Patent ID: 8135594

Claim:
A publish/subscribe message broker for routing publications from a plurality of publishers to interested subscribers, the broker being capable of interconnection in a network of similar brokers, the broker comprising: an input for receiving publications from publishers both directly and via other brokers; a controller responsive to the receipt of subscriptions and unsubscriptions from subscribers and from other brokers in the network for publications meeting predefined criteria identified in the subscriptions or unsubscriptions to create and manage a list correlating subscribers with the predefined criteria; a matching engine for comparing received publications with the subscription list and forwarding publications which match listed subscriptions which are in an active state to interested subscribers and interested other brokers in the list; and an output responsive to received subscriptions and unsubscriptions to generate and forward related proxy subscriptions and proxy unsubscriptions to other brokers; wherein the controller is responsive to receipt of an unsubscription from a subscriber or a proxy unsubscription from another broker to put the corresponding subscription in a retained state for a retention period during which matching publications will not be forwarded to the subscriber or other broker and no proxy unsubscriptions will be forwarded to other brokers, a new subscription for the same matching publications as the retained subscription during the retention period causing a reversion of the retained subscription to its active state, whereby propagation of proxy subscriptions and unsubscriptions is reduced in dependence on the duration of the retention period.