4B/5B
A block encoding scheme used to send Fast Ethernet data.
10BASE-T
10 Mbps Ethernet system based on Manchester signal encoding transmitted over Category 3 or better twisted-pair cable.
10BASE2
10 Mbps Ethernet system based on Manchester signal encoding transmitted over thin coaxial cable. Also called Cheapernet or ThinNet.
10BASE5
Original 10 Mbps Ethernet system based on Manchester signal encoding transmitted over thick coaxial cable. Also called ThickNet.
10BASE-F
10 Mbps Ethernet system based on Manchester signal encoding transmitted over fiber optic cable.
10BASE-FL
10 Mbps link fiber optic implementation.
10GBASE-S (R or W)
Multimode fiber with 850 nm laser transceiver with a bandwidth of 10 Gbps.
10GBASE-L (R or W)
Single mode fiber with 1310 nm laser transceiver with a bandwidth of 10 Gbps.
10GBASE-E (R or W)
Single mode fiber with 1550 nm laser transceiver with a bandwidth of 10 Gbps.
10GBASE-LX4
Single mode fiber with 1550 nm laser transceiver with a bandwidth of 10 Gbps.
10GBASE-CX4
Multimode fiber with 1310 nm laser transceiver with a bandwidth of 10 Gbps.
10GBASE-T
UTP, balanced twisted pair cabling using Category 6/class E cable
100BASE-FX
100 Mbps Fast Ethernet system based on 4B/5B signal encoding transmitted over fiber optic cable.
100BASE-T
100 Mbps Fast Ethernet system, including both twisted-pair and fiber optic media types.
100BASE-TX
100 Mbps Fast Ethernet system based on 4B/5B signal encoding transmitted over two pairs.
100BASE-X
Refers to any Fast Ethernet media system based on 4B/5B block encoding. Includes 100BASE-TX and 100BASE-FX media systems.
802.2
IEEE Working Group for Logical Link Control (LLC).
802.3
IEEE Working Group for CSMA/CD LANs (local area networks).
AUI
Attachment Unit Interface is a 15-pin signal interface defined in the original DIX Ethernet standard.
Auto-Negotiation
A protocol defined in the Ethernet standard that allows devices at either end of a link segment to advertise and negotiate modes of operation.
Bandwidth
The maximum capacity of a network channel. Usually expressed in bits per second (bps). Ethernet have a bandwidth of 10-, 100-, 1000 Mbps and 1 and 10 Gbps.
Bridge
A device that connects two or more networks at the data link layer.
BPDU
Bridge Protocol Data Unit are parts of the STP that help describe and identify attributes of a switch port.
Broadcast Domain
The set of all stations in a network that will receive each other’s broadcast frames.
Broadcast
A transmission initiated by one station to all stations on a network.
Bus
A shared connection for multiple devices over a cable or backplane.
Category 3
Twisted-pair cable with electrical characteristics suitable for carrying 10BASE-T. Not recommended for new installations.
Category 5
Twisted-pair cable with electrical characteristics suitable for all twisted-pair Ethernet media systems, including 10BASE-T and 100BASE-TX.
Category 5e
An enhanced version of Category 5 cable, developed to improve certain cable characteristics important to Gigabit Ethernet operation.
Category 6
A cable standard for Gigabit Ethernet and other interconnect. Category 6 is suitable for 10BASE-T / 100BASE-TX and 1000BASE-T connections.
Coaxial Cable
A cable with an outer conductor, surrounding an inner conductor. Coaxial cables are used for 10BASE5 and 10BASE2 Ethernet systems.
Collision
The result of having two or more simultaneous transmissions on a common signal channel such as half-duplex Ethernet or shared Ethernet.
Collision Domain
The set of all stations and repeaters connected to a network where faithful detection of a collision can occur.
CRC - Cyclic Redundancy Check.
An error checking technique used to ensure the accuracy of transmitted data.
CSMA / C D
Carrier Sense Multiple Access/Collision Detect. The medium access control (MAC) protocol used in Ethernet.
Data Link Layer
Layer 2 of the OSI reference model, which is responsible for transmitting and receiving frames. It includes both the media access control (MAC) protocol and logical link control (LLC) layers.
DIX
The first letter of the Digital Corp, the Intel Corp, and the Xerox Corp, which are the leading vendors defined the original Ethernet standards.
DSAP
Destination Service Access Point, part of LLC LSAP for data type.
Ethernet
Originally developed by DIX, then standardized by IEEE 802.3 for local area network communication. Now it is expanded to MAN and WAN services.
EtherType
A field in the Ethernet frame provides information of protocol used in the data field of the frame.
Fast Ethernet
A version of Ethernet as defined by IEEE 802.3u that operates at 100 Mbps.
Fast Link Pulse
A link pulse that encodes information used in the Auto-Negotiation protocol.
Flow Control
The process of controlling data transmission at the sender to avoid overfilling buffers and loss of data at the receiver.
Forwarding
The process of moving frames from one port to another in a switching hub.
Frame
The fundamental unit of transmission at the data link layer of the OSI model.
Full-Duplex Operation
A communications method that allows for the simultaneously transmission and reception of data.
GBIC
Gigabit Interface Converter is a standard for transceivers, commonly used with gigabit Ethernet and fibre channel.
Gigabit Ethernet
A version of Ethernet that operates at 1000 Mbps.
Half-Duplex Operation
A communications method in which transmissions and receptions can occur in either direction but not at the same time.
Hub
A device with three or more ports at the center of a star topology network to share all Ethernet signals among all ports.
IEEE
Institute of Electrical and Electronics Engineers. A professional organization and standards body.
Late Collision
A failure of the network in which the collision indication arrives too late in the frame transmission to be automatically dealt with by the medium access control (MAC) protocol.
Link Integrity Test
This test verifies that an Ethernet link is connected correctly and that signals are being received correctly.
LLC
Logical Link Control. A standardized protocol and service interface provided at the data link layer and independent of any specific LAN technology. Specified in the IEEE 802.2 standard.
LSAP
Link Service Access Point(LSAP), including both DSAP and SSAP, is the identifier field to indicate data types.
MAC
Medium Access Control is a protocol operating at the data link layer used to manage a station’s access to the communication channel.
MAC Address
A unique address assigned to a station interface, identifying that station on the network. With Ethernet, this is the unique 48-bit station address.
Manchester Encoding
Signal encoding method used in all 10 Mbps Ethernet media systems.
MAU
Medium Attachment Unit provides the physical and electrical interface between an Ethernet device and the medium system to which it is connected. Also referred to as a transceiver.
MDI
Medium Dependent Interface is used to make a physical and electrical connection between a transceiver and a media segment.
MII
Medium Independent Interface, provides a 40-pin connection to outboard transceivers (also called PHY devices). Used to attach 802.3 interfaces.
NIC
Network Interface Card, also called an adapter, network interface module, or interface card, provides a connection between a computer and a network.
OUI
Organizationally Unique Identifier is a 24-bit value assigned to an organization by the IEEE. It is used as part of MAC address.
Patch Cable
A twisted-pair or fiber optic jumper cable used to connect a NIC and a media segment, etc.
PHY
Physical Layer Device. The name used for a transceiver in Fast Ethernet and Gigabit Ethernet systems.
Physical Layer
The first layer in the OSI seven layers reference model, which defines the electrical and optical properties of signal transmission.
Port
A connection point for a cable at a network device. Hubs and switches typically provide multiple ports for connecting Ethernet devices.
Promiscuous Mode
A mode of operation where a device is configured to receive all frames on a network regardless of its destination address. Typically used by network analyzer tools.
Repeating Hub
A repeater with more than two ports. This name is frequently shortened to simply hub.
Q-in-Q
A provider bridge extensions in VLAN tag, also known as stackable VLANs.
RJ-45
An 8-pin modular connector used on twisted-pair links.
SC
Subscriber Connector, a type of fiber optic connector used in 100BASE-FX fiber optic media systems.
Segment
A cable made up of one or more cable sections and connections joined together to produce the equivalent of a continuous cable.
Slot Time
A unit of time used in the medium access control (MAC) protocol for Ethernet.
SNAP
Sub-Network Access Protocol is a standard for the transmission of IP datagrams over IEEE 802 networks.
SSAP
Source Service Access Point, part of the LLC LSAP for data type.
ST
Straight Tip, a type of fiber optic connector mostly used in 10BASE-FL and FOIRL links.
STP
Spanning Tree Protocol provides a loop free topology for any LAN or bridged network.
Star Topology
A network topology in which each station on the network is connected directly to a hub.
Switch
Is a device that interconnects network segments at the data link layer.
Twisted-Pair Cable
A multiple-conductor cable whose component wires are paired together, twisted, and enclosed in a single jacket.
Tagged frame
Frame with an 802.1Q VLAN identifier.
Untagged frame
Frame without an 802.1Q VLAN identifier UTP – Unshielded Twisted Pair cable is made of one or more twisted pairs of wires and is not surrounded by a metal shield.
VLAN
Virtual LAN as defined by IEEE 802.1q.