Re: help: how to do broadcast

[Ahmed A-G Helmy <ahelmy@catarina.usc.edu>]

> hi,
> 
> I have a node (let's call node A) connected to another few nodes.
> 
> 1. can someone tell me on how can i do broadcast fr. node A to all the
> other nodes?
> 
> 2. For node A to broadcast a pkt over a specific link without knowing
> who is at the other end of the link?
> 

I am not sure that subnetting is currently used in ns (although the 
hierarchical addressing scheme, I imagine, could be extended to implement 
that). [or maybe someone else, more knowledgeable about berkeley lans can 
talk about broadcasting on lans].

There is, however, support for well-known-groups (i.e. local multicast) 
over lans. 
So, one way to simulate your broadcast, is to have each node join a group 
(say all-routers-group, or all-nodes-group, on the lan) and exchange your 
messages through that group...
[currently, the hop-by-hop multicast messages are implemented this way, 
by using the ALL_PIM_ROUTERS group in the pim code, and the detailedDM 
code].
Packets sent to that group (a specific subset of the multicast group) are 
not forwarded beyond the directly connected lans, and are not given to 
the multicast routing protocols.

hope this helps,

Regards,
-Ahmed

> thanks in advance for any reply.
> 
>