messaging

messaging

the practice of sending and receiving written communications by computer or mobile phone

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

messaging

[′mes·ij·iŋ]

(communications)

Electronic communication in which a message is sent directly to its destination without being stored en route.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

messaging system

A system that sends text messages from one user to one or more other users. Email, chat and texting are the major messaging systems. Images are also included.

THIS IS ABOUT EMAIL
The following definition covers the Internet-based email system. For other messaging systems, see text messaging and chat.

Mail User Agent (Client)
The mail user agent (MUA or UA) is the client email program, such as Outlook, Eudora or Mac Mail, which is used to compose, send and receive messages.

Message Transfer Agent (Server)
The message transfer agent (MTA), or "mail transfer agent," is a mail server that forwards messages from user agents (MUAs) or delivers mail to its own message store (MS) for local recipients. Sendmail and Microsoft Exchange are the most widely used MTAs, and in a large enterprise, there may be several MTAs deployed.

Message Store
The message store (MS) holds the mail until it is selectively retrieved and deleted by an access server. A local delivery agent (LDA) writes the messages from the MTA to the message store, and the protocols used to retrieve the mail are POP and IMAP (see POP3 and IMAP4).

The Internet's SMTP
Internet email is based on the SMTP protocol. Prior to the Internet's enormous growth in the late 1990s, numerous proprietary messaging systems were widely used, including cc:Mail, Microsoft Mail, PROFS and DISOSS. See SMTP, messaging middleware, text messaging and instant messaging.

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unified messaging

Having access to email, voicemail and faxes via a common computer application or by telephone. For example, unified messaging may send faxes and digitized voicemail to a mail server that turns them into email attachments. Audio-based systems convert email messages to speech (text-to-speech) in order to deliver messages to a desk phone or cellphone. See unified communications and text-to-speech.

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