Additional IWF Steps

For calls originating in slow-start H.323 that require interworking to SIP, the Oracle® Enterprise Session Border Controller also takes addition steps for media release in hairpinned flows that the Oracle® Enterprise Session Border Controller routes as SIP to fast-start H.323.

For such a call, after the Oracle® Enterprise Session Border Controller has established logical channels on the slow-start H.323 side of the call, it sends a reINVITE on the SIP side. This reINVITE has an updated session description to correct the media connection information. The the Oracle® Enterprise Session Border Controller performs the hold-and-resume procedure on the fast-start side of the call. This procedure re-establishes the logical channels between the Oracle® Enterprise Session Border Controller and the called endpoint, avoiding the one-way media problem.

When you are configuring H.323 globally on your Oracle® Enterprise Session Border Controller , you might choose to set the noReInvite option. This option stops the Oracle® Enterprise Session Border Controller from sending a reINVITE after the logical channels are established on the slow-start H.323 side of the call. Instead, the Oracle® Enterprise Session Border Controller ’s H.323 task communicates internally with its own SIP task a SIP UPDATE message that corrects the SDP; then the SIP task updates media flow destinations. But the Oracle® Enterprise Session Border Controller does not send the UPDATE to the next hop, which can result in the one-way media problem if the call is hairpinned and media release occurs. For such cases, the default behavior for the noReInvite option is overridden. When the Oracle® Enterprise Session Border Controller detects media release in an H.323-SIP call, it forwards the UPDATE to the next hop even when you enable the noReInvite option.