On Sun, 10 Sep 2006 05:31:50 +0400, Roy Marples <uberl...@gentoo.org>
wrote:
Or that most people here have nfc what multicasting is.
MULTICASTing vs BROADCASTing is (in short):
You broadcast to "all ones" IP address on a segment, i.e. for
192.168.1.0/24 it is 192.168.1.255,
while multicasts go to imaginary IP address in the special range, in my
example this is 239.255.20.1
The advantage of MULTICAST is that if noone on a given segment needs|wants
your data - the data never enters such a segment. When some host decides
it needs that data it "joins" a multicast group, i.e. informs it's closest
router it needs to pass the multicasted data into a segment. When the last
host on a segment decides to "leave a group" - the closest router again
stops to route multicasted data into a segment.
With broadcasts it is not possible (for the receiving side) to control the
presense of the data - receive it or not - the sender will flood all of
your LAN with it's data.
Besides, in IPv6 there will be no conception of BROADCASTs any more, only
MULTICASTs should be used instead.
Tony.
