Re: Address allocation

["Mladen Sablic" <Mladen.Sablic@lucent.com>]

> Hello,
> If all sources use the same G , there is no meaning of multicast group.
> because S1 ....Sn can use the same address G and in that case all the
> multicast world is using the same address G. So we can maybe just assign or
> allocate a single multicast address to all the multicast recievers in the
> internet and use the S just to differciate between them.
> Isnt true??
> Ali

Ali,

If you used only S to differentiate between SSM sources
then ALL multicast packets from that source would go to
ALL the receivers interested in S.

By having channels (S,G) one can have (in SSM range)
2^24 independent multicast packet streams from one
source each going to a independent set of receivers.

Hence you can have receiver interested in (S,G1) &
not in (S,G2) and each (S,G) is likely to have a
chunk of bandwidth associated with it and bandwidth
is likely to be a limited resource at the receiver
end.

By having (S,G) you control bandwidth at the expense
of router memory which has to store state for each
(S,G) passing through it.
 
Mladen

<Mladen.Sablic@lucent.com>