1.
At which two layers of the OSI model does a WAN operate? (Choose two.)
Correct Answer(s)
A. pHysical Layer
B. Data Link Layer
Explanation
A WAN (Wide Area Network) operates at the Physical Layer and Data Link Layer of the OSI model. The Physical Layer is responsible for the transmission and reception of raw bit streams over a physical medium, such as cables or wireless signals. The Data Link Layer is responsible for the reliable transfer of data between two nodes on the same network, including error detection and correction. In the case of a WAN, these layers are crucial for establishing and maintaining the physical connections and ensuring the integrity of the data being transmitted over long distances.
2.
Which three WAN devices can be found in the cloud? (Choose three.)
Correct Answer(s)
A. ATM switches
B. Core routers
E. Frame Relay switches
Explanation
ATM switches, core routers, and Frame Relay switches can be found in the cloud. These devices are commonly used in wide area networks (WANs) to connect multiple networks or locations. ATM switches are used to manage and route data packets in an Asynchronous Transfer Mode network. Core routers are responsible for directing network traffic between different networks. Frame Relay switches are used to connect multiple devices in a Frame Relay network. These devices are typically deployed in cloud-based network architectures to provide efficient and reliable connectivity between different locations or networks.
3.
Which networking device is typically used to concentrate the dial-in and dial-out traffic of multiple users to and from a network?
Correct Answer
B. Access server
Explanation
An access server is a networking device that is typically used to concentrate the dial-in and dial-out traffic of multiple users to and from a network. It acts as a central point for managing and controlling remote access to the network, allowing multiple users to connect and authenticate themselves. This device is commonly used in environments where there is a need for remote access, such as in businesses or organizations with remote employees or branch offices.
4.
Which packet-switched WAN technology offers high-bandwidth connectivity capable of managing data, voice, and video all on the same infrastructure?
Correct Answer
B. Metro Ethernet
Explanation
Metro Ethernet is a packet-switched WAN technology that offers high-bandwidth connectivity capable of managing data, voice, and video all on the same infrastructure. It is a cost-effective solution for businesses that require fast and reliable internet access, as well as the ability to support various types of traffic. With metro Ethernet, organizations can consolidate their network services and reduce the need for multiple connections, resulting in simplified network management and improved efficiency.
5.
Which three features are identified with Frame Relay connections? (Choose three.)
Correct Answer(s)
A. CIR
B. DLCI
D. PVC
Explanation
Frame Relay connections are identified with three features: CIR, DLCI, and PVC.
CIR stands for Committed Information Rate, which is the guaranteed bandwidth that the service provider agrees to provide for the connection.
DLCI stands for Data Link Connection Identifier, which is a unique identifier used to differentiate between different virtual circuits within a Frame Relay network.
PVC stands for Permanent Virtual Circuit, which is a dedicated logical connection between two endpoints in a Frame Relay network.
These three features are essential for establishing and managing Frame Relay connections.
6.
Which WAN technology uses a fixed payload of 48 bytes and is transported across both switched and permanent virtual circuits?
Correct Answer
A. ATM
Explanation
ATM (Asynchronous Transfer Mode) is the correct answer because it uses a fixed payload of 48 bytes. It is a WAN technology that can be transported across both switched and permanent virtual circuits. ATM is known for its high-speed transmission and efficient use of bandwidth, making it suitable for various applications such as voice, video, and data transmission.
7.
What are two advantages of an analog PSTN WAN connection? (Choose two.)
Correct Answer(s)
A. Low cost
B. Availability
Explanation
An analog PSTN WAN connection offers two advantages: low cost and availability. The use of analog technology allows for a simpler and cheaper infrastructure compared to digital alternatives. Additionally, analog connections are widely available, making it easier to establish a connection in various locations. While analog connections do not provide traffic encryption or high available bandwidth, they do support voice and video communication.
8.
What three terms are associated with ISDN PRI? (Choose three.)
Correct Answer(s)
A. Circuit switching
C. Data bearer channels
E. Time-division multiplexing
Explanation
ISDN PRI (Integrated Services Digital Network Primary Rate Interface) is a telecommunications standard that allows for the transmission of voice, video, and data over digital lines. The three terms associated with ISDN PRI are circuit switching, data bearer channels, and time-division multiplexing. Circuit switching refers to the method of establishing a dedicated communication path between two devices, ensuring a consistent connection. Data bearer channels are the individual channels within the ISDN PRI line that can carry voice or data traffic. Time-division multiplexing is the technique used to divide the bandwidth of the ISDN PRI line into multiple channels, allowing for simultaneous transmission of multiple signals.
9.
What can cause a reduction in available bandwidth on a cable broadband connection?
Correct Answer
B. Number of subscribers
Explanation
The number of subscribers can cause a reduction in available bandwidth on a cable broadband connection because as more users connect to the same network, the available bandwidth is divided among them. This can lead to slower speeds and reduced performance for each individual user.
10.
What type of connectivity is established when VPNs are used from the remote site to the private network?
Correct Answer
C. Tunnels
Explanation
When VPNs are used from the remote site to the private network, a type of connectivity called "tunnels" is established. VPNs create secure and encrypted connections over public networks, allowing remote users to access the private network as if they were directly connected to it. These tunnels ensure that the data transmitted between the remote site and the private network remains secure and protected from unauthorized access or interception.
11.
A U.S. company requires a WAN connection used only to transfer sales data from individual stores to the home office. All transfers will occur after business hours. The required bandwidth for this connection is estimated to be less than 38 kbps. Which type of connection requires the least investment for this company?
Correct Answer
C. Analog dialup
Explanation
An analog dialup connection requires the least investment for this company. This is because analog dialup connections are the most basic and inexpensive type of connection. They use existing telephone lines and modems to establish a connection, making them a cost-effective option for low bandwidth requirements like transferring sales data from individual stores to the home office. The estimated bandwidth required for this connection is less than 38 kbps, which can easily be handled by an analog dialup connection.
12.
For digital lines, which device is used to establish the communications link between the customer equipment and the local loop?
Correct Answer
A. CSU/DSU
Explanation
CSU/DSU stands for Channel Service Unit/Data Service Unit. It is a device used to establish the communication link between the customer equipment and the local loop for digital lines. It acts as a bridge between the customer's equipment and the service provider's network, converting the digital signals from the customer's equipment into a format that can be transmitted over the digital line. The CSU/DSU also provides line conditioning and error correction functions to ensure reliable data transmission.
13.
Which term describes a device that will put data on the local loop?
Correct Answer
C. DCE
Explanation
A DCE (Data Circuit-terminating Equipment) is a device that connects to the local loop and is responsible for putting data onto it. It serves as an interface between the customer's equipment (DTE) and the telecommunications network. DLCI (Data Link Connection Identifier) is a term used in Frame Relay networks to identify virtual circuits. BRI (Basic Rate Interface) and PRI (Primary Rate Interface) are types of ISDN (Integrated Services Digital Network) connections. Therefore, the correct answer is DCE.
14.
Which switching type will allow the communication devices in the provider network to be shared and only allocated to an individual subscriber during data transfer?
Correct Answer
D. Packet-switched
Explanation
Packet-switched networks allow communication devices in the provider network to be shared and allocated to individual subscribers during data transfer. In a packet-switched network, data is divided into small packets and sent over the network independently. These packets can take different routes to reach their destination, allowing for efficient use of network resources and sharing of communication devices. This type of switching is commonly used in modern internet communication.
15.
A company needs a WAN connection that is capable of transferring voice, video, and data at a minimum data rate of 155 Mbps. Which WAN connection is the best choice?
Correct Answer
C. ATM
Explanation
ATM (Asynchronous Transfer Mode) is the best choice for the company's WAN connection because it is capable of transferring voice, video, and data at a minimum data rate of 155 Mbps. ATM uses fixed-length cells to efficiently transmit different types of traffic, making it suitable for multimedia applications. X.25, DSL, ISDN BRI, and ISDN PRI may not meet the required data rate or may not be optimized for multimedia traffic, making them less suitable options.
16.
Which two devices are commonly used as data communications equipment? (Choose two.)
Correct Answer(s)
A. Modem
C. CSU/DSU
Explanation
Modems and CSU/DSUs are commonly used as data communications equipment. Modems are used to convert digital signals from a computer into analog signals that can be transmitted over telephone lines, and vice versa. CSU/DSUs, on the other hand, are used to connect data terminal equipment (DTE) to digital lines, providing signal conversion and line conditioning. Both devices play crucial roles in facilitating the transmission of data over various communication networks.
17.
Which statement is true of the functionality of the layers in the hierarchical network model?
Correct Answer
E. The distribution layer aggregates WAN connections at the edge of the campus.
Explanation
The distribution layer in the hierarchical network model is responsible for aggregating WAN (Wide Area Network) connections at the edge of the campus. This layer acts as an intermediary between the access layer and the core layer, and its main function is to provide connectivity between different parts of the network. By aggregating WAN connections, the distribution layer helps to manage and control the flow of data between different areas of the network, ensuring efficient and reliable communication.
18.
Which statement is true about data connectivity between a customer and a service provider?
Correct Answer
B. The segment between the demarcation point and the central office is known as the "last mile."
Explanation
The "last mile" refers to the segment between the demarcation point and the central office. This is the final stretch of connectivity that connects the customer to the service provider's network. The CSU/DSU is the designated demarcation point for the service provider, not the customer. The local loop, on the other hand, is the segment between the CSU/DSU and the serial port on a router. The responsibility of putting data on the local loop lies with the DTE (Data Terminal Equipment).
19.
Which statement is true about the differences between a WAN and a LAN?
Correct Answer
C. A WAN often relies on the services of carriers, such as telepHone or cable companies, but a LAN does not.
Explanation
A WAN often relies on the services of carriers, such as telephone or cable companies, but a LAN does not. This statement is true because WANs are designed to connect devices over longer distances, often spanning multiple cities or even countries. In order to achieve this, WANs require the infrastructure and services provided by carriers, such as telephone or cable companies, to establish and maintain the network connections. On the other hand, LANs are typically confined to a single location, such as a home, office, or campus, and do not require the involvement of carriers as the network can be set up and managed locally.
20.
Why is the call setup time of a circuit-switched WAN implementation considered a drawback?
Correct Answer
D. Data cannot be transferred until a circuit has been established.
Explanation
The call setup time of a circuit-switched WAN implementation is considered a drawback because data cannot be transferred until a circuit has been established. This means that there is a delay in the transmission of data as the circuit needs to be set up before any communication can occur. This can lead to longer wait times and reduced efficiency in data transfer compared to other methods where data can be transferred immediately without the need for circuit establishment.
21.
Which statement about WAN protocols is correct?
Correct Answer
B. Most WAN protocols use HDLC or a variant of HDLC as a framing mechanism.
Explanation
Most WAN protocols use HDLC or a variant of HDLC as a framing mechanism. This means that HDLC is commonly used to encapsulate data and provide synchronization and error checking for data transmission over wide area networks. Other WAN protocols may also use a similar framing mechanism based on HDLC.
22.
What is an advantage of packet-switched technology over circuit-switched technology?
Correct Answer
B. Packet-switched networks can efficiently use multiple routes inside a service provider network.
Explanation
Packet-switched networks can efficiently use multiple routes inside a service provider network. This means that if one route becomes congested or fails, packets can be rerouted through alternative paths, ensuring reliable and efficient data transmission. In contrast, circuit-switched networks rely on a dedicated connection between the sender and receiver, which can be inefficient and costly, especially for long-duration connections. By utilizing multiple routes, packet-switched networks offer increased flexibility, scalability, and fault tolerance, making them advantageous over circuit-switched networks.