Cisco Cisco TelePresence Video Communication Server Expressway
Appendix 3 – Call flows for Multiway
Cisco VCS Deployment Guide: Multiway™ (Cisco VCS X7)
Page 25 of 30
Multiway
Conference
Initiator
Party
2
Party
3
Cisco VCS
MCU
OK
Notify
Notify
Bye (3)
Bye (3)
All 3 parties in an MCU hosted conference call
H.323
H.323 works in a similar manner, using routeCallToMC H.225 ‘Facility’ messages to indicate which
conference ID to dial.
conference ID to dial.
Cisco VCS interworks H.323 calls to Conference Factory into SIP, so the Conference Factory
always sees an INVITE when Join is pressed, and responds with the 302 temporarily moved.
Cisco VCS interworking converts the 302 into a routeCallToMC facility message.
always sees an INVITE when Join is pressed, and responds with the 302 temporarily moved.
Cisco VCS interworking converts the 302 into a routeCallToMC facility message.
The initiating H.323 endpoint then sends routeCallToMC facility messages to the endpoints that
are to join the Multiway conference.
are to join the Multiway conference.
The following sequence diagram shows the key H.323 messaging, although not all messages are
shown.
shown.
Multiway
Conference
Initiator
Party
2
Party
3
Cisco VCS
MCU
Setup
(Party 2)
Call Proceeding
Setup
(Party 2)
Alerting
Alerting
Connect
Connect
Call between Multiway Initiator and Party 2 in progress, put Party 2
on hold
H.245