RE: [ns] Difference between 8Gb and 8000Mb?

[Haobo Yu <haoboy@isi.edu>]

Read tcl/lib/ns-link.tcl:176. This set bandwidth, then delay.cc:54, this
is bind_bw(), then Tcl.cc:995 that is how bind_bw() linked to
InstVarBandwidth, then Tcl.cc:794, that's where bw_atof() is called, then
Tcl.cc:929, that's where bw_atof() is defined. Go down then u find no Gb
is handled. 

If you don't understand how bind_bw() works, pls check out the first
couple of chapters in ns manual.

If you do a grep on bw_parse in tcl/*/*.tcl, you'll find it's used only
for OTCL variables but not the bound ones.

On Sat, 8 Jul 2000, aemdad1 wrote:

> Date: Sat, 8 Jul 2000 16:35:41 -0400
> From: aemdad1 <aemdad1@triton.towson.edu>
> To: Haobo Yu <haoboy@ISI.EDU>
> Cc: ns-users <ns-users@ISI.EDU>
> Subject: RE: [ns] Difference between 8Gb and 8000Mb?
> 
> but bw_parse is the only procedure which will define bw ,so without bw_parse 
> ,bw has no meaning in the simulator ,so i think Bo Wen is right.
> 
> A Emdadi
> 
> 
> >===== Original Message From Haobo Yu <haoboy@ISI.EDU> =====
> >No it does not. bw_parse is never used in setting bandwidth of a _link_.
> >trace down to new SimplexLink for instance, you'll find it went down to
> >tclcl and uses bw_atof() in Tcl.cc which does not handle Gb. So use 8000Mb
> >for now.
> >
> >On Sat, 8 Jul 2000, Bo Wen wrote:
> >
> >> Date: Sat, 08 Jul 2000 00:46:58 -0700
> >> From: Bo Wen <bowen@mail.wsu.edu>
> >> To: Haobo Yu <haoboy@ISI.EDU>
> >> Cc: Kaleelazhicathu R R Kumar <iscp9133@nus.edu.sg>, ns-users@ISI.EDU
> >> Subject: Re: [ns] Difference between 8Gb and 8000Mb?
> >>
> >> No..., just check out ns tcl code, Simulator::bw_parse{}can
> >> do with Gb now.
> >>
> >> Haobo Yu wrote:
> >>
> >> > ns does not parse Gb (which was not that popular 3 years ago) You
> >> > have to use 8000Mb for now.
> >> >
> >> > On Fri, 7 Jul 2000, Bo Wen wrote:
> >> >
> >> > > Date: Fri, 07 Jul 2000 21:10:53 -0700
> >> > > From: Bo Wen <bowen@mail.wsu.edu>
> >> > > To: Kaleelazhicathu R R Kumar <iscp9133@nus.edu.sg>
> >> > > Cc: ns-users@ISI.EDU
> >> > > Subject: Re: [ns] Difference between 8Gb and 8000Mb?
> >> > >
> >> > > No..., what I mean is bandwidth, not storage size.  For
> >> > > bandwidth, they shouble be same.  My question might not
> >> > > be clear:
> >> > >
> >> > > In my simulation, I defined all links with 8Gb, run ns;
> >> > > defined all links with 8000Mb, run ns again.  I just found
> >> > > the latter is much faster (I guess abround 100 times) than
> >> > > the former.
> >> > >
> >> > > Why, is that possible the variable (bind_bw) binding problem?
> >> > >
> >> > > Thanks,
> >> > >
> >> > > Bo
> >> > >
> >> > > Kaleelazhicathu R R Kumar wrote:
> >> > >
> >> > > > it should be the other way i guess ...
> >> > > > 8GB should be 8*1024*1024*1024=8589934592b
> >> > > > 8000Mb=8000*1024*1024=8388608000b
> >> > > > where 1024=1k
> >> > > > by normal convention
> >> > > > so 8Gb > 8000Mb
> >> > > >   Renjish...
> >> > > >
> >> > > > -----Original Message-----
> >> > > > From: Bo Wen [mailto:bowen@mail.wsu.edu]
> >> > > > Sent: Saturday, July 08, 2000 8:18 AM
> >> > > > To: ns-users@ISI.EDU
> >> > > > Subject: [ns] Difference between 8Gb and 8000Mb?
> >> > > >
> >> > > > I've got a werid phenomen, that when I define link with 8Gb,
> >> > > > it runs 100(approximately) times slower than defining link
> >> > > > with 8000Mb.
> >> > > >
> >> > > > Seems I'll try 8000000b, see whether it runs faster?
> >> > > >
> >> > > > Thanks.
> >> > > >
> >> > > > Bo Wen
> >> > >
> >> > >
> >>
> >>
> 
>