HAJDUCZENIA LAYOUT_Layout 1 8/1/13 3:05 PM Page 88 QUANTUM COMMUNICATIONS Evolution of Ethernet Standards in the IEEE 802.3 Working Group David Law, Hewlett-Packard Ltd. Dan Dove, Applied Micro John D’Ambrosia, Dell Marek Hajduczenia, ZTE Corporation and Universidade de Coimbra Mark Laubach, Broadcom Corporation Steve Carlson, High Speed Design, Inc. ABSTRACT Ethernet is also venturing into brand new application areas, and is adding support for syn- Ethernet is constantly evolving, adapting to the chronization protocols or even potentially needs of the networking world, addressing the becoming a de facto standard for in-vehicle data requirements of both operators and end users, networks, providing a common transport plat- while making sure that the resulting technology is form for control and multimedia applications. cost-efficient, reliable, and operates in a plug-and- This article will examine the evolution of Eth- play manner. The IEEE 802.3 Working Group ernet standards taking place in the IEEE 802.3 has been working for the last 30+ years, pushing Working Group. There are a number of exciting the boundaries on the speed and capacity of wire- new projects, pushing the boundaries of Ether- line Ethernet links, migrating from shared medi- net into new application areas and markets. um CSMA/CD systems to switched point-to-point Ethernet and then introducing multilane technol- ogy and point-to-point emulation over shared EVOLUTION OF media of passive optical networks. In this article, THERNET TANDARDS we look at the latest projects adding new features E S and capabilities to the family of wired Ethernet The IEEE Std 802.3 Ethernet standard was first standards, enabling the exponential growth of the published in 1985, specifying a half-duplex carri- Ethernet ecosystem, driven by technical maturity, er sense multiple access with collision detection cost effectiveness, and broad market support. (CSMA/CD) medium access control (MAC) protocol operating at 10 Mb/s, and a medium INTRODUCTION attachment unit (MAU) for operation on a coax- ial cable medium, supporting a bus topology The total amount of data created or replicated on between the attached end stations. the planet in 2010 exceeded 1 zettabyte (1 Amendments to the IEEE 802.3 standard zettabyte is 1021 bytes), or 143 Gbytes for each of then added specifications for, among other the 7 billion people on the planet [1]. This volume items, a repeater to extend topologies supported, of information requires high-speed links between MAUs for operation over fiber optic cabling, a server farms, cloud storage, and end users to make MAU for operation over twisted pair cabling, sure that it can be processed in a timely and reli- 10BASE-T, and layer management. In 1995 able fashion. The relentless growth of the number amendment IEEE Std 802.3u was published of end stations connected to the network, whether adding operation at 100 Mb/s (fast Ethernet). permanent or nomadic (computer terminals, This included a number of physical layer (PHY) mobile devices, automated devices generating specifications for operation over fiber optic and machine-to-machine traffic), has led to explosive twisted pair cabling (100BASE-TX). growth in the volume of information exchanged at Amendment IEEE Std 802.3x published in all levels of the networking infrastructure. The 1997 added full duplex operation to the MAC popularity of Ethernet and its widespread use in and a flow control protocol to take advantage of access, aggregation, transport, core networks, and the full duplex capable medium, such as twisted data centers, combined with the unprecedented pair and fiber, for which PHYs were already demand for advanced data connectivity services, specified in IEEE 802.3, as well as support fuel the development of new Ethernet standards, switching, which was becoming more cost effec- providing higher-speed links to address the market tive due to increased device integration. demand. In 1998 amendment IEEE Std 802.3z was 88 0163-6804/13/$25.00 © 2013 IEEE IEEE Communications Magazine • August 2013 HAJDUCZENIA LAYOUT_Layout 1 8/1/13 3:05 PM Page 89 published, adding operation at 1000 Mb/s (Giga- bit Ethernet), and subsequently in 1999 amend- Rate (Gb/s) Backplane ment IEEE Std 802.3ab was published, adding 100 1000BASE-T PHY specifications to support Twin-axial 1000 Mb/s operation over twisted pair cabling. 10 Amendment IEEE 802.3ad (link aggregation) Multimode fiber was published in 2000, adding the ability to aggre- gate multiple full duplex point-to-point links in to 1 Voice-grade copper a single logical link from the perspective of the Coaxial MAC client. Since link aggregation has applica- 0.1 tion beyond Ethernet, as well as its architectural Twisted-pair copper positioning, it was subsequently moved the the 0.01 IEEE 802.1 Working Group in 2008 and is now Single-mode fiber titled IEEE Std 802.1AX Link Aggregation. 0.001 Multipoint fiber In 2002 amendment IEEE Std 802.3ae was 0.001 0.01 0.1 1 10 100 published adding operation at 10 Gb/s (10 Giga- Distance (km) bit Ethernet), and in 2006 amendment IEEE Std 802.3an was published adding the 10GBASE-T Figure 1. Speed and reach for various IEEE Std 802.3 MAUs and PHYs. PHY specifications to support 10 Gb/s operation over twisted pair cabling. It was followed in 2010 by the amendment IEEE Std 802.3ba, adding interface) electrical interface standard, requiring operation at 40 Gb/s and 100 Gb/s (40 Gigabit a relatively large number of interface data paths, Ethernet and 100 Gigabit Ethernet). The devel- and for the longer-reach power management opment of 40 Gb/s and 100 Gb/s Ethernet was devices (PMDs), a gearbox to reduce the num- done in close cooperation with International ber of optical lanes from 10 to 4. This gearbox Telecommunications Union Telecommunications would normally be included in the optical mod- Standardization Sector (ITU-T) SG15 to ensure ule, creating a power constraint that inhibits transparent connectivity into the optical transport higher port density; see Fig. 2 for differences in network (OTN). Operation at 10 Gb/s, 40 Gb/s, device architecture. Through the work being and 100 Gb/s only supports full duplex operation. done in IEEE 802.3, this gearbox can be moved Amendment IEEE Std 802.3ah published in out of the module and eventually integrated 2004 first added support for subscriber access directly into the host integrated circuit (IC). This network Ethernet (Ethernet in the first mile, or allows smaller lower-power modules, driving EFM for short). As well as the addition of a density up and cost per port down. number of fiber optic and voice grade copper While the 40 Gigabit Ethernet and 100 Giga- PHYs, it also specified a fiber optic point-to- bit Ethernet standards enabled Ethernet net- multipoint network topology using passive opti- working at 40G and 100G for the very first time, cal splitters known as Ethernet passive optical this next generation of 40G and 100G optical networks (EPONs). standards are expected to provide a substantial Amendment IEEE Std 802.3ap first added decrease in the cost and complexity required for support for backplane Ethernet in 2007. broad deployment of 100G Ethernet at just the A summary of the speed and distance for vari- right time as network providers and customers ous MAUs and PHYs supported by the approved see the demand curve rising. In addition, the 40 IEEE 802.3 standard (at the time of writing this km specification for 40G will enable near-term article) and amendments is shown in Fig. 1. deployment of long-reach optical channels. Other additions include IEEE Std 802.3af, The Study Group spent close to a year to “DTE Power via MDI,” published in 2003, also define a set of technical objectives, including known as power over Ethernet, which enables among others: power to be supplied on the same cabling as the •Provide appropriate support for optical data transmission, and IEEE Std 802.3at, pub- transport network (OTN) lished in 2009 which enhanced the maximum •Define retimed 4-lane 100G electrical inter- power available and the classification mechanism. faces for chip-to-chip and chip-to-module In addition, in 2010 amendment IEEE Std applications 802.3az added support for energy-efficient Eth- •Define a 40 Gb/s PHY for operation over at ernet (EEE) to, among others, the 100BASE-T, least 40 km of single-mode fiber (SMF) 1000BASE-T, and 10GBASE-T PHYs. This not •Define a 100 Gb/s PHY for operation up to only reduces the power consumption of the at least 500 m of SMF, at least 100 m of PHYs, but also specifies signaling that can multimode fiber (MMF), and at least 20 m enable the reduction of the power consumption of MMF in separate devices of the attached device. The addition of the 40 Gb/s PHY objective was made subsequent to the March 2012 meet- HIGH-SPEED OPTICAL P2P LINKS ing, addressing the demonstrated demand for a In August 2011, the IEEE 802.3 Working Group longer-reach solution at this particular speed. authorized the formation of a Study Group to Instead of creating a new project, it was decided address “Next Generation 100G Optical Ether- that this objective would be added to the scope net” with the goal of reducing the cost and of the Next Generation 100G project. power of, and improving density for 100G opti- The chip-to-chip interface objective calls for cal solutions. The IEEE P802.3ba project pro- the definition of a CAUI-4 electrical interface, duced a number of 100G optical PHYs based on which is anticipated to leverage the OIF CEI- the 10x10G CAUI (100 Gigabit attachment unit 28G-VSR specification [12].