Adaptation of FDDI physical layer chip to Playthrough protocol

Data flow design and very-high-speed integrated circuit (VHSIC) hardware description language (VHDL) behavioral simulation are presented for a physical layer encoder/decoder (ENDEC) chip that supports use of a Playthrough protocol on ring topology local area networks. The authors describe the Playthrough protocol's operational concept. The ENDEC design uses as much of the fiber distributed data interface (FDDI) standard as possible to support a 100-Mb/s data transfer rate on fiber-optic media with a chip that is plug compatible with the Advanced Micro Devices (AMD) FDDI ENDEC chip. The design uses an adaptation of the AMD FDDI ENDEC data flow structure; however, because the Playthrough media access control (MAC) protocol differs from FDDI's, a new control flow structure and a different internal structure are required to accommodate Playthrough MAC (PMAC) chip functions.<>