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[ns] RE: Bandwidth in 802.11 simulation
My understanding is that the bandwidth in 802.11
depends on many parameters, which are not all in the
802.11 code (some are in phy.cc...). Anyway I think
this 802.11 was developped to model a certain device,
with all values hard-coded, and some day a smart guy
decided have the bandwidth_ parameter modifiable from
Tcl, without checking what this bandwidth_ parameter
was about. For instance, the parameter used to
calculate the contention time (Which should change
with the bandwidth) is called DSS_slottime or
something and is hardcoded somewhere.
I also did some experiments, changing the bandwidth_
gradually and recording the number of packets actually
exchanged by 10 nodes, and the results were
desesperately random. Moreover at the time I saw 2
posts in the ns list about found bugs in 802.11...
I just needed a working mac layer, not a special
bandwidth, so I replaced 802.11 by a fake and
irrealistic Mac layer called mac-null. It has an
infinite bandwidth. You can find the mac-null code in
my zrp bundle.
(http://www.ee.cornell.edu/~haas/Software/zrp.tar.gz)
> -----Original Message-----
> From: Gaurav Jain [mailto:[email protected]]
> Sent: Wednesday, April 04, 2001 11:41 AM
> To: [email protected]
> Subject: Bandwidth in 802.11 simulation
>
>
> Hi Robin...
>
> I see in the ns archives that you had posted a
question about 802.11
> bandwidth about 6 months back.. I am facing the same
problem
> to change the
> wireless BW from the default 2MB (It's strange that
now I
> even can't see 2Mb
> anywhere in the ns code {mac-802.11.cc/h,
wireless-phy.cc/h}..
>
> Could you please let me know if you found any
solution to the
> problem..
>
> Regards,
> Gaurav.
>
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