The Messaging Agent performs the following activities:
Authenticates users to the Messenger system when they start the Messenger client, searches for contacts as users build their contact lists, saves users' option settings for the Messenger client, and so on
Transfers instant messages back and forth between Messenger users
Maintains presence information about Messenger users so that the Messenger client can show user availability status (such as online, busy, away, and idle)
Passes conversations to the Archive Agent if archiving is enabled
The Messaging Agent is highly scalable. If you are setting up a large Messenger system, you should run the Messaging Agent on a dedicated server with a processor speed of 1-2 GHz and with 1 GB of RAM. The Messaging Agent has been tested to easily support 1000 active conversations on such hardware. If you assume that 2% of Messenger users might be conversing simultaneously, you could plan on your Messenger system including as many as 50,000 users. Although Messenger has not been tested with this many actual users, you can be confident that it can scale to meet the needs of a very large number of users. For more information on the Messaging Agent, see Managing the Messaging Agent.