> Interesting that you say that about sip. We had a client that would use it > for sip on ships all the time. It wasn't the best but it worked. Ping times > were between 500-700ms.
It really depends on your expectations - or more to the point, your end-users' expectations. I've tested SIP in the lab up to 2000ms RTT. The protocols all hang together and keep working, but it's obviously very much in walkie-talkie mode, you can't hold a normal duplex conversation. 500ms there's more of the talking over each other / "sorry, you go" / "no, you go" dance, but it *is* workable. If your end-user is expecting land-line replacement though... Regards, Tim.