Gigabit Ethernet An Affordable Solution Group Members James Denaro Gaurav Asthana

Evolution of Gigabit Ethernet Ethernet standard first developed in 1970’s by Xerox PARC. IEEE 802 committee standardizes the ethernet. IEEE 802.3z task force finalizes the gigabit ethernet protocol in June 1998.

Gigabit Ethernet Protocol Architecture To go from 100mbps to 1000mbps, changes are made to the physical layer and data link layers only. Merging of 802.3 Ethernet and ANSI X3T11 FiberChannel technologies provides the solution. High speed of fiber channel and backward compatibility due to the IEEE 802.3 protocol is achieved.

Ethernet Protocol Stack

Gigabit Ethernet Interface Carrier Gigabit Ports: short-wave (SX), long-wave (LX), long-haul (LH), and copper physical interfaces (CX). Supported Media: short-wave laser, long-wave laser, and short copper. Fiber-optic cable comes in three types: multimode (62.5 um), multimode (50 um), and single mode.

802.3z and 802.3ab Distance Chart

The 802.3 Standard IEEE Std. 802.3 2000 Edition sets parameters for systems using CSMA/CD access method. Describes how the transmission and reception of data must occur. Section 38.6.5 details the transmitter optical waveform (transmit eye)

Transmitter Eye mask

Receiver Vertical eye-closure penalty [dB] = 10 log A0/AN Horizontal eye-closure jitter >= 65ps

Test Parameters Bit Error Rate (BER) is the ratio of bits that have errors relative to the total number of bits received in a transmission. Jitter is due to clock edges and position of data bits sent by the transmitter. IEEE specifies their requirements in the eye diagram.

Receiver and Post-Amplifier Optical receiver, a PIN diode or an Avalanche Photo Detector (APD) converts optical input to a small electrical current. The current is converted to an electrical voltage by a TIA. Post amp amplifies the incoming Trans-Impedance Amplifier (TIA) voltage signals to standard I/O levels. Improves signal integrity of the system.

Typical transceiver setup

Testing using the TDS 8000B scope and CSA

Project Goals Reduction of cost, by exploring cheaper parts, technologies and designs. New design is compatibile with the existing Ethernet protocols. Minimization of the Bit Error Rate and Jitter.