On Sat, 9 Jun 2001, Tim Winders wrote:
UUnet has two levels of multicast capabilities. Their "Basic" package is receive only and is free. Their "Gold" package is full send/receive, but they charge a ton for it. The basic package seems pretty useless to me. To join a multicast group, you have to be able to send to it, right?
not right. with many/most multicast protocols, you can (sometimes must) build a source-rooted tree, not a shared tree. joining as a receiver is then a matter of becoming another branch off the tree, hopefully along the reverse shortest path to the sender. in this case, you can send but not receive. possibly the difference is in your permissions to establish a (s,g) pair or to announce a core (RP). which multicast routing protocols are on offer? PIM-SM? MSDP? MBGP? if you can't get your multicast across the border, it may not be useful to you. there are better protocols in the literature than are deployed but the arcana is often politically anathema for inertial, commercial or plain lack-of-working-code reasons.
I have found that most sales reps don't know what multicast is, or why it is important to have.
many network engineers glaze over at the mention of multicast. it takes some serious grey matter work to fathom the entire subject.