CCNA Discovery 3: DRSEnt Chapter 7 Exam Answers v4.0

1. Why are Network Control Protocols used in PPP?

  • to establish and terminate data links
  • to provide authentication capabilities to PPP
  • to manage network congestion and to allow quality testing of the link
  • to allow multiple Layer 3 protocols to operate over the same physical link

2. What is the data transmission rate for the DS0 standard?

  • 44 kb/s
  • 64 kb/s
  • 1.544 Mb/s
  • 44.736 Mb/s

3. In which two layers of the OSI model are key differences found between a LAN and a WAN. (Choose two.)

  • Layer 1
  • Layer 2
  • Layer 3
  • Layer 4
  • Layer 6
  • Layer 7

4. Which statement is true about the Cisco implementation of the HDLC protocol?

  • It supports authentication.
  • It has a universally compatible frame format.
  • It is the default encapsulation for serial interfaces on Cisco routers.
  • It does not support multiple protocols across a single link.

5. Refer to the exhibit. A network administrator has a connectivity problem between the serial interfaces of Merida and Vargas. What is the cause of the problem?

  • Authentication is required on the serial link.
  • The encapsulation is misconfigured.
  • The IP addresses are on different subnets.
  • The serial interface on Vargas is shutdown.
  • The loopback interfaces on both routers are not configured.

6. Refer to the exhibit. What statement is true about the exhibited output?

  • LCP is in the process of negotiating a link.
  • LCP and NCP are waiting for CHAP authentication to complete.
  • LCP negotiation has completed successfully, but NCP negotiation is in progress.
  • LCP and NCP negotiation is complete, and the data link service is available to carry packets.

7. Which three statements are true regarding LCP? (Choose three.)

  • It is responsible for negotiating link establishment.
  • It negotiates options for Layer 3 protocols running over PPP.
  • It uses MD5 encryption while negotiating link-establishment parameters.
  • It terminates the link upon user request or the expiration of an inactivity timer.
  • It can test the link to determine if link quality is sufficient to bring up the link.
  • It monitors the link for congestion and dynamically adjusts the acceptable window size.

8. Why are Frame Relay paths referred to as virtual?

  • Frame Relay PVCs are created and discarded on demand.
  • The connections between PVC endpoints act like dialup circuits.
  • There are no dedicated circuits to and from the Frame Relay carrier.
  • The physical circuits inside the Frame Relay cloud do not contain exclusive links for a specific Frame Relay connection.

9. What best describes the use of a data-link connection identifier (DLCI)?

  • an address identifying a virtual circuit
  • a logical address identifying the DCE device
  • an address identifying a Layer 3 service across a Frame Relay network
  • a logical address identifying the physical interface between a router and a Frame Relay switch

10. What two services allow the router to dynamically map data link layer addresses to network layer addresses Frame Relay network? (Choose two.)

  • ARP
  • ICMP
  • Proxy ARP
  • Inverse ARP
  • LMI status messages

11. Which three statements describe functions of the Point-to-Point Protocol with regards to the OSI model?(Choose three.)

  • operates at all layers of the OSI model
  • provides a mechanism to multiplex several network layer protocols
  • can be configured on both synchronous and asynchronous serial interfaces
  • uses Layer 3 of the OSI model to establish and maintain a session between devices
  • uses the data link layer to configure such options as error detection and compression
  • uses network control protocols to test and maintain connectivity between devices

12. At what physical location does the responsibility for a WAN connection change from the user to the service provider?

  • demilitarized zone (DMZ)
  • demarcation point
  • local loop
  • cloud

13. What does a Frame Relay switch use to inform the sender that there is congestion?

  • FECN
  • BECN
  • DE
  • FCS

14. Refer to the exhibit. What statement is true about the debug output?

  • R2 is using PAP instead of CHAP.
  • The routers have different CHAP passwords configured.
  • The administrator performed a shutdown on the R2 PPP interface during negotiation.
  • The Layer 3 protocol negotiation caused the connection failure.

15. Which two statements describe the function of time-division multiplexing? (Choose two.)

  • Multiple data streams share one common channel.
  • Conversations that require extra bandwidth receive any unused time slices.
  • Time slots are utilized on a first-come, first-served basis.
  • Time slots go unused if a sender has nothing to transmit.
  • Priority can be dedicated to one data source.

16. When customers use credit cards to make purchases at a small business, a modem is heard dialing a telephone number to transfer the transaction data to the central office. What type of WAN serial connection is in use?

  • leased line
  • point-to-point
  • circuit switched
  • packet switched

17. Which best describes data communications equipment (DCE)?

  • serves as data source and/or destination
  • responsible for negotiating windowing and acknowledgements
  • physical devices such as protocol translators and multiplexers
  • equipment that forwards data and is responsible for the clocking signal

18. Permanent virtual circuits and switched virtual circuits are both part of which option for WAN connectivity?

  • leased line
  • cell switching
  • packet switching
  • circuit switching

19. Which field of a frame uses error detection mechanisms to verify that the frame is not damaged intransit?

  • FCS
  • MTU
  • flag
  • control
  • protocol

20. What occurs in the encapsulation process as a data packet moves from a LAN across a WAN?

  • The Layer 2 encapsulation changes to a format that is appropriate for the WAN technology.
  • The Layer 3 encapsulation changes to a format that is appropriate for the WAN technology.
  • Both Layer 2 and Layer 3 encapsulation change to a technology that is appropriate for the WAN.
  • Both Layer 2 and Layer 3 encapsulation remain constant as the data packet travels throughout the network.

21. Refer to the exhibit. The network administrator is configuring R1 to connect to R2, which is a non-Cisco router. Which encapsulation method will need to be configured for communication to occur?

  • HDLC
  • HSSI
  • ISDN
  • IPCP
  • PPP

22. A company is implementing dialup services for remote workers to connect to the local network. The company uses multiple Layer 3 protocols and requires authentication for security. Which protocol should be used for this remote access?

  • LMI
  • PPP
  • HDLC
  • Frame Relay

23. Which two options can LCP negotiate? (Choose two.)

  • compression
  • authentication
  • dynamic flow control
  • network layer address for IP
  • connection-oriented or connectionless communication methods

24. What statement best describes cell switching?

  • It uses a dedicated path between endpoints.
  • It creates a permanent physical link between two points.
  • It uses DLCIs to identify virtual circuits.
  • It creates fixed-length packets that traverse virtual circuits.
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