Relationship to Symmetric Latching

The current forced HNT symmetric latching feature lets the Oracle Communications Session Border Controller assume devices are behind NATs, regardless of their signaled IP/SIP/SDP layer addresses. The Oracle Communications Session Border Controller latches on any received RTP destined for the specific IP address/port of the Oracle Communications Session Border Controller for the call, and uses the latched source address/port for the reverse flow destination information.

If both restricted latching and symmetric latching are enabled, the Oracle Communications Session Border Controller only latches if the source matches the restriction, and the reverse flow will only go to the address/port latched to, and thus the reverse flow will only go to an address of the same restriction.

• Symmetric latching is enabled.

  If symmetric latching is enabled, the Oracle Communications Session Border Controller sends the media in the opposite direction to the same IP and port, after it latches to the source address of the media packet.

• Symmetric latching is disabled.

  If symmetric latching is disabled, the Oracle Communications Session Border Controller only latches the incoming source. The destination of the media in the reverse direction is controlled by the SDP address.