Tài liệu TestKing''''s Building Cisco® Remote Access Networks docx

642-821 (BCRAN®)
TestKing's Building Cisco® Remote Access Networks

Version 1.0


642 - 821

Important Note
Please Read Carefully

Study Tips
This product will provide you questions and answers along with detailed explanations carefully compiled and
written by our experts. Try to understand the concepts behind the questions instead of cramming the questions.
Go through the entire document at least twice so that you make sure that you are not missing anything.
Further Material
For this test TestKing plans to provide:
* Interactive Test Engine Examinator. Check out an Examinator Demo at
/>Latest Version
We are constantly reviewing our products. New material is added and old material is revised. Free updates are
available for 90 days after the purchase. You should check your member zone at TestKing an update 3-4 days
before the scheduled exam date.
Here is the procedure to get the latest version:
1. Go to www.testking.com
2. Click on Member zone/Log in
3. The latest versions of all purchased products are downloadable from here. Just click the links.
For most updates, it is enough just to print the new questions at the end of the new version, not the whole
document.
Feedback
Feedback on specific questions should be send to You should state: Exam number and
version, question number, and login ID.

Our experts will answer your mail promptly.
Copyright
Each pdf file contains a unique serial number associated with your particular name and contact information for
security purposes. So if we find out that a particular pdf file is being distributed by you, TestKing reserves the
right to take legal action against you according to the International Copyright Laws.

Leading the way in IT testing and certification tools, www.testking.com
-2-


642 - 821
QUESTION NO: 1
A bank needs to connect a branch office to the corporate network on the other side of town.
The branch office has twelve users that require constant access to the bank’s central accounting system
throughout the day.
Which two connection types may be most appropriate for this branch office? (Choose two)
A.
B.
C.
D.

ISDN BRI
Frame Relay
Asynchronous
Dedicated lease line

Answer: B D
Explanation:
The remote site must have a mix of equipment, but not as much as the Central site requires. Typical WAN
solutions that a remote site uses to connect to the Central site as follows:

• Leased line
• Frame Relay
• X.25
• ISDN
Reference: Building Cisco Remote Access Networks (Ciscopress) page 30
Incorrect Answers
A: Used for telecommuters
C: Used for telecommuters

QUESTION NO: 2
You need to support a mobile sales group who needs access to email from a variety of locations.
What best meets the needs of the sales group?
A.
B.
C.
D.

Digital service
Multi-mode service
Asynchronous service
High-Speed Serial (HSS) interface

Answer: C
Explanation:
An asynchronous dial-up solution using the existing telephony network and an analog modem is often the
solution for telecommuters because it is easy and the telephone facilities are already installed.

Leading the way in IT testing and certification tools, www.testking.com
-3-

642 - 821
Reference: Building Cisco Remote Access Networks (Ciscopress) page 31
QUESTION NO: 3
What are the advantages of Frame Relay connection over dedicated leased lines? (Choose two)
A.
B.
C.
D.

Better suited multiple branch locations.
Lower cost.
More control over the connection.
Full guaranteed bandwidth.

Answer: B, C
Explanation:
Frame Relay provides virtual circuit connectivity for enterprise networks that require 56 kbps up to T1/E1
speeds. It costs less than leased lines because it uses statistical multiplexing of packets to gain efficiencies
within the network, at the cost of a less-stringent bandwidth and latency guarantee. Frame Relay is being widely
deployed in enterprise networks to connect regional and branch offices into the enterprise backbone.
Reference:
/>QUESTION NO: 4
On an EIA/TIA-232 null modem cable with DB25 connectors, which two pins are cross connected?
(Choose two)
A.
B.
C.
D.
E.

F.

Pin 2
Pin 3
Pin 4
Pin 5
Pin 7
Pin 8

Answer: A, B
Explanation:
Null modems crisscross DB-25 pins 2, 3 and other corresponding pins so that the two DTE devices can
communicate. Some devices can be configured to operate either like a DTE or a DCE. Configuring a device as a
DCE usually means that it receives data on pin 2 and transmits data on pin 3.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 62

Leading the way in IT testing and certification tools, www.testking.com
-4-


642 - 821

QUESTION NO: 5
Which WAN connections are typically employed at telecommuter sites? (Choose three)
A.
B.
C.
D.
E.
F.

Asynchronous dial-up
ISDN BRI
Leased lines
HDSL
Cable modems
ADSL

Answer: A B F
Explanation:
Typical WAN connections employed at telecommuter sites are as follows:
• Asynchronous dial-up
• ISDN BRI
• Frame Relay (leased line)
Reference: Building Cisco Remote Access Networks (Ciscopress) page 31
QUESTION NO: 6
Which statement describes the differences between IPSec and Cisco Encryption Technology (CET)?
A.
B.
C.
D.

CET supports AH, ESP and Anti-Replay which are not available with IPSec.
IPSec supports AH, ESP and Anti-Replay which are not available with CET.
CET is the implementation of IPSec in the Cisco Secure Services package.
IPSec is used to encrypt IP-only packets, whereas CET is used to encrypt only non-IP packets.

Answer: B
Explanation:
If you require only Cisco router-to-Cisco router encryption, then you could run CET, which is a more mature,

higher-speed solution.
If you require a standards-based solution that provides multivendor interoperability or remote client
connections, then you should implement IPSec. Also, if you want to implement data authentication with or
without privacy (encryption), then IPSec is the right choice.
Reference:
/>d981b.html#77018

Leading the way in IT testing and certification tools, www.testking.com
-5-


642 - 821
QUESTION NO: 7
When using a CATV cable service as an Internet connection medium, what is “upstream traffic”?
A.
B.
C.
D.

Traffic getting at the user’s home traveling to the headend.
Traffic between the headend and the supplier antenna.
Broadcast traffic, including the cable TV signals.
Traffic from outside the local cable segment serving the user’s home.

Answer: A
Explanation:
In the upstream direction (subscriber cable modems transmitting towards the head-end) the environment is
many transmitters and one receiver. This introduces the need for precise scheduling of packet transmissions to
achieve high utilization and precise power control so as to not overdrive the receiver or other amplifier
electronics in the cable system. Since the upstream direction is like a single receiver with many antennas, the

channels are much much more susceptible to inter-fering noise products [5, 6] . In the cable industry, we
generally call this ingress noise.
..00000000000000
Reference:
/>7c.html
QUESTION NO: 8
Which feature will cache routes learned by dynamic routing protocols, enabling their use over DDR
connections?
A.
B.
C.
D.
E.

Route redistribution
Dynamic static routes
Snapshot routing
DDR route maps
Passive interfaces

Answer: A
Explanation:
On the corporate side, it is very important that you be able to distribute those addresses across the network, as
desired. To redistribute those routes, you need to configure the routes to be redistributed to a dynamic routing
protocol at the core side.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 190

Leading the way in IT testing and certification tools, www.testking.com
-6-

642 - 821

QUESTION NO: 9
Which statement is true regarding the ADSL (G.Lite G.922.2) standard?
A.
B.
C.
D.

Signals cannot be carried on the same wire as POTS signals.
It offers equal bandwidth for upstream and downstream data traffic.
It was developed specifically for the consumer market segment requiring higher download speeds.
It has limited operating range of less than 4,500 feet.

Answer: C
Explanation:
Asymmetric Digital Subscriber Line (ADSL) is designed to deliver more bandwidth downstream (from the
central office to the customer site) than upstream. Downstream rates range from 1.5 to 9 Mbps, whereas
upstream bandwidth ranges from 16 to 640 kbps. ADSL transmissions work at distances up to 18,000 feet
(5,488 meters) over a single copper twisted pair.
Reference: />
QUESTION NO: 10
Which statement is true regarding uninteresting traffic being carried over a DDR link?
A. Uninteresting traffic will keep DDR call established, even if no more interesting traffic is being routed
over the link.
B. Uninteresting traffic will be routed over an established DDR call, but at a lower priority than interesting
traffic.
C. Uninteresting traffic will not be routed over an established DDR call.
D. Uninteresting traffic will be routed over an established DDR call, as long as there is enough interesting

traffic to keep the call connected.
Answer: C
Explanation:
Packets that are permitted entry according to the access list are identified as interesting or packets of interest.
Packets that are not permitted entry or are denied entry by an access list are deemed uninteresting.
Reference:
/>87504.html

Leading the way in IT testing and certification tools, www.testking.com
-7-


642 - 821

QUESTION NO: 11
What is the default action of authentication when AAA is enabled but authentication is not set?
A.
B.
C.
D.
E.
F.

Allow a user to access all resources after login.
Disallow a user from access to all resources after login.
Record all access of resources and how long the user accessed each resources.
Not to record any access of resources after login.
Allow any user to login without checking the authentication data.
Disallow any user from logging in with or without a valid username and password.

Answer: F
Explanation:
If authentication is not specifically set for a line, the default is to deny access and no authentication is
performed.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 470

QUESTION NO: 12
Drag the queuing method from the list on the right to the appropriate description on the right.
Note: not all options will be used.

Answer:

Leading the way in IT testing and certification tools, www.testking.com
-8-


642 - 821

Explanation:
• Custom queuing
– reserves a certain percentage of bandwidth for each specified class of traffic.
• Weighted fair queuing – prioritizes interactive traffics over file transfers to ensure satisfactory
response time for common user applications.
• Basic queuing
– No such thing
• Priority queuing
– ensures the timely delivery of a specific protocol or type of traffic because
that traffic is transmitted before all others.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 399

QUESTION NO: 13
Under which circumstance would use of Kerberos authentication system be required, instead of
TACACS+ or RADIUS?
A.
B.
C.
D.

Authentication, authorization and accounting need to use the a single database.
Multiple level of authorization need to be applied to various router commands.
DES encrypted authentication is required.
The usage of various router functions needs to be accounted for by user name.

Answer: C
Explanation:
Kerberos is a client-server based secret-key network authentication method that uses a trusted Kerberos server
to verify secure access to both services and users. In Kerberos, this trusted server is called the key distribution
center (KDC). The KDC issues tickets to validate users and services. A ticket is a temporary set of electronic
credentials that verify the identity of a client for a particular service.
These tickets have a limited life span and can be used in place of the standard user password authentication
mechanism if a service trusts the Kerberos server from which the ticket was issued. If the standard user
password method is used, Kerberos encrypts user passwords into the tickets, ensuring that passwords are not

Leading the way in IT testing and certification tools, www.testking.com
-9-


642 - 821
sent on the network in clear text. When you use Kerberos, passwords are not stored on any machine, except for
the Kerberos server, for more than a few seconds. Kerberos also guards against intruders who might pick up the

encrypted tickets from the network.
Reference: />
QUESTION NO: 14
Which of the following are examples of DTE devices? (Choose three)
A.
B.
C.
D.
E.

Mainframe computer
CSU/DSU
Router
Terminal
Modem

Answer: A C D
Explanation:
Data terminal equipment (DTE) are end devices such as PCs, workstations, routers, and mainframe computers.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 57

QUESTION NO: 15
When the following configuration is present on the router, how many addresses will be available for
dynamic nat translation?
ip nat pool test 192.168.1.33 192.168.1.42 netmask 255.255.255.224 ip nat inside source list 7 pool test
A.
B.
C.
D.

7
9
10
31

Answer: C
Explanation
The IP address that is configured for dynamic nat translation is 192.168.1.33 19 192.168.1.42 netmask
255.255.255.224
The start-ip is 192.168.1.33
The end-ip is 192.168.1.42

Leading the way in IT testing and certification tools, www.testking.com
- 10 -


642 - 821
Start-ip – starting IP address that defines the range of addresses in the address pool.
End-ip – Ending IP address that defines the range of addresses in the address pool.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 446

QUESTION NO: 16
What is the default encapsulation type set on Cisco router serial interfaces?
A.
B.
C.
D.

Frame Relay
HDLC

PPP
LAPB

Answer: B
Explanation:
HDLC is the default encapsulation type on point-to-point, dedicated links. It is used typically when
communicating between two Cisco devices. It is a bit-oriented synchronous data link protocol. HDLC specifies
a data-encapsulation method on synchronous data links using frame characters and checksums.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 23
QUESTION NO: 17
Which six AAA accounting types will a TACACS+/RADIUS server record?
A.
B.
C.
D.
E.

Network, interface, exec, protocol, system, and resource
Resource, interface, connection, system, command, and network
Command, system, exec, network, connection, and resource
Connection, protocol, system, network, command, and resource
Crypto, system, network, protocol, command, and resource

Answer: C
Explanation:
system - Enables accounting for all system-level events not associated with users, such as reloads
network - Enables accounting for all network-related requests, including SLIP, PPP, PPP network control
protocols, and ARAP
connection - Enables accounting for outbound Telnet and rlogin
exec - Enables accounting for EXEC processes (user shells)

command - level Enables accounting for all commands at the specified privilege level

Leading the way in IT testing and certification tools, www.testking.com
- 11 -


642 - 821

Reference:
/>ml

QUESTION NO: 18
Which two are characteristics of Frame Relay? (Choose two)
A.
B.
C.
D.

Medium cost
High reliability
Circuit-switched
Branch site connectivity

Answer: B, D
Explanation:
Frame Relay provides virtual circuit connectivity for enterprise networks that require 56 kbps up to T1/E1
speeds. It costs less than leased lines because it uses statistical multiplexing of packets to gain efficiencies
within the network, at the cost of a less-stringent bandwidth and latency guarantee. Frame Relay is being widely
deployed in enterprise networks to connect regional and branch offices into the enterprise backbone.
Reference:

/>
QUESTION NO: 19
Which two WAN connections provide a single pre-established switched circuit reserved for the private
use of the customer? (Choose two)
A.
B.
C.
D.
E.

Digital cable
T1 leased line
ISDN
Asynchronous dial-in
56K dedicated line

Answer: C, D
Explanation:

Leading the way in IT testing and certification tools, www.testking.com
- 12 -


642 - 821
Circuit switching is a WAN-switching method, in which a dedicated physical circuit through a carrier network
is established, maintained and terminated for each communication session. Initial signal at the setup stage
determines the endpoints and the connection between the two endpoints.
Typical circuit switched connections are as follows:
• Asynchronous serial
• Integrated Service Digital Network (ISDN), Basic Rate Interface (BRI), and ISDN Primary rate

Interface (PRI)
Reference: Building Cisco Remote Access Networks (Ciscopress) page 20 21

QUESTION NO: 20
Which three are responsible of IKE in the IPSec protocol? (Choose three)
A.
B.
C.
D.
E.
F.

Negotiating protocol parameters
Packet encryption
Exchanging public keys
Integrity checking user hashes
Authenticating both sides of a connection
Implementing tunnel mode

Answer: A, C, E
Explanation:
IKE is a protocol used by IPSec for completion of Phase 1. IKE negotiates and assigns SAs for each
IPSec peer, which provide a secure channel for the negotiation of the IPSec SAs in Phase 2. IKE provides
the following benefits:
• Eliminates the need to manually specify all the IPSec security parameters at both peers
• Lets you specify a lifetime for the IKE SAs
• Allows encryption keys to change during IPSec sessions
• Allows IPSec to provide anti-replay services
• Enables CA support for a manageable, scalable IPSec implementation
• Allows dynamic authentication of peers

Reference:
/>7278c.html#39982

QUESTION NO: 21

Leading the way in IT testing and certification tools, www.testking.com
- 13 -


642 - 821
Frame Relay describes the interconnection process between which two types of equipment?
A.
B.
C.
D.

DTE and DTE
DCE and DCE
CPE and DTE
CPE and DCE

Answer: D
Explanation:
Frame relay defines the interconnection process between your customer premises equipment (CPE- also known
as data terminal equipment [DTE]) such as a router, and the service provider’s local access-switching
equipment (known as data communications equipment [DCE]).
Reference: Building Cisco Remote Access Networks (Ciscopress) page 340

QUESTION NO: 22
Drag and drop the ISDN in the options column to the related term in the target column.

Answer:

Leading the way in IT testing and certification tools, www.testking.com
- 14 -


642 - 821

Explanation:
U interface
TE1
R interface
S/T interface
TE2

– defines the two-wire interface between the NT and the ISDN cloud.
– designates a device that is compatible with the ISDN network.
– defines the interface between the TA and an attached non-ISDN device (TE2).
– is a four-wire interface (TX and RX).
– designates a device that is not compatible with ISDN and requires a terminal adapter.

Reference: Building Cisco Remote Access Networks (Ciscopress) page 171-173

QUESTION NO: 23
What is a benefit of choosing an Internet-based VPN over a point-to-point T1 connection?
A.
B.
C.
D.

VPNs offer more local control of the quality of service.
VPN users are not tied to a specific fixed location.
VPNs can provide reserved bandwidth for the individual user.
VPNs offer better queuing mechanisms than T1 connections.

Answer: B
Explanation:
VPNs enables today’s increasingly mobile workforce to connect to their corporate intranets or extranets
whenever, wherever, or however they require; improving productivity and flexibility while reducing access
costs.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 561

QUESTION NO: 24

Leading the way in IT testing and certification tools, www.testking.com
- 15 -


642 - 821
An Internet Service Provider is offering ADSL connections to its customers, providing 640 kbps upload
and 4 Mbps download speeds.
Which customers would benefit from this type of connection? (Choose two)
A.
B.
C.
D.

Small home offices requiring 24 hour connection to the Internet for email and web communication.
Web services companies providing dynamic web content serving, including video-on-demand.

Central data processing facilities receiving simultaneous uploads of data from remote offices.
Support organizations providing ftp services for software distribution and documentation.

Answer: A, C
Asymmetric Digital Subscriber Line (ADSL) is designed to deliver more bandwidth downstream (from the
central office to the customer site) than upstream.
The remote sites using ADSL would benefit this for the downloading of data from the Central data processing
facility.
Reference: />
QUESTION NO: 25
Which of the following terminals can be connected to an ISDN line? (Choose two)
A.
B.
C.
D.

TO2
TE1
TE2/TA
NU1

Answer: B, C
Explanation:
Terminal equipment 1(TE1) - Designates a device that is compatible with the ISDN network. A TE1 connects
to a Network Termination of either Type 1 or Type 2, such as a digital telephone, a router with ISDN interface,
or digital facsimile equipment.
Terminal equipment 2(TE2) - Designates a device that is not compatible with the ISDN and requires a
terminal adapter, such as terminals with X.21, EIA/TIA-232, or X.25 interfaces or a router without a ISDN
interface (AGS= and so on).
Terminal adapter – converts standard electrical signals into the form used by ISDN, so that non-ISDN devices

can connect to the ISDN network.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 171

Leading the way in IT testing and certification tools, www.testking.com
- 16 -


642 - 821
QUESTION NO: 26
Which two statements about Frame Relay subinterface configurations are true? (Choose two)
A.
B.
C.
D.

Any IP address must be removed from the subinterface.
Subinterface is configured either multipoint or point-to-point.
The physical interface and subinterface can each be configured with IP addresses.
The configuration must be added to the D channel.

Answer: B
Explanation:
Reference: Building Cisco Remote Access Networks (Ciscopress) page 353 354
QUESTION NO: 27
When configuring an asynchronous line, what is the result of issuing the flowcontrol hardware
command?
A.
B.
C.
D.

It sets RAM aside to buffer incoming and outgoing data.
It sets the line to use CTS/RTS flow control.
It sets the modem to handle flow control instead of the router.
It sets the modem to use MNP4 firmware.

Answer: B
Explanation:
flowcontrol hardware – Uses RTS/CTS for flow control.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 77

QUESTION NO: 28
Which statements are true regarding the command telnet 10.10.30.4 2009? (Choose two)
A.
B.
C.
D.

It is used to reverse Telnet connection.
It is used to Telnet to port 2009 on a specific computer.
A modem is connected to line 9.
It specified a BRI connection to be used for Telnet.

Answer: B, C

Leading the way in IT testing and certification tools, www.testking.com
- 17 -


642 - 821

Explanation:
Answer B. Telnet protocol uses 2000 base TCP port for individual lines.
Answer C. TTY lines 1 through 24 directly connect to modems 1/0 through 1/23, which are installed in the first
chassis slot in this example. The TTY lines 25 through 48 directly connect to modems 2/0 through 2/23, which
are installed in the second slot.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 70
/>ca657.html

QUESTION NO: 29
When using PPPoE to communicate over a DSL service connection, which process must be performed by
the host to establish a PPPoE SESSION_ID?
A.
B.
C.
D.

A Bootp process to request a configuration and session ID.
A Discovery process to identify a PPPoE server and request a session ID.
A DHCP request process to request and IP address and session ID.
A RARP request process to request a MAC address and session ID.

Answer: B
Explanation:
When a host wishes to initiate a PPPoE session, it must first perform discovery to identify the Ethernet MAC
address of the peer and establish a PPPOE SESSION_ID. Although PPP defines a peer-to-peer relationship,
discovery is inherently a client/server relationship. In the discovery process, a host (the client) discovers an
access concentrator (the server). Based on the network topology, there may be more than one access
concentrator that the host can communicate with. The Discovery Stage allows the host to discover all access
concentrators and then select one. When discovery is completed, both the host and the selected access
concentrator have the information they will use to build their point-to-point connection over Ethernet.

Reference:
/>
QUESTION NO: 30
Which physical factors can reduce the maximum speed available on a DSL connection? (Choose two)
A. Lack of loading coils and the subscriber’s line.
B. Distance from the CPE to the DSLAM.
C. Gauge of wire used on the local loop.

Leading the way in IT testing and certification tools, www.testking.com
- 18 -


642 - 821
D. Number of telephones attached to the local loop.
E. Lack of bridge taps in the local loop.
Answer: D, E
Determine if the local loop is too long. The maximum length range is 15,000 to 25,000 feet (4572 to
7620 meters). Within that range, wire gauge, cross talk, and multiple bridge taps reduce the distance over which
the modems can train.
Reference:
/>fb.html

QUESTION NO: 31
A network administrator would like to use an existing ISDN line as a backup for a Frame Relay line
connected on interface serial0.
Which statement is correct based on the following configuration of the Cisco Router?
interface serial0
ip address 192.168.10.1 255.255.255.0
backup interface bri0
backup delay 5 10

interface bri0
ip address 192.168.11.2 255.255.255.0
dialer idle-timeout 900
dialer-group 1

dialer-group 1 protocol ip permit
A. ISDN BRI line will be in “standby” mode after 900 seconds once the serial interface activates again.
B. ISDN BRI line will be in “standby” mode after 10 seconds once the serial interface activates again.
C. ISDN BRI line will be in “standby” mode after 10 seconds but will be in “standby” mode after 900
seconds once the serial interface activates again.
D. ISDN BRI line will be in “standby” mode after 10 seconds but will be in “up/ip” mode after 900 seconds
once the serial interface activates again.

Leading the way in IT testing and certification tools, www.testking.com
- 19 -


642 - 821

Answer: C
Explanation:
- backup delay 5 10 command:
backup delay enable-delay disable-delay
Specify delay between the physical interface going down and the backup being enabled, and between the
physical interface coming back up and the backup being disabled.
- dialer idle-timeout 900
This command specifies the time that the line can remain idle before it is disconnected.
Reference:
/>8721f.html

QUESTION NO: 32
Which three of the following router IOS commands defines “interesting” traffic for only one host using
dial on command routing (DDR) (Choose three)
A.
B.
C.
D.
E.
F.

RTA(config)#dialer-list 1 protocol ip permit 10.1.1.1
RTA(config)#access-list 2 permit host 192.168.1.12
RTA(config-if)#dialer-group 1
RTA(config)#dialer-group 2
RTA(config)#dialer-list 1 protocol ip list 2
RTA(config-if)#dialer-list 2 protocol ip permit

Answer: A B E
Explanation:
Define what constitutes interesting traffic by using the dialer-list command.
The access-list command specifies interesting traffic that initiates a DDR call.
These commands are assigned on the global configuration line.
The dialer-group command needs to be assigned to the interface responsible for initiating the call.
Reference: Building Cisco Remote Access Networks (Ciscopress) page 188

QUESTION NO: 33
Which command will change the specified Frame Relay encapsulation for a specific PVC on an interface?
A. no frame-relay encapsulation ietf

Leading the way in IT testing and certification tools, www.testking.com
- 20 -