On Thursday 10 March 2005 10:22 pm, Karl Foley wrote:
It's not a subnet, it's a whole new class off addresses. You've probably heard of class A, B and C ip addresses right? Multicast uses class D addresses. Multicast addresses range from 224.0.0.0 right up to 239.255.255.255.
Think of each multicast address as a channel on which servers can send info that can be received by clients tuned to the same channel/multicast address.
It differs from broadcast in that broadcast goes to all hosts (if allowed by the routers) whereas multicast only goes to "tuned in" hosts.
Clients tell their routers they're interested using a protocol called IGMP (Internet Group Messaging Protocol). Network stuff uses it to communicate with all the time. Now it's common to see streaming media using it. The BBC are even transmitting on it experimentally.
Thank you,
In a few short paragraphs you have answered a lot of questions I had about multicasting, turns out that I shouldn't actually need it for my application (TwonkyVision supports it but I don't think the MP101 needs it)
Thanks for the info though, that was really interesting. I would love to see a demo of the Videolan stuff at a ALUG meet (if you have a working and transportable setup)