Q: Both use dialing, but dial-up is based on the telephone system and A: uses analog lines, whereas ISDN and DSL are both digital.. engineer that users are no longer able to access the m
Trang 1What is the biggest difference between packet-switched and circuit-Q:
switched networks?
The biggest difference between packet-switched and circuit-A:
switched networks is that circuit switching requires someone
to configure and set up each individual connection before it is used, where as packet switching allows for dynamic setup and an always-on connection
Why is packet-switching technology so much more desirable? Q:
Packet switching is more desirable than circuit switching because A:
packet switching divides the transmitting data into packets and given sequence numbers so that they can all be put back together again in the right order at the destination The benefit of this is that each packet can take a different route to get to its destination Once there, the message will be recompiled and take its original form Circuit switching does not allow for this kind of flexibility because it is not an always-on switching method
Should I memorize the speeds of WAN protocols for the test? Q:
Understanding the different kinds of WAN protocols and proper-A:
ties, how they differ and why is vital to answering the CompTIA Network+ exam question correctly There will be plenty of questions on the exam that are scenario-based in which you have
to know the speeds of various WAN protocols and properties
Is Frame Relay more flexible compared to FDDI?
Q:
Frame Relay is more flexible than FDDI because if an organization A:
needs to communicate to their remote sites, they can add or take away channels as needed depending on how much bandwidth is required With FDDI, the idea is to provide high-speed service to all stations connected to the ring If you no longer need such services
at one remote site, you cannot change the fixed bandwidth without affecting all sites
What kind of organizations use Optical Carrier (OCx) links?
Q:
The SONET standard defines a hierarchy of interface rates that A:
allow data streams at different rates to be multiplexed (as shown
in Table 8.1) SONET establishes OCx levels from 51.8 Mbps to
40 Gbps OCs are usually implemented for large organizations like ISPs to transmit huge amounts of network traffic while allowing for types of data like voice and video to be sent and received around the world in seconds
Trang 2What is the difference between ADSL and SDSL?
Q:
The difference between ADSL and SDSL is that homes and small
A:
businesses use ADSL whereas larger companies use SDSL due
to the increased upstream and downstream data speeds SDSL
operates at approximately 2 to 2.5 Mbps both downstream and
upstream ADSL generates downstream speeds of approximately
8 Mbps and upstream speeds of up to 640 Kbps
Is ISDN the same thing as dial-up?
Q:
Both use dialing, but dial-up is based on the telephone system and
A:
uses analog lines, whereas ISDN (and DSL) are both digital For the
Network+ exam, you need to have a clear picture of each technology
and its basics, and you must be able to differentiate between them
What is the main difference between a satellite and WWANs?
Q:
The main difference is that satellites use low, medium, and
geosyn-A:
chronous Earth orbit satellites in space to transfer data; whereas
WWANs use antennas on Earth, not in space, to transfer data
SElF TEST
As the primary lead on your company’s helpdesk, you are asked to
1
help resolve a problem call with an ISDN line A customer wants to
upgrade an existing ISDN line because it’s currently too slow Right
now, he is using a single BRI ISDN circuit-switched B channel
From the available choices, what should his transmission rate be?
A 56 Mbps
B 64 Kbps
C 128 Kbps
D 256 Mbps
As the network administrator for your company, you are asked by
2
your CIO to design and deploy a data link between two offices of
your company There are 10 employees located in each office Your
main concerns are the speed of the connections, the reliability
of transferring of data, and the cost Which solution should you
implement? (Choose one)
A Place a modem on a server in each office so they can connect
B Connect an ISDN circuit to each workstation in both locations
Trang 3C Use an ISDN circuit connected to a dedicated location or server
in each building
D Have each workstation at both locations use a modem to connect to opposite offices
You are the IT manager for rsnetworks.net As the person
respon-3
sible for recommending the right technology, what would you select
as the solution to provide the fastest connectivity? (Select one)
A T3
B T1
C ISDN BRI
D Cable modem You want to connect a remote office to a corporate network The
4
only available service is an analog dial-up line provided by the local telephone company What device would you need to implement to use this analog dial-up solution?
A CSU/DSU
B ISDN adapter
C Modem
As the Network Manager for rsnetworks.net, you need to
imple-5
ment a solution that will allow for sporadic connection to the Internet Your only requirement is that you find a solution that will provide a connection of up to 128 Kbps to the Internet, only when needed Which solution should you implement?
A T1
B T3
C 56 Kbps
D BRI ISDN
As a network manager for your company’s high-speed network, you
6
are looking to implement a new line from a remote site (Chicago)
to the company’s core hub (New York) where the mainframe is located The mainframe is where all the company’s sales orders are placed daily The hub site is where all sites get their Internet access from, and where they upload and download files to and from Connection to this mainframe 24 hours a day is essential to meeting the business plan You have just heard from your systems
Trang 4engineer that users are no longer able to access the mainframe from
the remote sites; the users at the core site are still able to access the
mainframe
Within minutes, the connection is restored and all users are
able to access the mainframe once more From careful analysis, you
uncover that during the time that the remote users were not able to
access the mainframe, one user had been downloading a very large
file from the Internet to the remote site user’s PC You find that
the user was downloading a legitimate file and will be doing so each
day You cannot afford this type of network slowdown each day, so
you decide to allow for the upgrading of the line It’s currently at
128 Kbps using ISDN BRI You have found that after careful
analy-sis of the remote sites’ usage patterns and looking over the
docu-mentation of the current network, an upgrade of approximately
1.5 Mbps is needed across all links Which technology would you
implement? (Choose one)
B E1
C LAN adapter
D T1
The PSTN is the analog-based telephone system we have come
7
to be very familiar with today What are some of the features of
PSTN? (Choose all that apply)
A Compared to DSL and ISDN, it is inexpensive
B Worldwide installation base in use and readily available
C Easy to use and configure
D Transfer rates of 64 Kbps
You are a network administrator at your company Your company
8
has a number of sales and marketing users who work remotely and
telecommute from home or from sales meetings These users dial
into a remote access service (RAS) server to access the corporate
headquarters One day, one of the sales users dials up the RAS
server to connect to the corporate headquarters network to access a
few files The sales user dials up the RAS server and cannot
con-nect The sales user reports that there is no dial tone What is the
cause of the problem? (Choose one)
A Telephone company problem
B The modem does not support the PC
Trang 5C The modem settings are set incorrectly.
D There are no settings configured within Windows
You are the network technician at your company You are
configur-9
ing a Windows NT 4.0 laptop for dial-up networking The laptop will be used by a telecommuter The telecommuter will use the laptop to dial into a Microsoft Windows NT 4.0 RAS server Once connected, the telecommuter will need access to a UNIX machine What should you install on the laptop? (Choose two)
A TCP/IP Protocol
D Dial-up networking You are a consultant looking over network documentation for a
10
small company with one core site and two remote sites Router A shows the location of the corporate headquarters where there is also
a link out for Internet access and another remote site configured to also connect to the core From Figure 8.8, what type of WAN tech-nology is in use based on the information shown for Link A?
B T3
C T1
FIGurE 8.8 WAN Technology.
Router A Corporate HQ
Link A Speed � 1.544 Mbps
Link A Router B
Remote Site
Link B
Router C
Remote Site
Trang 6You are the network manager and you just sat down for lunch at your
11
desk You notice that you have to troubleshoot a circuit-switching
network from a note written by your boss Your boss has also placed
a picture of this circuit-switched network on your desk What is the
usual WAN technology associated with circuit-switched networks?
A Internet Services Digital Network
B Integrated Services Digital Netware
C Integrated Services Diagram Network
D Integrated Services Digital Network
What is the difference between ISDN and dial-up?
12
A Both use dialing, but dial-up is based on the WAN and uses
ana-log lines, whereas ISDN (and DSL) are both digital
B Neither use dialing, but dial-up is based on the telephone system
and uses analog lines, whereas ISDN (and DSL) are both analog
C Both use dialing, but dial-up is based on the telephone system
and uses digital lines, whereas ISDN (and DSL) are both digital
D Both use dialing, but dial-up is based on the telephone system
and uses analog lines, whereas ISDN (and DSL) are both digital
You just got hired on to a Mobile Telecommunication Cellular
13
company and your first assignment is to teach your junior network
engineers what WIMAX is What description best describes what
WIMAX is and stands for?
A WIMAX stands for WWW Interoperability for Microwave Access
It is based on IEEE 802.16 standards, or Broadband Wireless
Access An acceptable rule of thumb is that WIMAX will sustain
70 Mbps transmission rates at approximately 15 miles
B WIMAX stands for Worldwide Interoperability for Microwave
Access It is based on IEEE 802.11 standards, or Broadband
Wire-less Access An acceptable rule of thumb is that WIMAX will
sustain 70 Mbps transmission rates at approximately 30 miles
C WIMAX stands for Worldwide Internet for Microwave Access
It is based on IEEE 802.16 standards, or Broadband Wireless
Access An acceptable rule of thumb is that WIMAX will sustain
70 Mbps transmission rates at approximately 15 miles
D WMAX stands for Worldwide Interoperability for Microwave
Access It is based on IEEE 802.16 standards, or Broadband
Wire-less Access An acceptable rule of thumb is that WIMAX will
sustain 70 Mbps transmission rates at approximately 30 miles
Trang 7FIGurE 8.9
What is Figure 8.9 depicting? Choose the best answer
14
A WIMAX similar network
B Satellite-based network
C Wireless Wide Area Network
D Wide Area Network technology
15 How far do LEOs and MEOs orbit above the earth?
A LEOs 1,800 to 2,000 miles; MEOs 1,800 to 2,000 miles
B LEOs 1,800 to 2,000 miles; MEOs 2,000 to 10,000 miles
C LEOs 1,800 to 2,000 miles; MEOs 9,000 to 10,000 miles
D LEOs 9,000 to 10,000 miles; MEOs 9,000 to 10,000 miles
Trang 8SElF TEST quICK ANSwEr KEy
C
1
C
2
A
3
C
4
D
5
D
6
A, B, and C
7
A
8
A and D
9
C
10
D
11
D
12
D
13
B and D
14
C
15
Trang 10Security Standards and Services
ExAM oBJECTIvES IN ThIS ChApTEr
hArdwArE ANd SoFTwArE SECurITy dEvICES 386
INTroduCTIoN
In today’s network infrastructures, it is critical to know the fundamentals
of basic security infrastructure Before any computer is connected to the
Internet, planning must occur to make sure that the network is designed in
a secure manner Many of the attacks that hackers use are successful because
of an insecure network design That is why it is so important for a security
professional to use secure topologies and tools like intrusion detection and
prevention to help thwart attacks
Another security mechanism that may be deployed is a virtual local area
networks (VLANs) VLANs are responsible for securing a broadcast domain
to a group of switch ports This relates directly to secure topologies because
VLANs allow for different Internet Protocol (IP) subnets to be configured in
different port groupings and separated, either by routing or by applying an
access control list (ACL) This allows for separation of network traffic; for
example, the Executive group can be isolated from the general user
popula-tion on a network, which can aid in securing the infrastructure
Test day Tip
An ACL is a list of users that have permission to access a resource or modify a file
ACLs are used in nearly all modern-day operating systems (OSs) to determine what
permissions a user has on a particular resource or file.