CCNA 4 v6.0 (Connecting Networks v6) Chapter 1: WAN Concepts: Check Your Understanding Questions Answers
1. A small company with 10 employees uses a single LAN to share information between computers. Which type of connection to the Internet would be appropriate for this company?
- A broadband service, such as DSL, through the company’s local service provider
- A dialup connection that is supplied by the local telephone service provider
- Private dedicated lines through the local service provider
- A VSAT connection to a service provider
Explanation: For this small office, an appropriate connection to the Internet would be through a common broadband service called digital subscriber line (DSL), available from the company’s local telephone service provider. Because the company has so few employees, bandwidth is not a significant problem. If the company were bigger, with branch offices in remote sites, private lines would be more appropriate. VSATs are used to provide connectivity to remote locations and typically used only when no other connectivity options are available.
2. Which network scenario will require the use of a WAN?
- Employee workstations need to obtain dynamically assigned IP addresses.
- Employees in the branch office need to share files with the headquarters office that is located in a separate building on the same campus network.
- Employees need to access web pages that are hosted on the corporate web servers in the DMZ within their building.
- Employees need to connect to the corporate email server through a VPN while traveling.
Explanation: When traveling employees need to connect to a corporate email server through a WAN connection, the VPN will create a secure tunnel between an employee laptop and the corporate network over the WAN connection. Obtaining dynamic IP addresses through DHCP is a function of LAN communication. Sharing files among separate buildings on a corporate campus is accomplished through the LAN infrastructure. A DMZ is a protected network inside the corporate LAN infrastructure.
3. Which statement describes a characteristic of a WAN?
- A WAN operates within the same geographic scope of a LAN but has serial links.
- A WAN provides end-user network connectivity to the campus backbone.
- All serial links are considered WAN connections.
- WAN networks are owned by service providers.
Explanation: WANs are used to interconnect the enterprise LAN to remote branch site LANs and telecommuter sites. A WAN is owned by a service provider. Although WAN connections are typically made through serial interfaces, not all serial links are connected to a WAN. LANs, not WANs, provide end-user network connectivity in an organization.
4. Which two devices are needed when a digital leased line is used to provide a connection between the customer and the service provider? (Choose two.)
- Access server
- CSU
- Dialup modem
- DSU
- Layer 2 switch
Explanation: Digital leased lines require a channel service unit (CSU) and a data service unit (DSU). An access server concentrates dialup modem dial-in and dial-out user communications. Dialup modems are used to temporarily enable the use of analog telephone lines for digital data communications. A Layer 2 switch is used to connect a LAN.
5. What is a requirement of a connectionless packet-switched network?
- A virtual circuit is created for the duration of the packet delivery.
- Each packet has to carry only an identifier.
- Full addressing information must be carried in each data packet.
- The network predetermines the route for a packet.
Explanation: A connection-oriented system predetermines the network path, creates a virtual circuit for the duration of the packet delivery, and requires that each packet only carry an identifier. A connectionless packet-switched network, such as the Internet, requires each data packet to carry addressing information.
6. What is an advantage of packet-switched technology over circuit-switched technology?
- Packet-switched networks are less susceptible to jitter than circuitswitched networks are.
- Packet-switched networks can efficiently use multiple routes inside a service provider network.
- Packet-switched networks do not require an expensive permanent connection to each endpoint.
- Packet-switched networks usually experience lower latency than circuit-switched networks experience.
Explanation: Unlike circuit-switched networks which typically require expensive permanent connections, packet-switched networks can take alternate paths if available to reach the destination.
7. What is a long-distance fiber-optic media technology that supports both SONET and SDH, and assigns incoming optical signals to specific wavelengths of light?
- ATM
- DWDM
- ISDN
- MPLS
Explanation: ISDN (Integrated Services Digital Network), ATM (Asynchronous Transfer Mode), and MPLS (Multiprotocol Label Switching) do not describe fiber-optic technologies.
8. What is the recommended technology to use over a public WAN infrastructure when a branch office is connected to the corporate site?
- ATM
- ISDN
- Municipal Wi-Fi
- VPN
Explanation: ISDN and ATM are Layer 1 and 2 technologies that are typically used on private WANs. Municipal Wi-Fi is a wireless public WAN technology. Corporate communications over public WANs should use VPNs for security.
9. What are two common high-bandwidth fiber-optic media standards? (Choose two.)
- ANSI
- ATM
- ITU
- SDH
- SONET
Explanation: ATM (Asynchronous Transfer Mode) is a Layer 2 technology. ANSI (American National Standards Institute) and ITU (International Telecommunication Union) are standards organizations.
10. Which WAN technology establishes a dedicated constant point-to-point connection between two sites?
- ATM
- Frame Relay
- ISDN
- Leased lines
Explanation: A leased link establishes a dedicated constant point-to-point connection between two sites. ATM is cell-switched. ISDN is circuit-switched. Frame Relay is packet-switched.
11. A hospital is looking for a solution to connect multiple, newly established remote branch medical offices. Which consideration is important when selecting a private WAN connection rather than a public WAN connection?
- Data security and confidentiality during transmission
- Higher data transmission rate
- Lower cost
- Website and file exchange service support
Explanation: A private WAN solution that involves dedicated links between sites offers the best security and confidentiality. Both private and public WAN solutions offer comparable connection bandwidth, depending on the technology chosen. Connecting multiple sites with private WAN connections could be very expensive. The website and file exchange service support is not relevant.
12. A new corporation needs a data network that must meet certain requirements. The network must provide a low-cost connection to salespeople dispersed over a large geographical area. Which two types of WAN infrastructure would meet the requirements? (Choose two.)
- Dedicated
- Internet
- Private infrastructure
- Public infrastructure
- Satellite
Explanation: VPNs over the Internet provide low-cost, secure connections to remote users. VPNs are deployed over the Internet public infrastructure.
13. Which wireless technology provides Internet access through cellular networks?
- LTE
- Municipal Wi-Fi
- Satellite
- WiMAX
Explanation: LTE, or Long-Term Evolution, is a fourth-generation cellular access technology that supports Internet access.
14. Which equipment is needed for an ISP to provide Internet connections through cable service?
- Access server
- CMTS
- CSU/DSU
- DSLAM
Explanation: The equipment located at a cable service provider office, the cable modem termination system (CMTS), sends and receives digital cable modem signals on a cable network to provide Internet services to cable subscribers. A DSLAM performs a similar function for DSL service providers. A CSU/DSU is used in leased-line connections. Access servers are needed to process multiple simultaneous dial-up connections to a central office (CO).
15. A customer needs a WAN virtual connection that provides high-speed, dedicated bandwidth between two sites. Which type of WAN connection would best fulfill this need?
- Circuit-switched network
- Ethernet WAN
- MPLS
- Packet-switched network
Explanation: MPLS can use a variety of underlying technologies such as T- and E-carriers, Carrier Ethernet, ATM, Frame Relay, and DSL, all of which support lower speeds than an Ethernet WAN. Neither a circuit-switched network, such as the public switched telephone network (PSTN) or Integrated Service Digital Network (ISDN), nor a packet-switched network is considered high speed.