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642-821 (BCRAN®) TestKing's Building Cisco® Remote Access Networks Version 9.0 642 - 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 exam TestKing also provides: * Online Testing Practice the questions in an exam environment Try a demo: http://www.testking.com/index.cfm?pageid=724 * Study Guide Concepts and labs Provides a foundation of knowledge (Released shortly) 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: Go to www.testking.com Click on Member zone/Log in 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 feedback@testking.com 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 Note: Section A contains 124 questions Section B contains 111 questions The total number of questions is 235 Each section starts with QUESTION NO :1 There are no missing questions Section A QUESTION NO: 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: A remote site, or branch office, is a small-site connection to a campus over a WAN A remote site typically has fewer users than the central site and therefore needs a smaller-size WAN connection Remote sites connect to the central site and to some other remote site offices Telecommuters may also require access to the remote site A remote site can use the same or different media Remote site traffic can vary, but is typically sporadic The network designer must determine whether it is more cost effective to offer a permanent or dialup solution The remote site must have a variety of equipment, but not as much as the central site requires Typical WAN solutions a remote site uses to connect to the central site follow: * Leased line * Frame Relay * X.25 * ISDN As the keyword is here : "Constant Access" We don't need and dialup solution (ISDN or Asynchronous) As it would be to costly to keep the line up the entire day Leading the way in IT testing and certification tools, www.testking.com -3- 642 - 821 Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 2-25 QUESTION NO: 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: As WAN technologies improve, allowing many employees to their jobs almost anywhere, the growth in the number of telecommuter and small company sites has exploded Like that of central and remote sites, the telecommuter site must determine its WAN solution by weighing cost and bandwidth requirements An asynchronous dialup solution using the existing telephony network and an analog modem is often the solution for telecommuters because it is easy to set up and the telephone facilities are already installed As usage and bandwidth requirements increase, other remote access technologies should be considered The nonstationary characteristics of a mobile user make an asynchronous dialup connection the remote solution Employees on the road can use their PCs with modems and the existing telephone network to connect to the company Typical WAN connections employed at telecommuter sites are: * Asynchronous dialup * ISDN BRI * Frame Relay (if the user utilizes the link for an extended time, like half the day) * (A)DSL Typical considerations for a remote site WAN connection follow: * Cost * Authentication * Availability Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 2-27 QUESTION NO: Leading the way in IT testing and certification tools, www.testking.com -4- 642 - 821 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: A, B 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: http://www.cisco.com/en/US/products/hw/modules/ps2033/products_white_paper09186a0080091ca9.shtml QUESTION NO: Leading the way in IT testing and certification tools, www.testking.com -5- 642 - 821 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 Pin Pin Pin Pin Pin Answer: A, B Explanation: When two DTE devices (for example, an access server and a terminal) are near each other, it makes sense to connect them directly without going through a telephone network and two modems An ordinary EIA/TIA-232 cable will not work in this case because both DTE devices transmit on the TxD lead (pin 2), and both expect input on the RxD lead (pin 3) A “null modem cable” is required for the DTE-to-DTE connection Null modems crisscross DB-25 pins and and other corresponding pins (as shown in the figure) 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 and transmits data on pin For example, many serial printers are configured as DCE devices so they can be connected directly to a DTE (for example, a PC or a terminal server) with an ordinary EIA/TIA-232 cable, eliminating the need for a null modem Leading the way in IT testing and certification tools, www.testking.com -6- 642 - 821 connection Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 4-10 QUESTION NO: 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: As WAN technologies improve, allowing many employees to their jobs almost anywhere, the growth in the number of telecommuter and small company sites has exploded Like that of central and remote sites, the telecommuter site must determine its WAN solution by weighing cost and bandwidth requirements An asynchronous dialup solution using the existing telephony network and an analog modem is often the solution for telecommuters because it is easy to set up and the telephone facilities are already installed As usage and bandwidth requirements increase, other remote access technologies should be considered The nonstationary characteristics of a mobile user make an asynchronous dialup connection the remote solution Employees on the road can use their PCs with modems and the existing telephone network to connect to the company Typical WAN connections employed at telecommuter sites are: * Asynchronous dialup * ISDN BRI * Frame Relay (if the user utilizes the link for an extended time, like half the day) * (A)DSL Typical considerations for a remote site WAN connection follow: * Cost * Authentication * Availability Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 2-27 Leading the way in IT testing and certification tools, www.testking.com -7- 642 - 821 QUESTION NO: 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: Cisco Encryption Technology (CET) is a proprietary security solution introduced in Cisco IOS Release 11.2 It provides network data encryption at the IP packet level and implements the following standards: • • • Digital Signature Standard (DSS) Diffie-Hellman (DH) public key algorithm Data Encryption Standard (DES) IPSec is a framework of open standards developed by the Internet Engineering Task Force (IETF) that provides security for transmission of sensitive information over unprotected networks such as the Internet It acts at the network level and implements the following standards: • IPSec • Internet Key Exchange (IKE) • Data Encryption Standard (DES) • MD5 (HMAC variant) • SHA (HMAC variant) • Authentication Header (AH) • Encapsulating Security Payload (ESP) IPSec services provide a robust security solution that is standards-based IPSec also provides data authentication and anti-replay services in addition to data confidentiality services, while CET provides only data confidentiality services 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 Leading the way in IT testing and certification tools, www.testking.com -8- 642 - 821 Reference: http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_configuration_guide_chapter09186a00800 d981b.html#77018 QUESTION NO: 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: From an IP perspective, a CATV system almost appears to be another data link layer However, experience gained thus far has demonstrated that the marriage of IP over CATV radio frequency (RF) channels is not as straightforward as IP over any other high-speed serial point-to-point link In the CATV space, the downstream channels in a cable plant (cable head-end to subscribers) is a point-tomultipoint channel This does have very similar characteristics to transmitting over an Ethernet seg-ment where one transmitter is being listened to by many receivers The major difference is that baseband modulation has been replaced by a more densely modulated RF carrier with very sophisticated adaptive signal processing and forward error correction (FEC) 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 In the cable industry, we generally call this ingress noise As ingress noise is an inherent part of CATV plants, the observable impact is an unfortunate rise in the average noise floor in the upstream channel To overcome this noise jungle, upstream modulation is not as dense as in the downstream and we have to use more effective FEC as used in the downstream There is a further com-plication that there are many upstream “ports” on a fully deployed Hybrid Fiber-Coaxial (HFC) plant that requires matching head-end equipment ports for high-speed data Reference: http://www.cisco.com/warp/public/759/ipj_1-3/ipj_1-3_catv.html QUESTION NO: Which feature will cache routes learned by dynamic routing protocols, enabling their use over DDR connections? Leading the way in IT testing and certification tools, www.testking.com -9- 642 - 821 A B C D E Route redistribution Dynamic static routes Snapshot routing DDR route maps Passive interfaces Answer: A Explanation: In this example we have configured the remote leaves and their static routes are established, on the corporate side it is very important that we be able to distribute those addresses across the network as desired To redistribute those routes we need to configure the routes to be redistributed to a dynamic routing protocol at the core side The example in the figure shows we are using the Interior Gateway Routing Protocol (IGRP) as the dynamic routing protocol and will redistribute the static routes using the redistribute static command In this example, the router advertises that it knows the route to the 192.150.42.0 network Leading the way in IT testing and certification tools, www.testking.com - 10 - 642 - 821 Answer: E Explanation: The figure illustrates the cable connections available for the various WAN types No1 Asynchronous connectionsAsynchronous connections require RJ-11 cables attached from the modem’s line port to the telephone company jack If you are using an external modem attached to a Cisco router, you must also use a Cisco Electronic Industries Association/Telecommunications Industry Association (EIA/TIA)232 cable to attach the modem to the router’s serial interface The DB-60 end of the cable connects to the router The DB-25 end attaches to the modem No2 ISDN BRIISDN BRI connection interfaces require RJ-45 cables to connect the BRI interface to the ISDN network The BRI modules and BRI WAN interface cards are available with either an S/T interface that requires an external NT1, or a U interface with a built-in NT1 No3 ISDN PRI (North America)Channelized T1 (CT1)/PRI modules are available with or without a built-in CSU If you use an external CSU, attach a female DB-15 cable to the router’s interface The other end of the straightthrough cable will attach to the CSU, which in turn attaches to the ISDN network Routers with internal CSU modules attach directly to the ISDN network with a standard RJ-48 connector Leading the way in IT testing and certification tools, www.testking.com - 227 - 642 - 821 No4 ISDN PRI (Europe)Channelized E1 (CE1)/PRI modules are available with balanced and unbalanced interfaces CE1/PRI-balanced modules provide a 120-ohm E1 interface for network connections The unbalanced modules provide a 75-ohm E1 interface for network connections Four serial cables are available from Cisco for the CE1/PRI module All four cables have DB- 15 connectors on the router end and DNC, DB15, twinax, or RJ-45 connectors on the network end No5 Frame RelayIf you must establish a Frame Relay serial connection, Cisco routers support the following signaling standards: EIA/TIA-232, EIA/TIA-449, V.35, X.21, and EIA-530 Cisco supplies a DB-60 shielded serial transition cable with the appropriate connector for the standard you specify The router end of the shielded serial transition cable has a DB-60 connector, which connects to the DB-60 port on the router’s serial interface The other end of the serial transition cable depends on the standard you specify Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Chapter 3-8 and 3-9 QUESTION NO: 100 You are configuring Dial-on-demand routing (DDR) However, you run into problems and decide to troubleshoot the problem In particular you want to view the DDR events in real time Which command should use? A B C D show dialer debug dialer debug ppp dialer debug dialer negotiation Answer: B Explanation: Leading the way in IT testing and certification tools, www.testking.com - 228 - 642 - 821 There are many more commands and command outputs that are useful in troubleshooting the dial process in general For instance, the debug dialer command is one of the best tools to use to figure out which traffic is attempting to traverse the ISDN link Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 7-63 QUESTION NO: 101 Your trainee is checking PVC configuration Now she wants to acquire the remote network address related to each PVC Which command should she use to obtain this information? A B C D E show show show show show ip route frame-relay frame-relay frame-relay frame-relay lmi map pvc status Leading the way in IT testing and certification tools, www.testking.com - 229 - 642 - 821 Answer: D Explanation: The show frame-relay pvc command & show frame-relay map can be used to obtain this infomation However the show frame-relay pvc command is more detailed then the show frame-relay map command as you can see in the next two pictures viewing the status of statically or dynamically defined PVCs The show ip route command is used to display IP routing table entries Using the debug frame-relay lmi command enables you to watch the real-time communication between the router and the switch Leading the way in IT testing and certification tools, www.testking.com - 230 - 642 - 821 Reference: Cisco Press - BCRAN - 642-821 - Exam Certification Guide 2004 (ISBN 1-58720-084-8) Page 290 QUESTION NO: 102 You must to configure a Cisco access server which only supports external modems You must configure an asynchronous connection for pool dial-in users Which command sequence could be used for a partial configuration in this scenario? Leading the way in IT testing and certification tools, www.testking.com - 231 - 642 - 821 A line peer default address 10.2.3.4 async mode interactive ppp authentication chap B interface async peer default address 10.2.3.4 async mode interactive ppp authentication chap C interface async peer default address 10.2.3.4 async mode fixed ppp authentication chap D interface async peer default address 10.2.3.4 async mode fixed ppp authentication chap Answer: B Explanation: There is often confusion between the interface async and line commands The major difference is that the interface async command lets you configure the protocol (logical) aspects of an asynchronous port, while the line command lets you configure the physical aspects of the same port The async commands can be thought of as internal, while the line commands configure external characteristics of the configuration peer default ip address address - Assigns a predefined default IP address to the remote client node that dials in to the corresponding asynchronous line Additionally, the pool and dhcp arguments allow address allocation from a local pool of addresses or a DHCP server async mode interactive - This command allows the dial-in user to run SLIP, PPP, or EXEC on the specified line and is the default This command allows you to run the EXEC on a dial-in line The no async mode interactive command prevents users from running SLIP or PPP at the EXEC level There is no async mode fixed command Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 4-24 and 5-9 and 5-10 QUESTION NO: 103 You want have an existing modemcap entry called testking_opt Now you want to create a new modemcap entry named testking_custom based on the attributes of the existing entry testking_opt Which command should you use? Leading the way in IT testing and certification tools, www.testking.com - 232 - 642 - 821 A B C D copy modemcap testking_opt testking_custom modemcap edit testking_custom TPL= testking_opt modemcap edit testking_custom template testking_opt modemcap entry testking_custom template testking_opt Answer: C Explanation: The modem capability database (modemcap) is a list of modems with a known set of “AT” configuration commands for setting each modem type’s attributes For example, many modems use the string “AT&F” to reset the modem to its factory default attributes The modemcap database contains entries for supported modems You can the following tasks to manage a modemcap database entry: * View modem entries in the modemcap database with the show modemcap command * View the contents of a modem’s modemcap entry * Modify a modem’s modemcap entry * Create a modem database entry Use the modemcap edit new-modem-name command to the following: * Add a new entry to the modemcap database * Add new attributes to an existing modem entry in the modemcap database Additional commands that can be used when creating variant modem cap entries are: * Use modemcap edit command to edit user-created modemcap entries only * Use show modemcap command verifies the new access server’s modemcap entry * Use no modemcap edit modem-name command removes the specified modem from the modemcap database * Use no modemcap edit modem-name attribute command to remove a modem attribute from a modem’s modemcap entry The modemcap edit testking_custom template testking_opt command points to another modemcap entry to be used as a template As a result, any value not found in the current modemcap entry is set by the template modemcap entry You can have up to four layers of templates Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 4-41 QUESTION NO: 104 You must configure a Windows 98 computer so that it can dial-up a Cisco access server Which three configuration issues must be taken care of? (Choose three) A The LAN protocol to be used Leading the way in IT testing and certification tools, www.testking.com - 233 - 642 - 821 B C D E The type of security required The error rate on the phone line The connection protocol to be used The asynchronous interface on the access server Answer: A, B, D Explanation: A Windows 9x Dialup Networking configuration includes the following components: * * * * Dialup clients and servers Connection protocols Network LAN protocols and network servers Security Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 6-5 QUESTION NO: 105 Leading the way in IT testing and certification tools, www.testking.com - 234 - 642 - 821 You trainee is studying ISDN In particular he is interested in ISDN reference points defining demarcation between the CPE and the provider He knows how this works in North America, but now he asks you which reference points are used in Europe (Choose two) A B C D R reference point S reference point T reference point U reference point Answer: B, C Explanation: Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 7-10 QUESTION NO: 106 Leading the way in IT testing and certification tools, www.testking.com - 235 - 642 - 821 Which of the following are B-channel Layer protocols? (Choose two) A B C D HDLC LAPD LAPB DSS1 Answer: A, C Explanation: Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 7-14 QUESTION NO: 107 Exhibit: RouterTestKing#show isdn status Leading the way in IT testing and certification tools, www.testking.com - 236 - 642 - 821 Global ISDN Switchtype = basic-ni ISDN BRI1/0 interface Dsl 0, interface ISDN Switchtype = basic-ni Layer Status: ACTIVATE Layer Status: TEI = 112, Ces = 1,SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED TEI = 65, Ces = 2, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED You study the exhibit In particular you study the line: TEI = 65, Ces = 2, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED What TEI = 65 and State = MULTIPLE_FRAME_ESTABLISHED layer status messages indicate? (Choose two) A B C D This connection is a BRI This connection is a PRI You have Layer connectivity to the ISDN switch You have Layer connectivity to your configured Layer protocol Answer: A, C Explanation: A terminal endpoint can be any ISDN-capable device attached to an ISDN network The TEI is a number between and 127, where 0–63 are used for static TEI assignment, 64–126 are used for dynamic assignment, and 127 is used for group assignments (0 is used only for PRI.) The TEI provides the physical identifier, and the Service Access Point Identifier (SAPI) carries the logical identifier The process of assigning TEIs differs slightly between North America and Europe In North America, Layer and Layer are activated at all times In Europe, the activation does not occur until the call setup is sent (known as “.irst call”) This delay conserves switch resources In Germany and Italy, and in other parts of the world, the procedure for TEI assignment can change according to local practices Reference: Cisco Press - BCRAN - 642-821 - Exam Certification Guide 2004 (ISBN 1-58720-084-8) Page 290 QUESTION NO: 108 You are configuring ISDN BRI Which of the following tasks can be entered in global configuration mode? (Choose two) A Select switch type B DDR dialer information C Specify idle timeout value Leading the way in IT testing and certification tools, www.testking.com - 237 - 642 - 821 D Configure ISDN addressing E Specify traffic to trigger a DDR call Answer: A, E Explanation: When you use the isdn switch-type command in global mode, all ISDN interfaces on the router are configured for the same switch type If you use the command in interface configuration mode, only the interface for which you are configuring assumes that switch type The interface dialer map command identifies destination router information such as the phone number to dial The dialer-list global command is used to configure dial-on-demand calls that will initiate a connection The dialer-group interface command applies the dialer list specifications to an interface The dialer idle-timeout interface command specifies the number of seconds of idle time before the router drops the ISDN call Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 7-25 QUESTION NO: 109 You are configuring Dial-on-demand routing (DDR) and you want to hold packets that accumulate while waiting for the line to come up Which command can you use to achieve your goal? A B C D Use the hold-queue command Use the no fair-queue command Use the dialer hold-queue command Use the dialer wait-for-carrier-time command Answer: C Explanation: The dialer hold-queue timeout determines how long to wait before the client can make another call to the same destination The server must make the return call before the client hold-queue timer expires to prevent the client from trying again and possibly preventing the return call from being connected Syntax: dialer hold-queue packets timeout seconds Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 5-24 Leading the way in IT testing and certification tools, www.testking.com - 238 - 642 - 821 QUESTION NO: 110 You trainee asks you why you are using the backup delay command What should you tell him? A B C D To specify timers to activate/drop a backup line after failure To specify percentage of load before activating a backup line To specify the administrative distance of a DDR backup facility To define a line as a backup for load-balancing during high traffic Answer: A Explanation: The backup delay command is used to define how much time should elapse before a secondary line status changes after a primary line status has changed Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 12-10 Leading the way in IT testing and certification tools, www.testking.com - 239 - 642 - 821 QUESTION NO: 111 You are required to configure ISDN on your router In particular you must configure an ISDN interface You want the interface to be a member of a dialer pool 20 and you want to router to use this interface first when it dials out Furthermore, you must use the highest level of priority Leading the way in IT testing and certification tools, www.testking.com - 240 - 642 - 821 Answer: Explanation: The dialer pool-member interface configuration command is used to configure a physical interface to be a member of a dialer profile dialing pool Partial syntax: dialer pool-member number [priority priority] where : The number is the pool number, in the range through 255 The priority is the priority of this interface within the dialing pool, in the range (lowest) to 255 (highest) Reference: Cisco Press - Building Cisco Remote Access Networks Student Guide v1.1 Page 8-14 Note: Section A contains 124 questions Section B contains 111 questions The total number of questions is 235 Each section starts with QUESTION NO :1 There are no missing questions Leading the way in IT testing and certification tools, www.testking.com - 241 -