Enterprise Messaging System

An enterprise messaging system (EMS) is a set of published enterprise-wide standards that allows organizations to send semantically precise messages between computer systems. EMS systems promote loosely coupled architectures that allow changes in the formats of messages to have minimum impact on message subscribers. EMS systems are facilitated by the use of structured messages (e.g. using XML or JSON, and appropriate protocols, such as AMQP or SOAP with web services.

EMS usually take into account the following considerations:

1. Security: Messages must be encrypted if they travel over public interfaces. Messages must be authenticated or digitally signed if the receiver is to have confidence that the messages have not been tampered with in transit.
2. Routing: Messages need to be routed efficiently from the sender to the receiver. Intermediate nodes may need to route the messages if the body of the message is encrypted.
3. Metadata: The body of the document contains information that must be unambiguously interpreted. Metadata registries should be used to create precise definitions for each data element.
4. Subscription: Systems should be able to subscribe to all messages that match a specific pattern. Messages with a specific content may be routed differently. For example some messages may have different priority or security policies.
5. Policy: Enterprise messaging systems should provide some consideration for a centralized policy of messages such as what classes or roles of users can access different fields of any message.