Vol 1-2 - Fundamentals of Ethernet Lans

Question 1

10BASE-T

Answer 1

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 2

100BASE-T

Answer 2

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 3

1000BASE-T

Answer 3

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 4

auto-MDIX

Answer 4

auto-MDIX
An Ethernet standard feature, introduced at the same time as Gigabit Ethernet in 1998, that senses whether the link uses the correct UTP cable pinout (straight-through or crossover), and automatically swaps the signals internally to make the link work if the wrong UTP cable pinout is used.

Question 5

broadcast address(L2)

Answer 5

Generally, any address that represents all devices, and can be used to send one message to all devices. In Ethernet, the MAC address of all binary 1s, or FFFF.FFFF.FFFF in hex.

Question 6

cladding

Answer 6

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 7

core

Answer 7

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

Question 8

crossover cable

Answer 8

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 9

electromagnetic interference (EMI)

Answer 9

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 10

Ethernet

Answer 10

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 11

Ethernet address

Answer 11

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 12

Ethernet frame

Answer 12

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

Question 13

Ethernet link

Answer 13

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

Question 14

Ethernet port

Answer 14

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 15

Fast Ethernet

Answer 15

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

Question 16

fiber-optic cable

Answer 16

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

Question 17

Frame Check Sequence

Answer 17

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

Question 18

Gigabit Ethernet

Answer 18

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

Question 19

IEEE

Answer 19

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

Question 20

MAC address

Answer 20

MAC address
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 21

multimode fiber

Answer 21

multimode fiber
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 22

network interface card (NIC)

Answer 22

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 NICs are specifically Ethernet NICs, and most have an RJ-45 port, the most common type of Ethernet port.

Question 23

RJ-45

Answer 23

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. RJ-45 allows the connection of eight wires.

Question 24

single-mode fiber

Answer 24

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 25

straight-through cable

Answer 25

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 26

transceiver

Answer 26

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 27

unicast address

Answer 27

unicast address
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 28

wired LAN

Answer 28

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 29

wireless LAN

Answer 29

wireless LAN
A local-area network (LAN) that physically transmits bits using radio waves. The name “wireless” compares these LANs to more traditional “wired” LANs, which are LANs that use cables (which often have copper wires inside).