Ch. 2: Fundamentals of Ethrnet LANs

Question 1

Ethernet

Answer 1

A series of LAN standards defined by the IEEE, originally invented by Xerox Corporation and developed jointly by Xerox, Intel, and Digital Equipment Corporation.

Question 2

IEEE

Answer 2

Institute of Electrical and Electronics Engineers. A professional organization that develops communications and network standards, among other activities.

Question 3

wired LAN

Answer 3

A local-area network (LAN) that physically transmits bits using cables, often the wires inside cables. A term for local-area networks that use cables, emphasizing the fact that the LAN transmits data using wires (in cables) instead of wireless radio waves.

Question 4

Ethernet frame

Answer 4

A term referring to an Ethernet data-link header and trailer, plus the data encapsulated between the header and trailer.

Question 5

10BASE-T

Answer 5

The 10-Mbps baseband Ethernet specification using two pairs of twisted-pair cabling (Categories 3, 4, or 5): one pair transmits data and the other receives data. 10BASE-T, which is part of the IEEE 802.3 specification, has a distance limit of approximately 100 m (328 feet) per segment.

Question 6

100BASE-T

Answer 6

A name for the IEEE Fast Ethernet standard that uses two-pair copper cabling, a speed of 100 Mbps, and a maximum cable length of 100 meters.

Question 7

1000BASE-T

Answer 7

A name for the IEEE Gigabit Ethernet standard that uses four-pair copper cabling, a speed of 1000 Mbps (1 Gbps), and a maximum cable length of 100 meters.

Question 8

Fast Ethernet

Answer 8

The common name for all the IEEE standards that send data at 100 megabits per second.

Question 9

Gigabit Ethernet

Answer 9

The common name for all the IEEE standards that send data at 1 gigabit per second.

Question 10

Ethernet link

Answer 10

A generic term for any physical link between two Ethernet nodes, no matter what type of cabling is used.

Question 11

RJ-45

Answer 11

A popular type of cabling connector used for Ethernet cabling. It is similar to the RJ-11 connector used for telephone wiring in homes in the United States. It allows the connection of eight wires.

Question 12

Ethernet port

Answer 12

A generic term for the opening on the side of any Ethernet node, typically in an Ethernet NIC or LAN switch, into which an Ethernet cable can be connected.

Question 13

network interface card (NIC)

Answer 13

A computer card, sometimes an expansion card and sometimes integrated into the motherboard of the computer, that provides the electronics and other functions to connect to a computer network. Today, most are specifically Ethernet, and most have an RJ-45 port, the most common type of Ethernet port.

Question 14

straight-through cable

Answer 14

In Ethernet, a cable that connects the wire on pin 1 on one end of the cable to pin 1 on the other end of the cable, pin 2 on one end to pin 2 on the other end, and so on.

Question 15

crossover cable

Answer 15

An Ethernet cable that swaps the pair used for transmission on one device to a pair used for receiving on the device on the opposite end of the cable. In 10BASE-T and 100BASE-TX networks, this cable swaps the pair at pins 1,2 to pins 3,6 on the other end of the cable, and the pair at pins 3,6 to pins 1,2 as well.

Question 16

Ethernet address

Answer 16

A 48-bit (6-byte) binary number, usually written as a 12-digit hexadecimal number, used to identify Ethernet nodes in an Ethernet network. Ethernet frame headers list a destination and source address field, used by the Ethernet devices to deliver Ethernet frames to the correct destination.

Question 17

MAC address

Answer 17

A standardized data-link layer address that is required for every device that connects to a LAN. Ethernet MAC addresses are 6 bytes long and are controlled by the IEEE. Also known as a hardware address, a MAC layer address, and a physical address.

Question 18

unicast address

Answer 18

Generally, any address in networking that represents a single device or interface, instead of a group of addresses (as would be represented by a multicast or broadcast address).

Question 19

broadcast address

Answer 19

Generally, any address that represents all devices, and can be used to send one message to all devices.

Question 20

Frame Check Sequence

Answer 20

A field in many data-link trailers used as part of the error-detection process.

Question 21

transceiver

Answer 21

A term formed from the words transmitter and receiver. The hardware used to both send (transmit) energy over some communications medium (e.g., wires in a cable), as well as to process received energy signals to interpret as a series of 1s and 0s.

Question 22

multimode fiber

Answer 22

A type of fiber cable that works well with transmitters like LEDs that emit multiple angles of light into the core of the cable; to accommodate the multiple angles of incident, the cable has a larger core in comparison to single-mode fiber cables.

Question 23

single-mode fiber

Answer 23

A type of fiber cable that works well with transmitters like lasers that emit a single angle of light into the core of the cable, allowing for a smaller core in comparison to multimode fiber cables.

Question 24

electromagnetic interference (EMI)

Answer 24

The name of the effect in which electricity passes through one cable as normal, inducing a magnetic field outside the conductor. That magnetic field, if it passes through another conductor, like a nearby cable, induces new electrical current in the second cable, interfering with the use of electricity to transmit data on the second cable.

Question 25

core

Answer 25

In fiber-optic cabling, the center cylinder of the cable, made of fiberglass, through which light passes.

Question 26

cladding

Answer 26

In fiber-optic cabling, the second layer of the cable, surrounding the core of the cable, with the property of reflecting light back into the core.

Question 27

fiber-optic cable

Answer 27

A type of cabling that uses glass fiber as a medium through which to transmit light.