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.

DTMF Configuration

DTMF support requires you to configure a media profile named telephone-event. This section shows you how to set it up.

To configure a telephone-event media profile:

In Superuser mode, type configure terminal and press Enter.
```
ORACLE# configure terminal
```
Type session-router and press Enter to access the session-related configurations.
```
ORACLE(configure)# session-router
```
Type media-profile and press Enter. The system prompt changes to let you know that you can begin configuring individual parameters.
```
ORACLE(session-router)# media-profile
```
From this point, you can configure parameters for media profiles. To view see all media profile configuration parameters, enter a ? at the system prompt.
name—Enter the name telephone-event and press Enter.
parameters—Enter the parameters to be applied for the codec; these are the digits that endpoints can support.
media-type—Leave the default media type set to audio.
payload-type—Set the payload type to 101, which is the dynamic payload type needed to support this feature.
transport—Leave the default transport protocol set to RTP/AVP.
frames-per-packet—You can leave this parameter set to 0 (default).
req-bandwidth—You can leave this parameter set to 0 (default).

Applying the Media Profile

After you have configured the telephone-event media profile, you need to apply it either to a H.323 session agent or the global IWF configuration.

DTMF for all IWF translations

To use DTMF for all IWF translations:

In Superuser mode, type configure terminal and press Enter.
```
ORACLE# configure terminal
```
Type session-router and press Enter to access the session-related configurations.
```
ORACLE(configure)# session-router
```
Type iwf-config and press Enter. The system prompt changes to let you know that you can begin configuring individual parameters.
```
ORACLE(session-router)# iwf-config
```
From this point, you can configure IWF parameters. To view see all IWF configuration parameters, enter a ? at the system prompt.
Add the telephone-event media profile to the media profiles list and save your work. If you already have a media profiles for the IWF configuration set up and want to keep them (adding telephone-event to the list), then you must type in all of the media profiles that you want to use.
```
ORACLE(iwf-config)# media-profiles "PCMU telephone-event"
ORACLE(iwf-config)# done
```

DMTF Support on a Per-Session-Agent Basis

To use DMTF support on a per-session-agent basis:

In Superuser mode, type configure terminal and press Enter.
```
ORACLE# configure terminal
```
Type session-router and press Enter to access the session-related configurations.
```
ORACLE(configure)# session-router
```
Type session-agent and press Enter. The system prompt changes to let you know that you can begin configuring individual parameters.
```
ORACLE(session-router)# session-agent
```
From this point, you can configure IWF parameters. To view see all IWF configuration parameters, enter a ? at the system prompt.
When you configure a new H.323 session agent, you can configure DTMF support by simply adding the telephone-event media profile to the list of media profiles. You can add it along with the other media profiles you might want to use for that session agent.
```
ORACLE(session-agent)# media-profiles "telephone-event g711Ulaw64k"
```

When you want to add DTMF support to an H.323 session agent that you have already configured, you need to select that session agent, add the media profile, and save your work.

ORACLE(session-agent)# select
<hostname>:
1: 192.168.1.48 realm=         ip=
2: 192.168.1.49 realm=         ip=
3: 192.168.1.50 realm=external ip=
selection:3
ORACLE(session-agent)# media-profiles "telephone-event g711Ulaw64k"
ORACLE(session-agent)# done