Day 2

Question 1

OSI Model

refer to diagram 6-1 in student workbook

Answer 1

Application
Presentation
Session
Transport
Network 
Data link
Physical

Question 2

Application Layer (layer 7)

Answer 2

The interface between the user’s applications and the network when the user’s network-aware application requires network resources to accomplish a task.
Uses API’s

Question 3

Presentation Layer (layer 6)

Answer 3

Responsible for presenting the data at the destination with the same meaning and appearance as it had at the source

Question 4

Session Layer (Layer 5)

Answer 4

Sets up, coordinates, and terminates conversations, exchanges, and dialogues between devices across a network.
Sessions can be:
simplex: communications occur in only one direction
half-duplex: communications occur in two directions but not at the same time
full-duplex: communications occur in two directions simultaneously

Question 5

transport layer (layer 4)

Answer 5

manages data delivery between systems or hosts

Question 6

network layer (layer 3)

Answer 6

responsible for the logical addressing and routing of messages to their proper final destination.

Question 7

data link layer (layer 2)

Answer 7

provides reliable method of transmitting data across the communication link.
Contains two sub layers:
LLC: Upper layer and handles error checking and flow control, and communicates with network layer
MAC: lower layer and is responsible for mapping between logical and physical addressing

Question 8

physical layer (layer 1)

Answer 8

where communications between devices actually take place

Question 9

Project 802

Answer 9

IEEE group/standard that defines how multiple computers can connect without interfering with one another

802. 3 Ethernet LAN-CSMA/CD
803. 5 Token Ring LAN
804. 11 Wireless LAN (WLAN) & Mesh (Wi-Fi certification)

Question 10

Protocols

Answer 10

rules that govern a convention or standard that enables data transfer between two computing endpoints

Question 11

TCP/IP suite

Answer 11

most common suite in the world
developed by DOD
primarily operates in the client/server model
is routable

Question 12

network adapter/network interface card

Answer 12

provides interface between a computer and the network medium

Question 13

link lights

Answer 13

show status of the NIC:
green indicates a good connection
yellow means slow connection speeds
no light indicates a connection is not present

Question 14

attenuation

Answer 14

the loss of signal intensity over distance

Question 15

amplifier

Answer 15

a device that strengthens any noise, both intended noise and background noise

Question 16

repeater

Answer 16

receives and regenerates the original and desired signal

Question 17

hubs

Answer 17

multipoint repeaters that receive a digital signal, regenerate it, and then broadcast that signal to all connected ports

Question 18

switches

Answer 18

switches make decisions based on physical MAC addresses and only forward data through the appropriate port
(break up collision domains but not broadcast domains)

Question 19

routers

Answer 19

connects LAN’s and WAN’s.

determines the next network to which a packet is sent by scanning the destination IP address

Question 20

uplink port

Answer 20

device that electronically switches the transmit and receive wires eliminating the need for cross over cables.

Question 21

unicast addressing

Answer 21

sends traffic to a single host or destination

Question 22

multicast addressing

Answer 22

sends traffic to a group of hosts or recipients

Question 23

broadcast addressing

Answer 23

used to send traffic to everyone on a LAN

Question 24

anycast addressing

Answer 24

maps traffic to the nearest host providing a specific service

Question 25

MAC address

Answer 25

48 bit (6-byte) hex (physical) address burned into the NIC

Question 26

OUI

Answer 26

first half of the MAC address that identifies the manufacturer
a broadcast to all MAC addresses is FF:FF:FF:FF:FF:FF

Question 27

IPv4 address

Answer 27

4 octets
8 bits in an octet
0-255 in each octet

Question 28

subnet masks

Answer 28

identifies where the network part of the IP address stops and the host part begins

Question 29

Address resolution Protocol (ARP)

Answer 29

used to populate a hosts ARP cache when it knows the IP address of a computer in its network but not any MAC’s. The host sends a message to the IP address it knows and broadcasts it to all MAC’s. All of the hosts update their own ARP cache with the MAC that sent the message, and the intended IP host responds back to the host with its MAC.

Question 30

Reverse ARP

Answer 30

when a host knows a MAC address but not the IP address.

Question 31

classes of IP addresses

Answer 31

A 0-127 255.0.0.0 /8
B 128-191 255.255.0.0 /16
C 192-223 255.255.255.0 /24

Question 32

CIDR

Answer 32

denotes subnet mask and the size of the network

Question 33

subnetting

Answer 33

breaks larger networks into smaller networks, which contain fewer available host ID’s due to borrowing bits

Question 34

performing subnetting

Answer 34

refer to info sheet 6-3 in student workbook 
formula's
number of subnets:
2^n  n= borrowed bits
number of hosts:
2^h-2   h=host bits

Question 35

Private IP ranges

Answer 35

A 10.0.0.0-10.255.255.255
B 172.16.0.0-172.31.255.255
C 192.168.0.0-192.168.255.255

Question 36

Automatic Private IP addressing (APIPA)

Answer 36

when a machine cannot reach a DHCP server, it assigns itself its own address so that it can communicate within its own network.
Range:
169.254.0.0-169.254.255.255

Question 37

loopback address

Answer 37

used to test a NIC’s ability to send or receive traffic

127.0.0.1

Question 38

ipconfig

Answer 38

displays IP configurations

Question 39

ifconfig

Answer 39

used in UNIX to display and change parameters such as IP addresses

Question 40

supernetting

Answer 40

opposite of subnetting, network bits are taken back and utilized as host bits