Sametime

From Protocolinfo

Lotus Sametime is IBM's instant messaging and web conferencing protocol. There is also an open source reimplementation called Meanwhile.

A Sametime client uses a binary protocol built around a single TCP connection to a Sametime server, communicating in what is known as the Master protocol. Communication between clients is facilitated by a number of services. Services provide functionality such as messaging, conferencing, presence subscription, server-side storage of settings, and a user directory. Each service requires the client to handle a different sub-protocol over one or more Channels.

Sametime communities must be explicitly connected. If two communities are not explicitly connected, there is no way for a user on one community to communicate with a user of another community.

The Sametime protocol was originally published in draft form to the IETF as part of the IMPP working group. The "houri-draft" has long since expired, but was mostly a correct reference to the Master protocol and some sub-protocols. A copy is available here.