Guide To Networks Ch5 Terms

Front 1

10Base-T

Back 1

A Physical layer standard for networks that specifies baseband transmission, twisted pair media, and 10-Mbps throughput. 10Base-T networks have a maximum segment length of 100 meters and rely on a star topology.

Front 2

10GBase-ER

Back 2

A Physical layer standard for achieving 10-Gbps data transmission over singlemode, fiber-optic cable. In 10GBase-ER, the ER stands for extended reach. This standard specifies a star topology and segment lengths up to 40 kilometers.

Front 3

10GBase-EW

Back 3

A variation of the 10GBase-ER standard that is specially encoded to operate over SONET WAN links.

Front 4

10GBase-LR

Back 4

A Physical layer standard for achieving 10-Gbps data transmission over singlemode, fiber-optic cable using wavelengths of 1310 nanometers. In 10GBase-LR, the LR stands for long reach. This standard specifies a star topology and segment lengths up to 10 kilometers.

Front 5

10GBase-LW

Back 5

A variation of the 10GBase-LR standard that is specially encoded to operate over SONET WAN links.

Front 6

10GBase-SR

Back 6

A Physical layer standard for achieving 10-Gbps data transmission over multimode fiber using wavelengths of 850 nanometers. The maximum segment length for 10GBase-SR can reach up to 300 meters, depending on the fiber core diameter and modal bandwidth used.

Front 7

10GBase-SW

Back 7

A variation of the 10GBase-SR standard that is specially encoded to operate over SONET WAN links.

Front 8

10GBase-T

Back 8

A Physical layer standard for achieving 10-Gbps data transmission over twisted pair cable. Described in its 2006 standard 802.3an, IEEE specifies Cat 6 or Cat 7 cable as the appropriate medium for 10GBase-T. The maximum segment length for 10GBase-T is 100 meters.

Front 9

100Base-FX

Back 9

A Physical layer standard for networks that specifies baseband transmission, multimode fiber cabling, and 100-Mbps throughput. 100Base-FX networks have a maximum segment length of 2000 meters. 100Base-FX may also be called Fast Ethernet.

Front 10

100Base-T

Back 10

A Physical layer standard for networks that specifies baseband transmission, twisted pair cabling, and 100-Mbps throughput. 100Base-T networks have a maximum segment length of 100 meters and use the star topology. 100Base-T is also known as Fast Ethernet.

Front 11

100Base-TX

Back 11

A type of 100Base-T network that uses two wire pairs in a twisted pair cable, but uses faster signaling to achieve 100-Mbps throughput. It is capable of full-duplex transmission and requires Cat 5 or higher twisted pair media.

Front 12

1000Base-LX

Back 12

A Physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. 1000Base-LX can run on either singlemode or multimode fiber. The LX represents its reliance on long wavelengths of 1300 nanometers. 1000Base-LX can extend to 5000-meter segment lengths using single-mode, fiber-optic cable. 1000Base-LX networks can use one repeater between segments.

Front 13

1000Base-SX

Back 13

A Physical layer standard for networks that specifies 1-Gbps transmission over fiber-optic cable using baseband transmission. 1000Base-SX runs on multimode fiber. Its maximum segment length is 550 meters. The SX represents its reliance on short wavelengths of 850 nanometers. 1000Base-SX can use one repeater.

Front 14

1000Base-T

Back 14

A Physical layer standard for achieving 1 Gbps over UTP. 1000Base-T achieves its higher throughput by using all four pairs of wires in a Cat 5 or higher twisted pair cable to both transmit and receive signals. 1000Base-T also uses a different data encoding scheme than that used by other UTP Physical layer specifications.

Front 15

5-4-3 rule

Back 15

A guideline for 10-Mbps Ethernet networks stating that between two communicating nodes, the network cannot contain more than five network segments connected by four repeating devices, and no more than three of the segments may be populated.

Front 16

802.3ab

Back 16

The IEEE standard that describes 1000Base-T, a 1-Gigabit Ethernet technology that runs over four pairs of Cat 5 or better cable.

Front 17

802.3ae

Back 17

The IEEE standard that describes 10-Gigabit Ethernet technologies, including 10GBase-SR, 10GBase-SW, 10GBase-LR, 10GBase-LW, 10GBase-ER, and 10GBase-EW.

Front 18

802.3af

Back 18

The IEEE standard that specifies a way of supplying electrical Power over Ethernet (PoE). 802.3af requires Cat 5 or better UTP or STP cabling and uses power sourcing equipment to supply current over a wire pair to powered devices. PoE is compatible with existing 10Base-T, 100Base-TX, 1000Base-T, and 10GBase-T implementations.

Front 19

802.3an

Back 19

The IEEE standard published in 2006 that describes 10GBase-T, a 10-Gbps Ethernet technology that runs on Cat 6 or Cat 7 twisted pair cable.

Front 20

802.3u

Back 20

The IEEE standard that describes Fast Ethernet technologies, including 100Base-TX.

Front 21

802.3z

Back 21

The IEEE standard that describes 1000Base (or 1-Gigabit) Ethernet technologies, including 1000Base-LX and 1000Base-SX.

Front 22

access method

Back 22

A network’s method of controlling how nodes access the communications channel. For example, CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is the access method specified in the IEEE 802.3 (Ethernet) standard.

Front 23

active topology

Back 23

A topology in which each workstation participates in transmitting data over the network. A ring topology is considered an active topology.

Front 24

broadcast domain

Back 24

Logically grouped network nodes that can communicate directly via broadcast transmissions. For example, all nodes connected to a single hub and all nodes that participate in a bus-topology network belong to a single broadcast domain.

Front 25

bus

Back 25

The single cable connecting all devices in a bus topology.

Front 26

bus topology

Back 26

A topology in which a single cable connects all nodes on a network without intervening connectivity devices.

Front 27

circuit switching

Back 27

A type of switching in which a connection is established between two network nodes before they begin transmitting data. Bandwidth is dedicated to this connection and remains available until users terminate the communication between the two nodes.

Front 28

collapsed backbone

Back 28

A type of backbone that uses a router or switch as the single central

Front 29

collision

Back 29

In Ethernet networks, the interference of one node’s data transmission with the data transmission of another node sharing the same segment.

Front 30

collision domain

Back 30

The portion of an Ethernet network in which collisions could occur if two nodes transmit data at the same time.

Front 31

CSMA/CD

Back 31

(Carrier Sense Multiple Access with Collision Detection) A network access method specified for use by IEEE 802.3 (Ethernet) networks. In CSMA/CD, each node waits its turn before transmitting data to avoid interfering with other nodes’ transmissions. If a node’s NIC determines that its data has been involved in a collision, it immediately stops transmitting. Next, in a process called jamming, the NIC issues a special 32-bit sequence that indicates to the rest of the network nodes that its previous transmission was faulty and that those data frames are invalid. After waiting, the NIC determines if the line is again available; if it is available, the NIC retransmits its data.

Front 32

daisy chain

Back 32

A group of connectivity devices linked together in a serial fashion.

Front 33

data propagation delay

Back 33

The length of time data takes to travel from one point on the segment to another point. On Ethernet networks, CSMA/CD’s collision detection routine cannot operate accurately if the data propagation delay is too long.

Front 34

distributed backbone

Back 34

A type of backbone in which a number of connectivity devices (usually hubs) are connected to a series of central connectivity devices, such as hubs, switches, or routers, in a hierarchy.

Front 35

enterprise

Back 35

An entire organization, including local and remote offices, a mixture of computer systems, and a number of departments. Enterprise-wide computing takes into account the breadth and diversity of a large organization’s computer needs.

Front 36

Ethernet_II

Back 36

The original Ethernet frame type developed by Digital, Intel, and Xerox, before the IEEE began to standardize Ethernet. Ethernet_II contains a 2-byte type field to identify the upper-layer protocol contained in the frame. It supports TCP/IP and other higher-layer protocols.

Front 37

Fast Ethernet

Back 37

A type of Ethernet network that is capable of 100-Mbps throughput. 100Base-T and 100Base-FX are both examples of Fast Ethernet.

Front 38

fault tolerance

Back 38

The capability for a component or system to continue functioning despite damage or malfunction.

Front 39

Gigabit Ethernet

Back 39

A type of Ethernet network that is capable of 1000-Mbps, or 1-Gbps, throughput.

Front 40

hybrid topology

Back 40

A physical topology that combines characteristics of more than one simple physical topology.

Front 41

jamming

Back 41

A part of CSMA/CD in which, upon detecting a collision, a station issues a special 32-bit sequence to indicate to all nodes on an Ethernet segment that its previously transmitted frame has suffered a collision and should be considered faulty.

Front 42

logical topology

Back 42

A characteristic of network transmission that reflects the way in which data is transmitted between nodes (which may differ from the physical layout of the paths that data takes). The most common logical topologies are bus and ring.

Front 43

MPLS

Back 43

(multiprotocol label switching) A type of switching that enables any one of several layer 2 protocols to carry multiple types of layer 3 protocols. One of its benefits is the ability to use packet-switched technologies over traditionally circuit-switched networks. MPLS can also create end-to-end paths that act like circuit-switched connections.

Front 44

modal bandwidth

Back 44

A measure of the highest frequency of signal a multimode fiber-optic cable can support over a specific distance. Modal bandwidth is measured in MHz-km.

Front 45

packet switching

Back 45

A type of switching in which data is broken into packets before it is transported. In packet switching, packets can travel any path on the network to their destination, because each packet contains a destination address and sequencing information.

Front 46

padding

Back 46

The bytes added to the data (or information) portion of an Ethernet frame to ensure this field is at least 46 bytes in size. Padding has no effect on the data carried by the frame.

Front 47

parallel backbone

Back 47

A type of backbone that consists of more than one connection from the central router or switch to each network segment.

Front 48

passive topology

Back 48

A network topology in which each node passively listens for, then accepts, data directed to it. A bus topology is considered a passive topology.

Front 49

PD

Back 49

(powered device) On a network using Power over Ethernet, a node that receives power from power sourcing equipment.

Front 50

physical topology

Back 50

The physical layout of a network. A physical topology depicts a network in broad scope; it does not specify devices, connectivity methods, or addresses on the network. Physical topologies are categorized into three fundamental geometric shapes: bus, ring, and star. These shapes can be mixed to create hybrid topologies.

Front 51

PoE

Back 51

(Power over Ethernet) A method of delivering current to devices using Ethernet connection cables.

Front 52

preamble

Back 52

The field in an Ethernet frame that signals to the receiving node that data is incoming and indicates when the data flow is about to begin.

Front 53

PSE

Back 53

(power sourcing equipment) On a network using Power over Ethernet, the device that supplies power to end nodes.

Front 54

QoS

Back 54

(quality of service) The result of specifications for guaranteeing data delivery within a certain period of time after their transmission.

Front 55

ring topology

Back 55

A network layout in which each node is connected to the two nearest nodes so that the entire network forms a circle. Data is transmitted unidirectionally around the ring. Each workstation accepts and responds to packets addressed to it, then forwards the other packets to the next workstation in the ring.

Front 56

serial backbone

Back 56

A type of backbone that consists of two or more internetworking devices connected to each other by a single cable in a daisy chain. Hubs are often connected in this way to extend a network.

Front 57

SFD

Back 57

(start-of-frame delimiter) A 1-byte field that indicates where the data field begins in an Ethernet frame.

Front 58

signal bounce

Back 58

A phenomenon, caused by improper termination on a bus-topology network, in which signals travel endlessly between the two ends of the network, preventing new signals from getting through.

Front 59

star topology

Back 59

A physical topology in which every node on the network is connected through a central device, such as a hub. Any single physical wire on a star network connects only two devices, so a cabling problem will affect only two nodes. Nodes transmit data to the hub, which then retransmits the data to the rest of the network segment where the destination node can pick it up.

Front 60

star-wired bus topology

Back 60

A hybrid topology in which groups of workstations are connected in a star fashion to hubs that are networked via a single bus.

Front 61

star-wired ring topology

Back 61

A hybrid topology that uses the physical layout of a star and the token-passing data transmission method.

Front 62

switching

Back 62

A component of a network’s logical topology that manages how packets are filtered and forwarded between nodes on the network.

Front 63

terminator

Back 63

A resistor that is attached to each end of a bus-topology network and that causes the signal to stop rather than reflect back toward its source.

Front 64

collapsed backbone

Back 64

A type of backbone that uses a router or switch as the single central connection point for multiple subnetworks.

Front 65

message switching

Back 65

A type of switching in which a connection is established between two devices in the connection path; one device transfers data to the second device, then breaks the connection. The information is stored and forwarded from the second device after a connection between that device and a third device on the path is established.