Method and apparatus for error free switching in a redundant duplex communication carrier system

摘要

A method and apparatus for switching from an active to a standby controller in a redundant duplex carrier system without requiring retransmission of messages in progress during the switch. A main processor in the standby controller is periodically switched and made the active controller to ensure reliability of the system. The main processor in the active controller stops sending messages for a period of time before switching control to the standby controller. The main processor in the standby controller delays initiating any new communications until any current messages have been completed from the active controller. The main processor of the standby controller then retrieves any unprocessed messages that may have been sent to the active controller just before or during the switch from the active controller to the standby controller. The delay of new messages and retrieval of any unprocessed messages ensures that no data will be lost during the switch, thus removing the need for retransmission.