Ethernet: Not So Easy

Not Your Father’s Ethernet

Ethernet testing has evolved greatly since the introduction of the IEEE 802.3 standard.  Many engineers fondly look back on hooking up the most recent 10BASE-T silicon to an oscilloscope and being able to directly read the Manchester encoded bits of a packet.  The ever increasing speed of Ethernet devices has created greater complexity in coding, as well as the need for more accurate measurements.  We’ll provide our first technical perspective in this and upcoming blog posts by looking at the test and measurement techniques involved in some of the most recent developments in Ethernet, specifically Energy Efficient Ethernet and 40 and 100 Gigabit Ethernet.

Energy Efficient Ethernet

Energy Efficient Ethernet (EEE) is a recent update to the IEEE 802.3 standard.  The protocol is aimed at reducing the power consumption of Ethernet devices when there is low link utilization, addressing the growing need for companies and enterprises to be both energy efficient and energy conscious.

Much like in the fashion industry where the saying is “what’s old is new,” EEE utilizes a mechanism from 10BASE-T to save power in 100BASE-TX, 1000BASE-T, 10GBASE-T, and several other backplane Ethernet PHYs.  The goal is to enter a true idle period when there is no traffic to send, rather than perpetuate continous idle code groups that these PHYs were originally designed to send.  However, this lack of signal makes for more complicated transmitters and receivers, and the protocol also becomes more difficult to test.  We’ll examine the specific testing challenges of EEE in our next post.

40 and 100 Gigabit Ethernet

Following our look at EEE, we’ll explore some of the newest PHYs available on the market, 40 and 100 Gigabit Ethernet.  The 40 and 100 Gb/s standard, or IEEE 802.3ba, was created to handle higher Ethernet speeds, while maintaining compatibility with existing devices and preserve previous investments in research and development.  We’ll also provide insight into the unique testing challenges that these multi-lane 10 Gigabit + data rate physical layers present.

  Jeff Lapak - Senior Manager, Ethernet