Example 3 describes calls between two SIP stations within different Session Manager instances with the same Communication Manager administered as either a feature server or evolution server.

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 the same Communication Manager as a feature server.

Resources associated with each Session Manager instance for the call depicted in Figure : 1 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 the call depicted in Figure : 1 include:

• 2 SIP trunk channels if evolution server; 4 SIP trunk channels if feature server

• CPU for 2 SIP trunk call legs if evolution server; CPU for 4 SIP trunk call legs if feature server