Patent ID: 6532231
Filing Date: 2003-03-11
Classification: H04Q

Abstract:
In a system comprising a controlling unit and at least two controlled units, said controlling and controlled units being interconnected by data links operating under a single destination protocol, a method of switching transmission of data messages from a first of said controlled units to a second of said controlled units comprising the steps of:responsive to detection of a request to switch transmission of messages from said first of said controlled units to said second of said controlled uints, queuing subsequently received client messages in a queue in said controlling unit; transmitting drain request messages to said first controlled unit; responsive to receipt of drain message acknowledgments, transmitting a switch command to said first controlled unit; said controlling unit responsive to said switch command, disconnecting itself from one of said data links; responsive to receipt of said switch command, copying dynamic data from said first controlled unit to said second controlled unit; said second controlled unit connecting itself to another one of said data links; said second controlled unit transmitting a switch complete message to said controlling unit; and said controlling unit transmitting accumulated and new client messages to said second controlled unit over said another one of said data links.