Cisco ATA 186 Administrator's Manual page 193

Appendix D H.323 Signaling
Figure D-3
Endpoint 1
Table D-5 Action Descriptions
Step Action
Local Admission Request (ARQ)—Local
1.
endpoint to H.323 gatekeeper
Local Admission Confirm (ACF) or Admission
2.
Reject (ARJ)—H.323 gatekeeper to the local
endpoint
Open TCP Channel for Q.931 messaging
3.
Q.931 Call Setup—Local H.323 endpoint to
4.
remote H.323 endpoint
Q.931 Call Proceeding—Remote H.323
5.
endpoint to local H.323 endpoint
OL-4008-01
H.323 Call Setup from H.323 Network to Circuit Switched Network
H.225 Admission Request (ARQ)
H.225 Admission Confirm (ACF)
Open TCP Channel for Q.931
Open TCP Channel for H.245
H.245 Terminal Capabilites
H.245 Terminal Capabilites
H.245 Terminal Capabilites
H.245 Terminal Capabilites
Exchange of Master-slave Determination Messages
H.245 Open Audio Logical Channel
H.245 Open Audio Logical Channel Acknowledgement
H.245 Open Audio Logical Channel
H.245 Open Audio Logical Channel Acknowledgement
Bi-directional Audio with Transcoding Between Endpoint and Gateway
Description
Cisco ATA sends a local ARQ message to the H.323 gatekeeper
seeking authorization to place a call over the H.323 network.
H.323 gatekeeper returns a ACF or ARJ message, indicating
whether or not the responding gatekeeper is going to allow the
Cisco ATA device access to the network.
TCP port 1720 is opened, making way for the forward and reverse
flow of Q.931 signaling messages between the H.323 endpoint
and the CSN/PSTN Gateway.
Call setup initiates from the local H.323 endpoint.
Gateway acknowledges call setup initiation.
Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator's Guide (H.323)
Gatekeeper
V
Q.931 Call Setup
Q.931 Call Processing
H.225 Admission Request (ARQ)
H.225 Admission Confirm (ACF)
Q.931 Alerting
Q.931 Connect
H.323 Signaling Scenarios
Gateway to
CSN/PSTN
V
D-15