DTMF Support

For calls that require the IWF, you can enable support for the relay of RFC 2833 DTMF digits. The availability of this feature means that the Oracle® Enterprise Session Border Controller is compliant with RFC 2833, which defines two payload formats for DTMF digits. To learn more about this RFC, refer to http://www.ietf.org/rfc/rfc2833.txt.

Until the exchange of TCS messages with the H.323 endpoint, the Oracle® Enterprise Session Border Controller has no information about the endpoint’s RFC 2833 capabilities. The Oracle® Enterprise Session Border Controller adds telephone-event to the SDP on the SIP side of the call.

For calls that require SIP/H.323 translation, you can enable support for the relay of RFC 2833 DTMF digits.

To use this feature, you need to configure a media profile called telephone-event and set relevant parameters for it. Application of the media profile can happen either in a session agent configuration or in the IWF configuration.

• The name parameter in the media profiles configuration
• The media-profiles list in the IWF configuration
• The media-profiles list in the session agent configuration

All of the scenarios outlined here assume that you have established a telephone-event media profile configuration.

You can configure DTMF support using the following parameters. The way that the Oracle® Enterprise Session Border Controller uses these values is described below. The payload type, part of the media profiles configuration, is dynamic and varies with different endpoints, so there is no default configuration for the telephone-event media profile.

The telephone-event media profile is used as follows in these types of IWF sessions:

• Calls that require the IWF originating in H.323 Slow Start—There is no channel (media) information available on the H.323 side.
  • If the incoming H.323 endpoint is configured as a session agent on the Oracle® Enterprise Session Border Controller , then the telephone-event parameter in the media profiles set for that session agent configuration will be used in the SDP on the SIP side of the session.
  • If the H.323 endpoint is not a session agent or the telephone-event media profile is not configured in the session agent configuration corresponding to the endpoint, then the Oracle® Enterprise Session Border Controller refers to the media profile information configured for the IWF configuration.
• Calls that require the IWF originating in SIP—If the TCS was not exchanged before a 200 OK was sent on the SIP side, the Oracle® Enterprise Session Border Controller will behave in one of these two ways.
  • If the outbound H.323 endpoint is configured as a session agent, then the media profiles from that session agent configuration will be used.
  • If the outbound H.323 endpoint is not configured as a session agent, the media profile configured within the IWF configuration with the telephone-event value will be used.

As mentioned above, DTMF support is configured by using a combination of the telephone-event media profile and either the session agent or IWF configuration. First you set up the media profile, then you apply it to a session agent or to the IWF configuration.