Example 4 describes calls between two SIP stations within different Session Manager instances with different Communication Managers administered as either feature servers or evolution servers.

Call between two SIP stations with different Session Manager instances and same Communication Manager shows the signaling flow associated with a call between two SIP stations registered to different Session Manager instances and using a different feature servers, different evolution servers, or one of each.

Resources associated with each Session Manager instance for the call depicted in Session Manager call types: Example 3 include:

• 2 SIP sessions

  • SIP A or SIP B - Session Manager - Communication Manager

  • Communication Manager - one Session Manager - other Session Manager

Communication Manager resources associated with each Communication Manager for the call depicted in Session Manager call types: Example 3 include:

• 2 SIP trunk channels (for either feature server or evolution server)

• CPU for 2 SIP trunk call legs (for either feature server or evolution server)