Communication System Architecture

At least one computer readable medium storing executable code which is configured to implement a method of managing a communication event between a plurality of endpoints connected via a communication network of a communication system comprising a plurality of processing units other than said endpoints, each having access to computer storage holding executable code modules for managing the communication event, the code modules being configured to implement a media modality controller configured to manage media modality of an established communication event and a call controller configured to establish the communication event, the method comprising:

• receiving an instruction via the network;
• in response to receiving the instruction, assigning an instance of the call controller to progress the establishment of the communication event;
• and
• the call controller instance initiating an instruction to at least one of:
• the media modality controller;
• and at least one of the endpoints;
• wherein the code modules are configured to implement a transport controller configured to manage transport of media of the communication event between the endpoints,
• wherein an instance of the transport controller is assigned to convey transport control signals of the communication event to respective transport agents of the endpoints without accessing the call agents of the endpoints, the transport controller instance being so assigned independently of the call controller and responsive to a first instruction received via the network;
• and
• wherein the transport controller instance is released from said assignment responsive to the transport controller instance returning a response to the received instruction while the call controller continues to operate in communication with the call agents of the endpoints and/or the media modality controller.