A new feature in Lync Server 2013 is the XMPP proxy role on the Edge Server, which allows federation with XMPP servers across the Internet such as Google. The XMPP functionality is similar to PIC for AOL in that it is two-party only, and only allows for instant messaging and presence information to be exchanged. There are no audio/video capabilities between Lync and Google or any other XMPP partner today.
When discussing the XMPP proxy, organizations should do the following:
• Identify any needs to federate with partners that currently leverage XMPP presence and IM services.
• Collect the XMPP partner domains and a proxy FQDN if the DNS SRV records are not published in public DNS.