You can use a global cache to store state for integrations. With a global cache, each broker can handle replies, even when the request was processed by another broker.
When IBM® Integration Bus is used to integrate asynchronous systems, the broker records information about the requester to correlate the replies correctly, as shown in the following diagram.
When this integration is deployed to multiple brokers for workload balancing, the reply will not necessarily return through the same broker as the original request.
With a global cache, each broker can handle replies, even when the request was processed by another broker.