Re: [ns] Satnode Queries !!

[Lloyd Wood <l.wood@eim.surrey.ac.uk>]

On Mon, 4 Sep 2000, Lloyd Wood wrote:

> On Mon, 4 Sep 2000, Martin Koyabe wrote:
> 
> > regarding my first query, add-gsl passes the bw to the to add-interface
> > which is later assigned as mac_bw (for both in-link and out-link interface).
> > 
> > How then do you allocate bandwidth in order to have scenario 1 and 2 !!
> 
> As it stands, it looks like the code assumes symmetry; opt(bw_down)
> forms part of linkargs in the example scripts, but linkargs isn't
> used.

...in sat-teledesic.tcl; it is in sat-teledesic-nodes.tcl. Duh.
ignore everything I said...

In sat-teledesic scripts:

$n100 add-gsl polar $opt(ll) $opt(ifq) $opt(qlim) $opt(mac) $opt(bw_up) \
  $opt(phy) [$n(100) set downlink_] [$n(100) set uplink_]

sets the uplink rate, using $opt(bw_up) for the node

while in sat-teledesic-nodes:
                
set n($i) [$ns satnode-polar $alt $inc [expr 15 * ($a - 1)] \
[expr $stagger + $imod * 15] $a $linkargs $chan]

sets the downlink rate from each satellite, since $opt(bw_down) forms
part of $linkargs.

sat-aloha.tcl uses a _repeater_, so link asymmetry is out; you can
only repeat what you receive. If you don't use a geo repeater, but a
normal geo satellite, I don't see why asymmetry shouldn't work; just
install an extra gsl for a gateway, and away you go.

> (I'm not even sure if the wireless code supports asymmetry for link
> bandwidths, since there's only one channel...)

...which merely means that anisotropic mediums aren't available
as an option, right? hardly a major concern.

L.

mst thnk b4 pstng!

<L.Wood@surrey.ac.uk>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>