Review Questions

1.	Which of the following protocols support PPP? (Choose all that apply.) HDLC LCP SDLC NCP LAPB
2.	Which of the following contains Frame Relay flow control information? DLCI IARP LMI BECN
3.	Which of the following is a method used by Frame Relay for addressing PVCs to IP addresses? IARP MIL SLARP DLCI
4.	What is a TE2 device used for in an ISDN connection? Connecting an NT2 device to a U reference point Connecting an S/T interface to a U reference point Connecting a non-ISDN terminal to ISDN through a TA Connecting to ISDN through a four-wire, twisted-pair digital link
5.	Which of the following statements are true regarding DLCIs? (Choose all that apply.) DLCIs are not necessarily unique. DLCIs are not necessary with PVCs. DLCIs initiate a Frame Relay communication exchange. DLCIs are logical identifiers for Frame Relay virtual circuits.
6.	In the Have-A-Seat case study, they currently have ISDN lines. Which of the following tasks would best demonstrate that the ISDN lines are adequate? Set up a lab and simulate a 64Kbps leased line connected to the Internet for browsing. Perform a simple demonstration of a web browser’s performance on an ISDN line to an Internet site. Implement the network with the existing 9600bps lines and let Have-A-Seat see that the performance is lacking. Perform a simple demonstration of a web browser’s performance on the internetwork on a 33Kbps connection.
7.	Suppose that you want to create a full mesh network. Which of the following will be the most cost-effective WAN type? PPP DDR SONET Frame Relay
8.	Which of the following are valid LMI features? (Choose all that apply.) Multicasting Global addressing Route determination Connectionless routing Dynamic host addressing Virtual circuit status messaging
9.	What is one of the first things you should do when determining if you should upgrade your network to a switched network? Pull fiber to all the floors. Determine the characteristics of the network traffic. Configure your VLANs. Change the TTL on your PCs to 1.
10.	Which of the following statements are true about CIR (committed information rate)? (Choose all that apply.) Choose a CIR based on realistic, anticipated traffic rates. The CIR must match the DLCI of the PVC. You can use a zero CIR to save money if retransmission of packets is acceptable. The LMI keeps track of the CIR and provides the route information to the PVC.
11.	How many LMI types are supported? Two Three Four Five
12.	Which of the following statements are true about LMI? (Choose all that apply.) LMIs map DLCI numbers to virtual circuits. LMIs map X.121 addresses to virtual circuits. LMIs report the status of virtual circuits. LMI messages provide information about the current DLCI values.
13.	Which of the following is a disadvantage of having point-to-point connections? A point-to-point connection requires that tariffs be paid even when the connection is in an idle state and no data are being transmitted. A point-to-point connection requires users to dial the connection manually when data need to be transmitted. A point-to-point connection requires interesting traffic to be defined on the router with access lists when data need to be transmitted. A point-to-point connection requires a lease through an ISP using a point-to-point routing protocol.
14.	What is the solution for using partial mesh Frame Relay networks with split-horizon protocols? DLCI addressing X.121 addresses Secondary Ethernet interfaces Subinterfaces
15.	Which of the following are the types of LMI methods used by Cisco routers? (Choose all that apply.) Cisco ANSI IETF q933a
16.	Which of the following DSL types generally uses asymmetric transmission? ADSL SDSL IDSL HDSL
17.	Which of the following DSL types can share a line with a PSTN line? (Choose all that apply.) ADSL SDSL IDSL HDSL
18.	Which of the following DSL types is similar to ISDN? ADSL SDSL IDSL HDSL
19.	Which type of network is Frame Relay? Private network Leased line Packet-switched network Circuit-switched network
20.	Which network type generally has the highest up-front costs? Private network Leased line Packet-switched network Public network

Answers

1.	A, B, D PPP is a vendor-neutral protocol. PPP supports many vendor-specific protocols.
2.	D BECN contains Frame Relay backward explicit control notification information, which requests that the source router slow down its transmission rate.
3.	A Inverse ARP provides dynamic mapping of DLCI to IP addresses.
4.	C A TE2 device is for connecting non-ISDN equipment directly to the ISDN line.
5.	A, D DLCIs are only locally significant and are used to identify the user ends of a Frame Relay circuit.
6.	B Testing a user’s application on the customer’s existing network can help to demonstrate performance issues.
7.	D Frame Relay supports subinterfaces, allowing you to create full mesh design with less than a full mesh connection topology.
8.	A, B, F Multicasting, global addressing, and virtual circuit status messaging are supported by LMIs because of their globally significant addressing.
9.	B Characteristics, better known as baselines, allow you to measure network traffic for planning and design purposes.
10.	A, C To meet the cost and performance goals of your network design, you should purchase a CIR that meets your needs.
11.	B Three LMI types were created by the Gang of Four: Cisco, ANSI, and q933a, but the Cisco LMI type is the default for Cisco routers.
12.	C, D LMIs include Frame Relay virtual circuit status messages and DLCI values.
13.	A Point-to-point connections can be a more expensive option than dial-in, dial-on-demand, or packet-switched connections.
14.	D Implementing subinterfaces is the correct solution for use in Frame Relay networks supporting split-horizon routing protocols.
15.	A, B, D Cisco, ANSI, and q933a are the three LMI methods supported by Cisco routers.
16.	A As the name implies, asymmetric DSL (ADSL) uses asymmetric transmission.
17.	A, D ADSL can share a line with a PSTN line, as can HDSL-2.
18.	C IDSL is similar to ISDN, the main difference being that IDSL is not circuit-switched.
19.	C Frame Relay is a packet-switched network. While it could be a private network, Frame Relay is generally purchased from a service provider.
20.	A A private network implies that the infrastructure is owned by the enterprise using the network and thus has higher up-front costs than leased or public network types.