Codec Fallback Enabled

With H.323 codec fall back enabled, the Oracle® Enterprise Session Border Controller attempts to use the preferred codec that the slow-start side of the call specifies. The Oracle® Enterprise Session Border Controller determines matching based on the incoming TCS from the slow-start side and the OLC on the egress side. If the codecs do not match, the Oracle® Enterprise Session Border Controller sends an empty TCS on the egress side and closes the logical channels on the outgoing side of the call.

To trigger a new capabilities exchange, the Oracle® Enterprise Session Border Controller forwards the TCS from the ingress side of the call to the egress endpoint. Then the TCS from the egress endpoint is propagated to the ingress endpoint, and the logical channels are opened.

The following diagram shows a call scenario using the H.323 codec fallback feature.