Gigabit Ethernet (GbE or 1 GigE) is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second, as defined by the IEEE 802.3-2005 standard. Ethernet is a family of frame -based Computer networking technologies for Local area networks (LANs In telecommunications Bit rate or Data transfer rate is the average number of Bits characters or blocks per unit time passing between equipment in a data transmission IEEE 8023 is a collection of IEEE standards defining the Physical layer, and the media access control (MAC sublayer of the Data link layer, Half-duplex gigabit links connected through hubs are allowed by the specification but in the marketplace full-duplex with switches is the norm. A duplex Communication system is a system composed of two connected parties or devices which can communicate with one another in both directions A duplex Communication system is a system composed of two connected parties or devices which can communicate with one another in both directions A

Intel Pro/1000 GT PCI network interface card

History

The result of research done at Xerox Corporation in the early 1970s, Ethernet has evolved into the most widely implemented physical and link layer protocol today. The Peripheral Component Interconnect, or PCI Standard (commonly PCI) specifies a Computer bus for attaching peripheral devices to a Computer Xerox Corporation ( (name ˈziːrɒks is a global document management company which manufactures and sells a range of color and black-and-white printers, multifunction The Physical Layer is the first level in the seven-layer OSI model of computer networking. The Data Link Layer is Layer 2 of the seven-layer OSI model. It responds to service requests from the Network Layer and issues service requests to the Fast Ethernet increased speed from 10 to 100 megabits per second (Mbit/s). In Computer networking Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s against the original Gigabit Ethernet was the next iteration, increasing the speed to 1000 Mbit/s. The initial standard for gigabit Ethernet was standardized by the IEEE in June 1998 as IEEE 802. The Institute of Electrical and Electronics Engineers or IEEE (read eye-triple-e) is an international Non-profit, professional organization 3z. 802. 3z is commonly referred to as 1000BASE-X, where -X refers to either -CX, -SX, -LX, or (non-standard) -ZX.

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. Category 5 cable, commonly known as Cat 5, is a Twisted pair cable type designed for high signal integrity Category 6 cable, commonly referred to as Cat-6, is a cable standard for Gigabit Ethernet and other Network protocols that is Backward compatible With the ratification of 802. 3ab, gigabit Ethernet became a desktop technology as organizations could utilize their existing copper cabling infrastructure.

Initially, gigabit Ethernet was deployed in high-capacity backbone network links (for instance, on a high-capacity campus network). A backbone network or network backbone is a part of Computer network infrastructure that interconnects various pieces of network providing a path for the exchange In 2000, Apple's Power Mac G4 and PowerBook G4 were the first mass produced personal computers featuring the 1000BASE-T connection. Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics The Power Mac G4 is a series of Personal computers that was designed manufactured and sold by Apple between 1999 and 2004. The PowerBook G4 was a series of Notebook computers that was manufactured marketed and sold by Apple Computer Inc ^[1] It quickly became a built-in feature in many other computers.

Since that time, faster 10 gigabit Ethernet standards have become available as the IEEE ratified a fiber-based standard in 2002, and a twisted pair standard in 2006.

Summary

There are four different physical layer standards for gigabit Ethernet using optical fiber, twisted pair cable, or balanced copper cable. The Physical Layer is the first level in the seven-layer OSI model of computer networking. An optical fiber (or fibre) is a Glass or Plastic fiber that carries Light along its length Twisted pair Cabling is a form of wiring in which two conductors (two halves of a single circuit) are wound together for the purposes of canceling out

The IEEE 802. 3z standard includes 1000BASE-SX for transmission over multi-mode fiber, 1000BASE-LX for transmission over single-mode fiber, and the nearly obsolete 1000BASE-CX for transmission over balanced copper cabling. Multi-mode optical fiber ( multimode fiber or MM fiber or fibre) is a type of Optical fiber mostly used for communication over shorter distances In Fiber-optic communication, a single-mode optical fiber ( SMF) is an Optical fiber designed to carry only a single ray of light (mode These standards use 8B/10B encoding, which inflates the line rate by 25%, from 1000 Mbit/s to 1250 Mbit/s to ensure a DC balanced signal. In Telecommunications 8b/10b is a Line code that maps 8-bit symbols to 10-bit symbols to achieve DC-balance (see The symbols are then sent using NRZ. In Telecommunication, a non-return-to-zero ( NRZ) Line code is a binary code in which "1s" are represented by one Significant

IEEE 802. 3ab, which defines the widely used 1000BASE-T interface type, uses a different encoding scheme in order to keep the symbol rate as low as possible, allowing transmission over twisted pair.

Ethernet in the First Mile later added 1000BASE-LX10 and -BX10. Ethernet in the First Mile ( EFM) also known as IEEE 8023ah, is a collection of protocols specified in IEEE 802

1000BASE-X

1000BASE-X is used in industry to refer to gigabit Ethernet transmission over fiber, where options include 1000BASE-SX, -LX, -BX10, or the non-standard -LH/-ZX implementations. Multi-mode optical fiber ( multimode fiber or MM fiber or fibre) is a type of Optical fiber mostly used for communication over shorter distances In Fiber-optic communication, a single-mode optical fiber ( SMF) is an Optical fiber designed to carry only a single ray of light (mode In Fiber-optic communication, a single-mode optical fiber ( SMF) is an Optical fiber designed to carry only a single ray of light (mode In Fiber-optic communication, a single-mode optical fiber ( SMF) is an Optical fiber designed to carry only a single ray of light (mode In Fiber-optic communication, a single-mode optical fiber ( SMF) is an Optical fiber designed to carry only a single ray of light (mode

1000BASE-SX

1000BASE-SX is a fiber optic gigabit Ethernet standard for operation over multi-mode fiber using a 850 nanometer, near infrared (NIR) light wavelength. An optical fiber (or fibre) is a Glass or Plastic fiber that carries Light along its length A nanometre ( American spelling: nanometer, symbol nm) ( Greek: νάνος nanos dwarf; μετρώ metrό count) is a Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. The standard specifies a distance capability between endpoints of 220 m over 62. 5/125 µm fibre although in practice, with good quality fibre and terminations, 1000BASE-SX will usually work over significantly longer distances. Modern 50/125 µm fibres can reliably extend the signal to 500 m or more. This standard is highly popular for intra-building links in large office buildings, co-location facilities and carrier neutral internet exchanges. Typical optical power parameters of SX interface: maximum mean output power = -5 dBm; stressed receiver sensitivity = -14 dBm. For other uses see DBM (disambiguation dbm was the first of a family of simple Database engines originally written by Ken

1000BASE-LX

1000BASE-LX is a fiber optic gigabit Ethernet standard which uses a long wavelength laser (See IEEE 802. 3 Clause 38), with a wavelength of 1270 to 1355 nm, and a maximum RMS spectral width of 4 nm. Typically, GbE lasers will be specified as having a 1300 or 1310 nm wavelength.

1000BASE-LX is specified to work over a distance of up to 5 km over 9 µm single-mode fiber. In practice it will often operate correctly over a much greater distance. Many manufacturers will guarantee operation up to 10 or 20 km, provided that their equipment is used at both ends of the link. 1000BASE-LX can also run over multi-mode fiber with a maximum segment length of 550 m. For any link distance greater than 300 m, the use of a special launch conditioning patch cord may be required. This launches the laser at a precise offset from the center of the fiber which causes it to spread across the diameter of the fiber core, reducing the effect known as differential mode delay which occurs when the laser couples onto only a small number of available modes in multi-mode fiber.

1000BASE-ZX and 1000BASE-LH

1000BASE-ZX and 1000BASE-LH are non-standard but industry accepted terms to refer to gigabit Ethernet transmission using 1550 nm wavelength to achieve distances of at least 70 km over single-mode fiber.

1000BASE-BX10

This latest addition to the standard also includes the 1000-BASE-BX10 transmission over a single strand of fibre (which is itself single-mode fiber), with one different wavelength going in each direction. In Fiber-optic communication, a single-mode optical fiber ( SMF) is an Optical fiber designed to carry only a single ray of light (mode The terminals on each side of the fibre are not equal, as the one transmitting "downstream" (from the center of the network to the outside) uses the 1490 nm wavelength, and the one transmitting "upstream" uses the 1310 nm wavelength.

1000BASE-CX

1000BASE-CX is an initial standard for gigabit Ethernet connections over copper cabling with maximum distances of 25 meters using balanced shielded twisted pair. Twisted pair Cabling is a form of wiring in which two conductors (two halves of a single circuit) are wound together for the purposes of canceling out It is still used for specific applications where cabling is not done by general users, for instance the IBM BladeCenter uses 1000BASE-CX for the Ethernet connections between the blade servers and the switch modules. 1000BASE-T succeeded it for general copper wiring use.

1000BASE-T

1000BASE-T capable network interface card from Intel

1000BASE-T (also known as IEEE 802. 3ab) is a standard for gigabit Ethernet over copper wiring. Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 It requires, at a minimum, Category 5 cable (the same as 100BASE-TX), but Category 5e ("Category 5 enhanced") and Category 6 cable may also be used and are often recommended. Category 5 cable, commonly known as Cat 5, is a Twisted pair cable type designed for high signal integrity Category 6 cable, commonly referred to as Cat-6, is a cable standard for Gigabit Ethernet and other Network protocols that is Backward compatible 1000BASE-T requires all four pairs to be present and is far less tolerant of poorly installed wiring than 100BASE-TX.

Each network segment can have a maximum distance of 100 meters. Autonegotiation of speed and duplex is a requirement for using 1000BASE-T^[2] according to the standard. Autonegotiation (formerly NWay) is an Ethernet procedure by which two connected devices choose common transmission parameters such as speed and duplex mode Several device drivers will allow you to force 1000 Mbit/s full duplex to eliminate autonegotiation issues.

1000BASE-T details

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. Pulse-amplitude modulation, acronym PAM, is a form of signal Modulation where the message information is encoded in the Amplitude of a series of signal The symbol rate is identical to that of 100BASE-TX (125 Mbaud) and the noise immunity of the 5-level signaling is also identical to that of the 3-level signaling in 100BASE-TX, since 1000BASE-T uses 4-dimensional Trellis Coded Modulation (TCM) to achieve a 6 dB coding gain across the 4 pairs. In Telecommunications and Electronics, baud (ˈbɔːd unit symbol "Bd" is synonymous to symbols/s or pulses/s. In Telecommunication, trellis modulation (also known as trellis coded modulation, or simply TCM) is a modulation scheme which allows highly efficient The decibel ( dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power or intensity relative to

The data is transmitted over four copper pairs, eight bits at a time. A bit is a binary digit, taking a value of either 0 or 1 Binary digits are a basic unit of Information storage and communication First, eight bits of data are expanded into four 3-bit symbols through a non-trivial scrambling procedure based on a linear feedback shift register; this is similar to what is done in 100BASE-T2, but uses different parameters. A linear feedback shift register (LFSR is a Shift register whose input bit is a linear function of its previous state The 3-bit symbols are then mapped to voltage levels which vary continuously during transmission. One example mapping is as follows:

Non-trivial DSP algorithms and processing power were involved with the introduction of PAM-5, hence its delayed introduction after 802. 3z.

1000BASE-TX

The Telecommunications Industry Association (TIA) created and promoted a version of 1000BASE-T that was simpler to implement, calling it 1000BASE-TX (TIA/EIA-854). The Telecommunications Industry Association ( TIA) is a trade association in the US that represents about 600 Telecommunications companies The simplified design would, in theory, have reduced the cost of the required electronics by only using two pairs in each direction. However, the two-pair solution required Category 6 cable and has been a commercial failure, likely due to the rapidly falling cost of 1000BASE-T products combined with the Category 6 cable requirement. Many 1000BASE-T products are advertised as 1000BASE-TX due to lack of knowledge that 1000BASE-TX is actually a different standard.

See also

• 10 Gigabit Ethernet
• 100 Gigabit Ethernet
• Ethernet Alliance
• GBIC
• SFP transceiver
• Jumbo Frames

Footnotes

Bibliography

• Norris, Mark, Gigabit Ethernet Technology and Applications, Artech House, 2002. Mark Norris is a British consultant in the field of Software engineering and Telecommunications, particularly noted as a prolific writer on technology subjects ISBN 1-580-53505-4

External links

• Get IEEE 802.3
• IEEE 802.3
• IEEE and Gigabit Ethernet Alliance Announce Formal Ratification of gigabit Ethernet Over Copper Standard - Announcement from IEEE 28 June 1999
• IEEE P802.3ab 1000BASE-T Task Force (historical information)
• IEEE 802.3 CSMA/CD (ETHERNET)