Sockets

TCP

ZeroMQ

High-level abstraction layer for sockets.

Pair creation P, Q (one receives, the other one sends).

All communications are asynchronous.

Patterns

• Request-Reply,

• Publish-Subscribe,

• Pipeline.

Queues

Persistent and asynchronous communication through a middleware of queues. Queues are buffers in the communication servers.

Operations

• PUT - Adds a message to a specific queue.

• GET - Locks until it has a message in the queue, and removes the first message.

• POLL - checks for the existence of messages in a specific queue, and removes the first message. Never locks.

• NOTIFY - Installs a handler that will be called when a message is placed in a specific queue.

Modelo Geral

Message Broker

In a message queueing (MQ) system, a common message protocol is assumed.

Broker functions:

• Convert messages to the correct format.

• Gateway applications.

• Routing functionalities (e.g: publish-subscribe).

Architecture