcp_src_1 set nrexmitbytes_]
> #thruput is then the (total bytes sent - total bytes retransmitted)/time
>
> Thanks.
>
> Aashish Patil
> On Sun, 16 Dec 2001, jie zhang wrote:
>
> > hi,
> >    I am learning ns and I encounter a problem.I donnt
> > know how to compute a TCP flow's throughput.Is there a
> >
> > program available.
> >
> > Sincerely yours,
> > Jiezhang
> >
> >
> >
> >
> >
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