Cisco Systems ATA 188 manual Action Description, Csn/Pstn

Appendix D H.323 Signaling

H.323 Signaling Scenarios

Figure D-3 H.323 Call Setup from H.323 Network to Circuit Switched Network
	Gatekeeper	Gateway to
Endpoint 1		CSN/PSTN
	V	V

			H.225 Admission Request (ARQ)
			H.225 Admission Confirm (ACF)
				Open TCP Channel for Q.931
					Q.931 Call Setup
					Q.931 Call Processing
						H.225 Admission Request (ARQ)
						H.225 Admission Confirm (ACF)
					Q.931 Alerting
					Q.931 Connect
				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
							79600
Table D-5 Action Descriptions
	Step	Action			Description
1.		Local Admission Request (ARQ)—Local			Cisco ATA sends a local ARQ message to the H.323 gatekeeper
		endpoint to H.323 gatekeeper			seeking authorization to place a call over the H.323 network.
2.		Local Admission Confirm (ACF) or Admission			H.323 gatekeeper returns a ACF or ARJ message, indicating
		Reject (ARJ)—H.323 gatekeeper to the local			whether or not the responding gatekeeper is going to allow the
		endpoint			Cisco ATA device access to the network.
3.		Open TCP Channel for Q.931 messaging			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.
4.		Q.931 Call Setup—Local H.323 endpoint to			Call setup initiates from the local H.323 endpoint.
		remote H.323 endpoint
5.		Q.931 Call Proceeding—Remote H.323			Gateway acknowledges call setup initiation.
		endpoint to local H.323 endpoint
			Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide (H.323)
	OL-4008-01							D-15