Patent ID: 7412499

Claim:
A method for adding new members to a group of nodes in a connected data processing network, said method comprising the steps of: periodically sending, from a first group leader node a proclaim message to select nodes in the network configuration but which are not currently part of the group; responding to said proclaim message from said first group leader node with a join message from a group leader of an other group having said lower network address, said join message including a membership list for any joining groups; transmitting a prepare-to-commit message to said nodes within any of said joining groups; receiving, at said first group leader node, an acknowledgment of said prepare to commit message, from at least one node; sending a commit message with updated membership list to all nodes on the updated list; following said periodic sending, determining that a specified number of said prepare-to-commit message transmissions have not been received from a potentially failed node; and sending an echo-request message to said potentially failed node, said echo request message being directed to an other program running on said potentially failed node that is less susceptible than said prepare-to-commit message to being delayed.