Before standardizing a new protocol in this area, you
may want to take a good look at the ICE protocol and
the ICElib library for it, which is part of X11R6,
and which was released this past summer.
ICE also supports multiple conversations over a single
connection, with support for separate authentication
of each conversation. ICE is designed to be
used over TCP or any other reliable connection-oriented
transport. ICElib is thread-safe and can be used in either
a single or multi-thread environment.
A great deal of design work and testing went into ICE,
both as part of the X Consortium review process, and
as a result of using it to implement the X Session
Management protocol and library.
The best contact for more information is Ralph Mor
at the X Consortium, mor@x.org
-- Ellis