Question
GMS can provide push email capability to devices that are able to use the IMAP service to access email. To do this it makes use of an extension to IMAP called IMAP IDLE.
A huge advantage to IMAP IDLE is that the connecting client no longer needs to make periodic (and often costly!) connections to the server in order to check if new mail has arrived.
Answer
IMAP IDLE is initiated on a per device basis. The device client may then obtain summary information about the new messages to present to the user, and can (automatically) download the message when appropriate.
This means that an active client will always be kept up to date on new message traffic to their mail box. When the user is inactive, and does not wish to receive notifications, the client simply stops using IDLE. The IMAP IDLE command has a very low network usage impact and therefore bandwidth usage is also extremely efficient.
Note: This functionality is only available if the device client supports IMAP IDLE.
See Also:
Keywords:push, wireless, IMAP, idle, poll, PDA, mobile, cell phone