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Re: Node throughput and packet delay
On Sat, 9 Oct 1999, Sean Murphy wrote:
> > I am new in ns. Several questions:
> > 1. How to simulate the throughput of the node? For example, I have $n1 and
> > $n2, the link between them is with bandwidth 2M bps. But $n1 can only
> > process data at 500kps (the $n1 throughput). How to simulate that?
>
> Complete guess - you could just install an artificial link and an
> artificial node to model the 500kb/s bottleneck within the node. So the
> real node would then be modelled by 2 simulation nodes joined by a 500kb/s
> link.
>
> > 2. How to trace the packet delay time and variation?
>
> I wrote some code to do this - I implemented another c++ object to log
> packet transmission and arrival times to a file. It involves slightly
> modifying ns and recompiling ns, which is not ideal if you're a new user,
> but it's not that hard to do especially if you're familiar with makefiles.
> Let me know if you want more info.
>
> Another solution that doesn't involve modifying ns is to create trace
> files for your simulation and perform filtering on the trace file using
> awk, for example to obtain the info you want. I've never done this, so I
> don't know exactly what it entails.
Something like the script in:
http://www-mash.cs.berkeley.edu/dist/archive/ns-users/9907/0350.html
L.
some people's idea of 'hard' is just weird.
> If you plan on pursuing this, I think
> you should probably use different flows and use these to perform your
> filtering.
>
> Sean.
> -----
> Sean Murphy, Email: [email protected]
> Teltec Ireland, Phone: +353-1-7045080
> DCU, Dublin 9, Fax: +353-1-7045092
> Ireland.
<[email protected]>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>