Hi,
You are kind of stuck with real options with 4.x CCM and OCS integration. First off CCM4.x has not got a great implementation of SIP and like integration with exchange UM probably not going to be support by MS. Not to say it won’t work but will you have full functionality is the real question. Also Cisco CallManager doesn’t support E164 standards which may cause some issues. How do you get rid of the plus sign from the called number going to CallManager. Most folks are just limiting inbound trunks to just 10 digits which is fine for US only calls but causes issues for 911 and international.
At the company I work at we have designed the integration around a Cisco router running IP-IP gateway software and configuration which offers the greatest flexibility. This of course is more expensive than just a straight SIP trunk between the two systems but we need the flexibility that Ip-IP GW offers. There are a number of threads in this forum that talk both about 4.x and 5.x integration and your best bet is to take a look at them. The thread below is a good start and has a lot of good discussion on the subject.
SIP trunk between OCS and Cisco Unified Communications Manager
Cheers
Chris
