MSC diagram

A Message Sequence Chart, which is normally abbreviated to MSC, describes the message flow between instances. One Message Sequence Chart describes a partial behaviour of a system.

An MSC describes the communication between a number of system components, and between these components and the rest of the world, called environment. For each system component covered by an MSC there is an instance axis. The communication between system components is performed by means of messages. The sending and consumption of messages are two asynchronous events. It is assumed that the environment of an MSC is capable of receiving and sending messages from and to the Message Sequence Chart; no ordering of message events within the environment is assumed.

<msc diagram> ::=

<msc symbol> contains

{ <msc heading> { <msc body area> | <mscexpr area> } }