Configuring fast connection and tunneling
Fast connection and tunneling
According to the specification of H.225.0 recommendation, fast connection means that a Setup, CallProceeding, Alerting, or Connect message carries a standard H.245 message (for example, Open Logical Channel message) so that an RTP/RTCP voice channel can be established before the gateway (GW) receives a Connect message, avoiding H.245 message exchange on TCP connection, and thereby shortening connection time. There is no capability negotiation process in fast connection mode, so the capability of both parties is determined by the terminating GW. When fast connection is enabled, a Setup message sent from the originating GW carries locally supported codecs. After receiving this message, the terminating GW selects one suitable codec to notify the originating GW through a CallProceeding, Alerting, or Connect message. In this way, both parties adopt this codec for communication.
Tunneling means that in fast connection mode, non-standard H.245 messages (for example, transparent transmission capability of DTMF digit) are encapsulated in an H.225.0 Facility message to complete capability negotiation and call forwarding. This makes it unnecessary to establish an independent H.245 TCP connection for transmission of H.245 message.
Enabling fast connection and tunneling on the originating GW
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter voice view. | voice-setup | N/A |
3. Enter voice dial program view. | dial-program | N/A |
4. Enter VoIP voice entity view. | entity entity-number voip | N/A |
5. Enable fast connection. | fast-connect | Disabled by default. |
6. Enable the local end to play ringback tones. | send-ring | Optional. In the fast connection mode, the remote end plays ringback tones by default. This command is available on an H.323 voice entity only after fast connection is enabled for it. If you want the local end to play ringback tones, carry out this command. |
7. Enable tunneling. | tunnel-on | Optional. Disabled by default. This command is applicable only after the fast connection is enabled. |
Enabling fast connection and tunneling on the terminating GW
You can enable or disable fast connection for each outgoing call on the originating GW. If fast connection is enabled on the originating GW, the terminating GW will determine whether to enable fast connection for call initialization or enable tunneling, depending on the configurations of the voip called-start and voip called-tunnel enable commands.
To enable fast connection and tunneling on the terminating GW:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter voice view. | voice-setup | N/A |
3. Enter voice dial program view. | dial-program | N/A |
4. Configure the call initialization method for the terminating GW. | voip called-start { fast | normal } | Optional. Fast connection by default. |
5. Enable tunneling on the terminating GW. | voip called-tunnel enable | Optional. Enabled by default. |