Some of the bigger factors are less to do with where the server is, but what kind of connectivity you get for it. The best thing I can suggest is to get trunking close to where your calls end up (Canada, U.S., Singapore), and locate the machine close to them. I agree that having a Singapore server and a North American server is a good idea. Normally, you can have the media path go straight from the SIP trunking provider to the endpoint, but it still has to go through FS to do IVR, queues, voicemail, etc. Put FS close to the trunking provider. Just as an example, we co-locate with a metro Ethernet carrier at 151 Front St. in Toronto. This provider has connectivity to the Toronto Internet exchange, and the NY Internet exchange. We get our trunking from a CLEC that is also connected to the Toronto Internet Exchange, and our customers are on ISPs that are also connected to TORIX. That keeps latency and jitter very low. For our U.S. DIDs, we have a SIP trunk with a carrier that peers on NYIX. Even though their equipment is in Denver, they are only about 5 hops from us, and latency is around 20 ms. We have one customer in Portugal, and they get better call quality with less latency than our U.S. customers. Their ISP is a vDSL carrier that peers directly with a transit carrier who is also on NYIX. A lot has to do with routing and peering arrangements. More so than physical geography. Traceroute is your friend here. -Tim