Ethernet Networking and Data Encapsulation

Question 1

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

Answer 1

ethernet

Question 2

ethernet uses both ___ and ___ layer specifications, presented with information relative to both layers, and need to effectively implement, troubleshoot, and maintain an ethernet network

Answer 2

data link and physical layer

Question 3

refers to a network scenario wherein one device sends a frame out on a physical network segment forcing every other device on the same segment to pay attention to it

Answer 3

collision domain

Question 4

true or false: the hosts connected ot each hub are in the same collision domain, so if one of them transmits, all the others must take the time to listen for and read the digital signal

Answer 4

true

Question 5

true or false: each port of a switch is a single collision domain

Answer 5

true

Question 6

true or false: switches can’t break broadcast domains

Answer 6

true

Question 7

refers to a group of devices on a specific network segment that hear all the broadcasts sent out on that specific network segment

Answer 7

broadcast domain

Question 8

is usually a boundary delimited by physical media like switches and routers

Answer 8

broadcast domain

Question 9

broadcast domain can also refer to a _______ of a network segment, where all hosts can communicate via a data link layer, hardware address broadcast

Answer 9

logical division

Question 10

this helps devices share the bandwidth evenly while preventing two devices from transmitting simultaneously on the same network medium

Answer 10

carrier sense multiple access with collision detection (csma/cd)

Question 11

created to overcome the problem of the collisions that occur when packets are transmitted from different nodes at the same time

Answer 11

csma/cd

Question 12

enumerate what happens when a collision occurs on an ethernet LAN

Answer 12

1. a jam signal informs all devices that a collision occurred.
2. the collision invokes a random backoff algorithm
3. each device on the ethernet segment stops transmitting for a short time until its backoff timer expires.
4. all hosts have equal priority to transmit after the timers have expired

Question 13

defined in the original IEEE 802.3 Ethernet specification, Cisco says Ethernet uses only one wire pair with a digital signal running in both directions on the wire

Answer 13

half-duplex

Question 14

what protocol does half-duplex use?

Answer 14

csma/cd

Question 15

true or false: if a hub is attached to a switch, it must operate in half-duplex mode because the end stations must be able to detect collisions

Answer 15

true

Question 16

what are the six situations where you can operate in full-duplex ethernet

Answer 16

with a connection from a:
switch to a host
switch to a switch
host to a host
switch to a router
router to a router
router to a host

Question 17

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

Answer 17

auto-detect mechanism

Question 18

enumerate the important points in full-duplex

Answer 18

1. there are no collisions in full-duplex mode
2. a dedicated switch port is required for each full-duplex mode
3. the host network card and the switch port must be capable of operating in full-duplex mode
4. the default behavior of 10Base-T and 100Base-T hosts is 10 mbps half-duplex if the auto-detect mechanism fails, so it is always goo practice to set the speed and duplex of each port on a switch if you can

Question 19

____ at the data link layer is responsible for ethernet addressing, commonly referred to as MAC orr hardware addressing

Answer 19

ethernet

Question 20

it is also responsible for framing packets received from the network layer and preparing them for transmission on the local network through the ethernet contention-based media access emthod

Answer 20

ethernet

Question 21

ethernet addressing uses _____ address burned into each and every ethernet network interface card (nic)

Answer 21

media access control (MAC)

Question 22

how many bits and bytes is in a MAC address

Answer 22

48 bits or 6 bytes

Question 23

in what format is the MAC address written in

Answer 23

Hexadecimal format

Question 24

what does OUI mean

Answer 24

organizationally unique identifier (OUI)

Question 25

the OUI is assigned by whom

Answer 25

IEEE

Question 26

what does IEEE mean

Answer 26

institute of electrical and electronics engineers

Question 27

it is composed of 24 bits or 3 bytes and it assigns a globally administered address also made up of 24 bits or 3 bytes, which is unique to each and every adapter an organization manufactures

Answer 27

organizationally unique identifier (OUI)

Question 28

the high order bit is in the

Answer 28

individual/group (I/G) bit

Question 29

true or false: when the high-order bit has a value of 0, we can assume that the address is the MAC address of a device and that it may well appear in the source portion of the MAC header

Answer 29

true

Question 30

when the high-order bit in the MAC address is a 1, what does it represent

Answer 30

the address represents either a broadcast or multicast address in the ethernet

Question 31

this is used to send data to multiple devices on a network

Answer 31

multicast MAC address

Question 32

this MAC address is used to send data to all devices on a local network segment

Answer 32

Broadcast MAC Address (FF:FF:FF:FF:FF:FF)

Question 33

what does G/L bit or U/L bit mean

Answer 33

global/local bit or universal/local bit

Question 34

what does the G/L bit represent when it's set to 0 or 1

Answer 34

0 - globally administered address 1 - locally governed and administered address

Question 35

represents a locally administered or manufacturer/vendor-assigned code

Answer 35

the low order 24 bits

Question 36

the use to limit either 1 or 0

Answer 36

binary digits or bits

Question 37

a group of either 4 or 8 bits together

Answer 37

nible or byte

Question 38

placed in a value spot, starting at the right and moving left, with each spot having double the value of the previous spot

Answer 38

binary numbers

Question 39

short for hexadecimal, which is a numbering system that uses the first six letters of the alphabet

Answer 39

hex

Question 40

responsible for combining bits into bytes and bytes into frames

Answer 40

data link layer

Question 41

the MAC frame format provides error detection from a

Answer 41

cyclic redundancy check (CRC)

Question 42

encapsulating a frame within a different type of frame is called

Answer 42

tunneling

Question 43

what is the typical ethernet format

Answer 43

ethernet ii preamble - 7 bytes sfd - 1 byte destination - 6 bytes source - 6 bytes type - 2 bytes data and pad - 46 to 1500 bytes fcs - 4 bytes

Question 44

an alternating 1, 0 pattern providing a 5 MHHz clock at the start of each packet, which allows the receiving devices to lock the incoming bit stream

Answer 44

preamble

Question 45

how many octets is the preamble

Answer 45

seven

Question 46

how many octets is the SFD

Answer 46

one

Question 47

10101011, where the last pair of 1s allows the receiver to come into alternating 1, 0 pattern somewhere in the middle and still sync up to detect the beginning of the data

Answer 47

start frame delimiter (SFD)/Synch

Question 48

transmits a 48-bit value using the least significant bit (LSB) first; used by receiving stations to determine whether an incoming packet is addressed to a particular node.

Answer 48

Destination Address

Question 49

true or false: the destination address can be an individual address or a broadcast or multicast MAC address

Answer 49

true

Question 50

true or false: broadcast address is all 1s or all Fs in hex sent to all devices

Answer 50

true

Question 51

this is only sent to a similar subset of nodes on a network

Answer 51

multicast

Question 52

this is a 48-bit MAC address used to identify the transmitting device, and it uses the least significant bit first.

Answer 52

source address (SA)

Question 53

true or false: broadcast and multicast address formats are illegal within the SA field

Answer 53

true

Question 54

uses a length field, but the ethernet_ii frame uses a type field to identify the network layer protocol.

Answer 54

length or type 802.3

Question 55

true or false: the old, original 802.3 cannot identify the upper-layer protocol and must be used with a proprietary LAN-IPX, for example

Answer 55

true

Question 56

a field at the end of the frame that's used to store the cyclic redundancy check answer

Answer 56

frame check sequence

Question 57

it uses a math algorithm that runs when each frame is built based on the data in the frame when a receiving host receives the frame and runs the CRC, the answer should be the same if not the frame is discarded assuming errors have occured

Answer 57

cyclic redundancy check (CRC)

Question 58

they created and implemented the first ethernet LAN specification, which the IEEE used to create the IEEE 802.3 committee

Answer 58

Digital, Intel, and Xerox (DIX)

Question 59

true or false: DIX was a 10 mbps network running on a coax then eventually twisted pair and fiber physical media

Answer 59

truea

Question 60

what does eia/tia mean

Answer 60

electronic industries alliance and the newer telecommunications industry association

Question 61

standard body that creates physical layer specifications for ethernet

Answer 61

eia/tia

Question 62

this specifies that ethernet uses a registered jack (RJ) connector on unshielded twisted pair (UTP) cabling (RJ45)

Answer 62

eia/tia

Question 63

what are the three types of cables

Answer 63

straight-through cable crossover cable rolled cable

Question 64

can handle speeds up to a gigabit with a distance of up to 100 meters typically used for 100 mbps

Answer 64

category 5 enhanced UTP cable

Question 65

what cable is used for a gigabit

Answer 65

category 6

Question 66

1. rated for gigabit speeds 2. rated for 10gbp

Answer 66

1. cat5 2. cat6

Question 67

use cases of straight-through cable

Answer 67

host to switch router to switch

Question 68

how many wires are used in straight through cable to connect ethernet devices

Answer 68

four wires

Question 69

on what pins do straight through cables transmit and receive pins

Answer 69

transmit: 1 & 2 receive: 3 & 6

Question 70

sequence of a t-568a wiring standard

Answer 70

WG G WO B WB O WB B

Question 71

sequence of a t-568b wiring standard

Answer 71

WO O WG B WB G WB B

Question 72

use cases of crossover cable

Answer 72

switch to switch hub to hub host to host hub to switch router direct to host router to router

Question 73

setup of a crossover ethernet cable

Answer 73

device 1: receive on pins 1 & 2 transmit on pins 3 & 6 device 2: transmit on pins 3 & 6 receive on pins 1 & 2

Question 74

what is 1000base-t

Answer 74

UTP gigabit wiring

Question 75

isn't used to connect any ethernet connections together, used to connect to a host EIA-TIA 232 interface to a router console serial communication (COM) port

Answer 75

rolled cable

Question 76

how many wires are used in a rolled cable

Answer 76

eight wires, though not all is used to send information

Question 77

the easiest cables to make because you just cut the end off on one side of a straight-through cable, turn it over, and put it back on-with a new connector

Answer 77

rolled cable

Question 78

what emulation program is used to create a console connection and configure the device

Answer 78

PuTTY or SecureCRT

Question 79

cable that allows for very fast transmission of data, made of glass or plastic, is very thin and works as a waveguide to transmit light between two ends of the fiber

Answer 79

fiber optic

Question 80

true or false: fiber optic is immune to interference like crooss-talk

Answer 80

true

Question 81

fiber cable parts

Answer 81

core, cladding, buffer

Question 82

125 microns, a fiber standard that allows manufacturers to make connectors for all fiber cables

Answer 82

cladding

Question 83

protects the delicate glass in fiber cables

Answer 83

buffer

Question 84

two types of fiber optics

Answer 84

single-mode multimode

Question 85

more expensive, has a tighterr cladding, and can go much farther distances than multimode

Answer 85

single-mode

Question 86

looser cladding and has a larger core so it allows multiple light particles to travel down the glass

Answer 86

multimode

Question 87

when a host transmits data across the network to another device, the data goes through a process and wrapped with protocol information at each layer of the OSI model

Answer 87

encapsulation

Question 88

used to communicate and exchange information in each layer

Answer 88

protocol data units (PDUs)

Question 89

these hold the control information attached to theh data at each layer of the model. they are usually attached to the header in front of the data field but can also be at the trailer or end of it

Answer 89

protocol data units (PDUs)

Question 90

a piece of data created and attached data field in transport layer

Answer 90

segment

Question 91

used to get each segment to the correct network

Answer 91

logical addressing

Question 92

adds a control header to the segment handed down from the transport layer

Answer 92

packet or datagram

Question 93

how does the data encapsulation method work

Answer 93

1. user information is converted to data for transmission on the network 2. data is converted to segments and a reliable connection is set up between the transmitting and receiving hosts 3. segments are converted to packets or datagrams, and a logical address is placed in the header so each packet can be routed through an internetwork 4. packets or datagrams are converted to frames for transmission on the local network 5. frames are converted to bits, and a digital encoding and clocking scheme is used

Question 94

port number used in part to define the virtual circuit

Answer 94

source port: 1028

Question 95

port number used to define upper layer process or application

Answer 95

destination port: 23

Question 96

what are the three layers in the cisco hierarchical model

Answer 96

core, distribution, access

Question 97

this helps us understand where things belong, how things fit together, and what functions go where helps us summarize a complex collection of details into an understandable model, bringing order from the chaos

Answer 97

hierarchy

Question 98

can help you design, implement, and maintain a scalable, reliable, cost-effective hierarchical internetwork

Answer 98

cisco hierarchical model

Question 99

core of the network responsible for transporting large amounts of traffic both reliably and quickly; switches traffic as fast as possible

Answer 99

the core layer

Question 100

don't do in core layer

Answer 100

]don't use access lists or perform routing between VLAN or implement packet filtering in the core layer don't support workgroup access avoid expanding the core; upgrade than expand

Question 101

sometimes referred to as the workgroup layer and is the communication point between the access layer and the core

Answer 101

distribution layer

Question 102

provides routing, filtering, and WAN access and to determine how packets can access the core, if needed

Answer 102

Distribution layer

Question 103

must determine the fastest way that network service requests are handled-for example, how a file request is forwarded to a server

Answer 103

distribution layer

Question 104

what are the things handled by the distribution layer

Answer 104

routing, implementing tools, access lists, packet filtering, queuing, implementing security and network policies, redistributing between routing protocols, routing between VLANS and other workgroup fucntions, define broadcast and multicast domains

Question 105

controls user and workgroup access to internetwork resources

Answer 105

access layer

Question 106

the access layer is sometimes referred to as

Answer 106

desktop layer

Question 107

this layer handles any traffic for remote services

Answer 107

access layer

Question 108

functions of the access layer

Answer 108

use of access control and policies, separation of collision domains (microsegmentation), workgroup connectivity, device connectivity, resiliency and security services, advanced technology capabilities

Question 109

what are the common ethernet standards, starting with 10 mbps ethernet

Answer 109

10Base-T (IEEE 8022.3) 100Base-TX (IEEE 802.3u) 100Base-FX (IEEE 802.3u) 100Base-CX (IEEE 802.3z) 1000Base-T (IEEE 802.3ab) 1000Base-SX (IEEE 802.3z) 1000Base-LX (IEEE 802.3z) 1000Base-Zx (Cisco Standard) 10GBase-T (802.3.an) 10GBase-T

Question 110

most commonly known as fast ethernet, uses eia/tia category 5, 5e, or 6 utp two-pair wiring upto 100 meters long uses an rj45 connector

Answer 110

100Base-TX (IEEE 802.3u)