Subject: RE: Questions

From: vishwas <[email-masked]>
Date: Tue, 17 Nov 98 18:42:00 PST

vishwas wrote:
>
> Mean while I was wondering what if the mobile host has moved to a
> location where in the local subnet doesent have a Multicast router..!!
> Then we may have to go for some thing like, Dynamic Tunnelling with the
> nearest Multicast router. In this case MSDP may be of some use (Just a
> hunch). Though it can be thought of joinig the nearest router through
> tunnel somehow, there may be security and administrative issues, which
> cant provide a seamless mobility to a Mobile host.
>      If we consider again the Home Agent to redirect the multicast
> traffic to the new location by tunnelling them, again there may be
> Modifications required to the Multicast routing protocol, to support
> MOBILITY extensions.

If the home agent is appointed to tunnel the multicast packets to mobile
hosts, there is modifications required to the home agent instead of
Multicast routing protocol. In that case, a home agent will participate
in the multicast communication on behalf of the mobile hosts.
[vishwas]
I dont agree to the point that no modifications need to be done to   
Multicast Routers(M.R), because all multicast traffic has to be given to   
M.R module by IP, and once it comes there M.R. will make a RPF, check, if   
it passes this, then routing decision is taken. Here it may need to give   
a copy of the Multicast packet to Mobility Module, for its own decision.   
Further if a M.H has registered for a group on a tunnelled interface,   
then the Mobilty Table may be cunsulted to route the traffic using   
Bidirectional tunnelling Method(because of source spoofing).

> In general what I would like to ask is, Does Mobility is in the scope   
of
> Multicast routing...?

Mobility can be supported by routers or not. I think that Mobile IP can
be enhanced to support seamless multicast communication without
modifications of the existing multicast infrastructures.
[vishwas]
I would appriciate U can clearly prove it with an example.

 -vishu