Cisco Unified MeetingPlace H.323/SIP Administrator's Manual page 14

Information About Cisco Unified MeetingPlace H.323/SIP IP Gateway Software Release 5.2.1 Components
Step Cisco IP Phone Description
Cisco Unified CallManager and Release 5.2.1
3.
communicate by using H.323. This
communication process involves H.225 for call
signaling and H.245 for media exchange.
a.
b.
c.
d.
4. Cisco Unified CallManager and Release 5.2.1 exchange the IP address and UDP port number of the
Cisco IP phone or voice gateway and the Cisco Unified MeetingPlace Audio Server system
a.
b.
5. After codec information, IP address, and UDP port number are received, the Cisco IP phone or voice
gateway uses the information to send voice traffic directly to the Cisco Unified MeetingPlace Audio
Server system. The Cisco IP phone or voice gateway is connected to the Cisco Unified MeetingPlace
Audio Server system after each device exchanges data.
Administrator Guide for Cisco Unified MeetingPlace H.323/SIP IP Gateway Software Release 5.2.1
1-8
Chapter 1
Cisco Unified CallManager and Release 5.2.1 use H.225 to determine if the Cisco Unified
MeetingPlace Audio Server system can accept the call. By using Cisco Unified MeetingPlace
GWSIM, Release 5.2.1 communicates directly with the Cisco Unified MeetingPlace Audio
Server system to determine its availability.
If the Cisco Unified MeetingPlace Audio Server system is unavailable, Release 5.2.1 informs
Cisco Unified CallManager, and the caller hears a fast busy signal.
If the call is accepted, Cisco Unified CallManager and Release 5.2.1 use H.245 to negotiate
which codec will carry the voice activity. Release 5.2.1 uses G.711 or G.729a to carry the
encoded speech.
Once codec negotiation is complete, Release 5.2.1 uses the Gateway SIM to retrieve an IP
address and UDP port number from the Cisco Unified MeetingPlace Audio Server system. This
IP address and UDP port number provide access to the meeting.
Cisco Unified CallManager sends the IP address and UDP port number of the Cisco Unified
MeetingPlace Audio Server system to the Cisco IP phone or voice gateway.
Release 5.2.1 sends the IP address and UDP port number of the Cisco IP phone or voice gateway
to the Cisco Unified MeetingPlace Audio Server system.
Introducing Cisco Unified MeetingPlace H.323/SIP IP Gateway Software Release 5.2.1
PSTN Phone Description
Cisco Unified CallManager examines its routing
table to resolve the dialed number with the IP
address of the IP-gateway server.
Cisco Unified CallManager and Release 5.2.1
communicate by using H.323. This communication
process involves H.225 for call signaling and H.245
for media exchange.
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