Yesterday I completed Direct SIP testing with Global Crossing using OCS 2007 R2 and thought I’d share the results in case others are considering using an ITSP after R2 is released. Global Crossing has a very useful interop testing process whereby they provision 1 or 2 DIDs and provide an engineer for 90 minutes to work through your configuration so you can test and modify both sides in realtime until you have a known working configuration. Once this is confirmed they document the configuration so it can be easily applied when you order service from them. Here are the notable items that they had to change for OCS:
- Naturally, SIP needed to take place over TCP rather than UDP
- The + sign needed to be added to the request (INVITE) by specifying the format as E.164. Note that your Mediation server could do this for you using the appropriate xml file configuration, but I personally prefer to get this from the carrier. In my case we added +1 because I had specified the test user’s TEL URI as tel:+1 followed by 10 digits. The bottom line is that the number on the INVITE request must match your TEL URI.
- NPDI had to be disabled. The NDPI indicator (ndpi=yes) indicates to downstream providers that the Number Portability Database has been “dipped” or verified for that particular number. Since OCS is the last leg of the call flow this isn’t relevant.
I’m looking forward to seeing the official ITSP launch partners in February and also to see how many more get on board following the release.