It's now been several weeks of tinkering to install an OCS Server collection (AD, SQL, OCS, Edge, Mediation, Web Access) on a brand new Dell M-Series Blade Server. The goal of the Unified Communications (UC) group in the INTEROP Labs (iLabs) is seeking to delve into the intricacies of interfacing XMPP and SIMPLE based UC systems so that they can exchange VoIP calls, IM and most importantly presence.
Glenn Evans of DiVitas has this to say about UC:
Unified Communications (UC) is a commonly used term for the integration of disparate communications systems, media, devices and applications. This potentially includes the integration of fixed and mobile voice, e-mail, instant messaging, presence, Internet Protocol (IP)-PBX, Voice over IP (VoIP), Voice over Wireless LAN (VoWLAN), voice mail, fax, audio, video and web conferencing, unified messaging, and unified voicemail into a single environment. UC represents a communication’s “Holy Grail” by magazines and writers in the science fiction community.
However, the team ran into a snag on the part that should have been easy. Sending a voice call from an OCS Client to the SIP gateway (asterisk) only to find log entries saying the target was "actively refusing" the connection.
Start-Line: Exception: Microsoft.Rtc.Signaling.ConnectionFailureException: Unable to establish a connection. ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused
Using TCPDUMP with the syntax "tcpdump -i eth0 -m mediation_server_address" we got the following:
12:11:35.000777 IP ipaddr_mediation_server.65529 > asterisk.0: UDP, length 36
12:11:35.000789 IP asterisk > ipaddr_mediation_server: ICMP asterisk udp port 0 unreachable, length 72
*NOTE: ipaddr_mediation_server was substituted in place of the actual IP address