The WebSphere® MQ link, defined on a messaging
engine in the service integration bus, describes the attributes required
to connect to, and send or receive messages to or from, a
WebSphere MQ queue manager or (for
WebSphere MQ for z/OS®
) queue sharing group that
acts as a gateway to the
WebSphere MQ network.
Point-to-point messaging might be:
- A request from
WebSphere Application Server to
WebSphere MQ, optionally followed by
a
WebSphere MQ reply.
- A request from a
WebSphere MQ network,
optionally followed by a
WebSphere Application Server reply.
The following figure shows the flow of point-to-point messages
across the WebSphere MQ link.
Figure 1. Exchanging
messages between WebSphere MQ link sender and receiver channels,
and a gateway queue manager with receiver and sender channels.
See Request-reply messaging through a WebSphere MQ link for more
information about the reply messages transmitted across the
WebSphere MQ link.
Point-to-point messaging might also include:
The following figure shows how messages can be exchanged between
applications and messaging engines that are on the same bus, as well
as between the WebSphere MQ link and queue managers connected
to the gateway queue manager in the
WebSphere MQ network.
Figure 2. Exchanging
messages between messaging engines on a bus that has a WebSphere MQ
link that is connected to a gateway queue manager on a foreign bus.
Notes:
- If your
WebSphere Application Server application
sends point-to-point messages to a
WebSphere MQ application that is not
JMS, such as a
WebSphere MQ message-driven
application in CICS (using the CICS MQ bridge) or IMS (using the IMS
MQ bridge), then your
WebSphere Application Server application
has to use special techniques to ensure that the service integration
messages (most likely JMS messages) are presented to the non-JMS application
in a way that the application can understand. For more information,
see Programming for interoperation with WebSphere MQ , How service integration converts messages to and from WebSphere MQ format,
and How to process WebSphere MQ message headers, which describes
WebSphere Application Server helper classes that assist
in the creation of suitable headers and body content.
- Some
WebSphere MQ applications
can process messages that include an MQRFH2 header (generally these
are JMS or XMS or
WebSphere MQ Version
7 applications) and some applications cannot do so (generally these
are
WebSphere MQ applications that
predate the MQRFH2 header). You must set the destination context
to inhibit adding an MQRFH2 header when messages are destined for
a
WebSphere MQ application that cannot
handle this header. For information about setting the destination
context, see Specifying whether messages are forwarded to WebSphere MQ as JMS messages. The MQRFH2
header contains fields unique to the service integration bus. For
details of these fields, see Mapping additional MQRFH2 header fields in service integration.
- Any
WebSphere MQ queue name is
also valid as a bus destination name and, as a general rule, you should
configure a bus destination that is a
WebSphere MQ queue to use the
WebSphere MQ queue name. If your bus
applications have to use a different name, you can achieve this by
using an alias destination.
-
WebSphere MQ channel or conversion
exits (for example, for data conversion) are not supported by the WebSphere MQ link.