Physical medium dependent sublayers or PMDs further help to define the physical layer of

computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...

protocols. They define the details of transmission and reception of individual bits on a physical medium. These responsibilities encompass bit timing, signal encoding, interacting with the physical medium, and the properties of the cable, optical fiber, or wire itself. Common examples are specifications for

Fast Ethernet In computer networking, Fast Ethernet physical layers carry traffic at the nominal rate of 100 Mbit/s. The prior Ethernet speed was 10 Mbit/s. Of the Fast Ethernet physical layers, 100BASE-TX is by far the most common. Fast Ethern ...

Gigabit Ethernet In computer networking, Gigabit Ethernet (GbE or 1 GigE) is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use ...

and

10 Gigabit Ethernet 10 Gigabit Ethernet (10GE, 10GbE, or 10 GigE) is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE 802.3ae-2002 standard. Unlike previous ...

defined by the Institute of Electrical and Electronics Engineers (IEEE). For cable modems physical medium dependent sublayers define the physical sub-layer.

Description

The Ethernet PMD sublayer is part of the

Ethernet physical layer The physical-layer specifications of the Ethernet family of computer network standards are published by the Institute of Electrical and Electronics Engineers (IEEE), which defines the electrical or optical properties and the transfer speed ...

(PHY). The hierarchy is as follows: * Data link layer (Layer 2) **

Logical link control In the IEEE 802 reference model of computer networking, the logical link control (LLC) data communication protocol layer is the upper sublayer of the data link layer (layer 2) of the seven-layer OSI model. The LLC sublayer acts as an interface ...

(LLC) sublayer **

Medium access control In IEEE 802 LAN/MAN standards, the medium access control (MAC, also called media access control) sublayer is the layer that controls the hardware responsible for interaction with the wired, optical or wireless transmission medium. The MAC sublay ...

(MAC) sublayer *** Reconciliation sublayer (RS) - This sublayer processes PHY local/remote fault messages and handles DDR conversion *

PHY PHY is an abbreviation for the physical layer of the OSI model and refers to the circuitry required to implement physical layer functions. PHY or Phy may also refer to: * Phy, the drug methadone * Phetchabun Airport (IATA code), Thailand See ...

layer (Layer 1) ** Physical coding sublayer (PCS) - This sublayer performs auto-negotiation and coding such as 8b/10b ** Physical medium attachment (PMA) sublayer - This sublayer performs PMA framing, octet synchronization/detection, and

x^7+x^6+1

scrambling/descrambling ** Physical medium dependent (PMD) sublayer - This sublayer consists of a transceiver for the physical medium

Physical medium dependent sublayer specifications

10 Gigabit Ethernet

;10GBASE-E: has been defined for single mode fiber operation only. It operates in the 1550 nm band allowing for distances of up to 40 km to be reached. ;10GBASE-L: was also defined for single mode fiber operations, uses the 1300 nm band allowing it to reach up to 10 km. ;10GBASE-S: was defined for use in

multimode fiber Multi-mode optical fiber is a type of optical fiber mostly used for communication over short distances, such as within a building or on a campus. Multi-mode links can be used for data rates up to 100 Gbit/s. Multi-mode fiber has a fairly large ...

and ultimately costs less than the other 10GbE standards. It uses 850 nm lasers and only reaches distances ranging between 26 and 82 metres on older fiber technology. In newer optimized multimode fibers (a.k.a. OM3) it can reach up to 300 m. ;10GBASE-LX4: uses four lasers that each transmit at 3.125 Gbit/s. The receiver is arranged in a

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, t ...

-division multiplexing manner. On legacy FDDI multimode fiber it can reach up to 300 m while on single mode fiber it can reach up to 10 km. After these specifications have been laid out, they are then completed with

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger ...

and

wide area network A wide area network (WAN) is a telecommunications network that extends over a large geographic area. Wide area networks are often established with leased telecommunication circuits. Businesses, as well as schools and government entities, u ...

specifications using different Physical Coding Sublayer standards.

References

*{{cite journal, last=Barbieri, first=Alessandro, title=10 GbE and Its X Factors, journal=Packet: Cisco Systems Users Magazine, volume=17, issue=3, pages=25–28, url=http://www.cisco.com/c/dam/en_us/about/ac123/ac114/downloads/packet/pdf/packetQ3-05.pdf, accessdate=2016-04-06
Ethernet 1000BASE-X PCS/PMA Technology Basics
Ethernet