Exam Prep Questions

Question 1	Which protocol is responsible for establishing, configuring, testing, maintaining, and terminating PPP connections? A. BRI B. PRI C. LCP D. NCP
A1:	The correct answer is C. LCP has the primary responsibility for a PPP connection. Answers A and B are incorrect because BRI and PRI are not components within PPP. Answer D is incorrect because NCP is responsible for the configuration supporting Network layer protocols.
Question 2	Which of the following is an authentication type that would be appropriate for an environment that requires strong encrypted passwords? A. PAP B. CHAP C. LCP D. NCP
A2:	The correct answer is B. CHAP uses encrypted passwords, making it a much stronger protocol than PAP. Answer A is incorrect because PAP uses clear text to send passwords. Answers C and D are incorrect because neither is an authentication type.
Question 3	Which of the following physical interfaces will PPP operate on? A. Asynchronous serial B. Synchronous serial C. HSSI D. ISDN E. All of the above
A3:	The correct answer is E. PPP can operate on a variety of DTE/DCE physical interfaces, including asynchronous serial, synchronous serial, HSSI, and ISDN.
Question 4	Which PPP authentication protocol uses a three-way handshake? A. PAP B. CHAP C. LCP D. NCP1
A4:	The correct answer is B. The CHAP three-way handshake includes the local host requesting authentication, the remote host sending an encrypted response, and the local host comparing the received information and then accepting or rejecting the connection. PAP only uses a two-way handshake. Therefore, answer A is incorrect. LCP and NCP1 are not authentication protocols. Therefore, answers C and D are incorrect.
Question 5	If your router does not have an ISDN BRI interface, which devices will you need to connect to ISDN services? (Choose the two best answers.) A. NT1 B. TA C. TE1 D. TE2
A5:	The correct answers are A and B. You need a TA to convert the serial signal from your router into a BRI signal, and you need an NT1 to convert the BRI signal for use by the ISDN digital line. A TE1 is a device that has a built-in BRI and already transmits BRI signals. Therefore, answer C is incorrect. Answer D is incorrect because a device that does not have a built-in BRI is considered a TE2.
Question 6	How can you use ISDN? (Choose all that apply.) A. To improve Internet response times B. To encapsulate other WAN services C. To add bandwidth for telecommuting D. To carry multiple Network-layer protocols
A6:	The correct answers are A, B, C, and D.
Question 7	DCE devices provide which of the following functions? A. Provides a clock to the DTE B. Converts data into a suitable format C. Switches data across the provider's network D. All of the above
A7:	The correct answer is D. Answers A, B, and C are all functions of DCE devices.
Question 8	Frame Relay operates at which layer of the OSI model? A. Transport B. Network C. Data Link D. Physical
A8:	The correct answer is C. Frame Relay operates at the Data Link layer. Answers A and B are incorrect because Frame Relay does not include any specifications for Layer 4 (Transport) or Layer 3 (Network). Although Frame Relay can operate on several different physical media, it does not include specifications for Layer 1 (Physical). Therefore, answer D is incorrect.
Question 9	Which of the following devices can serve as a DTE device? (Choose the two best answers.) A. Router B. Terminal C. Modem D. CSU
A9:	The correct answers are A and B. Routers and terminals can be configured to act as DTE devices. Modems and CSUs cannot be configured as DTE devices, but they can be configured as DCE devices. Therefore, answers C and D are incorrect.
Question 10	Which of the following are common WAN services supported by Cisco? (Choose the five best answers.) A. ISDN B. Frame Relay C. PPP D. BGP E. HDLC F. SDLC
A10:	The correct answers are A, B, C, E, and F. ISDN, Frame Relay, PPP, HDLC, and SDLC are all WAN services supported by Cisco equipment. Although BGP is supported by Cisco equipment, it is an exterior routing protocol. Therefore, answer D is incorrect.
Question 11	Which of the following can be used to establish bidirectional communication between two DTE devices? (Choose the two best answers.) A. CVC B. DVC C. PVC D. SVC
A11:	The correct answers are C and D. A permanent virtual circuit (PVC) remains established between two DTE devices, even when data is not being transmitted. A switched virtual circuit (SVC) is established only when two DTE devices need to transmit data; it is disconnected when the transmission is over. CVC and DVC are not related to virtual circuits between DTE devices. Therefore, answers A and B are incorrect.
Question 12	Which of the following serves as the addressing scheme within a Frame Relay network? A. DLCI B. LMI C. NBMA D. SVC
A12:	The correct answer is A. A DLCI number serves as the addressing scheme and is assigned to each PVC. LMI provides several enhancements to Frame Relay specifications. Therefore, answer B is incorrect. Answer C is incorrect because NBMA describes how a router must send broadcasts within a Frame Relay network. An SVC is established to enable DTE to communicate. Therefore, answer D is incorrect.
Question 13	Cisco supports which of the following Frame Relay LMI protocol variations? (Choose the three best answers.) A. IETF B. ANSI C. Q933A D. Cisco
A13:	The correct answers are B, C, and D. Cisco supports LMI extensions from American National Standards Institute (ANSI), International Telecommunication Union “Telecommunication standardization sector (Q933A), and Cisco's "Gang of Four." Answer A is incorrect because IETF is a type of frame encapsulation supported by Cisco that enables Cisco devices to communicate with non-Cisco devices across a Frame Relay network.
Question 14	Frame Relay uses what mechanism to perform error checking? A. CRC B. LMI C. TA/NT1 D. Inverse ARP
A14:	The correct answer is A. Frame Relay uses CRC to derive the FCS, which is a calculated value based on the data portion of each frame. If a device calculates an FCS value that is different from the FCS value it receives, the frame is dropped. LMI is communicated between DTE and DCE devices and contains the status of the virtual circuit. Therefore, answer B is incorrect. Answer C is incorrect because a TA/NT1 is a DCE device and has nothing to do with error checking. Answer D is incorrect because inverse ARP is the method by which DTE devices discover Layer 3 protocol address information about each other.