Hi All,

I have some quries regarding MULTICASTING. As recently I was looking
out net for building a simple multicast application, using
setsockopt(IP_ADD_MEMBERSHIP). By using that application I thought
there will be some multicast routers, and we will be subscribing to
them using their IP addresses. But while using sniffer I was surprised
to see the results.


However I was sending multicast join report through
setsockopt(IP_ADD_MEMBERSHIP) to a IP address 234.5.6.7 (assuming the
IP address of Multicast router), but actually outgoing IP datagram had
224.0.0.2 as its destination IP address........Seeing this I could make

out that the actual ip address of multi-router would be 224.0.0.22
only, whereas it will be holding some groups like 234.5.6.7 etc. But
later I found this 224.0.0.2 is a special class D address, which is to
make sure delivery of this mutlicast join request to each router, with
TTL of 1. But still I am not clear with the whole process, like what
are the things each router will do one receipt of this join request, as

well as until when this packet will be circulated in the net, to make
sure its delivery for each router??


Next how we could make sure of a exclusive group, say A and B wanted to

use a special multicast address 234.5.6.7 exclusively for their use
only, how would they make sure that this multicast wont be in use by
others??


And how the routing will take place for IP 234.5.6.7, from multicast
router to subscribed clients. Like way so many question are going
around in my mind, could any body put some light over basics.

Thanks,
Rajat.