Integration Limitations

This form of integration historically provided a very limited feature set between the two systems. The capability to make and receive calls works well, but little or no presence information is shared between Lync users and the other system. Lync users can add the third-party endpoints to a contact list, but the presence will always appear as “Presence Unknown.” This is not a great experience for the end users because there is no way to tell whether the user on the other end is actually online and available. Even worse, if the third-party endpoint is in a conference room, there is not a way to determine whether someone else has a meeting in progress at that time.

There is also no capability to share any kind of content between the two systems in this scenario. Calls are purely an audio and/or video conversation, and information shared by one side is not visible to the other. The protocols Lync uses for sharing desktops, PowerPoint, whiteboards, and polls do not follow the standards traditionally used in video conferencing systems.

This type of integration typically does not support media encryption, or remote user connectivity, and becomes a single point of failure between the two systems. If the signaling gateway is unavailable, there is no way for the third-party endpoints to contact the Lync endpoints and vice versa. Most signaling gateways support some form of high-availability with redundant pairs in an active/active or active/passive configuration.