CIS 321 Data Communication and Networking Exam 2 Study Guide

Réussis tes devoirs et examens dès maintenant avec Quizwiz!

A router will discard a packet if the TTL value reaches ________.

0

Cat 5e and Cat 6 wiring can carry Ethernet traffic 100 meters up to ________.

1 Gbps

What are some frequency dependent wireless propagation problems?

1. Higher-frequency waves suffer more rapidly from absorptive attenuation than lower-frequency waves because they are absorbed more rapidly by moisture in the air, leafy vegetation, and other water-bearing obstacles. 2. Shadow zone problems grow worse with frequency because radio waves are less able to go through and bed around objects at higher frequencies.

What are 5 common wireless propagation problems?

1. Inverse square law attenuation - because radio signals are not traveling through wires or optical fibers, they tend to attenuate more rapidly. 2. Absorptive attenuation - when radio signals are partially absorbed by the air molecules, plants, and other things it passes through. 3. Shadow zones (dead spots) - when large or dense objects prevent signals from reaching the receiver 4. Multipath interference - most serious propagation problem for WLAN frequencies that happens when strong and weak signals reach a receiver and cancel each other out. 5. Electromagnetic interference (EMI) - Interference caused by devices like cordless telephones, microwaves, and devices on other nearby wireless networks.

In which frequency band can NFC operate?

13.56 kHz

In the mask /14, how many 1s are there?

14

For full-duplex transmission, optical fiber normally uses ________.

2 strands

Bluetooth uses the ________ service band.

2.4 GHz

Which unlicensed band is defined the same way in most countries around the world?

2.4 GHz

If I simplify the address 2001:0000:0000:00fe:0000:0000:0000:cdef, I get ________.

2001:::fe::cdef

Row 2707 has the mask /16 and the speed metric 20. Row 4400 has the mask /16 and the speed metric 10. Which row will the router choose if both are matches?

2707

In the UTP wiring used in LANs, how many wire pairs are there in a cord?

4

The main version of Internet Protocol in use today is IP version ________.

4

What are the diameters of multimode fiber?

50 microns and 62.5 microns

In the 5 GHz band, how many channels can you have with 802.11ac with 80 GHz channels?

6

In Bluetooth, a master can have up to ________ slaves at any moment.

7

In the UTP wiring used in LANs, how many wires are there in a cord?

8

Develops standards used in multiple working groups, for instance, security standards

802.1 Working Group

Creates the wireless LAN standards

802.11 Working Group

Which of the following brings gigabit speeds to clients? A. 802.11ac B. 802.11g C. 802.11n D. None of the above

802.11ac

Which of the following can operate in the 5 GHz band? A. 802.11g B. 802.11ac C. Both A and B D. Neither A nor B

802.11ac

If an 802.11n access point and an 802.11g client communicate, they communicate using ________.

802.11g

'802.1X needs security between the authenticator and the computer in ________.'

802.11i

Out of WPA and 802.11i, which has the stronger security?

802.11i

What is the strongest security protocol for 802.11 today?

802.11i

advanced form of 802.11 wireless LAN security

802.11i (WPA2)

Compared with WPA, 802.11i is attractive because ________.

802.11i offers stronger security

For which standard is 300 Mbps a typical rated speed?

802.11n

The standard for roaming among access points is ________.

802.11r

The ________ standard was created to prevent attackers from walking in and simply plugging a computer into a wall jack and therefore accessing the network.

802.1X

In what mode of 802.11i operation is a central authentication server used?

802.1X mode

What 802 Working Group creates Ethernet standards?

802.3

Creates Ethernet standards

802.3 Working Group

For wireless backup, which of the following is adequate? A. 802.11ac B. 802.11g C. 802.11n D. All of the above

A. 802.11ac

What propagation problem becomes worse as frequency increases?

Absorptive attenuation

consists of an access point and the set of hosts it serves

Basic service set (BSS)

Has two states (conditons), where one state represents 0 and the other represents 1.

Binary signaling

Bluetooth is standardized by the ________.

Bluetooth Special Interest Group

Out of CSMA/CA+ACK and RTS/CTS, which is more efficient?

CSMA/CA+ACK

Which UTP quality levels can send signals at 10 gigabits per second?

Category 6 and Category 6A

What type switch connects switches to other switches?

Core switches

What is Wi-Fi Protected Setup and what are the risks?

Created by the Wi-Fi Alliance, it is an easy way to add a new client to a WPA2 pre-shared key mode access point. The PIN is divided into two 4 digit halves and will notify a user when the first half is correct, This cuts the time it takes to crack the second half of the PIN substantially.

Has few states. Also, because each state represents a certain number of bits, the number of states is always a multiple of two.

Digital signaling

What is the Ethernet fram called?

Ethernet media access control (MAC) fram

When a WLAN is in use, the distribution system is the ________.

Ethernet network

Single switched networks taht use standards at the physical layer and the data link layer

Ethernet networks

There is a row for each address in a(n) ________.

Ethernet switch table

A(n) ________ must find the best-matching row in its ________ table by comparing several row matches.

Ethernet switch, switching router, routing

Group of BSSs that are connected to the same distribution system (network) and have the same SSID

Extended service set (ESS)

A TCP ________ segment is a request to close a connection.

FIN

Four-way closes use ________ segments.

FIN

True or False. The presence of a client that is distant from the access point reduces the individual throughput of other clients served by that access point.

False

True or False. Binary transmission is not a type of digital signaling. All digital signaling, however, is binary signaling.

False. Binary transmission is a type of digial signaling. Not all digital signaling, however, is binary signaling.

Which Bluetooth profile would a tablet use with a Bluetooth keyboard?

Human interface device profile

________ is used for supervisory messages at the internet layer.

ICMP

Using two or more trunk lines to connect a single pair of switches. This allows you to increase trunk speed incrementally, by a factor of two or three, instead of by a factor of ten.

IEEE- link aggregation; Networking professionals - bonding

What does a router do with ARP request messages?

It broadcasts them

A company has more control over its ________ technology.

LAN

Modal bandwidth is a fiber quality measure for ________ fiber.

LAN

How can you reduce attenuation?

Limit cord distance to 100 m

How can you reduce terminal crosstalk interference?

Limit the untwisting of the wires in each pair to 0.5 in when placing them in RJ-45 connectors.

standards beyond 802.11g use this technique to achieve speeds far more than increasing bandwidth alone can provide

MIMO

What are the parts of an IP address?

Network, subnet, and host

The most common standard for extended 802.1X security is ________.

PEAP

In 802.11i ________, hosts must know a shared initial key.

PSK mode

At what layer is the 100BASE-TX standard?

Physical

WPS is applicable to ________.

Preshared key mode

________ are interior dynamic routing protocols.

RIP, OSPF, and EIGRP

The standard connector at the end of a UTP cord

RJ-45 connector

In ________, when a wireless host wishes to send, it first sends a message to the wireless access point asking for permission to send. When the access point sends back a response, the host sending the original message may transmit. All other hosts must wait.

RTS/CTS

Standard to detect and break loops in Ethernet networks

Rapid Spanning Tree Protocol (RSTP)

The ________ is the identifier in a basic service set.

SSID

identifies the access point

Service set identifier (SSID)

What can be used to centrally manage remote access points?

Smart access points and WLAN switches

Out of TCP and IP, which is reliable?

TCP

Out of TCP and UDP, which is more reliable?

TCP

________ operate at the transport layer.

TCP and UDP

At the beginning of a telephone call placed through a Bluetooth headset with the Hands-Free Profile, which device is initially the master?

The Bluetooth headset.

Who created WPA?

The Wi-Fi Alliance

What happens if two nearby access points use the same channel?

They will interfere with each other

What are the characteristics of 1000BASE-T?

Transmission speed: 1 Gbps UTP Quality Category: Category 5e, 6, or higher Maximum Cord Length: 100 meters

What are the characteristics of 10BASE-T

Transmission speed: 10 Gbps UTP Quality Category: Category 6 and Category 6A Maximum Cord Length: Cat 6 - 55 meters Cat 6A - 100 meters

What are the characteristics of 100BASE-TX?

Transmission speed: 100 Mbps UTP Quality Category: Category 5e, 6, or higher Maximum Cord Length: 100 meters

Which protocols are connectionless?

UDP and IP

Network cordd that contains four twisted pairs of wire within a sheath

Unshielded Twisted Pair (UTP)

Which of the following can increase reliability considerably in an Ethernet LAN?

Using the Rapid Spanning Tree Protocol

________ secures communication all the way between the wireless computer and the server it is communicating with.

VPNs

Groups of clients and servers that are allowed ot communicate with each other but not with clients or servers on others

Virtual LANs (VLANs)

What security protocol originally came with 802.11 equipment?

WEP

What does the Wi-Fi Alliance call 802.11i?

WPA2

What are Denial of Service attacks?

When the attacker overloads an access point or causes a client to disassociate from an access point.

permits direct transmission between two 802.11 devices without using an access point

Wi-Fi Direct

Weak security mechanism for 802.11

Wired Equivalent Privacy (WEP)

802.11 security method created as a stopgap between WEP and 802.11i

Wireless Protected Access (WPA)

If a radio transmission is easily blocked by obstacles, then you need to maintain ________.

a clear line of sight

The total range of possible 802.11 WLAN frequencies in the 2.4 GHz band constitutes ________.

a frequency spectrum

When a host moves from one wireless access point to another in a WLAN, this is ________.

a handoff or roaming

The Ethernet data field contains ________.

a packet

An Ethernet switch knows ________.

a single port number for each MAC address

In the Shannon Equation, if you quadruple the bandwidth in a channel while the signal-to-noise ratio remains the same, you can transmit ________.

about 4 times as fast

In optical fiber, attenuation due to the absorption of signal strength as a signal propagates

absorptive attenuation

The principal distance limiting factor for carrier fiber is ________.

absorptive attenuation

Media access control governs transmission by ________.

access points and wireless hosts

In a routing table, the default row ________.

always has the mask /32 and will always match the IP address of an incoming packet

Intensity of a wave

amplitude

Cellular telephony uses ________.

an omnidirectional antenna

Weaking of a signal's strength during propagation

attenuation

signals spread over a range of frequencies and can be measured by subtracting the lowest frequency from the highest

bandwidth

in radio transmission, directing energy toward a wireless device without using a dish antenna

beamforming

channels with large bandwidths

broadband

Businesses can select multimode fiber to transmit 1000BASE-SX signals farther by ________.

buying fiber with higher modal bandwidth

How do you determine UTP cable quality?

category number ex. Cat 5e, Cat 6, etc.

In the 60 GHz service band, ________.

channel bandwidth can be very wide

subdivided frequency ranges of service bands

channels

Thin glass cylinder that surrounds the core

cladding

Period of time during which a transmission line's state is held constant

clock cycle

Companies must use carriers for WAN transmission because ________.

companies lack rights of way

The first Step in the Routing process involves ________.

comparing the packet's destination IP address to all rows

VLANs address the problem of ________.

congestion

In optical fiber, light travels through the ________.

core

Thin glass strand of glass that optical fiber carries light signals through

core

Switches that connect switches to other switches

core switches

Managed switches ________.

decrease overall costs

ARP is used to find the destination data link layer destination addresses of ________.

destination hosts and routers

Creating effective backup links in RSTP is ________.

difficult and time consuming

Beamforming can allow an access point to ________.

direct power to individual clients and send signals to two different clients at the same time

point in a particular direction, which allows them to focus stronger outgoing signals in that direction for the same power to receive weaker incoming signals from that direction

dish antennas

network to which access points connect

distribution system

Breaking into WLANs is ________.

drive-by hacking

Pinging sends ICMP ________ messages to the target host.

echo

To see if a target host can be reached, you normally would send it an ICMP ________ message.

echo

The Wi-Fi Alliance refers to 802.1X mode as ________ mode.

enterprise

Compared to normal routing, decision caching is ________.

faster

A denial-of-service attack against a wireless network can be implemented by ________.

flooding the network with traffic and sending disassociate commands to clients

Used to describe the radio waves used in WLANs

frequency

Consists of all possible frequencies from zero hertz to infinity

frequency spectrum

WPA ________.

has been partially cracked

Measurement used to describe one cycle per one second

hertz (Hz)

Managed access points should ________.

identify rogue access points and be able to push updates out to access points

In 802.11 networks, the speed I receive on my portable devices is a(n) ________.

individual throughput

CSMA/CA+ACK is ________.

inefficient

Routers send packets out ________.

interfaces

Spread spectrum transmission is used in WLANs because ________.

it is required by regulators

Ethernet is inexpensive thanks to ________.

its hierarchical topology

Operate entirely on the custumer premises - an office suite, offfice building, or other property owned by the corporation that can connect hundreds of hosts throughout a building.

local area networks (LANs)

Ethernet became the dominant LAN technology because of its ________.

low cost, compared with competing technologies

In the Shannon Equation, C is the ________.

maximum possible speed of transmission in a channel

Type of WAN limited to a large city and its surrounding communities

metropolitan area network (MAN)

How do you determine LAN fiber quality?

modal bandwidth experessed in MHz-km

Modes entering the core at higher angles will take longer to travel than straight modes

modal dispersion

When the light energies of two pulses arrive at overlapping times, this is ________.

modal dispersion

Light rays entering the fiber at different angles

modes

Modal dispersion limits transmission distance in ________.

multimode fiber

Simultaneous transmission in a single channel by multiple devices that are using a single access point

multiuser MIMO

channels with small bandwidths

narrowband

Circuitry that implements Ethernet

network interface card (NIC)

Random energy in copper wires that adds or subtracts from signals.

noise

Transmit signals equally strongly in all directions and receive incoming signals equally well from all directions

omnidirectional antennas

Mesh networking in 802.11 is likely to use ________.

only wireless devices

Ethernet signalling standard where more than one pair of wires carrying transmission bits

parallel transmission

When a light ray hits the boundary between the core and cladding and it reflects back into the core

perfect internal reflection

standard can bring power to RJ-45 wall jacks, limited to 25 Watts of power

power over Ethernet (POE)

Determines when two frames arraive at a switch at the same time which will be sent out first

priority

Travelling of signals down the transmission link to the device at the other end of the physical link

propagation

A LAN is a network that ________.

provides service within a site

An unauthorized internal access point is a(n) ________.

rogue access point

Dynamic ________ protocols allow routers to transmit routing table information to one another.

routing

When a router forwards incoming packets closer to their destination hosts, this is ________.

routing

Transmitting over a single pair of wires

serial transmission

division of the frequency spectrum into contiguous spectrum ranges that are dedicated to specific services

service bands

What factors can be used to increase speed in signaling?

shorter clock cycles and more states

transmission that uses far wider channels than transmission speed requires

spread spectrum transmission

Untwisting wire pairs no more than 1.25 cm (a half inch) at their ends reduces ________.

terminal crosstalk interference

The main benefit of IPv6 over IPv4 is ________.

the ability to support more possible hosts

Two Bluetooth devices will peer ________.

the first time they connect

In TCP/IP, routing means ________.

the process that routers use to forward incoming packets and the process that routers use to exchange routing table information.

Passive RFID chips are powered by ________.

the signal sent by the device querying the RFID chip

In LANs, optical fiber typically is used in ________.

trunk lines

In binary signaling there is (are) ________ state(s).

two

To drive around a city looking for working access points that are unprotected is ________.

war driving

Distance between successive wave heights, troughs, starts, staops and so forth that are measured in nanometers

wavelength

Operate outside the customer premises that connect different sites within an organization or transmit data between organizations.

wide area networks (WANs)

Use radio for physical layer transmission on the customer premises

wireless local area networks (WLANs)

Switches that connect hosts to the network

workgroup switches

In unlicensed bands, ________.

you can use radios wherever you please


Ensembles d'études connexes

Integrated Marketing Communication

View Set

Machine Learning Interview Questions, Machine Learning General

View Set