Method and apparatus for providing sticky bindings using version vectors

A system to maintain a client session between a client device and a replica of a network application running in a network having a plurality of routers, comprising:

• a network interface to receive a request from a client to access the network application
• wherein the network interface is configured to receive an update of change events for the database from another router in the plurality of routers in the network;
• and
• the controller is further configured to reconcile the database according to the received update and to update the current version vector in response to reconciling the database,
• wherein to reconcile of reconciling the current version vector comprises the steps of:
• comparing a least recent event number of the router that generated the update to the event number in the current version vector entry for that router;
• if the least recent event number is in series with the event numbers in the database as determined by the current version vector entry for that other router, then entering the most recent event number of the received update into the current version vector entry for the router that generated the update of change events;
• and
• if the least recent event number in the update is not in succession to the event number in the current version vector entry for the router that generated the update of change events, then discarding the received update;
• a storage device to store a database of bindings, where a binding relates the client device to the network application to a replica of the network application, where the client device is identified by an IP address, where the replica is identified by an IP address, and where the network application is identified by a DNS name, and where a binding includes a binding expiration time, the storage device to further store a change log and a current version vector associated with the change log where the change log includes records added to the database by the system and the current version vector has an entry for each router in the network, each entry storing a version vector of a particular router;
• and
• a controller coupled to the interface and the storage device, the controller configured to route the request, if the controller finds a binding matching the request, the controller to route the request to a replica of the network application according to the binding and to reset the binding expiration time in the binding, if the controller does not find a binding matching the request, the controller to add a new record to the database of bindings.