Patent ID: 7940651

Claim:
A momentary-disconnection-free switching device, which processes a data frame of a synchronous communication network, in a redundant network device, comprising: a first pointer processing unit as an active device, to process a pointer which indicates a starting position of a payload included in a subframe accommodated by the data frame; a second pointer processing unit, as a standby device of said first pointer processing unit, to process a pointer which indicates a starting position of a payload included in the subframe; a transferring unit to transfer write and read address values, which are used to process the pointer, of data to/from a memory from said first pointer processing unit as an active device to said second pointer processing unit as a standby device; a clock generating unit to generate a first timing clock, which is intended to drive said first pointer processing unit, from a common high-frequency timing clock; and a clock reproducing unit to reproduce a second timing clock, which is intended to drive said second pointer processing unit and a phase of which matches a phase of the first timing clock, from the first timing clock generated by said clock generating unit, wherein said second pointer processing unit as the standby device processes a pointer by using the write and read address values transmitted from said first pointer processing unit as an active device and wherein said first pointer processing unit and said second pointer processing unit are driven respectively based on the first and the second timing clocks, whereby said first pointer processing unit and said second pointer processing unit are driven with timing clocks having a same phase.