CIS 321 Data Communication and Networking Exam 2 Study Guide
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
