Abstract: A process for reducing the amount of overhead data in ATM cell headers prior to transmission both upstream and downstream on an HFC cable plant or other transmission media using SCDMA on at least the upstream path, without loss of either IP or Ethernet addressing information. A virtual link between each remote unit and a central unit is established using multiplexing to establish a virtual link to every remote unit. Downstream ATM cells are optimized by stripping off all but 2 bytes to leave a 50 byte cell. Incoming IP packets have their IP addressing information used to look up Ethernet domain address information for the RU and destination process to which this RU is coupled. An Ethernet header is appended to each IP packet as is RFC 1483 bytes to signal the start of the packet. The packet is parsed into 48 byte ATM cell payloads. VPI/VCI information for the virtual link of the remote unit to which the packet is bound is looked up using the Ethernet address information.

Abstract: A method and apparatus for carrying an ATM communication protocol on a hybrid fiber coax CATV system. Point to point communication is supported by use of synchronous code division multiplexing on the physical and by assigning on the MAC layer one or more orthogonal SCDMA codes exclusively for use by pairs of devices needing to communicate such the head end and any customer premises equipment. Quality of service or guaranteed bandwidth availability is implemented by controlling the code space at the MAC layer such that certain CPEs having in use peripherals which cannot tolerate interruptions in data flow may reserve one or more SCDMA codes for use exclusively by them. Standard ATM cells are modified by the addition of a two byte virtual link header which identifies to which CPE a particular ATM packet is destined. This virtual header also makes possible broadcast and multicast of packets from the head end to all CPEs.