WebSphere® MQ
Telemetry Transport is
a lightweight publish/subscribe protocol flowing
over TCP/IP for remote sensors and control devices through low bandwidth communications.
This protocol is used by specialized applications on
small footprint devices that require a low bandwidth communication, typically
for remote data acquisition and process control.
A typical
system might comprise several hundred client devices communicating with a
single WebSphere Event
Broker, where each client is identified
by a unique ID. A single broker can manage a maximum of approximately 2000
clients.
Client applications use WebSphere MQ
Telemetry Transport to
send messages to SCADAInput nodes
and receive messages from Publication or SCADAOutput nodes in a message flow.
WebSphere Event
Broker uses the SCADAInput node
to receive messages from WebSphere MQ
Telemetry Transport client
applications. The node interacts with a TCP/IP port to receive the messages.
Output is typically returned to the client application using a Publication node which embeds a SCADAOutput node. The Publication node
filters and sends output from a message flow to subscribers who have registered
an interest in a particular set of topics. If an application is using WebSphere MQ, the Publication node
puts the message to the WebSphere MQ queue on
the queue manager. For WebSphere MQ
Telemetry Transport applications,
the embedded SCADAOutput node routes
the message to a subscribing WebSphere MQ
Telemetry Transport client
using a TCP/IP port.
SCADAInput nodes
are available on all platforms except z/OS®.
It is unlikely that you will use the SCADAOutput node
directly, unless you write your own publication node for advanced applications.
Unlike WebSphere MQ and WebSphere MQ Everyplace®, WebSphere MQ
Telemetry Transport does not provide any security, although
you can encrypt data, if required.
The transport is described in the following topics: