Chapter 4

Question 1

(CIDR)

Answer 1

Classless inter-domain routing; a standard notation that indicates what portions of an IP address are used for network ID and host ID

Question 2

binary

Answer 2

using 1s and 0s to represent hexadecimal

Question 3

You are given the following address: 00-90-4B-AD-2A-AC What type of address is this?

Answer 3

MAC address

The physical address, also known as MAC address, assigned to a NIC by its manufacturer is 48 bits long. Because of the way this address is divided up into two 24-bit parts, each manufacturer has only 16 million or so unique addresses to use before the manufacturer has to start reusing physical addresses.

Question 4

Public Class C IP range

Answer 4

192.0.0.0 - 223.255.255.255

Question 5

What technology takes a voice communication, breaks the data into small packets, and sends the packets from one network segment to another?

Answer 5

packet switching

Packet switching opens up connections only long enough for a small data packet to move from one network segment to another. Data—regardless of type, content, or structure—is broken into small blocks called packets and sent to its destination.

Question 6

What device has each port as its own collision domain?

Answer 6

switch

A basic switch can be referred to as a multiport bridge because like a bridge, it can separate a network out into multiple collision domains.

Question 7

Which Ethernet standard was developed to work over fiber?

Answer 7

100Base-FX

100Base-FX is the version of Fast Ethernet that is intended to be used over fiber-optic cable. Introduced at the same time as 100Base-TX, 100Base-FX was part of the same IEEE 802.3y standard.

Question 8

What connects two network segments together, yet only forwards packets based on MAC addresses from one segment to another segment only when needed?

Answer 8

bridge

Bridges are intended to break up networks into smaller sections; as a result, they are more intelligent than your average hub. Because bridges work on the Data-Link layer of the OSI model, they can read and make sense of MAC addresses. Based on these MAC or Physical addresses, a bridge can determine whether a frame is allowed to pass through to the other side of the bridge.

Question 9

What is a set of agreed-upon instructions designed to allow computers to communicate to each other across a network connection?

Answer 9

protocol

In computer networking, a protocol is a set of agreed-upon instructions designed to allow computers to communicate to each other across a network connection. Many protocols are used in networking because many different tasks need to be done to allow computers to communicate with each other.

Question 10

What device converts one type of media to another type?

Answer 10

media converter

Media converters are used to convert one type of media to another type. Such devices are used to convert coaxial to twisted pair or fiber to copper. These types of devices are important for allowing two different types of technologies on the same network.

Question 11

What type of server acts as an intermediary between a client and other servers?

Answer 11

proxy server

Proxy servers act as intermediaries between a client and other servers. They can fulfill many roles and can be used for many different jobs.

Question 12

public IP address

Answer 12

can be used on the Internet; must be registered with the Network Information Center

Question 13

What protocol is used to provide bi-directional interactive command-line access to either a remote or local host?

Answer 13

TELNET

TELNET, short for TErminaL NETwork, is used to provide bi-directional interactive command-line access to either a remote or local host. TELNET was first introduced in 1969 in RFC 15. In 1983, TELNET was extended in RFC 854. TELNET client software can be found for pretty much every computer platform out there.

Question 14

Public Class B IP range

Answer 14

128.0.0.0 - 191.255.255.255

Question 15

physical address

Answer 15

MAC address; physical binary address that every network device is given when it is created by its manufacturer

Question 16

Which wireless mode does not use a central WAP?

Answer 16

ad hoc

An ad hoc wireless network is formed when a wireless network is composed of only independent wireless computers in which each device participates in forwarding wireless packets. An ad hoc wireless network has no central WAP to monitor and control it. In effect, an ad hoc wireless network is the wireless network version of a peer-to-peer network.

Question 17

EUI

Answer 17

Extended Unique Identifiers; the variations of MAC addresses

Question 18

In what type of technology is the whole message routed to its destination one hop at a time?

Answer 18

message switching

In message switching, whole messages are routed to their destination one hop at a time. Over time, the message switching idea evolved into what we call packet switching today. With message switching, the entire message is sent out at once.

Question 19

TCP/IP Protocol Suite

Answer 19

A group of protocols to carry out the functions needed to communicate across a network

Question 20

What helps protect data that is sent using a wireless network?

Answer 20

encryption

Encryption is where a device such as a computer or a WAP takes the data that it is sending out and first runs an algorithm on it so that it cannot be read without first having the key to read it. This capability increases the security of a network by making it more difficult for an outsider to read what is passing across a network.

Question 21

Which protocol is used to resolve host names to IP addresses?

Answer 21

DNS

Domain Name System (DNS) makes it possible for us to use the Internet the way we do. DNS is the protocol that converts all those URLs we can easily remember to IP addresses that the Internet can use.

Question 22

What was the first Ethernet standard used on UTP?

Answer 22

10Base-T

While 10Base-T was not the first XBase-Y standard developed, it was the first twisted-pair XBase-Y standard developed. In 1990 IEEE 802.3i formalized the 10Base-T standard. 10Base-T used CAT 3 UTP and could carry 10 mbps throughput for a distance of 100 meters. 10Base-T was a baseband technology. This standard became known as Twisted-Pair Ethernet.

Question 23

What protocol do multiple switches on the same network use to ensure that an infinite loop is not created?

Answer 23

STP

Spanning Tree Protocol (STP) is used when multiple switches are implemented on the same network. As a Data-Link layer protocol, STP is used primarily to prevent endless loops from developing on switch-based LANs. The protocol gets its name from a mathematical algorithm called “spanning tree,” which takes a group of points and connects them all together without allowing any loops to form.

Question 24

Which protocol is used to send messages about the network when a route goes bad?

Answer 24

ICMP

The Internet Control Message Protocol (ICMP) is used mainly by a computer’s operating system to send messages about the network. When an error occurs in the IP packet, a service is unreachable or down, a host is not found, or a router is down, among other situations, an ICMP message is sent.

Question 25

What is used to monitor the activity of a network and notify network administrators when it identifies something as suspicious?

Answer 25

IDS Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS) are related technologies. An IDS usually sits inside a network and monitors the network’s activities. When something suspicious is noted, the IDS then notifies network administrators so that they can take steps to stop the suspect activity. Because an IDS only monitors activity, it is considered passive.

Question 26

classful subnet mask for a Class C IP address

Answer 26

255.255.255.0

Question 27

What type of access method does Ethernet use?

Answer 27

CSMA/CD Carrier Sensing Media Access/Collision Detection (CSMA/CD) is the primary method that Ethernet uses to access wired LANs. Ethernet uses a different method to access wireless LANs.

Question 28

What is used to protect a network from unauthorized access?

Answer 28

firewall The firewall that is mentioned here, is not the “firewall” that you load onto your computer to protect it from internet attacks. A firewall is a networking device whose purpose is to prevent unauthorized packets from getting into your network. It is also used as the first line of defense between a private network and the Internet.

Question 29

private IP address

Answer 29

cannot be used on the Internet; is not registered with the Network Information Center

Question 30

What is used to determine which upper-layer protocols, services, and processors each data segment is intended for?

Answer 30

port Protocols on the Transport layer have port addresses, also known as ports. These ports are used to determine which upper-layer protocols, services, and processes each data segment is intended for. Port addresses ensure that the correct protocol, service, or process can get the data intended for it. The two main protocols on the Transport layer, UDP and TCP, both use ports.

Question 31

When a collision occurs, what do the two sending nodes do?

Answer 31

They both wait a random amount of time and try again. When computers on the network segment “hear” a collision on the network, they all immediately activate something called a hold-down timer. This timer is effectively a clock that activates in each NIC on the network and starts counting down from a randomly set point of time. While the clock on a particular NIC is counting down, it cannot send any packets. As each computer on the network segment finishes its random countdown, it can begin listening to the network again to find an open point where it can begin to send its data packet.

Question 32

What type of access method is used in wireless networks?

Answer 32

CSMA/CA Like CSMA/CD, Carrier Sensing Media Access/Collision Avoidance (CSMA/CA) is a method used by Ethernet to access a local area network. Where CSMA/CD is most commonly used for wired networks, CSMA/CA is most commonly used for wireless networks.

Question 33

At what OSI layer do routers operate?

Answer 33

Network layer Network Routers are networking devices used to move packets around a larger network. To do this, they have to be very intelligent and able to read data packets to know where they are intended to go and where they have come from. Because routers are meant to relay based on IP addresses, they work on the Network layer.

Question 34

IPv4

Answer 34

32 bits long

Question 35

Which Ethernet frame type supports TCP/IP?

Answer 35

Ethernet II The most widely used Ethernet frame type is Ethernet II or Ethernet DIX. It is so widely used because the Internet Protocol (IP) can use it directly.

Question 36

What media type can carry multiple data signals at the same time?

Answer 36

broadband Baseband means is that a cable can carry only one signal one way at one time. In the case of most modern Ethernet cables, this means that there is one line for sending signals and another line for receiving signals inside an Ethernet cable.

Question 37

hop

Answer 37

each time a computer or network device sends data frame to the next computer or network device

Question 38

What is referred to as a group of hosts in the Data-Link layer that share a common set of communications requirements and can be isolated from other groups?

Answer 38

VLAN In its most basic form, a VLAN (short for Virtual LAN) enables you to break up a much larger network into smaller networks within the Data-Link layer of the OSI model. In other words, a VLAN refers to a group of hosts that share a common set of communications requirements whether or not they are attached to the same device.

Question 39

Which connectionless transport protocol does not guarantee reliable delivery?

Answer 39

UDP User Datagram Protocol (UDP) is the connectionless counterpart of TCP. It does not guarantee reliable delivery and is used primarily to give other protocols, such as IP, access to datagram services like port numbers. Due to the limited functionality provided by UDP, the header is correspondingly much smaller and less complex.

Question 40

EUI-60

Answer 40

60-bit Extended Unique Identifier; a MAC address where the host extension is 36-bits long

Question 41

What is used to repeat a signal it receives and rebroadcast it?

Answer 41

repeater A repeater is a device that repeats a signal it receives in order to rebroadcast it, thus extending the range of a particular cable run. A repeater is always active and requires a power source of some sort. It has one cable coming in and one going out.

Question 42

What command is used to test IP connectivity between two hosts?

Answer 42

ping Ping is a network administration utility that is used to test connectivity to specific nodes on a network and to measure the round-trip time it takes for a packet to get to a specific destination and back.

Question 43

Which protocol is used to retrieve emails?

Answer 43

POP3 Post Office Protocol (POP) is used to connect to an email server and retrieve any emails on that server before closing the connection. When POP3 retrieves emails, it can either leave copies on the server, or delete the emails from the server after it downloads them to the client system.

Question 44

. What represents the number of routers it takes to get from one destination to another?

Answer 44

hops Within a routing table database are several information fields. The three most common of these fields are the network ID of the destination network, the cost of path the packet will need to take to get to the destination network, and the next hop. The cost refers to the network cost (not money cost) of getting to the destination network, which is based on available bandwidth, speed and other factors.

Question 45

Today, what type of cable is the most common for Ethernet?

Answer 45

UTP Today, virtually all Ethernet cabling is done with either UTP or fiber. Because UTP is easier to configure, is less expensive, and has been widely available longer, UTP is much more common then fiber.

Question 46

What is the copper version of Gigabit Ethernet?

Answer 46

1000Base-T 1000Base-T is the copper version of Gigabit Ethernet and was standardized in 1999. The standard used for copper-based Gigabit Ethernet was IEEE 802.3ab, which was designed to use CAT 5, 5e, or 6.

Question 47

What port does HTTP use by default?

Answer 47

80 Hyper-Text Transfer Protocol (HTTP) uses TCP port 80 to display web pages via a browser.

Question 48

Which connection-oriented protocol ensures that data gets its final destination?

Answer 48

TCP TCP focuses on the two end devices, whereas IP focuses on getting the network packet from one device to the next toward its ultimate destination.

Question 49

What protocol is used to transport and display web pages using a browser?

Answer 49

HTTP Hyper-Text Transport Protocol (HTTP) is used to transport Hyper-Text Markup Language (HTML) documents, otherwise known as web pages, over the Internet. HTTP can also be used to retrieve graphics, images, and other types of media and it can be used with email.

Question 50

What happens when two computers broadcast at the same time on the network, causing both sets of data to be garbled?

Answer 50

collision When two different computers need to send data at the same time, they will listen to the network. If neither computer hears any activity on the network, they both will conclude that they are clear to send data at that time. As a result, both computers end up sending data packets simultaneously; however, because only one data packet can be on the network cable at one time, a collision occurs. The collision results in a slight power spike on the network as well as destruction of the data in the two packets.

Question 51

What protocol is used to send and manipulate files over a TCP/IP network?

Answer 51

FTP The most commonly used current version of File Transfer Protocol (FTP) was first introduced in 1985 in RFC 959. However, FTP in its original form was introduced in 1971 using RFC 114.

Question 52

10Base-5 uses what type of cable?

Answer 52

coaxial Because 10Base-5 used thick coaxial cables to carry data, it was called Thick Ethernet.

Question 53

When a DNS client needs to resolve a host name to an IP address, where will it first check?

Answer 53

its own DNS cache When you open your web browser and put in a URL, the browser checks the local web cache to see if the IP address of the entered URL can be found. If it cannot be found, your computer sends a query to your ISP’s DNS server asking it for the URL’s IP address.

Question 54

What is the physical address assigned to a NIC?

Answer 54

MAC address he physical address, also known as the MAC address, assigned to a NIC by its manufacturer is 48 bits long. Because of the way this address is divided up into two 24 bit parts, each manufacturer has only 16 million or so unique addresses they can use before the manufacturer has begun reusing physical addresses.

Question 55

EUI-64

Answer 55

64-bit Extended Unique Identifier; a MAC address where the host extension is 40-bits long; creates a unique interface identifier through IPv6

Question 56

classful IP address

Answer 56

a network addressing architecture used in the Internet from 1981 until 1993. The method divides the address space for Internet Protocol Version 4 (IPv4) into five address classes.

Question 57

What type of hub does not amplify or resend a signal?

Answer 57

passive hub A passive hub is really nothing more than a cable splitter. If you have seen old cable TV connections where a coaxial cable is connected to a cable splitter and two or more cables come out, you have seen what is essentially a passive hub. These types of devices are not used very commonly in data networks.

Question 58

On which OSI layer does the network interface card work?

Answer 58

Physical A NIC is required to work on both the Data-Link and Physical layers of the OSI model. The NIC acts as translator between the software in the upper layers of the OSI model and the physical components of the media.

Question 59

What communications term describes the establishment of a dedicated communications channel for the duration of a given transmission?

Answer 59

circuit switching In its most basic definition, circuit switching is a type of communications that establishes a dedicated communications channel for the duration of a given transmission. Initially, circuit switching was done manually, where operators would perform physical connections to establish a circuit or connection. Later, this type of switching was done electronically.

Question 60

Which protocol translates an IP address into a MAC address?

Answer 60

ARP In network addressing—when a packet is passed along a network via routers—the MAC address is actually changed at each hop so that the data frame can move on to the next hop in its journey. The Address Resolution Protocol (ARP)is responsible for changing the MAC address. Part of ARP’s job is to determine what the MAC address is for the next hop and then adjust the frame accordingly so that the frame can be moved to the next hop.

Question 61

Private Class B IP range

Answer 61

172.16.0.0 - 162.31.255.255

Question 62

(IP)

Answer 62

Internet Protocol; contains IPv4 and IPv6

Question 63

classful subnet mask for a Class A IP address

Answer 63

255.0.0.0

Question 64

What routing type is manually defined?

Answer 64

static routing The most basic way of building routing tables is to manually create one in a router. As new routes are needed on a network or old routes change, the routing tables must be manually changed or updated on the affected routers. This process is called static routing, which is time-consuming and prone to errors.

Question 65

What is a multiport repeater?

Answer 65

hub Hubs work as though they are the bus of a larger network. When a computer connected to one port of a hub want to connect to a computer connected to a different port on a hub, it has to broadcast the signal to all devices connected to that hub. In this way, a hub acts as a bus. As a signal comes into a hub, it is regenerated or repeated and sent to its destination.

Question 66

In what type of network segment do computers have the possibility of having their signals collide with each other?

Answer 66

collision domain A network segment where computers have the possibility of having their signals collide with each other is called a collision domain. If too many computers are on a single collision domain, a network can reach a point where it has so many collisions, no computers can actually communicate with each other. Therefore, the goal of a hub-based network is to have as few computers as possible on a single collision domain.

Question 67

subnetting

Answer 67

breaking an IP address range into smaller pieces to be used in more than one network.

Question 68

What protocol is used to assign IP addresses automatically to a host?

Answer 68

DHCP DHCP was first introduced in RFC 1541 in 1993 and was intended as a replacement for the older and less wieldy BOOTP. DHCP assigns IP addresses and IP configurations automatically for the host.

Question 69

What networking device is used to modulate an analog signal in such a way that it can encode digital information?

Answer 69

modem The word modem is short for modulator/demodulator. A modem is a networking device that is used to modulate an analog signal in such a way that it can encode digital information or to demodulate the encoded signal so that it can be decoded back into something a computer can read. Any device used to encode digital information onto analog communication links, regardless of throughput, can rightfully be called a modem.

Question 70

To connect to a wireless network, you would start with what?

Answer 70

SSID of the wireless router SSID (short for Set Service Identifier) acts as the network name for a particular WAP. If you are using multiple WAPs in the same network, they will all need to have the same SSID. In Linksys WAPs, the SSID can be up to 32 characters long.

Question 71

Ethernet is considered \_\_\_\_\_\_\_\_\_\_\_.

Answer 71

baseband Ethernet is what is called a baseband technology. Most modern Ethernet cables have one line for sending signals and another line for receiving signals.

Question 72

What command tests connectivity between two hosts while showing each hop between the two hosts?

Answer 72

tracert The traceroute/tracert utility is used to report back each hop along a route to a specific IP destination.

Question 73

When you use port authentication, what is used to limit access to the network?

Answer 73

MAC addresses Port authentication provides security to the entire network because it limits access via a particular port to pre-authorized MAC addresses.

Question 74

Private Class C IP range

Answer 74

192.168.0.0 - 192.168.X.X

Question 75

Where would you place a web server that will be accessed from the Internet?

Answer 75

DMZ Because a web server that needs to be accessed needs to have some security but should be isolated from the internal network, you should place the web server on the DMZ.

Question 76

hexadecimal

Answer 76

base 16 numbering system that replaces every fourth 1 and 0 with numerals 0-9 or the alphabetic letters A-F

Question 77

What mathematical function is performed on data to ensure that it has not been changed or corrupted?

Answer 77

checksum Before data is sent, a mathematical calculation is done on the data and is sent with the data. When the data is received, the same mathematical calculation is done and the two checksum calculations are compared. If they are the same, the data packet has not been changed or corrupted.

Question 78

Which wireless encryption is considered the weakest?

Answer 78

WEP Available encryption schemes are WPA Enterprise and Personal, WPA2 Enterprise and Personal, RADIUS, and WEP. Of these options, WEP is the weakest.

Question 79

Which core protocol used on the Internet moves data packets from one location on a packet-switched network to another location based on a logical address?

Answer 79

IP The TCP/IP model’s Internet layer is the first layer to have TCP/IP protocol suite–specific protocols. The Internet Protocol (IP) is the most important protocol on this layer and is one of the two protocols used to name the TCP/IP protocol suite.

Question 80

What measurement is used to choose the best route to a specific location?

Answer 80

metrics The purpose of any routing protocol is to compile a table listing all routes known to it so that IP can use the table to find the best route to a specific location. The measurements used by a routing protocol to determine the best routes available to it are called metrics.

Question 81

classful subnet mask for a Class B IP address

Answer 81

255.255.0.0

Question 82

On what OSI layer does a switch operate?

Answer 82

Data-Link Switches, like bridges, work primarily on the Data-Link layer of the OSI model.

Question 83

What mechanism is used to send one set of packets to multiple hosts at the same time?

Answer 83

multicasting IP multicasting is basically an IP host’s capability to send a datagram or data packet to all IP hosts within a host group. A host group consists of all the IP computers currently connected to a particular IP multicast host that are set to receive the same transmission from that host. These host groups can be set to contain 0 or more hosts.

Question 84

What is used to convert digital signals from one frame format to another, specifically to convert Frame Relay into Ethernet signals?

Answer 84

CSU/DSU A Channel Service Unit/Data Service Unit (CSU/DSU) converts a digital signal from one frame format to another. Most commonly, it is used to convert Frame Relay or T-1 signals into Ethernet signals.

Question 85

Which type of routing protocol are RIP and IGRP?

Answer 85

distance vector routing protocol The simplest type of routing protocol is a distance vector routing protocol. Some examples of distance vector routing protocols are RIP, RIPv2, and IGRP. In a distance vector routing protocol, each router periodically sends an update of its routing table to all routers directly connected to it. In this way, periodically the entire network of routers gets updated. The time it takes for this update to take place is called convergence.

Question 86

What type of port ranges from 0 to 1023?

Answer 86

well-known ports The first group is called the well-known ports. Port numbers in this group range from 0–1023. Well-known ports can be assigned only by the Internet Assigned Numbers Authority (IANA). The ports in this range, according to IANA, can be used only by the system or root processes and by programs executed by privileged users.

Question 87

192.130.277.277/8