Patent ID: 7382720

Claim:
An active/standby switching system comprising two AAL 2 (ATM Adaptation Layer Type 2 ) cell assembling/disassembling processor units ( 20 , 30 ) as an active system and a standby system so that active/standby switching is carried out between the active system and said standby system; the active/standby switching being carried out by transferring, from one of said AAL 2 cell assembling/disassembling processor units which has been the active system to the other AAL 2 cell assembling/disassembling processor unit which has been the standby system, handover information to prevent cell loss of AAL 2 cells from occurring as a result of the active/standby switching and uncompleted cell data in the course of disassembling, said AAL 2 cell assembling/disassembling processor unit to become a new active system receiving the handover information and the uncompleted cell data and carrying out AAL 2 cell assembling or disassembling; wherein the handover information includes at least one of an ATM connection information, a sequence number (SN), a short cell header, a short cell residual payload length, and a cross-header byte number across short cell headers.