Chapter 1

A new corporation needs a data network that must meet certain requirements. The network must be fast and reliable to transmit secure video conferencing calls between two branches. If cost is not a consideration, which two types of WAN infrastructure would best meet the requirements? (Choose two.)

private infrastructure dedicated

A new corporation needs a data network that must meet certain requirements. The network must provide a low cost connection to sales people dispersed over a large geographical area. Which two types of WAN infrastructure would meet the requirements? (Choose two.)

public infrastructure internet

A construction firm is building a power plant at a remote and isolated mine site and needs to connect the data network of the plant to the corporate network. Which public technology is the most suitable to meet the connection needs?

satellite Internet

Which three traffic-related factors would influence selecting a particular WAN link type? (Choose three.)

type of traffic amount of traffic security needs

Connectionless systems

ull addressing information must be carried in each packet. Each switch must evaluate the address to determine where to send the packet. An example of a connectionless system is the Internet.

Dual-homed Topology

A dual-homed topology provides redundancy

WAN switch

A multiport internetworking device used in service provider networks. These devices typically switch traffic, such as Frame Relay or ATM, and operate at Layer 2

Leased Line

A permanent, dedicated WAN connection which uses a T- or E- carrier system

Core router/Multilayer switch

A router or multilayer switch that resides within the middle or backbone of the WAN, rather than at its periphery. To fulfill this role, a router or multilayer switch must be able to support multiple telecommunications interfaces of the highest speed used in the WAN core

Match the scenario to the WAN solution. (Not all options are used.)

A teleworker would like to bundle the Internet connection with other phone and TV services. - Answer: cable A company requires higher download speeds than upload speeds and wants to use existing phone lines. - Answer: DSL A company has a headquarters and four remote locations. The headquarters site will require more bandwidth than the four remote sites. - Answer: Frame Relay A multisite college wants to connect using Ethernet technology between the sites. - Answer: MetroE A company would like guaranteed bandwidth using a point-to-point link that requires minimal expertise to install and maintain. - Answer: T1

Broadband modem

A type of digital modem used with high-speed DSL or cable Internet service. Both operate in a similar manner to the voiceband modem, but use higher broadband frequencies and transmission speeds.

Which WAN technology is cell-based and well suited to carry voice and video traffic?

ATM

Which WAN technology uses a fixed payload of 48 bytes and is transported across both switched and permanent virtual circuits?

ATM

Data Communications Equipment (DCE)

Also called data circuit-terminating equipment, the DCE consists of devices that put data on the local loop. The DCE primarily provides an interface to connect subscribers to a communication link on the WAN cloud.

Dialup

Analog telephone lines are used to provide a switched WAN connection

Which equipment is needed for an ISP to provide Internet connections through cable service?

CMTS

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.)

CSU DSU

Match the connectivity type to the description. (Not all options are used.)

Cable - uses traditional video network DSL - uses traditional phone network municipal WI-Fi - set up by a city to provide free internet access Satellite internet - slow access (upload speed is about one-tenth download speed)

Availability

Constant availability is essential for some applications, such as e-commerce. Point-to-point communication links provide permanent, dedicated capacity which is required for VoIP or Video over IP.

ISDN

Converts analog to digital signals to provide a switched WAN connection over telephone lines

Which feature is used when connecting to the Internet using DSL?

DSLAM

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?

DWDM

CSU/DSU

Digital-leased lines require a CSU and a DSU. A CSU/DSU can be a separate device like a modem or it can be an interface on a router. The CSU provides termination for the digital signal and ensures connection integrity through error correction and line monitoring. The DSU converts the line frames into frames that the LAN can interpret and vice versa.

Which network scenario will require the use of a WAN?

Employees need to connect to the corporate email server through a VPN while traveling.*

What can cause a reduction in available bandwidth on a cable broadband connection?

number of subscribers

A customer needs a metropolitan area WAN connection that provides high-speed, dedicated bandwidth between two sites. Which type of WAN connection would best fulfill this need?

Ethernet WAN

Which two technologies are categorized as private WAN infrastructures? (Choose two.)

Frame Relay MetroE

What is a requirement of a connectionless packet-switched network?

Full addressing information must be carried in each data packet.*

Which one of the WAN technologies is inadequate for video traffic but operates adequately for voice traffic?

ISDN BRI

Basic Rate Interface (BRI)

ISDN BRI is intended for the home and small enterprise and provides two 64 kb/s bearer channels (B) for carrying voice and data and a 16 kb/s delta channel (D) for signaling, call setup and other purposes

Primary Rate Interface (PRI)

ISDN is also available for larger installations. In North America, PRI delivers 23 B channels with 64 kb/s and one D channel with 64 kb/s for a total bit rate of up to 1.544 Mb/s. This includes some additional overhead for synchronization

Which wireless technology provides Internet access through cellular networks?

LTE

Which geographic scope requirement would be considered a distributed WAN scope?

many-to-many

A company needs to interconnect several branch offices across a metropolitan area. The network engineer is seeking a solution that provides high-speed converged traffic, including voice, video, and data on the same network infrastructure. The company also wants easy integration to their existing LAN infrastructure in their office locations. Which technology should be recommended?

ethernet WAN

Which medium do service providers use to transmit data over WAN connection with SONET, SDH, and DWDM

fiber optic

What is a disadvantage of leased lines

high cost

Ethernet WAN

includes MetroE, EoMPLS, and VPLS as WAN connection options

Match the private WAN technology to its application. (Not all options are used.)

leased line - when permanent point-to-point dedicated connections are required VSAT - when connectivity in a remote location is needed and there are no service providers that offer WAN service ISDN BRI - when 2 B channels and 1 D channel are used to provide additional capacity dialup - when intermittent, low-volume data transfers are needed

Which WAN technology establishes a dedicated constant point-to-point connection between two sites?

leased lines

Which statement correctly describes a WAN technology?‹

MPLS can be used to deliver any type of packet between sites.

What are two common types of circuit-switched WAN technologies? (Choose two.)

PSTN ISDN

What is an advantage of packet-switched technology over circuit-switched technology?

Packet-switched networks can efficiently use multiple routes inside a service provider network.*

Simplicity

Point-to-point communication links require minimal expertise to install and maintain.

Quality

Point-to-point communication links usually offer high service quality, if they have adequate bandwidth. The dedicated capacity removes latency or jitter between the endpoints.

Cost

Point-to-point links are generally the most expensive type of WAN access. The cost of leased line solutions can become significant when they are used to connect many sites over increasing distances.

Router

Provides internetworking and WAN access interface ports that are used to connect to the service provider network

What are two common high-bandwidth fiber-optic media standards? (Choose two.)

SDH SONET

VSAT

Satellite to router communications for WAN connections

Public WAN infrastructure

Service providers may offer broadband Internet access using digital subscriber line (DSL), cable, and satellite access.

Private WAN infrastructure

Service providers may offer dedicated point-to-point leased lines, circuit-switched links, such as PSTN or ISDN, and packet-switched links, such as Ethernet WAN, ATM, or Frame Relay.

Which two WAN infrastructure services are examples of private connections? (Choose two.)

T1/E1 Frame Relay

Central Office (CO)

The CO is the local service provider facility or building that connects the CPE to the provider network.

Customer Premises Equipment (CPE)

The CPE consists of the devices and inside wiring located on the enterprise edge connecting to a carrier link.

Local Loop

The actual copper or fiber cable that connects the CPE to the CO of the service provider. The local loop is also sometimes called the "last-mile".

Data Terminal Equipment (DTE)

The customer devices that pass the data from a customer network or host computer for transmission over the WAN. The DTE connects to the local loop through the DCE.

Connection-oriented systems

The network predetermines the route for a packet, and each packet only has to carry an identifier. The switch determines the onward route by looking up the identifier in tables held in memory. The set of entries in the tables identifies a particular route or circuit through the system. When the circuit is established temporarily while a packet is traveling through it, and then breaks down again, it is called a virtual circuit (VC). An example of a connection-oriented system is Frame Relay

Toll network

This consists of the long-haul, all-digital, fiber-optic communications lines, switches, routers, and other equipment inside the WAN provider network

Demarcation Point

This is a point established in a building or complex to separate customer equipment from service provider equipment.

Access server

This server controls and coordinates dialup modem, dial-in and dial-out user communications. Considered to be a legacy technology, an access server may have a mixture of analog and digital interfaces and support hundreds of simultaneous users.

What is the recommended technology to use over a public WAN infrastructure when a branch office is connected to the corporate site?

VPN

Which connectivity method would be best for a corporate employee who works from home two days a week, but needs secure access to internal corporate databases?

VPN

Which public WAN technology provides security by using encrypted tunnels over Internet connections?

VPN

Which solution can provide Internet access to remote locations where no regular WAN services are available?

VSAT

Dialup modem

Voiceband modems are considered to be a legacy WAN technology. A voiceband modem converts (i.e., modulates) the digital signals produced by a computer into voice frequencies. These frequencies are then transmitted over the analog lines of the public telephone network. On the other side of the connection, another modem converts the sounds back into a digital signal (i.e., demodulates) for input to a computer or network connection.

Which statement describes a characteristic of a WAN?

WAN networks are owned by service providers.

What is a characteristic of a WAN

WAN service providers include carriers such as a telephone network or satellite service.

Limited flexibility

WAN traffic is often variable, and leased lines have a fixed capacity, so that the bandwidth of the line seldom matches the need exactly.

A home user lives within 10 miles (16 kilometers) of the Internet provider network. Which type of technology provides high-speed broadband service with wireless access for this home user?

WiMAX

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 their local service provider*

Hub-and-Spoke

a single interface to the hub can be shared by all spoke circuits.

Full Mesh

any site can communicate directly with any other site. The disadvantage here is the large number of virtual circuits that need to be configured and maintained.

Match each component of a WAN connection to its description. (Not all options are used.)

data communications equipment - devices that put data on the local loop customer premises equipment - devices and inside wiring located on the enterprise edge and which connect to a carrier link demarcation point - a point that is established in a building or complex to separate customer equipment from service provider equipment data terminal equipment - customer devices that pass the data from a customer network or host computer for transmission over the WAN

A corporation is looking for a solution to connect multiple, newly established remote branch offices. Which consideration is important when selecting a private WAN connection rather than a public WAN connection?

data security and confidentiality during transmission*

Layer 2 protocols

define how data is encapsulated for transmission toward a remote location, and the mechanisms for transferring the resulting frames. A variety of different technologies are used, such as the Point-to-Point Protocol (PPP), Frame Relay, and ATM. Some of these protocols use the same basic framing or a subset of the High-Level Data Link Control (HDLC) mechanism.

Layer 1 protocols

describe how to provide electrical, mechanical, operational, and functional connections to the services of a communications service provider.

Match the type of WAN device or service to the description. (Not all options are used.)

devices and inside wiring that are located on the enterprise edge and connect to a carrier link - CPE a physical connection from the customer to the service provider POP - local loop customer devices that pass the data from a customer network for transmission over the WAN - DTE devices that provide an interface for customers to connect to within the WAN cloud - DCE

Which two technologies use the PSTN network to provide an Internet connection? (Choose two.)

dialup ISDN

Point-to-Point

employs a point-to-point circuit between two endpoints. Typically involving dedicated leased-line connections like T1/E1 lines, a point-to-point connection involves a Layer 2 transport service through the service provider network. Packets sent from one site are delivered to the other site and vice versa. A point-to-point connection is transparent to the customer network, as if there was a direct physical link between two endpoints.