Net+ Ch4, The Current Ethernet Specifications

ethernet

a contention media-access method that allows all hosts on a network to share the same bandwidth of a link

collision domain

an Ethernet term that refers to a particular network scenario wherein one device sends a packet out on a network segment and thereby forces every other device on that same physical network segment to pay attention to it

collision event

a situation where each device's digital signals interfere with another on the wire—occurs and forces the devices to retransmit later

broadcast domain

refers to the set of all devices on a network segment that hear all the broadcasts sent on that segment. typically a boundary delimited by physical media like switches and repeaters, it can also reference a logical division of a network segment

carrier sense multiple access with collision detection (CSMA/CD)

a media access control contention method that helps devices share the bandwidth evenly without having two devices transmit at the same time on the network medium.

broadband

send multiple frequencies of different signals down the same wire at the same time (called frequency-division multiplexing) and to send both analog and digital signals

baseband

what all LANs use. all the bandwidth of the physical media is used by only one signal

bit rate

measure of the number of data bits (0s and 1s) transmitted in one second in either a digital or analog signal

wavelength

distance between peaks

auto-detect mechanism

decides on the exchange capability, which means it checks to see if it can run at 10, 100, or even 1000 Mbps. It then checks to see if it can run full-duplex, and if it can't, it will run half-duplex instead

data link layer

responsible for ethernet and MAC addressing

10000000

128

11000000

192

11100000

224

11110000

240

11111000

248

11111100

252

11111110

254

11111111

255

organizationally unique identifier (OUI)

assigned by the Institute of Electrical and Electronics Engineers (IEEE) to an organization. It's composed of 24 bits, or 3 bytes.

Individual/Group bit (I/G)

used to signify if the destination MAC address is a unicast (0) or a multicast/broadcast (1) layer 2 address

Local/Global bit (L/G)

used to tell if the MAC address is the burned-in-address (BIA) (0) or a MAC address that has been changed locally (1)

data link layer

responsible for combining bits into bytes and bytes into frames

tunneling

Encapsulating a frame within a different type of frame

inherent attenuation

defined as the loss of signal strength as it travels the length of a cable and is measured in decibels

crosstalk

unwanted signal interference from adjacent pairs in the cable

10BaseT

UTP, 10 Mbps, 100 meters per segment, one of the most popular network cabling schemes

100BaseTX

UTP, STP, 100 Mbps, 100 meters per segment, two pairs of Category 5 UTP

10BaseFL

Fiber, 10 Mbps, varies (ranges from 500 meters to 2,000 meters), Ethernet over fiber optics to the desktop

100BaseFX

MMF, 100 Mbps, 2,000 meters, 100 Mbps Ethernet over fiber optics

1000BaseT

UTP, 1000 Mbps, 100 meters, four pairs of Category 5 or higher

1000BaseTX

UTP, 1000 Mbps, 100 meters, two pairs of Category 6 or higher

1000BaseSX

MMF, 1000 Mbps, 550 meters, uses SC fiber connectors, max length depends on fiber size

1000BaseCX

Balanced shielded copper, 1000 Mbps, 25 meters, uses a special connector, the HSSDC

1000BaseLX

MMF and SMF, 1000 Mbps, 550 meters multimode/2,000 meters single mode, uses longer wavelength laser than 1000BaseSX, uses SC and LC connectors

10GBaseT

UTP, 10 Gbps, 100 meters, connects to the network like a Fast Ethernet link using UTP

10GBaseSR

MMF, 10 Gbps, 300 meters, 850 nm laser, max length depends on fiber size and quality

10GBaseLR

SMF, 10 Gbps, 10 kilometers, 1,310 nm laser, max length depends on fiber size and quality

10GBaseER

SMF, 10 Gbps, 40 kilometers, 1,550 nm laser, max length depends on fiber size and quality

10GBaseSW

MMF, 10 Gbps, 400 meters, 850 nm laser transceiver

10GBaseLW

SMF, 10 Gbps, 10 kilometers, typically used with SONET

10GBaseEW

SMF, 10 Gbps, 40 kilometers, 1,550 nm optical wavelength

40GBaseT

UTP, Category 8, 40 Gbps, 30 meters, connects to the network like a Fast Ethernet link using UTP