System for encapsulating ethernet frames over very high speed digital subscriber lines

Abstract

An apparatus for and method of encapsulating Ethernet frame data in Very high speed Digital Subscriber Line (VDSL) frames. The VDSL frames are transmitted over a point to point VDSL link where they are subsequently extracted and forwarded as standard Ethernet frames. The VDSL facility transport system comprises an Ethernet to VDSL Consumer Premises Equipment (CPE) coupled to a DSL Access Multiplexor (DSLAM) over a VDSL transport facility. The Ethernet to VDSL CPE functions to receive a 10BaseT Ethernet signal and encapsulate the Ethernet frame into a VDSL frame for transmission over the VDSL facility. The DSLAM is adapted to receive VDSL frames, extract Ethernet frames therefrom and generate and output a standard Ethernet signal. Ethernet frames are encapsulated within VDSL frames and transmitted on the wire pair without regard to the state of the SOC signals. This overcomes the problems associated with syncing the transmission of the Ethernet data with the SOC signals. The present invention also provides a method of providing the receiving station an indication of the start of a VDSL frame. A preamble having certain desirable characteristics such as good autocorrelation properties, is used by the receiving station to identify the start of a VDSL frame. To further ensure that a detected start of frame is valid, the length field of the VDSL frame is examined for a legal length value.