Ethernet frame encapsulation over VDSL using HDLC

#The present invention relates generally to data communication systems and more particularly relates to a system for transporting Ethernet frames over Very high speed Digital Subscriber Line (VDSL) using the HDLC protocol.

#There is a growing need among both individuals and enterprises for access to a commonly available, cost effective network that provides speedy, reliable services. There is high demand for a high-speed data network, one with enough bandwidth to enable complex two-way communications. Such an application is possible today if, for example, access is available to a university or a corporation with sufficient finances to build this type of network. But for the average home computer user or small business, access to high speed data networks is expensive or simply impossible. Telephone companies are therefore eager to deliver broadband services to meet this current explosion in demand.

#One of the problems is that millions of personal computers have found their place in the home market. Today, PCs can be found in approximately 43% of all United States households and a full 50% of United States teenagers own computers. Virtually every PC sold today is equipped with a modem, enabling communication with the outside world via commercial data networks and the Internet. Currently, people use their PCs to send and receive e-mail, to access online services, to participate in electronic commerce and to browse the Internet. The popularity of the Internet is such that there are an estimated 50 million users around the globe. These figures indicate that in the past few years the personal computer has fueled a dramatic increase in data communications and the corresponding demands on the data networks that carry the traffic.

#The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

#FIG. 1 is a block diagram illustrating a plurality of Ethernet to VDSL CPEs coupled to a DSLAM over a VDSL transport facility that utilizes the HDLC protocol;

#FIG. 2 is a diagram illustrating the format of a standard Ethernet frame;

#1 Notation Used Throughout The following notation is used throughout this document. Term Definition ADSL Asymmetric Digital Subscriber Line AGC Automatic Gain Control ANSI American National Standards Institute CAD Computer Aided Design CAP Carrierless Amplitude Modulation/Phase Modulation CPE Consumer Premises Equipment CRC Cyclic Redundancy Check DBS Direct Broadcast Satellite DC Direct Current DSL Digital Subscriber Line DSLAM DSL Access Multiplexer EEPROM Electrically Erasable Programmable Read Only Memory EPROM Erasable Programmable Read Only Memory ETSI European Telecommunications Standards Institute FCS Frame Check Sequence FDM Frequency Division Multiplexing FEXT Far End Crosstalk FTTB Fiber to the Building FTTC Fiber to the Curb FTTCab Fiber to the Cabinet FTTEx Fiber to the Exchange FTTH Fiber to the Home FTTN Fiber to the Node HDLC High level Data Link Control HFC Hybrid Fiber Coax IFG Interframe Gap ISDN Integrated Services Digital Network LAPD Link Access Procedure D MAU Media Attachment Unit MMDS Multichannel Multipoint Distribution Service MPEG Motion Picture Entertainment Group NEXT Near End Crosstalk ONU Optical Network Unit OSI Open Systems Interconnect PC Personal Computer PLS Physical Layer Signaling POTS Plain Old Telephone Service PROM Programmable Read Only Memory QAM Quadrature Amplitude Modulation QoS Quality of Service RF Radio Frequency RFI Radio Frequency Interference SCC Serial Communication Controller SDLC Synchronous Data Link Control SDRAM Synchronous Dynamic Random Access Memory SNMP Simple Network Management Protocol SOC Start of Cell SOF StartofFrame USSB US Satellite Broadcasting UTP Unshielded Twisted Pair VDSL Very High Speed Digital Subscriber Line WWW World Wide Web

#The present invention is an apparatus for and method of encapsulating Ethernet frame data in HDLC frames for transport over a Very high speed Digital Subscriber Line (VDSL) facility. The HDLC protocol formatted frames are transmitted over a point to point VDSL link where they are subsequently extracted and forwarded as standard Ethernet frames. The invention utilizes the widely known HDLC communications protocol to encapsulate Ethernet frames for transmission over the VDSL transport facility of the invention. An HDLC controller is employed to perform the conversion between Ethernet frames and HDLC frames.

#As used throughout this document, the term HDLC frame is intended to denote a frame of data having a variable length that is transmitted over the VDSL transport facility. The HDLC frame appears on the line as a VDSL standard compatible analog signal representing the contents of the HDLC frame. The length of the HDLC frame varies in accordance with the length of the Ethernet frame encapsulated within. The HDLC frame of the present invention bears no relationship and should not be confused with the VDSL frame having a fixed length of 405 bytes as described in the VDSL Draft Specification published by the ANSI T1E1.4 Subcommittee.