Combining and isolating topic spaces in multiple clusters

Isolate some topic spaces to a specific cluster, and combine other topic spaces to make them accessible in all the connected clusters.

Before starting

Examine the topic Combining the topic spaces of multiple clusters. It might be sufficient for the needs, without adding an additional queue manager as a bridge. Note: We can only complete this task using direct routed publish/subscribe clusters. We cannot do this using topic host routed clusters.

About this task

A potential improvement on the topology shown in Figure 1 in Combining the topic spaces of multiple clusters is to isolate cluster topics that are not shared across all the clusters. Isolate clusters by creating a bridging queue manager that is not in any of the clusters; see Figure 1. Use the bridging queue manager to filter which publications and subscriptions can flow from one cluster to another.

Use the bridge to isolate cluster topics that we do not want exposed across the bridge on the other clusters. In Figure 1, USA is a cluster topic shared in all the clusters, and Atlanta, New York and Washington are cluster topics that are shared only in one cluster each.

Model your configuration using the following procedure:

Procedure

Modify all the SYSTEM.BASE.TOPIC topic objects to have SUBSCOPE ( QMGR ) and PUBSCOPE ( QMGR ) on all the queue managers. No topics (even cluster topics) are propagated onto other queue managers unless you explicitly set SUBSCOPE ( ALL ) and PUBSCOPE ( ALL ) on the root topic of the cluster topics.
Define the topics on the three cluster topic host queue managers that we want to be shared in each cluster with the attributes CLUSTER (clustername), SUBSCOPE ( ALL ) and PUBSCOPE ( ALL ). If we want some cluster topics shared between all the clusters, define the same topic in each of the clusters. Use the cluster name of each cluster as the cluster attribute.
For the cluster topics we want shared between all the clusters, define the topics again on the bridge queue manager ( QM10 ), with the attributes SUBSCOPE ( ALL ), and PUBSCOPE ( ALL ).

Example

In the example in Figure 1, only topics that inherit from USA propagate between all three clusters.

What to do next

Subscriptions for topics defined on the bridge queue manager with SUBSCOPE ( ALL ) and PUBSCOPE ( ALL ) are propagated between the clusters.

Subscriptions for topics defined within each cluster with attributes CLUSTER (clustername), SUBSCOPE ( ALL ) and PUBSCOPE ( ALL ) are propagated within each cluster.

Any other subscriptions are local to a queue manager.

Parent topic: Combining topic spaces in publish/subscribe networks