1. A method for load sharing among cluster nodes providing session initiation protocol (SIP) services, the method comprising: (a) providing a plurality of cluster nodes for performing SIP services; (b) periodically sending messages to each of the cluster nodes to monitor the operational status of each of the cluster nodes; (c) maintaining a connection tuple table containing active connection information for each of the cluster nodes; and (d) load sharing between the cluster nodes based on the operational status and the connection tuple table.