Patent ID: 7606808

Claim:
A computer implemented method for providing event notifications for notification subscriptions from a plurality of load-balanced servers in a server tier to a client tier in a communications network, said method comprising: receiving, at the server tier, a first subscription request from a subscriber via the client tier, said subscription request defining an event of interest and an address in the client tier of the subscriber, said first subscription request including an expiration parameter from the client tier specifying a defined period of time after which to verify that the subscription is working properly, said subscription request being generated in response to input data received from the subscriber; creating, by a particular server of the server tier, a first notification subscription corresponding to the received first subscription request, wherein the particular server is designated to host the created first notification subscription; periodically querying a data tier maintaining an event log, and being queried by the particular server to identify relevant event data based on the first notification subscription; sending a notification request from the particular server of the server tier to the client tier to notify the client tier of the identified relevant event data; receiving, at the server tier, a second subscription request automatically generated at the subscriber via the client tier, the second subscription request defining the event of interest and the address in the client tier of the subscriber if the client tier does not receive the notification request from the particular server for a period of time specified by the expiration parameter; wherein the server tier receives the second subscription request and creates a second notification subscription corresponding to the received second subscription request independent of the particular server of the server tier, wherein the second subscription request includes an expiration parameter defined by a subscriber, said expiration parameter specifying a period of time after which the client tier is to be notified of the failure of the server tier to identify relevant event data; and wherein the subscriber via the client tier automatically sends a cancellation request for the first notification subscription in response to receiving a subsequent notification request associated with the first notification subscription.