Re: [ns] Multicast over satellite link

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

On Fri, 13 Oct 2000, [ISO-2022-JP] $B>.@n!!??Bg(B  wrote:

> I want to do the simulation of the multicast communication over
> satellite link in NS.

Doesn't work. The multicast routing code is in Tcl, the
wireless/satellite routing code doesn't have hooks for it.

If you're doing a GEO satellite, you can forget the satellite code
entirely and just create 'normal' long-delay links - but that means
that playing with MAC stuff in the wireless code to do
broadcast/multicast/capacity allocation is not an option.

If you're doing a LEO constellation, you can use the satellite code
as a geometry engine to generate topologies at a point in time, which
you dump as tcl code using a modified dump_sats(), to be sourced by
another simulation that uses that to build the 'normal' topoloogy
before running multicast simulations over it.

> Therefore, I think that a terminal(Sat Node) will be made multicast
> support.
> Concretely, I am thinking about the following topology:
> 
>   Terminal----Geo----Terminal----node
>                                   .
>                                   . (multicast)
>                                   . 
>                                  node
> 
> Is such a topology possible on NS? 

yes. skip the wireless stuff, and just create a couple of long delay
links to simulate the satellite delay. You're not trying to do
multicast in the satellite environment; it's just a distant group
member.

L.

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