FLAG FIELD-BASED ROUTING MECHANISM FOR FIBER OPTIC TELECOMMUNICATION SYSTEM EMPLOYING STS-BASED TRANSMISSION FORMAT CONTAINING ASYNCHRONOUS TRANSFER MODE CELLS

摘要

A two-stage cell routing filter mechanism employs a customer premises associated flag bit field (133) in ATM data cells being serially transmitted from a host digital terminal's data transport path through an optical fiber (22) to a downstream optical network unit (23) associated with a plurality of customer premises equipments (40). The first stage of the cell routing filter is comprised of a look-up table (LTU) and an associated comparator mechanism. The state of each bit of the flag field of an ATM cell preamble will indicate whether or not the ATM cell is intended for the customer premises equipment associated with the bit. A downstream optical network unit contains an associated set of ATM cell filters associated with customer premises equipment. Each customer equipment cell filter examines a given bit position in the flag field portion of each received ATM cell preamble, to see whether the flag field bit of the preamble of the received ATM cell is set to a prescribed bit value (e.g. one) - indicating a customer channel request.