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Re: [ns] generate new multicast groups dynamically



On Mon, 27 Mar 2000, Jian Wang wrote:

> Given the following topology for a video on demand system:
> 
> S---R0---R1---R2---C1
>          |
>          |
>          C2
> 
> Say if at time 0.1 client C1 asks for a video from server S, 
> S will send the video data to client C1. At time 0.4 client
> C2 asks for the same video from S, then R1 may serve C2 if 
> it has cached the data needed. In order to realize these, 
> I put every node in a multicast group so that the intermediate
> routers can cache the data sent from S. If R1 is going to
> serve C2, then a new multicast group needs to be created
> dynamically, where R1 is working as a server to send video
> data to C2.

Not necessarily.

C2 joins the same multicast group as C1 and S, which R1 is a router
in; R1 then serves up everything it has cached (and requests upstream)
as a result of the new join received from C2. I think your problem is
the caching, not multiple groups.

L.

> Could you give me some hints how to do that in
> C++ level? Is it ok for a node to belong to multiple multicast
> groups?

<[email protected]>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>