Sugar collaboration is built on top of XMPP (Jabber), an open and extensible instant messaging protocol. Collaboration via a server is more scalable than over link local connections. This server is a Jabber server (with a few extra modules and patches) and is usually included in the XS schoolserver for school deployments.
Community members such as G1G1 XO users, and developers, can use a Jabber server for collaboration without needing the rest of the schoolserver functionality. In this way, "mesh view" can be extended over the Internet for regional or global communities.
Running your own server
Currently the only Jabber server that works for Sugar collaboration is ejabberd with Sugar-specific patches. See Installing ejabberd for instructions on installing and configuring it.
For those interested in the details, more details on the ejabberd configuration are here: Ejabberd Configuration
If you get a community server up, consider adding it to Community/A list of Jabber networks around the world.