Edge Traversal and More

Native registration to Lync also allows for additional features to be used, such as STUN/TURN and secure RTP media encryption. The signaling gateway scenario usually only allows for calls to work within the internal network. Since the signaling gateway does not register to a Lync Edge Server, no remote or relay candidates are presented during the media negotiation phase, and the calls will fail if a remote Lync user has not connected a VPN before calling a third-party system.

With native registration the third-party endpoint will receive MRAS credentials from the Lync Edge Server and present remote and relay candidates when participating in Lync calls, enabling remote users to seamlessly connect without VPN.

Additionally, native registration will support secure RTP transport of the media stream. The signaling gateway method provides an unencrypted media stream between Lync endpoints and the third-party systems.

Polycom endpoints also support Lync Enterprise Voice features, so they can be enabled for inbound and outbound voice calls. The dial-plan normalization rules are applied by the Lync server, but dial plans, voice policies, and conferencing policies can all be assigned to an HDX account. Another advantage to this native registration is that Polycom supports Lync Call Admission Control policies. No other vendor supports this functionality today.