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The Ethernet physical layer is the physical layer component of the Ethernet standard.

The Ethernet physical layer evolved over a considerable time span and encompasses quite a few physical media interfaces and several magnitudes of speed. The speed ranges from 3 Mbit/s to 10 Gbit/s in speed while the physical medium can range from bulky coaxial cable to twisted pair to optical fiber. In general, network protocol stack software will work identically on most of the following types.

The following sections provide a brief summary of all the official Ethernet media types (section numbers from the IEEE 802.3-2002 standard are parenthesized). In addition to these official standards, many vendors have implemented proprietary media types for various reasons—often to support longer distances over fiber optic cabling.

Many Ethernet adapters and switch ports support multiple speeds, using autonegotiation to set the speed and duplex for the best values supported by both connected devices. If auto-negotiation fails, a multiple speed device will sense the speed used by its partner, but will assume half-duplex. A 10/100 Ethernet port supports 10BASE-T and 100BASE-TX. A 10/100/1000 Ethernet port supports 10BASE-T, 100BASE-TX, and 1000BASE-T.
Contents
[hide]

* 1 Physical layers
o 1.1 Xerox experimental Ethernet
o 1.2 Early implementations (10 Mbit/s and 1 Mbit/s)
o 1.3 Fast Ethernet (100 Mbit/s)
o 1.4 Gigabit Ethernet
o 1.5 10 Gigabit Ethernet
o 1.6 40 Gigabit Ethernet
o 1.7 100 Gigabit Ethernet
* 2 Ethernet over twisted-pair cable
* 3 Ethernet Minimum Cable Lengths
* 4 See also
* 5 References
* 6 External links

[edit] Physical layers

[edit] Xerox experimental Ethernet
Name Description
Xerox Ethernet The original, 3 Mbit/s Ethernet implementation, which had a frame format different from the production forms of Ethernet.

[edit] Early implementations (10 Mbit/s and 1 Mbit/s)
Name Standard Description
10BASE5 802.3 (8) 10 Mbit/s, Manchester coded signaling, copper RG-8X (expensive) coaxial cabling, bus topology with collision detection (aka Thick Ethernet)
10BASE2 802.3 (10) 10 Mbit/s, Manchester coded signaling, copper RG-58 (cheap) coaxial cabling, bus topology with collision detection (aka Thin Ethernet)
10BROAD36 802.3 (11) 10 Mbit/s, scrambled NRZ signaling modulated (PSK) over high frequency carrier, broad bandwidth coaxial cabling, bus topology with collision detection
1BASE5 802.3 (12) 1 Mbit/s, Manchester coded signaling, copper twisted pair cabling, star topology
StarLAN 10 10 Mbit/s, Manchester coded signaling, copper twisted pair cabling, star topology - evolved into 10BASE-T
10BASE-T 802.3 (14) 10 Mbit/s, Manchester coded signaling, copper twisted pair cabling, star topology - direct evolution of 1BASE-5
FOIRL Fiber-optic inter-repeater link; the original standard for Ethernet over fiber
10BASE-F 802.3 (15) (also called 10BASE-FX) -- A generic term for the family of 10 Mbit/s Ethernet standards using fiber optic cable: 10BASE-FL, 10BASE-FB and 10BASE-FP. Of these only 10BASE-FL is in widespread use. 10 Mbit/s, Manchester coded signaling, fiber pair
10BASE-FL 802.3 (15) an updated version of the FOIRL standard
10BASE-FB 802.3 (15) intended for backbones connecting a number of hubs or switches; it is now obsolete
10BASE-FP 802.3 (15) a passive star network that required no repeater, it was never implemented

[edit] Fast Ethernet (100 Mbit/s)

For more details on this topic, see Fast Ethernet.

Name Standard Description
100BASE-T A term for any of the three standards for 100 Mbit/s Ethernet over twisted pair cable up to 100 meters long. Includes 100BASE-TX, 100BASE-T4 and 100BASE-T2. All of them use a star topology.
100BASE-TX 802.3 (24) 4B5B MLT-3 coded signaling, CAT5 copper cabling with two twisted pairs.
100BASE-T4 802.3 (23) 8B6T PAM-3 coded signaling, CAT3 copper cabling (as used for 10BASE-T installations) with four twisted pairs (uses all four pairs in the cable). Now obsolete, as Cat-5 cabling is the norm. Limited to half-duplex.
100BASE-T2 802.3 (32) No products exist. PAM-5 coded signaling, CAT3 copper cabling with two twisted pairs, star topology. Supports full-duplex. It is functionally equivalent to 100BASE-TX, but supports old telephone cable. However, special sophisticated digital signal processors are required to handle encoding schemes required, making this option fairly expensive.
100BASE-FX 802.3 (24) 4B5B NRZI coded signaling, two strands of multi-mode optical fiber. Maximum length is 400 meters for half-duplex connections (to ensure collisions are detected) or 2 kilometers for full-duplex.
100BASE-SX TIA 100 Mbit/s Ethernet over multi-mode fiber. Maximum length is 300 meters. Unlike 100BASE-FX using lasers as light sources, 100BASE-SX uses LEDs, so it is cheaper.
100BASE-BX10 802.3 100 Mbit/s Ethernet bidirectionally over a single strand of single-mode optical fiber. A multiplexer is used to split transmit and receive signals into different wavelengths allowing them to share the same fiber. Supports up to 10 km.
100BASE-LX10 802.3 100 Mbit/s Ethernet up to 10 km over a pair of Single Mode Fibers.
100Base-VG 802.12 Standardized by a different IEEE 802 subgroup, 802.12, because it used a different, more centralized form of media access ("Demand Priority"). Championed by only HP, 100VG-AnyLAN (as was the marketing name) was the earliest in the market. It needed four pairs of Cat-3 cables. Now obsolete (802.12 has been "inactive" since 1997).

[edit] Gigabit Ethernet

For more details on this topic, see Gigabit Ethernet.

All of these use a star topology.
Name Standard Description
1000BASE-T 802.3 (40) PAM-5 coded signaling, CAT5/CAT5e/CAT6 copper cabling with four twisted pairs (used in both directions)
1000BASE-TX TIA 854 over only Cat-6 copper cabling. Unimplemented.
1000BASE-SX 802.3 8B10B NRZ coded signaling, multi-mode fiber (up to 550 m).
1000BASE-LX 802.3 8B10B NRZ coded signaling, multi-mode fiber (up to 550 m) or single-mode fiber (up to 2 km; can be optimized for longer distances, up to 10 km).
1000BASE-LH multi-vendor over single-mode fiber (up to 100 km). A long-haul solution.
1000BASE-CX 802.3 8B10B NRZ coded signaling, balanced shielded twisted pair (up to 25 m) over special copper cable. Predates 1000BASE-T and rarely used.
1000BASE-BX10 802.3 up to 10 km. Bidirectional over single strand of single-mode fibre.
1000BASE-LX10 802.3 Up to 10 km over a pair of single-mode fibres.
1000BASE-PX10-D 802.3 downstream (from head-end to tail-ends) over single-mode fiber using point-to-multipoint topology (supports at least 10 km).
1000BASE-PX10-U 802.3 upstream (from a tail-end to the head-end) over single-mode fiber using point-to-multipoint topology (supports at least 10 km).
1000BASE-PX20-D 802.3 downstream (from head-end to tail-ends) over single-mode fiber using point-to-multipoint topology (supports at least 20 km).
1000BASE-PX20-U 802.3 upstream (from a tail-end to the head-end) over single-mode fiber using point-to-multipoint topology (supports at least 20 km).
1000BASE-ZX Unknown Up to 100 km over single-mode fibre.[1]
1000BASE-KX 802.3ap 1 m over backplane

[edit] 10 Gigabit Ethernet

For more details on this topic, see 10 Gigabit Ethernet.

Name Standard Description
10GBASE-SR 802.3ae designed to support short distances over deployed multi-mode fiber cabling, it has a range of between 26 m and 82 m depending on cable type. It also supports 300 m operation over a new 2000 MHz.km multi-mode fiber.
10GBASE-LX4 802.3ae uses wavelength division multiplexing to support ranges of between 240 m and 300 m over deployed multi-mode cabling. Also supports 10 km over single-mode fiber.
10GBASE-LR 802.3ae supports 10 km over single-mode fiber
10GBASE-ER 802.3ae supports 40 km over single-mode fiber
10GBASE-SW 802.3ae A variation of 10GBASE-SR using the WAN PHY, designed to interoperate with OC-192 / STM-64 SONET/SDH equipment
10GBASE-LW 802.3ae A variation of 10GBASE-LR using the WAN PHY, designed to interoperate with OC-192 / STM-64 SONET/SDH equipment
10GBASE-EW 802.3ae A variation of 10GBASE-ER using the WAN PHY, designed to interoperate with OC-192 / STM-64 SONET/SDH equipment
10GBASE-CX4 802.3ak designed to support short distances over copper cabling, it uses InfiniBand 4x connectors and CX4 cabling and allows a cable length of up to 15 m.
10GBASE-T 802.3an Uses unshielded twisted-pair wiring.
10GBASE-LRM 802.3aq Extend to 220 m over deployed 500 MHz.km multimode fiber
10GBASE-KX4 802.3ap 1 m over 4 lanes of backplane
10GBASE-KR 802.3ap 1 m over a single lane of backplane

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Posted by waqasahmad

Single mode fibder is used in 10 GBase-ER and 10 GBase-LR

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Posted by adalson007