Hmm. I think you're right.Craig wrote:Here is what will happen,
- Client program will send out 100k/s as a multicast on VPN network
- VPN network stack will see this multicast, look at the end point addresses and say oh crud I cant reach them via multicast as they are all on different subnets so I can't send to the router and ask it to multicast any more than I could without a VPN.
- VPN network then sends 100k/s to each machine other machine individually, so you end up sending 400k/s for four other clients not just 100k/s.
The VPN creates another layer of IP addresses on top of IP, but I don't see any way to route packets more efficiently other than sending them multiple times. The reason is that the routers between clients will only work at Layer 3 (the IP layer) and not at the higher layer being created by the VPN.
Even those the IPOP protocol itself supports multicasting, I don't see any way to take advantage of that. The only reason for IPOP to support multicasting (that I can see now) is to support applications that require it. But there is no performance benefit to it.
Okay, everyone can ignore the last 2 pages of this thread. I took everyone down a path that turns out to be a dead end.