what kind of latency and other overhead should I expect on an oc3 connection?

Question

multiple routers, IDS, firewalls between source/destination

Answer 1

Very few people get the privilege of working with an OC3. The best possible solution is to test the system.The more routers, firewalls, etc the more the latency may be. I suspect it should still be very low but if not CALL THE PROVIDER - you pay enough for that connector. The other end of that connection has more to due with your delays than the line in most cases.