Hi & welcome,
Andy Thank you for your post; I believe that you have pretty much covered the answer.
Live Communications Server is the "Farm", whilst Microsoft Office Communicator is the front-end portal.
As Andy has pointed out communication can be either client-to-Server using SIP or Server-to-Server using MTLS.
Initial commucation is established using SIP, however, if the user invokes multinodal communication, (audio visual, applications sharing, whiteboarding ect), then RTP will be established using direct Peer-to-Peer via ports 7100, 7101, 7102, 7103.
In its' true form SIP will be used to establish initial communication, and then call the relevant protocol to handle the method of transmission required.
I've provided a list of protocols and standards below that can be used within LCS/MSOC when integrated with other systems.
Protocol Brief Description
XMPP Extensible Messaging and Presence protocol. This is an IETF proposed
protocol for open XML based messaging and presence interactions
Simple Session Initiation Protocol for IM and Presence leveraging Extensions
is an application ofthe SIP protocol to the area of Instant Messaging
SOAP Simplified Objects Accessing Protocol with features for Presence
description as part of its access facilities
H.323 ITU standard applying to audio adn video conferencing,
(multinodal communicatiosn),handling session issues such as call-signing,
call-control an framing protocols
SMS is a text based service that was developed by the European Telecommunications
Standards Institute, (ETSI), as part of the Global System for Mobile, (GSM),
Communication infrastructure
MMS allows the transmission of graphics, animation, video and sound
Additional Protocol Standards
T.120 ITU standard defining how data conferencing deals with interchange of data
T.126 ITU standard defining whiteboards with
T.128 ITU standard defining program and application sharing
Hopefully this is of some help,
Thank you
Arthur
Arthur Pounder