초록 ▼

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

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. The last cell in the packet is indicated by encoding 9th bits. The CU cable data modem formatter then generates optimized downstream 2-byte headers for each downstream ATM cell by stripping off all but 2 bytes of VPI/VCI data. 9th bits are added to each byte, and these 9th bits are encoded with last cell, normal cell and idle cell information and start codes so that cell boundaries can be located.

대표청구항 ▼

[ What is claimed is:] [1.] A method of processing and transmitting digital data from one of a plurality first circuits to a single second circuit in a physically distributed system, comprising:in each first circuit:receiving local area network (hereafter LAN) packets and adding unique marker bits t

[ What is claimed is:] [1.] A method of processing and transmitting digital data from one of a plurality first circuits to a single second circuit in a physically distributed system, comprising:in each first circuit:receiving local area network (hereafter LAN) packets and adding unique marker bits to the front of said LAN packet to mark the start thereof to generate modified packets;parsing each said modified packet into a plurality of ATM cell payloads having a plurality of first bit groups and adding a plurality of additional bits to each ATM cell payload to generate from each ATM cell payload a modified ATM cell payload, and encoding said additional bits with auxiliary data indicating where the start of each said modified ATM cell payload is and also at least indicating which ATM cell payload contains the last bytes of said LAN packet;parsing said modified ATM cell payloads into individual second bit groups which may or may not be the same size as said first bit groups, and transmitting each of said second bit groups to a synchronous code division multiple access transmitter in said first circuit;receiving said second bit groups and spreading the spectra thereof using spreading codes assigned to said virtual link assigned to said first circuit and transmitting said spread spectra to said second circuit.