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Gigabit Ethernet
Protocol

by Candice Block Lombardi

Copyright 2017, Faulkner Information
Services. All Rights Reserved.

Docid: 00016542

Publication Date: 1707

Report Type: STANDARD

Preview

The Ethernet protocol – also known as IEEE 802.3 – has been a standard
desktop, enterprise, and service provider backbone access method for more
than a generation. With skyrocketing data demands taxing existing networks
and Internet infrastructure, developers are still looking to Ethernet to
push networks to handle mobile, physical, cloud, streaming media, and
other data paths. As of 2017, with speeds in development ranging from
non-chronological rates of 2.5Gbps to 50Gbps to 400Gbps and higher,
Gigabit Ethernet protocols are branching out beyond the enterprise to
focus on fields such as automotive and interconnecting devices. In late
2016, a breakthrough in 2.5G and 5G Ethernet boosted the current top speed
of traditional Ethernet five-times without the need to remove current
cabling, which will help address emerging needs in platforms such as
enterprise and wireless networks.

Report Contents:

• Executive
  Summary

• Description
• Competing
  Standards and Protocols

• Current View
• Web
  Links

• Related
  Reports

Executive Summary

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Corporations and
end-users have a constant need for more bandwidth to connect computers and power
applications across multiple platforms–including physical, virtual, cloud, and
mobile. As soon as one networking protocal arrives, a higher-speed alternative
is
already be in development to meet this demand.

Powering High Speed Networks. Gigabit Ethernet, or high-speed
Ethernet connectivity at 1,000,000,000 bits per second or greater, was
originally designed to power a higher-speed local area network (LAN) than
the original Ethernet standard released in 1980. Since its launch in the
1990s, Gigabit Ethernet has advanced to become not only an in-house
computer network standard but a carrier-grade standard to deliver
Internet access services. 

The standard has come a long way from the efforts to ramp up
bandwidth speeds averaging 10-Mbps. In 2014,
the Ethernet Alliance launched a 400GbE Subcommittee to meet what it
considered the "urgent" need to upgrade global networks, predicting that 1
Terabit-per-second (1TbE, or 1,000GbE) would be required to support global
data by 2015 and 10TbE by 2020.¹

Evolution of Gigabit Standard. Ethernet’s evolution over the past 40 years
illustrates the constant development of networking standards. In the
mid-1990s, 10Mbps download speeds for desktop computers became
commonplace, and carriers worked to meet and exceed demand with the
Ethernet standard. When it became clear that Ethernet would become ubiquitous, vendors tried to
leverage the technology to support other applications. Thanks to this
development philosophy, companies could run Ethernet
from their desktops to servers and then to backbones without having to
utilize multiple protocols and connection types. The subsequent iteration
of the technology, "Fast Ethernet," which
operates at 100Mbps, first gained popularity in server farms where
companies linked groups of special purpose systems to complete specific
processing tasks, including serving as small and medium-sized backbone networks or
handling processing for desktops
where users work with complex graphic or video applications. Now it is the
norm for service to the desktop.

With the need for bandwidth outpacing Ethernet development and
diversification, as recently as 2014 the IEEE began development of four new speeds
(not
in chronological order from previous speeds due to the opening of new
transition lanes): 2.5 Gigabit per second (Gbps); 5 Gbps; 25 Gbps; and
400 Gbps Ethernet. The industry is also looking into 50Gb/s and 200 Gb/s
Ethernet.²
To continue this momentum, the Ethernet Alliance developed the 2015 Ethernet
Roadmap to clarify development of speeds, application spaces, and market
conditions, and is looking beyond 2020 to the development of 800 Gbps; 1 Terabyte per
second; 1.6 Tbps; 6.4 Tbps; and 10 Tbps Ethernet protocol.³

GigE has delivered on vendors’ expectations.
Once the standard was completed, both enterprises and startups quickly adopted GigE switches or added GigE
connections to their products. The protocoal quickly became a
prime player in the backbone network arena and surpassed asynchronous
transfer mode (ATM) to become the dominant backbone networking technique.
The subsequent emergence of GigE over copper, as well as 10Gbps transmissions over fiber for
wide
area network (WAN) connections, propelled Ethernet technology further
into the enterprise and into consumer homes as part of high-speed Internet
connection.

Table 1 summarizes the current GigE physical
layer standards.

Table 1. Gigabit Ethernet Physical Layer Standards

Ethernet Gigabit Speed	Standard 802.5 Implementation	Applications
1GbE	1998: Multimode Fiber Cable Single Mode Fiber Cable 1999: Category 5e or Higher 2016: Single Twisted Pair Copper Cable	Upgrade from 100Mbps Ethernet using same frame format, protocol, and frame size. Small-to-medium companies run Ethernet from desktop to servers, then to backbone networks in server farms. 2016 protocal operates in harsh environments found in automotive and industrial applications
2.5GbE	2016: Twisted Pair System	Enterprises and campuses.
5GbE	2016: Twisted Pair System	Enterprises and campuses.
10GbE	2003: Laser Optimized MMF Cable, Single mode fiber cable 2006: Category 6A Cabling	Suitable for Wide Area Networks, Local Area Networks, and Metropolitan Area Networks.
25GbE	2016: Twisted Pair System	Auto-negotiation capabilities and Energy Efficient Ethernet (EEE) support for data center applications.
40GbE	2016:  Twisted Pair System Media Access for single-lane server and switch interconnects for data centers.	Auto-negotiation capabilities and Energy Efficient Ethernet (EEE) support for data center applications. Single-lane server and switch interconnects for data centers.
50GbE	2018-2020: Estimated Completion	Suitable for Hyperscale Data Centers, Wide Area Networks, Local Area Networks, and Metropolitan Area Networks.
100GbE	2010: Laser-Optimized MMF or SMF Cable (2015): Laser-Optimized MMF	Larger service provider backbone networks for the aggregation of network traffic.
400GbE	(2017): Laser-Optimized MMF or SMF	Expected to meet the rising need for bandwidth growth. Supports data from smartphones, tablets, Wi-Fi 3G/4G/LTE mobile deployments, 10 Gb/s servers, Internet enabled TV, cloud and its applications, social media, video calling, online gaming, new database technologies (automotive, industrial).
1 Terabit Ethernet (1TbE)	(2020+) No current projection	This desired standard currently is impeded by restrictions with current fiber optic cable capacity. New light-modulation technology not advanced enough for commercial application. Projected costs to develop new platform are currently prohibitive.

Description

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GigE is an extension of the highly
successful 10M-bps and 100M-bps Ethernet standards, and builds on the
Institute of Electrical and Electronics Engineers’ (IEEE) 802.3 Ethernet
standard. In November 1995, the IEEE 802.3 working group discussed the
feasibility of upgrading Fast Ethernet to a higher speed. After reviewing
various options on how to achieve 1000Mbps, the IEEE standards board
issued a Project Authorization Request (PAR) for the GigE protocol in June 1996.

Gigabit Ethernet. The GigE task force was born in July
1996, one month after the PAR was issued. The main objective of the task
force was to develop a standard that allows both half and full duplex
operation at 1000M bps and is backwardly compatible with 10BaseT and
100BaseT technologies. The new standard defined gigabit links that can be
used for interconnecting high performance servers and workstations, and
backbone connections between 100BaseT Fast Ethernet switches. This new
generation of Ethernet links was designed to provide 10 times the speed
of 100BaseT at much less than ten times the price.

The initial standard for gigabit Ethernet was ratified by the IEEE in
June 1998 as IEEE 802.3z, and required optical fiber. IEEE 802.3z is
commonly referred to as 1000BASE-X. There are 10 different physical layer
standards since the introduction of the original 802.3z gigabit Ethernet
using optical fiber (1000BASE-X).

While select vendors began
delivering GigE products in 1997, most waited until the standard was
ratified in 1998. Because Ethernet and Fast Ethernet were so
successful, vendors moved quickly to deliver such products. Table 2 summarizes the GigE physical layer standards.

IEEE 802.3ab, ratified in 1999, defines gigabit Ethernet transmission
over unshielded twisted pair (UTP) category 5, 5e, or 6 cabling and became
known as 1000BASE-T. In a departure from both 10BASE-T and 100BASE-TX,
1000BASE-T uses all four cable pairs for simultaneous transmission in both
directions through the use of echo cancellation and a 5-level pulse
amplitude modulation (PAM-5) technique.

With the ratification of 802.3ab, gigabit Ethernet became a desktop
technology with which organizations could use their existing copper
cabling infrastructure.

For many, GigE was still not fast enough. In June 2002, a
standard for 10GbE over fiber, designated 802.3ae, was ratified, and
quickly became the new standard for more than two dozen companies. Unlike previous
versions of Ethernet, 10GbE is full duplex, so does not support CSMA/CD.

IEEE 802.3ah, ratified in 2004 added two more Gigabit fiber standards,
1000BASE-LX10 (which was already widely implemented as vendor specific
extension) and 1000BASE-BX10. This was part of a larger group of protocols
known as Ethernet in the First Mile.

10GbE. In April 2003, the IEEE approved a
project to add copper physical media to 802.3ae 10GbE. IEEE P802.3ak,
"Physical Layer and Management Parameters for 10 Gb/s Operation, Type
10GBASE-CX4," allowed for a copper physical medium in conjunction with the
IEEE 802.3ae standard for 10GbE networks. It provided a lower-cost option for
interconnecting equipment located within about 15 m of fiber optic cable,
typically within a stack or between equipment racks. In addition, late in
2010, a separate IEEE study group, many of whose members worked on
1000Base-T, began work on 10GBase-T, which will support
10-Gigabit Ethernet over 25 to 100 meters of standard twisted-pair
cable.

There are two significant differences between 10 GbE and lower- speed
Ethernet standards. The first is the inclusion of support for a long-haul (40
kms) optical transceiver. It can be used as either a LAN interface or a WAN
interface when building MANs. The second is a WAN physical interface that allows
10 GbE to be transported across existing OC-192 SONET networks. This interface
includes a SONET framer and operates at a data rate compatible with OC-192c/SDH
VC-4-64c specifications.

Standards introduced in 2016 include IEEE 802.3bp,

IEEE 802.3bq, IEEE 802.3br, and IEEE 802.3by. Table 3 traces the key evolution of the

standard from its inception to the present.

In 2007, the IEEE 802.3 working group formed the Higher Speed Study Group

(HSSG), which found that the Ethernet ecosystem needed something faster than 10 GbE. The HSSG

determined that computing and network aggregation applications were growing at

different rates, requiring different speeds. These are:

• 40G bps for server and computing applications

• 100G bps for network aggregation applications

As a result, the IEEE 802.3ba 40G-bps and 100G-bps standard was ratified in

June 2010.

40/100GbE. The 40/100 GbE standard includes:

• Support for full-duplex operation.
• Preservation of the 802.3 Ethernet frame format using the 802.3 media access controller (MAC).
• Preservation of minimum and maximum frame size of current 802.3 standard.
• Support for a bit error rate (BER) better than or equal to 10^-12 at the MAC/physical layer service interface.
• Provision for appropriate support for optical transport network

  (OTN).

• Support for a MAC data rate of 40G bps.
  • Provision of physical layer specifications supporting 40G-bps operation over:
    • at least 10 kms on single mode fiber (SMF)
    • at least 100 ms on OM3 multi-mode fiber (MMF)
    • at least 10 ms over a copper cable assembly
    • at least 1 m over a backplane

• Support for a MAC data rate of 100G bps.

  • Provision of physical layer specifications that support 100G-bps operation over:

    • at least 40 kms on SMF

    • at least 10 kms on SMF

    • at least 100 ms on OM3 MMF

    • at least 10 ms over a copper
      cable assembly

400GbE. The 400GbE standard was submitted by the Ethernet Alliance and
IEEE 400G Ethernet group to the IEE 802 Plenary in Beijing in March 2014. This
marked the first phase of project documentation related to physical layer
standards.⁴

Terabit Ethernet. The urgent need for 1TbE
(1,000GbE) is in discussions, but its introduction is not entirely practical due to restrictions
inherent in
current fiber optic cable capacity.

Standards for Automotive and Networked Devices (1G bps,
25G bps, and 40G bps). IEEE workgroups are focused on branching out Ethernet into
untapped sectors.⁵ In 2016, standards released included updates to previous speeds,
as well as new speeds and target markets:

• 1 Gb/s Ethernet, IEEE 802.3bp, for Operation over a Single Twisted
  Pair Copper Cable

  • Physical layer specifications (including optional
    single-pair autonegotiation and Energy Efficient Ethernet) and
    parameters for full-duplex 1 Gb/s Ethernet operating in harsh
    environments found in automotive and industrial applications.

• 25 Gb/s and 40 Gb/s, Types 25GBASE-T and 40GBASE-T,
  IEEE 802.3bq

  • Higher-speed twisted pair systems with auto-negotiation capabilities
    and Energy Efficient Ethernet (EEE) support for data center
    applications.

• IEEE 802.3br, “Standard for Ethernet Amendment Specification and
  Management Parameters for Interspersing Express Traffic”, addresses the
  needs of industrial control system manufacturers and the automotive market
  by specifying a pre-emption methodology for time-sensitive traffic.

• 25 Gb/s, IEEE 802.3by, cost-optimized 25 Gb/s specifications
  for single-lane server and switch interconnects for data centers.

Competing Standards
and Protocols

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of this report]

GbE’s initial thrust was towards backbone connections, an
area where customers have other options, such as Asynchronous Transfer
Mode (ATM) or Multiprotocol Label Switching (MPLS). No product
is right for every situation and the proper selection depends on company
specific information, such as the applications flowing over its network,
and its budget.

The WAN is an area where ATM’s performance found many
adherents. This network
option offered significant benefits compared to the Time Division
Multiplexer (TDM) systems traditionally used for such connections. ATM
enables carriers to use bandwidth more efficiently and provide Quality of
Service (QoS) features to important applications, but today Internet
Protocol networks have become ubiquitous, and with their adoption, ATM’s
market position began to decline. The same thing is not true in the MAN or WAN where true competitive

technologies exist. Some of the technologies, such as ATM and SONET, are aging

and are being replaced, but optical technologies exist that match 10 GbE and

40G-/100G-bps architectures for throughput and cost. These include:

• SONET/SDH – – Developed by Bellcore and standardized by the American
  National Standards Institute (ANSI), SONET served as the

  preferred standard for WANs, carrying large volumes of voice and data traffic

  over a single fiber-optic cable. The current upper limit for SONET/SDH

  throughput is OC-192, which provides for a 9.6G-bps payload. OC-192 has been

  deployed in backbone networks but not in links to the backbone, which top out

  at OC-48 with a payload of 2.4G bps. OC-768 and OC-3072 have been defined but

  neither has been deployed in commercial networks. OC-3072 would provide a

  payload of approximately 160G bps.

• Dense Wave Division Multiplexing (DWDM) – As originally developed,

  WDM refers to the optical transmission technique in which multiple optical

  signals are transmitted on a single optical fiber using different wavelengths

  between two switches. DWDM, a higher capacity version of WDM, is used for

  systems that support 16 channels or more. DWDM serves as a multiplier in

  adding more data channels to existing optical fibers. While the capabilities

  of DWDM are impressive, the technology requires expensive components. 10G-bps

  DWDM is in the testing stage and is expected to be deployed in service

  provider networks to connect high-powered data centers. It is not expected

  that 10G DWDM will be used in customer facing applications.

• Coarse Wave Division Multiplexing (CWDM) – Formalized in 2004 by the

  IEEE, CWDM is usually used for shorter distances than DWDM, such as in MANs.

  The average CWDM system produces laser emissions on eight channels at eight

  defined wavelengths, although the technology does allow for up to 18 different

  channels. Since the channels in a CWDM system are spread out over a larger

  range of wavelengths, low-cost lasers can be used, making it less expensive

  than DWDM. Lower precision lasers and lower power requirements also help keep

  costs down.

• Reconfigurable Optical Add/Drop Multiplexing (ROADM) – Allows

  wavelengths to be remotely added and dropped at each network node in a

  WDM-based network. Network service providers can control the direction and

  flow of infrared and visible light transmissions within a range of

  wavelengths. ROADM makes it unnecessary to translate traffic from optical to

  electrical at termination points. ROADM can provide simplified optical power

  balancing, wavelength monitoring, wavelength provisioning, and add/drop

  flexibility features.

• Passive Optical Networking (PON) – A PON is an all-optical network

  that uses only passive optical components, such as fibers, couplers,

  wavelength routers, and filters, as opposed to active networks, and brings the

  optical fiber cabling and signals most of the way to the end user. A PON can

  be used for local loop and FTTx deployments. PONs have no power requirements

  and have no electronic parts. PONs were developed partially to allow the cost

  of the deployment to be shared among subscribers.

Current View

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Gigabit Ethernet is now integral to enterprise and
consumer products, as well as home networking. In fact, most
higher-end home routers, both wired-only and those offering Wi-Fi, now
incorporate at least 1Gbps Ethernet port. Several factors are at work that
should drive growth, including:

• Commercial use of multi-core CPUs with multi-threaded networking stacks.
• 10 GbE allows for the

  aggregation of terabits network traffic, without increasing the complexity of

  the network deployments in the

  data center.

• Increasing use of server virtualization

  and the demands for network bandwidth per physical

  server.

• Introduction of ROADM- and PON -based networks by

  service providers, allowing for faster access and MAN networks by

  aggregating data transport.

Task forces are working to finalize 400G
Ethernet standards; diversify channels to offer 2.5G, 5G, 25G, and 50G
speeds; and consider what the future holds for Ethernet.⁶ As of
2016, IEEE workgroups are focused on branching out into sectors such as
automotive and interconnecting devices to support the "Internet of
Things."⁷ In late 2016, a breakthrough in 2.5G and 5G
boosted the current top speed of traditional Ethernet five-times without
the need to remove current cabling, which will help address
emerging needs in platforms such as enterprise and wireless networks.⁸

Web Links

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• 10 Gigabit Ethernet Alliance: http://www.10gea.org/
• Ethernet Alliance: http://www.ethernetalliance.org/
• Broadband Forum: http://www.broadband-forum.org
• Ethermanage: http://www.ethermanage.com/ethernet/gigabit.html
• Institute of Electrical and Electronic Engineers (IEEE): http://www.ieee.org/

References

• ¹ "400 Gb/s Ethernet: Why Now?"
  Ethernet
  Alliance. April 2014.
• ² "Ethernet Alliance Unveils 2015 Ethernet Roadmap."
  Ethernet
  Alliance. March 24, 2015.
• ³ "Ethernet Alliance Unveils 2015 Ethernet Roadmap."
  Ethernet
  Alliance. March 24, 2015.
• ⁴ John D’Ambrosia. "400G Ethernet Effort Begins."
  
  EETimes. February 27, 2014.
• ⁵ "Ethernet’s Expansion Continues Unabated with New Standards."
  Ethernet
  Alliance. July 6, 2016.
• ⁶ "2015 Ethernet Roadmap."
  Ethernet
  Alliance. March 2015.
• ⁷
  "Ethernet’s Expansion Continues Unabated with New Standards."
  Ethernet
  Alliance. July 6, 2016.
• ⁸ Michael
  Cooney. "IEEE sets new Ethernet standard that brings 5X the speed without
  disruptive cable changes. Network World. September 27, 2016.

About the Author

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Candice Block Lombardi

has tracked and written about enterprise
software and security, the IT services sector, telecommunications, and
data networking. She is a frequent contributor to Faulkner’s information
services.

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