Data Over Cable Service Interface Specification Quiz

1. If a 10 dB step attenuator is installed to reduce the amount of ingress/noise that originates in the customer premises what would be the expected improvement in carrier-to-noise C/N?

5 dB.

No change.

10 dB.

15 dB.

Installing a 10 dB step attenuator would result in a 10 dB improvement in carrier-to-noise (C/N) ratio. Attenuators are used to reduce the signal strength, and in this case, it is specifically used to reduce the amount of ingress/noise that originates in the customer premises. By reducing the noise level by 10 dB, the carrier-to-noise ratio improves by the same amount. This means that the carrier signal is now 10 dB stronger compared to the noise, resulting in a better overall signal quality.

Explanation

Installing a 10 dB step attenuator would result in a 10 dB improvement in carrier-to-noise (C/N) ratio. Attenuators are used to reduce the signal strength, and in this case, it is specifically used to reduce the amount of ingress/noise that originates in the customer premises. By reducing the noise level by 10 dB, the carrier-to-noise ratio improves by the same amount. This means that the carrier signal is now 10 dB stronger compared to the noise, resulting in a better overall signal quality.

2. Which of the following devices have diagnostic pages which can be used to confirm and verify operation of the return path?

Most cable modems, test generators, and set-top boxes (STB) have diagnostic pages.

Most leakage detectors, cable emulators, and return path testers have diagnostic pages.

Most cable modems, embedded multimedia terminal adapters (EMTA), and set-top boxes (STB) have diagnostic pages.

Most leakage detectors, cable emulators, and test generators have diagnostic pages.

The correct answer is that most cable modems, embedded multimedia terminal adapters (EMTA), and set-top boxes (STB) have diagnostic pages. This means that these devices can be used to confirm and verify the operation of the return path.

Explanation

The correct answer is that most cable modems, embedded multimedia terminal adapters (EMTA), and set-top boxes (STB) have diagnostic pages. This means that these devices can be used to confirm and verify the operation of the return path.

3. The most common source of ingress and egress is located at which of the following points in the broadband cable network?

At the coax interface on the node.

At the distribution amplifier.

The customer premises and the drop cable.

At the headend.

The customer premises and the drop cable are the most common points of ingress and egress in the broadband cable network. This is because the customer premises is where the cable service is accessed and the drop cable is the physical connection between the network and the customer's location.

Explanation

The customer premises and the drop cable are the most common points of ingress and egress in the broadband cable network. This is because the customer premises is where the cable service is accessed and the drop cable is the physical connection between the network and the customer's location.

4. Where is a logical place to begin troubleshooting a high-speed data (HSD) problem in the customer premises?

The ground block.

The network interface card (NIC) in the customer's computer.

The cable modem.

The customer's wireless router.

The cable modem is a logical place to begin troubleshooting a high-speed data (HSD) problem in the customer premises because it is responsible for establishing the connection between the customer's computer and the internet service provider. If there is an issue with the cable modem, such as a faulty connection or a configuration problem, it can result in a loss of internet connectivity. Therefore, checking the cable modem would be the first step in identifying and resolving the HSD problem.

Explanation

The cable modem is a logical place to begin troubleshooting a high-speed data (HSD) problem in the customer premises because it is responsible for establishing the connection between the customer's computer and the internet service provider. If there is an issue with the cable modem, such as a faulty connection or a configuration problem, it can result in a loss of internet connectivity. Therefore, checking the cable modem would be the first step in identifying and resolving the HSD problem.

5. In a client/server relationship there are two types of client categories: thin clients and thick clients. What is the difference between the two client categories?

Thin clients are not capable of running applications independent of the server. Thick clients are capable of downloading and running installed applications independent of a server.

Thin clients are small portable devices such as laptop computers and smart phones. Thick clients are stationary devices such as desktop and mainframe computers.

Thin clients will only work with one dedicated server. Thick clients will work with multiple servers simultaneously.

Thin clients are used for home applications such as game consoles or to download movies. Thick clients are used for business applications in computers.

Thin clients are client devices that rely on a server to perform most of their processing tasks. They are not capable of running applications independently and require a constant connection to the server to function. On the other hand, thick clients are capable of downloading and running installed applications independently of a server. They have their own processing power and can perform tasks without relying heavily on the server. Thick clients are often used in business settings where more processing power and independence are required.

Explanation

Thin clients are client devices that rely on a server to perform most of their processing tasks. They are not capable of running applications independently and require a constant connection to the server to function. On the other hand, thick clients are capable of downloading and running installed applications independently of a server. They have their own processing power and can perform tasks without relying heavily on the server. Thick clients are often used in business settings where more processing power and independence are required.

6. The converged data/voice network

Solutions need not accommodate features such as automatic attendant capability, teleconferencing, or caller ID.

Fulfills all but the most fundamental aspect of network management of integrating the transport of information cost-effectively.

Uses a variety of hardware and software products for voice digitization and compression that enable voice to be transported on public and private networks originally developed to transport data.

Is required to treat different data types exactly alike and must have high delay for voice telephony, megabit data streams for video, and high error rates for mission-critical data.

The converged data/voice network uses a variety of hardware and software products for voice digitization and compression. This allows voice to be transported on public and private networks that were originally developed to transport data. This explanation highlights the key aspect of the correct answer, which is the use of voice digitization and compression technology to enable voice transmission on data networks.

Explanation

The converged data/voice network uses a variety of hardware and software products for voice digitization and compression. This allows voice to be transported on public and private networks that were originally developed to transport data. This explanation highlights the key aspect of the correct answer, which is the use of voice digitization and compression technology to enable voice transmission on data networks.

7. The first version of the Data Over Cable Service Interface Specification (DOCSIS) was approved as an international standard by what organization?

The Institute of Electrical and Electronics Engineers (IEEE).

The Society of Cable Telecommunications Engineers (SCTE).

The International Organization for Standardization (ISO).

The International Telecommunication Union (ITU).

The correct answer is The International Telecommunication Union (ITU). The ITU is a specialized agency of the United Nations that is responsible for coordinating and standardizing telecommunications and information and communication technologies (ICTs) worldwide. It plays a crucial role in developing and approving international standards for various technologies, including data over cable service interface specification (DOCSIS). Therefore, it makes sense that the first version of DOCSIS was approved as an international standard by the ITU.

Explanation

The correct answer is The International Telecommunication Union (ITU). The ITU is a specialized agency of the United Nations that is responsible for coordinating and standardizing telecommunications and information and communication technologies (ICTs) worldwide. It plays a crucial role in developing and approving international standards for various technologies, including data over cable service interface specification (DOCSIS). Therefore, it makes sense that the first version of DOCSIS was approved as an international standard by the ITU.

8. Which of the following describes the methods used to determine if a set-top box (STB) is non-responsive?

STBs are always in communications with the headend. A non-responsive STB generates an e-mail alert.

STBs send a status message to the cable modem to let it know when it loses contact with the headend.

STBs are polled to see if they respond and a report is created. Non-responsive STBs can result in a significant loss of revenue.

STBs are polled by the EMTA periodically to see if they respond. Non-responsive SIGs are replaced.

STBs are polled to see if they respond and a report is created. This method is used to determine if a set-top box (STB) is non-responsive. Non-responsive STBs can result in a significant loss of revenue, so it is important to monitor their responsiveness. By polling the STBs and creating a report, it allows for easy identification of any non-responsive STBs, allowing for prompt action to be taken to address the issue and minimize revenue loss.

Explanation

STBs are polled to see if they respond and a report is created. This method is used to determine if a set-top box (STB) is non-responsive. Non-responsive STBs can result in a significant loss of revenue, so it is important to monitor their responsiveness. By polling the STBs and creating a report, it allows for easy identification of any non-responsive STBs, allowing for prompt action to be taken to address the issue and minimize revenue loss.

9. During which part of provisioning is the Data Over Cable Service Interface Specification (DOCSIS) modem authorized for high-speed data service?

Ranging and automatic adjustment.

Characterizing.

Registration

Synchronization of data.

The DOCSIS modem is authorized for high-speed data service during the registration process. This is when the modem establishes communication with the cable provider's network and provides necessary information such as its unique identifier and capabilities. Registration ensures that the modem is authorized to access the high-speed data service and enables the provider to manage and monitor the modem's usage.

Explanation

The DOCSIS modem is authorized for high-speed data service during the registration process. This is when the modem establishes communication with the cable provider's network and provides necessary information such as its unique identifier and capabilities. Registration ensures that the modem is authorized to access the high-speed data service and enables the provider to manage and monitor the modem's usage.

10. When aligning the return amplifiers, which method will deliver the most accurate alignment results?

A forward sweep from 54-860 MHz will deliver the most accurate alignment results.

A return sweep from 5-42 MHz will deliver the most accurate alignment results.

Injecting RF frequencies from 5-108 MHz at 6 MHz intervals will deliver the most accurate alignment results.

Injecting RF frequencies from 5-42 MHz at 6 MHz intervals will deliver the most accurate alignment results.

A return sweep from 5-42 MHz will deliver the most accurate alignment results because it covers a narrower frequency range compared to the other options. This allows for a more focused and precise alignment process, ensuring that the return amplifiers are properly calibrated within this specific frequency range. The narrower range also reduces the potential for interference or signal distortion that may occur when aligning over a wider frequency range.

Explanation

A return sweep from 5-42 MHz will deliver the most accurate alignment results because it covers a narrower frequency range compared to the other options. This allows for a more focused and precise alignment process, ensuring that the return amplifiers are properly calibrated within this specific frequency range. The narrower range also reduces the potential for interference or signal distortion that may occur when aligning over a wider frequency range.

11. What are some possible causes of signal reflections?

Overloaded input levels to a house amplifier that are reflected back to their source.

The use of splitters instead of directional couplers in the drop system.

Unpowered house amplifiers that reflect signals back to their source.

Loose or bad connections at the tap or unterminated splitter ports in the drop system.

Possible causes of signal reflections include loose or bad connections at the tap or unterminated splitter ports in the drop system. When there are loose or bad connections, the signal can bounce back instead of being properly transmitted, leading to signal reflections.

Explanation

Possible causes of signal reflections include loose or bad connections at the tap or unterminated splitter ports in the drop system. When there are loose or bad connections, the signal can bounce back instead of being properly transmitted, leading to signal reflections.

12. Why is it a good practice to reboot the customer's computer after you have successfully accessed an Internet site?

Rebooting the computer ensures that the modem provisioning software installed on the computer remains in place.

Rebooting the computer confirms that any changed settings are stored in the computer's memory and that the computer and modem continue to operate together after rebooting.

Rebooting the computer prevents the unintentional downloading of modem-specific features into the customer's computer.

Rebooting the computer ensures that the modem installation client is installed in the customer's computer.

Rebooting the customer's computer after successfully accessing an Internet site is a good practice because it ensures that any changes made to the computer's settings are stored in its memory. This helps to maintain the proper functioning of the computer and modem as they continue to operate together after the reboot.

Explanation

Rebooting the customer's computer after successfully accessing an Internet site is a good practice because it ensures that any changes made to the computer's settings are stored in its memory. This helps to maintain the proper functioning of the computer and modem as they continue to operate together after the reboot.

13. Which of the following describes the primary source of attenuation in the return path?

Attenuation in the return path is primarily due to fiber-optic cable.

Attenuation in the return path is primarily due to the coaxial cable.

Attenuation in the return path is primarily due to the passive devices.

Attenuation in the return path is primarily due to the active devices.

Question #31: Multiple Choice - choose 1 answer (page 4.7)
Which of the following describes the primary source of attenuation in the return path?
A) Attenuation in the return path is primarily due to fiber-optic cable.
B) Attenuation in the return path is primarily due to the coaxial cable.
C) Attenuation in the return path is primarily due to the passive devices.
D) Attenuation in the return path is primarily due to the active devices.

Explanation

Question #31: Multiple Choice - choose 1 answer (page 4.7)
Which of the following describes the primary source of attenuation in the return path?
A) Attenuation in the return path is primarily due to fiber-optic cable.
B) Attenuation in the return path is primarily due to the coaxial cable.
C) Attenuation in the return path is primarily due to the passive devices.
D) Attenuation in the return path is primarily due to the active devices.

14. What would be the downstream throughput if two 256-QAM channels with a throughput of 38 megabits per second (Mbps) were bonded?

38 Mbps.

152 Mbps.

108 Mbps.

76 Mbps.

When two 256-QAM channels are bonded, their throughputs do not simply add up. Instead, the throughput is limited by the channel with the lower throughput. In this case, both channels have a throughput of 38 Mbps, so the maximum downstream throughput when they are bonded would also be 38 Mbps. Therefore, the correct answer is 38 Mbps, not 76 Mbps.

Explanation

When two 256-QAM channels are bonded, their throughputs do not simply add up. Instead, the throughput is limited by the channel with the lower throughput. In this case, both channels have a throughput of 38 Mbps, so the maximum downstream throughput when they are bonded would also be 38 Mbps. Therefore, the correct answer is 38 Mbps, not 76 Mbps.

15. Which of the following is one mode of wireless access?

Analog CDMA technology.

Analog TDMA technology.

Digital CDMA technology.

Digital FDMA technology.

Digital CDMA technology is one mode of wireless access. CDMA stands for Code Division Multiple Access, which is a digital cellular technology that allows multiple users to share the same frequency band simultaneously. It uses spread spectrum techniques to divide the available bandwidth into multiple channels. This enables more efficient use of the spectrum and allows for increased capacity and improved call quality. Analog CDMA and TDMA technologies are outdated and have been replaced by digital technologies. Digital FDMA technology, on the other hand, does not use code division and is not a mode of wireless access.

Explanation

Digital CDMA technology is one mode of wireless access. CDMA stands for Code Division Multiple Access, which is a digital cellular technology that allows multiple users to share the same frequency band simultaneously. It uses spread spectrum techniques to divide the available bandwidth into multiple channels. This enables more efficient use of the spectrum and allows for increased capacity and improved call quality. Analog CDMA and TDMA technologies are outdated and have been replaced by digital technologies. Digital FDMA technology, on the other hand, does not use code division and is not a mode of wireless access.

16. Wireless applications

And equipment include cellular phones, pagers, cordless phones, cordless laptops, palmtops, computer peripheral devices, home entertainment control systems, and other products.

Require a minimum bit rate of 10 kbps to satisfy intersystem matching between wireless and wired LANs.

Using wireless local area network technology can offer substantially higher data rates by increasing the size of the coverage area.

Using cordless and wireless local area network (WLAN) technology have higher mobility and higher cost than cellular systems.

The given answer correctly identifies the various wireless applications and equipment such as cellular phones, pagers, cordless phones, cordless laptops, palmtops, computer peripheral devices, home entertainment control systems, and other products. It accurately lists the different devices that fall under the category of wireless applications and equipment.

Explanation

The given answer correctly identifies the various wireless applications and equipment such as cellular phones, pagers, cordless phones, cordless laptops, palmtops, computer peripheral devices, home entertainment control systems, and other products. It accurately lists the different devices that fall under the category of wireless applications and equipment.

17. Where in the outside plant return path is one of the largest funnel points of RF return signals in the network?

At the directional coupler of the drop farthest away from the node.

At the return amplifier farthest away from the node.

At the node.

At the tap farthest away from the node.

At the node is the correct answer because the node is the central point where the RF return signals from all the drop cables converge. This convergence creates a funnel effect, making the node one of the largest funnel points for RF return signals in the network.

Explanation

At the node is the correct answer because the node is the central point where the RF return signals from all the drop cables converge. This convergence creates a funnel effect, making the node one of the largest funnel points for RF return signals in the network.

18. Which of the following describes thermal noise?

Thermal noise is always present in a transmission path and is created by the temperature fluctuations of the laser in an optical node.

Thermal noise is microwave ingress in a transmission path and is caused by local public safety radio transmissions.

Thermal noise is intermittent in a transmission path and is caused by the occasional electrical switching device like a motor or transformer.

Thermal noise is caused by fluctuations in electron density within amplifier circuitry. As the signal passes through an amplifier, thermal noise is generated and added to the amplified signal.

Thermal noise is caused by fluctuations in electron density within amplifier circuitry. As the signal passes through an amplifier, thermal noise is generated and added to the amplified signal. This means that the noise is inherent to the system and is not caused by external factors such as temperature fluctuations or radio transmissions.

Explanation

Thermal noise is caused by fluctuations in electron density within amplifier circuitry. As the signal passes through an amplifier, thermal noise is generated and added to the amplified signal. This means that the noise is inherent to the system and is not caused by external factors such as temperature fluctuations or radio transmissions.

19. Which of the following statements is true regarding the wireless industry?

It is evolving quickly and rather unpredictably as the products and services are changing.

It has no set of competing standards for communications protocols, interfaces, and networks.

It only uses visible light waves to carry a signal through atmospheric space rather than along a wire.

It has appeal because all frequencies do not require any form of licensing by the Federal Communications Commission.

The wireless industry is constantly changing and evolving at a fast pace, making it unpredictable. This is because new products and services are constantly being developed and introduced. The industry is characterized by rapid advancements, innovations, and emerging technologies, which contribute to its quick and unpredictable nature.

Explanation

The wireless industry is constantly changing and evolving at a fast pace, making it unpredictable. This is because new products and services are constantly being developed and introduced. The industry is characterized by rapid advancements, innovations, and emerging technologies, which contribute to its quick and unpredictable nature.

20. Which of the following is true about cellular technologies?

CDMA spread spectrum technology separates users by assigning them digital codes within the available frequency.

CDMA makes it easy for hackers to grab orderly, meaningful data and does not ensure secure communications.

FDMA divides the frequency spectrum into time slots, and TDMA divides the frequency spectrum into frequency slots.

CDMA has the same capacity of TDMA but nearly 10 times that of FDMA.

CDMA spread spectrum technology separates users by assigning them digital codes within the available frequency. This means that each user is assigned a unique code, allowing multiple users to share the same frequency without interfering with each other. This technology provides a higher capacity for simultaneous communication compared to FDMA and TDMA. It also provides better security as the digital codes make it difficult for hackers to intercept and decipher the data being transmitted.

Explanation

CDMA spread spectrum technology separates users by assigning them digital codes within the available frequency. This means that each user is assigned a unique code, allowing multiple users to share the same frequency without interfering with each other. This technology provides a higher capacity for simultaneous communication compared to FDMA and TDMA. It also provides better security as the digital codes make it difficult for hackers to intercept and decipher the data being transmitted.

21. In the token-passing process,

Each station receives and then regenerates the token.

Network access is disorderly and response time is unpredictable.

If any station or node goes down, the entire network collapses only when bypass software is used.

When the addressed station receives the data, it cannot modify the packet's control field.

In the token-passing process, each station receives and then regenerates the token. This means that the token, which is a special control message, is passed sequentially from one station to another in a network. Each station receives the token, performs its required actions, and then passes the token to the next station. This ensures that each station has an equal opportunity to transmit data and prevents collisions in the network. By regenerating the token, each station ensures that the token keeps circulating in the network, allowing for fair access to the network resources.

Explanation

In the token-passing process, each station receives and then regenerates the token. This means that the token, which is a special control message, is passed sequentially from one station to another in a network. Each station receives the token, performs its required actions, and then passes the token to the next station. This ensures that each station has an equal opportunity to transmit data and prevents collisions in the network. By regenerating the token, each station ensures that the token keeps circulating in the network, allowing for fair access to the network resources.

22. When a Data Over Cable Service Interface Specification (DOCSIS) modem is powered up and connected to the cable system it will automatically begin the initialization process. What is the first step to occur during the initialization process?

Scanning for downstream carrier.

Ranging.

Obtaining an IP address.

Downloading configuration data.

The first step to occur during the initialization process of a DOCSIS modem is scanning for downstream carrier. This is because the modem needs to find and lock onto the downstream signal from the cable system before it can proceed with the rest of the initialization process, such as ranging, obtaining an IP address, and downloading configuration data.

Explanation

The first step to occur during the initialization process of a DOCSIS modem is scanning for downstream carrier. This is because the modem needs to find and lock onto the downstream signal from the cable system before it can proceed with the rest of the initialization process, such as ranging, obtaining an IP address, and downloading configuration data.

23. Microwave-based local area networks

Are available in analog and digital system configurations, with analog configurations dominating the current products.

Must use line-of-sight for the transmit/receive antennas, which cannot be more than about 30 miles apart.

Are not affected by atmospheric conditions such as rain and humidity.

Using digital technology consist of four major components on both sides of the link: modem, RF unit, waveguide, and an antenna.

Microwave-based local area networks must use line-of-sight for the transmit/receive antennas, which cannot be more than about 30 miles apart. This means that there should be a clear path between the antennas without any obstacles such as buildings or trees. This is because microwaves used in these networks have a high frequency and short wavelength, which allows them to transmit data quickly but also makes them susceptible to interference from obstacles. Therefore, the antennas need to be within a certain distance to ensure a clear and reliable connection.

Explanation

Microwave-based local area networks must use line-of-sight for the transmit/receive antennas, which cannot be more than about 30 miles apart. This means that there should be a clear path between the antennas without any obstacles such as buildings or trees. This is because microwaves used in these networks have a high frequency and short wavelength, which allows them to transmit data quickly but also makes them susceptible to interference from obstacles. Therefore, the antennas need to be within a certain distance to ensure a clear and reliable connection.

24. Studies of trouble call resolution data show that the majority of ingress/noise in the upstream originates in the customer premises. What can be installed to eliminate or minimize ingress/noise that originates in the customer premises?

Two-way house amplifiers, window filters, or step attenuators.

High-pass filters, two-way house amplifiers, or step attenuators.

High-pass filters, window filters, or step attenuators.

High-pass filters, window filters, or two-way house amplifiers.

High-pass filters, window filters, and step attenuators can be installed to eliminate or minimize ingress/noise that originates in the customer premises. These devices are designed to filter out unwanted frequencies and attenuate the signal, reducing the interference caused by ingress/noise.

Explanation

High-pass filters, window filters, and step attenuators can be installed to eliminate or minimize ingress/noise that originates in the customer premises. These devices are designed to filter out unwanted frequencies and attenuate the signal, reducing the interference caused by ingress/noise.

25. What is the preferred connection when connecting the cable modem to the customer's computer?

Using an unshielded twisted-pair (UTP) cable.

Using a flat silver-satin telephone cable.

Using a shielded twisted-pair (STP) cable.

Using the universal serial bus (USB) cable.

The preferred connection when connecting the cable modem to the customer's computer is using an unshielded twisted-pair (UTP) cable. This type of cable is commonly used for Ethernet connections and is designed to reduce electromagnetic interference. It is a reliable and cost-effective option for connecting the cable modem to the computer.

Explanation

The preferred connection when connecting the cable modem to the customer's computer is using an unshielded twisted-pair (UTP) cable. This type of cable is commonly used for Ethernet connections and is designed to reduce electromagnetic interference. It is a reliable and cost-effective option for connecting the cable modem to the computer.

26. Which of the following devices is the best choice when trying to isolate the cause of cable telephony or high-speed data (HSD) cable modem performance problems?

A ground fault detector can easily isolate the cause of cable telephony or HSD cable modem problems in the drop system.

A modem emulator function in a signal level meter (SLM) can aid in troubleshooting the cause of cable telephony or HSD cable modem problems in the drop system.

A digital multimeter (DMM) can easily isolate the cause of cable telephony or HSD cable modem problems in the drop system.

A return path tester can be used to easily isolate the cause of cable telephony or HSD cable modem problems in the drop system.

A modem emulator function in a signal level meter (SLM) can aid in troubleshooting cable telephony or high-speed data (HSD) cable modem problems in the drop system. This device can simulate the behavior of a cable modem, allowing technicians to test and diagnose potential issues without actually connecting a real modem. By using the modem emulator function, technicians can isolate the cause of the problems and determine if it is related to the cable modem or other factors in the system. This helps in efficiently identifying and resolving performance issues in cable telephony or HSD cable modem systems.

Explanation

A modem emulator function in a signal level meter (SLM) can aid in troubleshooting cable telephony or high-speed data (HSD) cable modem problems in the drop system. This device can simulate the behavior of a cable modem, allowing technicians to test and diagnose potential issues without actually connecting a real modem. By using the modem emulator function, technicians can isolate the cause of the problems and determine if it is related to the cable modem or other factors in the system. This helps in efficiently identifying and resolving performance issues in cable telephony or HSD cable modem systems.

27. In a cellular phone system,

Typically, every seventh cell uses the same set of frequencies.

Cells use an unlimited number of transmission frequencies.

The base station hands off the call to the mobile switching center in the next cell into which the user is traveling.

Two cells can use the same frequency for different conversations as long as the cells are adjacent to each other.

In a cellular phone system, typically every seventh cell uses the same set of frequencies. This is because the cells are organized in a pattern called a frequency reuse pattern. In this pattern, the available frequencies are divided into groups, and each group is assigned to a set of cells. The cells within each group are spaced apart by a certain distance, such as six cells, so that they do not interfere with each other. This allows for efficient use of the limited frequency spectrum and helps to minimize interference between cells.

Explanation

In a cellular phone system, typically every seventh cell uses the same set of frequencies. This is because the cells are organized in a pattern called a frequency reuse pattern. In this pattern, the available frequencies are divided into groups, and each group is assigned to a set of cells. The cells within each group are spaced apart by a certain distance, such as six cells, so that they do not interfere with each other. This allows for efficient use of the limited frequency spectrum and helps to minimize interference between cells.

28. Synchronous optical network (SONET)

Defines the properties of an optical bit stream that specify the characteristics of optical fiber, which allow data to move across the medium.

Is based upon half the fundamental rate of 150 Mbps.

Is identical to synchronous digital hierarchy.

Cannot be installed over fiber because it was designed to operate over copper cable by ensuring interoperability.

not-available-via-ai

Explanation

not-available-via-ai

29. Dotted decimal notation

Divides a 32-bit IP address into four 8-bit (1-byte) fields, with the value of each field specified as a decimal number.

Expresses IP addresses via the use of three-letter identifiers with "com" or "edu" endings separated by hyphens.

IP addresses can be translated into meaningful and easy-to-remember domain names through the use of an EDU server.

For Class A addresses sets the left-hand bit position in the first byte field to five.

The given answer correctly explains dotted decimal notation. It states that dotted decimal notation divides a 32-bit IP address into four 8-bit (1-byte) fields, with the value of each field specified as a decimal number. This notation is commonly used to represent IP addresses and makes it easier for humans to read and understand the address.

Explanation

The given answer correctly explains dotted decimal notation. It states that dotted decimal notation divides a 32-bit IP address into four 8-bit (1-byte) fields, with the value of each field specified as a decimal number. This notation is commonly used to represent IP addresses and makes it easier for humans to read and understand the address.

30. Which of the following describes why the hybrid fiber/coax (HFC) return path design is especially sensitive to ingress and noise?

Ingress and noise from each drop is filtered at each common point, affecting only the signals from that drop's customer premises equipment (CPE).

Ingress and noise from each drop is carried independently over fiber to the headend where the noise is filtered out.

Ingress and noise from multiple drops along a service area funnels into a common point, affecting all signals from that service area.

Ingress and noise from multiple drops funnels into multiple points along the return path, affecting just the signals from the first service area.

In a hybrid fiber/coax (HFC) return path design, the ingress and noise from multiple drops along a service area all converge into a common point. This means that any ingress or noise from one drop can affect all signals from that entire service area. This sensitivity to ingress and noise is due to the fact that all the signals are funneled into a single point, making it more susceptible to interference.

Explanation

In a hybrid fiber/coax (HFC) return path design, the ingress and noise from multiple drops along a service area all converge into a common point. This means that any ingress or noise from one drop can affect all signals from that entire service area. This sensitivity to ingress and noise is due to the fact that all the signals are funneled into a single point, making it more susceptible to interference.

31. Which eight-position, eight-contact (8P8C) modular connector wiring scheme is recommended for residential use?

ANSI/TIA/EIA-5708.

T568B.

T568A.

Universal Service Order Codes (USOC).

The T568A wiring scheme is recommended for residential use. This wiring scheme is commonly used for Ethernet connections and is the most widely used wiring standard. It specifies the arrangement of the eight wires in the connector, ensuring that the connection is made correctly and consistently. The T568A scheme is compatible with most networking equipment and is the preferred choice for residential installations.

Explanation

The T568A wiring scheme is recommended for residential use. This wiring scheme is commonly used for Ethernet connections and is the most widely used wiring standard. It specifies the arrangement of the eight wires in the connector, ensuring that the connection is made correctly and consistently. The T568A scheme is compatible with most networking equipment and is the preferred choice for residential installations.

32. Which of the following procedures will reduce impulse noise?

Impulse noise can be reduced by transmitting power on the distribution amplifiers.

Impulse noise can be reduced by tightening all connections and installing 75 Q terminators on unused tap ports.

Impulse noise can be reduced by locating taps and splitters close to switching power supplies.

Impulse noise can be reduced by tightening all connections and installing 10 dB attenuator pads on all used tap ports.

Tightening all connections and installing 75 Q terminators on unused tap ports can reduce impulse noise. This is because loose connections can cause signal interference and create noise, while terminators on unused tap ports help to absorb and eliminate any unwanted signals or noise that may be present in the system. By implementing these measures, the overall quality and clarity of the signal can be improved, reducing the impact of impulse noise.

Explanation

Tightening all connections and installing 75 Q terminators on unused tap ports can reduce impulse noise. This is because loose connections can cause signal interference and create noise, while terminators on unused tap ports help to absorb and eliminate any unwanted signals or noise that may be present in the system. By implementing these measures, the overall quality and clarity of the signal can be improved, reducing the impact of impulse noise.

33. How is the data throughput of the hybrid fiber/coax (HFC) network most accurately measured?

From the customer's computer to the throughput server that is connected to the cable modem termination system (CMTS) in the headend or hub.

From the customer's computer to a Web site server on the Internet.

From the customer's computer to a speed test Web site on the Internet.

From the customer's computer to a special cable modem located in the headend or hub.

The data throughput of the hybrid fiber/coax (HFC) network is most accurately measured from the customer's computer to the throughput server that is connected to the cable modem termination system (CMTS) in the headend or hub. This is because the CMTS is the central point where the network connects to the internet and where the data transmission is managed. By measuring the throughput from the customer's computer to this server, it provides an accurate representation of the network's performance and the actual data speed experienced by the customer.

Explanation

The data throughput of the hybrid fiber/coax (HFC) network is most accurately measured from the customer's computer to the throughput server that is connected to the cable modem termination system (CMTS) in the headend or hub. This is because the CMTS is the central point where the network connects to the internet and where the data transmission is managed. By measuring the throughput from the customer's computer to this server, it provides an accurate representation of the network's performance and the actual data speed experienced by the customer.

34. A communications satellite

Contains 42 translators, which are similar to transceivers, each a dedicated communications channel.

Has a translator that receives a signal from an earth station, amplifies the signal, changes its frequency, and then retransmits the signal back to Earth.

Operating at low earth orbit (LEO) is traveling at an elevation between 1,800 and 6,500 miles.

Operating at a geostationary orbit (GEO) is traveling above the equator at an altitude of 22,300 miles.

The correct answer is that operating at a geostationary orbit (GEO) means that the satellite is traveling above the equator at an altitude of 22,300 miles. This type of orbit allows the satellite to remain in a fixed position relative to the Earth's surface, making it ideal for communication purposes. By staying in this orbit, the satellite can provide continuous coverage to a specific region on Earth.

Explanation

The correct answer is that operating at a geostationary orbit (GEO) means that the satellite is traveling above the equator at an altitude of 22,300 miles. This type of orbit allows the satellite to remain in a fixed position relative to the Earth's surface, making it ideal for communication purposes. By staying in this orbit, the satellite can provide continuous coverage to a specific region on Earth.

35. In Ethernet LAN configurations,

The system is described as a heavy-duty network because as the number of hosts increase, the share each gets of the total available bandwidth increases.

The 10BaseT supports a 100 Mbps transmission rate and uses a bus topology, which is implemented by a hub or wiring concentrator.

Gigabit Ethernet can operate over fiber-optic, CAT-5 UTP, and coaxial cabling, typically.

The 100BaseT standard does not support applications and networking software running on 10BaseT networks.

The given answer is correct because Gigabit Ethernet is capable of operating over different types of cabling, including fiber-optic, CAT-5 UTP, and coaxial. This flexibility allows for faster transmission rates and greater bandwidth capacity compared to other Ethernet standards.

Explanation

The given answer is correct because Gigabit Ethernet is capable of operating over different types of cabling, including fiber-optic, CAT-5 UTP, and coaxial. This flexibility allows for faster transmission rates and greater bandwidth capacity compared to other Ethernet standards.

36. If the drop loss at the ground block is 3.2 dB and is connected to a three-way splitter's hot leg and then connected to the 9 dB leg of a directional coupler (DC), what will be the total return path loss?

The drop cable loss is 3.2 dB plus 7.0 dB (the loss of a three-way splitter) plus 9 dB (DC loss), for a total of 19.2 dB in drop return path loss.

The drop cable loss is 3.2 dB minus 3.5 dB (the hot-leg loss of a three-way splitter) plus 9 dB (DC loss) for a total of 8.7 dB in drop return path loss.

The drop cable loss is 3.2 dB plus 3.5 dB (the hot-leg loss of a three-way splitter) plus 9 dB (DC loss), for a total of 15.7 dB in drop return path loss.

The drop cable loss is 3.2 dB plus 3.5 dB (the hot-leg loss of a three-way splitter) minus 9 dB (DC loss), for a total of -2.3dB in drop return path loss.

The total return path loss is calculated by adding the drop cable loss (3.2 dB) to the hot-leg loss of a three-way splitter (3.5 dB) and the DC loss (9 dB). This gives a total of 15.7 dB in drop return path loss.

Explanation

The total return path loss is calculated by adding the drop cable loss (3.2 dB) to the hot-leg loss of a three-way splitter (3.5 dB) and the DC loss (9 dB). This gives a total of 15.7 dB in drop return path loss.

37. Virtual private networks (VPNs)

Maintain the privacy of communications mainly by encrypting and tunneling the data forwarded between sites.

Continue the connection between locations even after the transmission session is terminated.

Are characterized by connections that occur between point-to-point secure clients and are controlled by hardware and switching made prior to the connection.

Are static and maintain permanent links between the end-points that make up the corporate network.

VPNs maintain the privacy of communications by encrypting and tunneling the data forwarded between sites. Encryption ensures that the data is scrambled and cannot be easily understood if intercepted, while tunneling allows the data to be transmitted securely through public networks. By combining these two techniques, VPNs ensure that sensitive information remains private and protected from unauthorized access.

Explanation

VPNs maintain the privacy of communications by encrypting and tunneling the data forwarded between sites. Encryption ensures that the data is scrambled and cannot be easily understood if intercepted, while tunneling allows the data to be transmitted securely through public networks. By combining these two techniques, VPNs ensure that sensitive information remains private and protected from unauthorized access.

38. What layers of the open systems interconnection (OSI) model are applied between Data Over Cable Service Interface Specification (DOCSIS) modems and the cable modem termination system (CMTS)?

Layers four through seven (Transport Layer, Session Layer, Presentation Layer, and Application Layer) are applied between the DOCSIS modem and CMTS.

Layers one through four (Simple Network Management Protocol, Trivial File Transfer Protocol, Dynamic Host Configuration Protocol, and E-mail) are applied between the DOCSIS modem and CMTS.

Layers four through seven (Physical Layer, Data Link Layer, Network Layer, and Transport Layer) are applied between the DOCSIS modem and CMTS.

Layers one through four (Physical Layer, Data Link Layer, Network Layer, and Transport Layer) are applied between the DOCSIS modem and CMTS.

The correct answer is that layers one through four (Physical Layer, Data Link Layer, Network Layer, and Transport Layer) are applied between the DOCSIS modem and CMTS. This means that the communication between the DOCSIS modem and CMTS involves the physical transmission of data, the establishment of a reliable connection, the routing of data packets, and the management of end-to-end communication. These layers are responsible for ensuring that the data is properly transmitted, received, and delivered between the two devices.

Explanation

The correct answer is that layers one through four (Physical Layer, Data Link Layer, Network Layer, and Transport Layer) are applied between the DOCSIS modem and CMTS. This means that the communication between the DOCSIS modem and CMTS involves the physical transmission of data, the establishment of a reliable connection, the routing of data packets, and the management of end-to-end communication. These layers are responsible for ensuring that the data is properly transmitted, received, and delivered between the two devices.

39. What Internet protocol (IP) address modes can a Data Over Cable Service Interface Specification (DOCSIS) 3.0 modem be provisioned in?

IP version 4 (IPv4), IP version 6 (IPv6), dynamic host configuration protocol (DHCP), and dual-stack mode (DPM).

IP version 4 (IPv4), IP version 6 (IPv6), alternate provisioning mode (APM), and dual-stack mode (DPM).

IP version 4 (IPv4), IP version 6 (IPv6), alternate provisioning mode (APM), and dynamic host configuration protocol (DHCP).

IP version 4 (IPv4), IP version 6 (IPv6), IP multicast, and dual-stack mode (DPM).

A Data Over Cable Service Interface Specification (DOCSIS) 3.0 modem can be provisioned in IP version 4 (IPv4), IP version 6 (IPv6), alternate provisioning mode (APM), and dual-stack mode (DPM). This means that the modem can support both IPv4 and IPv6 protocols, as well as different provisioning modes such as APM and DPM. The inclusion of dual-stack mode allows the modem to handle both IPv4 and IPv6 traffic simultaneously.

Explanation

A Data Over Cable Service Interface Specification (DOCSIS) 3.0 modem can be provisioned in IP version 4 (IPv4), IP version 6 (IPv6), alternate provisioning mode (APM), and dual-stack mode (DPM). This means that the modem can support both IPv4 and IPv6 protocols, as well as different provisioning modes such as APM and DPM. The inclusion of dual-stack mode allows the modem to handle both IPv4 and IPv6 traffic simultaneously.

40. Wireless local area networks (WLANs)

Are more reliable than wired LANs; error rates are lower when compared with wired media.

Are regulated by the IEEE 802.11 standard, which defines some common features for connectivity on the 2.4 GHz licensed radio band.

Have the exact same physical medium as the wired media; both are shared and have limited point-to-point connection ranges.

Are flexible communications systems implemented as extensions to or as alternatives for the wired LANs in buildings or on campuses.

Wireless local area networks (WLANs) are flexible communications systems that can be implemented as extensions to or alternatives for wired LANs in buildings or on campuses. They provide the convenience of wireless connectivity, allowing devices to connect to the network without the need for physical cables. WLANs offer flexibility in terms of mobility, as users can move around within the coverage area while maintaining network connectivity. This makes them a suitable choice for environments where wired connections may be impractical or inconvenient.

Explanation

Wireless local area networks (WLANs) are flexible communications systems that can be implemented as extensions to or alternatives for wired LANs in buildings or on campuses. They provide the convenience of wireless connectivity, allowing devices to connect to the network without the need for physical cables. WLANs offer flexibility in terms of mobility, as users can move around within the coverage area while maintaining network connectivity. This makes them a suitable choice for environments where wired connections may be impractical or inconvenient.

41. In ISDN, which of the following is true regarding the basic rate interface (BRI)?

The BRI is appropriate for a business that utilizes a T-1 line, since it offers an economic alternative for connecting analog PBXs, LANs, and other devices to the network.

The BRI uses one "B" channel and 23 "D" channels, all at 128 kbps, yielding a 1.544 Mbps line.

The BRI is a "2B+D" interface, with two 64 kbps bearer ("B") channels that can carry voice, data or video, and one 16 kbps data ("D") channel that provides intelligent line management.

The phone company replaces the basic rate interface (BRI) circuit with a conventional analog circuit.

The BRI interface in ISDN consists of two 64 kbps bearer channels (B channels) that can carry voice, data, or video, and one 16 kbps data channel (D channel) that provides intelligent line management. This configuration allows for simultaneous transmission of multiple types of information over a single BRI line.

Explanation

The BRI interface in ISDN consists of two 64 kbps bearer channels (B channels) that can carry voice, data, or video, and one 16 kbps data channel (D channel) that provides intelligent line management. This configuration allows for simultaneous transmission of multiple types of information over a single BRI line.

42. What is channel bonding?

Channel bonding combines the data throughput of a single channel with a number of channels to achieve a maximum data throughput equal to the cumulative total of the bonded channels.

Channel bonding ties the downstream and upstream RF data carriers to fixed frequencies so that the cable modem always knows what frequency to tune to receive downstream data.

Channel bonding combines the data throughput of up to eight adjacent data channels to create a single wide bandwidth data channel to achieve a maximum data throughput equal to the cumulative total of the bonded channels.

Channel bonding ties the downstream cable modem carrier to the out-of-band (00B) data carrier sent to the digital set-top box (STB) to enable the cable modem to receive television signals over the Internet.

Channel bonding is a technique used to increase the data throughput of a network connection by combining multiple channels. By combining the data throughput of a single channel with a number of additional channels, the maximum data throughput can be increased to the cumulative total of all the bonded channels. This allows for faster and more efficient data transmission, improving overall network performance.

Explanation

Channel bonding is a technique used to increase the data throughput of a network connection by combining multiple channels. By combining the data throughput of a single channel with a number of additional channels, the maximum data throughput can be increased to the cumulative total of all the bonded channels. This allows for faster and more efficient data transmission, improving overall network performance.

43. In the RF return, what is the relationship between noise, data rate, and bandwidth?

The lower the bandwidth, the higher the data throughput, the higher the susceptibility to noise.

The higher the bandwidth, the higher the data throughput, the lower the susceptibility to noise.

The higher the bandwidth, the lower the data throughput, the higher the susceptibility to noise.

The higher the bandwidth, the higher the data throughput, the higher the susceptibility to noise.

The relationship between noise, data rate, and bandwidth is that the higher the bandwidth, the higher the data throughput, and consequently, the higher the susceptibility to noise. This means that as the bandwidth increases, more data can be transmitted, but there is also a greater chance for noise to interfere with the signal. Therefore, a higher bandwidth can result in a higher data rate, but it also increases the likelihood of noise affecting the transmission.

Explanation

The relationship between noise, data rate, and bandwidth is that the higher the bandwidth, the higher the data throughput, and consequently, the higher the susceptibility to noise. This means that as the bandwidth increases, more data can be transmitted, but there is also a greater chance for noise to interfere with the signal. Therefore, a higher bandwidth can result in a higher data rate, but it also increases the likelihood of noise affecting the transmission.

44. Which of the following device applications can be used in a system to reduce ingress noise?

The use of a step attenuator or a high-pass filter on the combiner at the headend will block any noise generated on the drop in the return frequencies from entering the leg.

The use of a step attenuator between the drop and the cable modem will block any noise generated on the drop in the return frequencies from entering the leg.

The use of a diplex filter at the ground block will block any noise generated on the drop in the return frequencies from entering the leg.

The use of a high-pass filter at the tap will block any noise generated on the drop in the return frequencies from entering the leg.

Question #22: Multiple Choke - choose 1 answer (pg 3.8)
Which of the following device applications can be used in a system to reduce ingress noise?
A) The use of a step attenuator or a high-pass filter on the combiner at the headend will block any noise generated on the drop in the return frequencies from entering the leg.
B) The use of a step attenuator between the drop and the cable modem will block any noise generated on the drop in the return frequencies from entering the leg.
C) The use of a diplex filter at the ground block will block any noise generated on the drop in the return frequencies from entering the leg.
D) The use of a high-pass filter at the tap will block any noise generated on the drop in the return frequencies from entering the leg.

Explanation

Question #22: Multiple Choke - choose 1 answer (pg 3.8)
Which of the following device applications can be used in a system to reduce ingress noise?
A) The use of a step attenuator or a high-pass filter on the combiner at the headend will block any noise generated on the drop in the return frequencies from entering the leg.
B) The use of a step attenuator between the drop and the cable modem will block any noise generated on the drop in the return frequencies from entering the leg.
C) The use of a diplex filter at the ground block will block any noise generated on the drop in the return frequencies from entering the leg.
D) The use of a high-pass filter at the tap will block any noise generated on the drop in the return frequencies from entering the leg.

45. What are three primary features of Data Over Cable Service Interface Specification (DOCSIS) version 3.0?

Channel bonding, IP version 6 (IPv6) support, and enhanced use of IP broadcast.

Channel bonding, IP version 6 (IPv6) support, and enhanced use of IP multicast.

Channel bonding, IP version 6 (IPv6) support, and best effort delivery of IP multicast.

Channel bonding, IP version 6 (IPv6) support, and exclusive quality of service (QoS).

The three primary features of DOCSIS version 3.0 are channel bonding, IP version 6 (IPv6) support, and enhanced use of IP multicast. Channel bonding allows for the aggregation of multiple channels to increase data throughput. IPv6 support enables the use of the newer version of the Internet Protocol, which allows for a larger number of unique IP addresses. Enhanced use of IP multicast improves the efficiency of data transmission by allowing for the simultaneous delivery of data to multiple recipients.

Explanation

The three primary features of DOCSIS version 3.0 are channel bonding, IP version 6 (IPv6) support, and enhanced use of IP multicast. Channel bonding allows for the aggregation of multiple channels to increase data throughput. IPv6 support enables the use of the newer version of the Internet Protocol, which allows for a larger number of unique IP addresses. Enhanced use of IP multicast improves the efficiency of data transmission by allowing for the simultaneous delivery of data to multiple recipients.

46. Of the four Internet protocol (IP) provisioning modes available in Data Over Cable Service Interface Specification (DOCSIS) 3.0, which are designed to provide a smooth transition from IP version 4 (IPv4) to IP version 6 (IPv6)?

Dynamic host configuration provisioning (DHCP) and dual-stack provisioning mode (DPM).

Alternate provisioning mode (APM) and multistack provisioning mode (MPM).

Alternate provisioning mode (APM) and dual-stack provisioning mode (DPM).

Alternate provisioning mode (APM) and dynamic host configuration protocol (DHCP) mode.

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Explanation

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47. The cellular network

Since 1969 exclusively has used a simplex mode of operation and manual call placement.

Uses a base station consisting of a transmitter, receiver, controller, and an antenna system and has a wired link to a mobile switching center (MSC).

Is any mobile communications network with a series of overlapping hexagonal cells in a honeycomb pattern.

Began with the advanced mobile phone service (AMPS) that was introduced in the United States in 1993.

The given correct answer states that a cellular network is any mobile communications network with a series of overlapping hexagonal cells in a honeycomb pattern. This is an accurate explanation of a cellular network as it describes the physical layout of the network, where each cell represents a geographic area covered by a base station. The hexagonal shape allows for efficient coverage and minimizes interference between cells. This is a fundamental concept in cellular network design and operation.

Explanation

The given correct answer states that a cellular network is any mobile communications network with a series of overlapping hexagonal cells in a honeycomb pattern. This is an accurate explanation of a cellular network as it describes the physical layout of the network, where each cell represents a geographic area covered by a base station. The hexagonal shape allows for efficient coverage and minimizes interference between cells. This is a fundamental concept in cellular network design and operation.

48. In the contention-based carrier sense multiple access with collision detection (CSMA/CD) system,

Any of the network devices can transmit data onto the network at will; there is no central controller.

Stations are unable to listen to the network to hear if it is in use before they send data.

An interface can transmit when another one is transmitting, a technique called carrier sensing.

The response time is predictable under conditions of a heavily loaded system.

In a contention-based carrier sense multiple access with collision detection (CSMA/CD) system, any network device can transmit data onto the network without the need for a central controller. This means that each device has the freedom to send data whenever it wants. Additionally, stations in this system do not have the ability to listen to the network to check if it is being used before sending data. However, they employ carrier sensing, which allows them to transmit even when another device is already transmitting. This technique helps in preventing collisions. Despite the lack of a central controller, the system still maintains predictable response times even under heavy load conditions.

Explanation

In a contention-based carrier sense multiple access with collision detection (CSMA/CD) system, any network device can transmit data onto the network without the need for a central controller. This means that each device has the freedom to send data whenever it wants. Additionally, stations in this system do not have the ability to listen to the network to check if it is being used before sending data. However, they employ carrier sensing, which allows them to transmit even when another device is already transmitting. This technique helps in preventing collisions. Despite the lack of a central controller, the system still maintains predictable response times even under heavy load conditions.

49. Which of these statements is true about LAN technologies?

The most common baseband LAN technologies are token bus, token ring, fiber distributed data interface, and Ethernet.

Token ring is a 4 or 16 Mbps ring-architectured system, which uses a token-passing access method with unpredictable response time under all loads.

FDDI stations are connected in a dual bus with fiber-optic cable, and the LAN uses the token-passing concept but operating at a slower speed.

Ethernet is a star-architectured broadband system in which each physical link uses a shared media access control (MAC)-addressed port.

The correct answer states that the most common baseband LAN technologies include token bus, token ring, fiber distributed data interface, and Ethernet. This means that these four technologies are widely used in local area networks.

Explanation

The correct answer states that the most common baseband LAN technologies include token bus, token ring, fiber distributed data interface, and Ethernet. This means that these four technologies are widely used in local area networks.

50. Switches

Are transceivers that receive, amplify, and retransmit information.

Are being replaced by hubs and routers as the dominant form of internetworking.

Establish point-to-point connection between ports at the full wire speed of the network.

Have the ability to filter out and block unwanted or unauthorized traffic.

Switches establish point-to-point connections between ports at the full wire speed of the network. This means that they can send and receive data at the maximum speed that the network can handle. Switches are able to direct traffic to the specific port that the intended recipient is connected to, allowing for efficient and direct communication. This is in contrast to hubs and routers, which have different functionalities and are not specifically designed for point-to-point connections.

Explanation

Switches establish point-to-point connections between ports at the full wire speed of the network. This means that they can send and receive data at the maximum speed that the network can handle. Switches are able to direct traffic to the specific port that the intended recipient is connected to, allowing for efficient and direct communication. This is in contrast to hubs and routers, which have different functionalities and are not specifically designed for point-to-point connections.

51. Which of the following statements is true?

A packet will travel through only one network point with a router before arriving at its destination.

Router performance is measured by its packet-forwarding rate.

The gateway is processor-intensive, and the device is designed to link only compatible networks.

A router is a network bridge combined with a switch.

Router performance is commonly measured by its packet-forwarding rate, which refers to the speed at which a router can process and forward packets of data. This is an important metric for evaluating the efficiency and effectiveness of a router in handling network traffic. The other statements in the question are either incorrect or do not provide information about router performance.

Explanation

Router performance is commonly measured by its packet-forwarding rate, which refers to the speed at which a router can process and forward packets of data. This is an important metric for evaluating the efficiency and effectiveness of a router in handling network traffic. The other statements in the question are either incorrect or do not provide information about router performance.

52. In trunking,

Four fast Ethernet ports can be trunked to work only like one big 20 Mbps pipe.

A Layer 2 switch is used as a trunk port.

A networking device bonds multiple physical links into a group that works like one logical link.

A computing device such as a server or desktop computer cannot be used.

The correct answer is that a networking device bonds multiple physical links into a group that works like one logical link. This is known as trunking in networking. Trunking allows for increased bandwidth and redundancy by combining multiple connections into a single logical link. This is commonly used in environments where high network throughput is required, such as data centers or large enterprise networks. By bundling multiple physical links together, the network device can effectively increase the available bandwidth and provide a more efficient and reliable network connection.

Explanation

The correct answer is that a networking device bonds multiple physical links into a group that works like one logical link. This is known as trunking in networking. Trunking allows for increased bandwidth and redundancy by combining multiple connections into a single logical link. This is commonly used in environments where high network throughput is required, such as data centers or large enterprise networks. By bundling multiple physical links together, the network device can effectively increase the available bandwidth and provide a more efficient and reliable network connection.

53. Of the two sets of protocols, transmission control protocol/Internet protocol (TCP/IP) and simple network management protocol (SNMP), which is used for routing the packets of data over the Internet?

TCP/IP provides the basic protocol for directing data traffic over the Internet by dividing the data packet into four elements: the packet sequence; the data; the destination address; and the checksum of data.

TCP/IP provides the basic protocol for directing data traffic over the Internet by dividing the data packet into two elements: the data and the destination address.

SNMP provides the basic protocol for directing data traffic over the Internet by dividing the data packet into four elements: the packet sequence; the data; the destination address; and the checksum of data.

SNMP provides the basic protocol for directing data traffic over the Internet by dividing the data packet into two elements: the data and the destination address.

TCP/IP is the correct answer because it is the set of protocols used for routing packets of data over the Internet. It divides the data packet into four elements: the packet sequence, the data, the destination address, and the checksum of data. This division allows for efficient and reliable transmission of data over the network. SNMP, on the other hand, is a different set of protocols used for network management, not for routing data packets.

Explanation

TCP/IP is the correct answer because it is the set of protocols used for routing packets of data over the Internet. It divides the data packet into four elements: the packet sequence, the data, the destination address, and the checksum of data. This division allows for efficient and reliable transmission of data over the network. SNMP, on the other hand, is a different set of protocols used for network management, not for routing data packets.

54. What is a common solution to impulse noise and ingress problems in the network where tap values are less than 17 dB?

Replacing tap plates of 17 dB or less with higher value tap plates.

Installing high-pass filters on all unused tap ports.

Installing high-pass filters on tap ports that are 17 dB or less.

Installing terminators on all unused tap ports.

Installing terminators on all unused tap ports is a common solution to impulse noise and ingress problems in the network where tap values are less than 17 dB. Terminators help to absorb and eliminate any unwanted signals or noise that may be present on the unused tap ports, ensuring a cleaner and more reliable network signal. This solution is effective in reducing interference and improving the overall performance of the network.

Explanation

Installing terminators on all unused tap ports is a common solution to impulse noise and ingress problems in the network where tap values are less than 17 dB. Terminators help to absorb and eliminate any unwanted signals or noise that may be present on the unused tap ports, ensuring a cleaner and more reliable network signal. This solution is effective in reducing interference and improving the overall performance of the network.

55. In packet-switching networks,

The frame relay layer establishes logical channels and a virtual circuit from each source to each destination.

Each packet contains all of the necessary control and routing information to deliver the packet across the network.

A packet connects two sites, the same as a leased line, except the bandwidth is shared.

Analog circuits deliver error performance of at least 10-9 and often better.

In packet-switching networks, each packet contains all of the necessary control and routing information to deliver the packet across the network. This means that the packet itself carries the information needed for it to be properly routed and delivered to its destination. This is different from other types of networks, such as circuit-switching networks, where the routing information is established beforehand and does not need to be included in each packet. In packet-switching networks, this approach allows for more efficient use of network resources as packets can be dynamically routed based on the information they contain.

Explanation

In packet-switching networks, each packet contains all of the necessary control and routing information to deliver the packet across the network. This means that the packet itself carries the information needed for it to be properly routed and delivered to its destination. This is different from other types of networks, such as circuit-switching networks, where the routing information is established beforehand and does not need to be included in each packet. In packet-switching networks, this approach allows for more efficient use of network resources as packets can be dynamically routed based on the information they contain.

56. The use of a directional coupler requires which of the following adjustments in the return paths?

Each return amplifier must be adjusted so that the levels received at the next amplifier are 25 dBmV.

The output of each return amplifier must be adjusted so that the input levels received at the next amplifier are the same.

Each return amplifier must be adjusted by the decibel (dB) value of the directional coupler (DC).

Each return amplifier must be adjusted so that the levels received at the next amplifier are within 15 dB of each other.

Each return amplifier must be adjusted so that the input levels received at the next amplifier are the same. This is because a directional coupler is used to split the signal between the main path and the return path. In order to ensure proper signal transmission, the input levels at each amplifier in the return path must be balanced and consistent. Adjusting the output of each return amplifier to match the input levels at the next amplifier ensures that the signal is properly distributed and avoids any signal loss or distortion.

Explanation

Each return amplifier must be adjusted so that the input levels received at the next amplifier are the same. This is because a directional coupler is used to split the signal between the main path and the return path. In order to ensure proper signal transmission, the input levels at each amplifier in the return path must be balanced and consistent. Adjusting the output of each return amplifier to match the input levels at the next amplifier ensures that the signal is properly distributed and avoids any signal loss or distortion.

57. When using a digital signal analyzer to troubleshoot data throughput in the Data Over Cable Service Interface Specification (DOCSIS) network, what is the minimum modulation error ratio (MER) into the cable modem for a 256-QAM carrier?

26 dB or less.

32 dB or greater.

32 dB or less.

26 dB or greater.

The minimum modulation error ratio (MER) into the cable modem for a 256-QAM carrier in the DOCSIS network is 32 dB or greater. This means that the MER value should be at least 32 dB or higher for proper data throughput. A higher MER indicates better signal quality and less error in the modulation. Therefore, a minimum of 32 dB or greater is required to ensure reliable data transmission in the DOCSIS network.

Explanation

The minimum modulation error ratio (MER) into the cable modem for a 256-QAM carrier in the DOCSIS network is 32 dB or greater. This means that the MER value should be at least 32 dB or higher for proper data throughput. A higher MER indicates better signal quality and less error in the modulation. Therefore, a minimum of 32 dB or greater is required to ensure reliable data transmission in the DOCSIS network.

58. In the client/server network,

Some hardware and software, such as the network interface card (NIC) and the network drivers, reside in the server.

The software that interacts between an application and a network is defined as client software.

The network operating system (NOS) software resides on a computer called the "server."

The cost of hardware maintenance is significantly increased because the client machines are more complex and expensive.

The correct answer is that the network operating system (NOS) software resides on a computer called the "server." This means that the server is responsible for managing and controlling the network, including tasks such as user authentication, file sharing, and network security. The client machines, on the other hand, do not have the NOS software installed and rely on the server to provide network services. This arrangement allows for centralized management and control of the network, but it also means that the server requires more powerful hardware and maintenance compared to the client machines.

Explanation

The correct answer is that the network operating system (NOS) software resides on a computer called the "server." This means that the server is responsible for managing and controlling the network, including tasks such as user authentication, file sharing, and network security. The client machines, on the other hand, do not have the NOS software installed and rely on the server to provide network services. This arrangement allows for centralized management and control of the network, but it also means that the server requires more powerful hardware and maintenance compared to the client machines.

59. Which of the following statements is true?

If reliability is ensured at a higher layer, such as the application layer, then UDP, which is less efficient than TCP, cannot be used for transport.

TCP cannot be used with 051 Layer 3 protocols such as IP.

In comparison with TCP, UDP is a reliable, connection- oriented protocol with more overhead.

Connectionless means that a protocol does not require a session to be established between two devices, and transmission occurs on a best-effort basis.

The statement that connectionless means that a protocol does not require a session to be established between two devices, and transmission occurs on a best-effort basis is true. Connectionless protocols, such as UDP, do not establish a dedicated connection between devices before transmitting data. Instead, they send data packets independently, without any guarantee of delivery or order. This best-effort approach allows for faster transmission and lower overhead compared to connection-oriented protocols like TCP, which require a connection setup and guarantee reliable delivery.

Explanation

The statement that connectionless means that a protocol does not require a session to be established between two devices, and transmission occurs on a best-effort basis is true. Connectionless protocols, such as UDP, do not establish a dedicated connection between devices before transmitting data. Instead, they send data packets independently, without any guarantee of delivery or order. This best-effort approach allows for faster transmission and lower overhead compared to connection-oriented protocols like TCP, which require a connection setup and guarantee reliable delivery.

60. Internet protocol version 4 (IPv4)

Multicast addressing for Class D networks is decreasing in usage because it consumes too much bandwidth.

Addressing supports five different network classes, with the bits to the far left indicating the network class.

Addressing requires a unique 48-bit address for each host on an IP-based network.

Addresses for Class A networks are intended mainly for use with small networks, with a maximum of 200 Class A networks available.

The explanation provided states that addressing supports five different network classes, with the bits to the far left indicating the network class. This means that the first few bits of an IP address determine the network class to which it belongs. This is a correct statement and accurately describes how addressing works in IPv4.

Explanation

The explanation provided states that addressing supports five different network classes, with the bits to the far left indicating the network class. This means that the first few bits of an IP address determine the network class to which it belongs. This is a correct statement and accurately describes how addressing works in IPv4.

61. Which of the following describes the typical sub-band return frequency design for a cable modem?

Most cable modems are configured to operate above 38 and below 42 MHz.

Most cable modems are configured to operate above 5 and below 20 MHz.

Most cable modems are configured to operate above 38 and below 54 MHz.

Most cable modems are configured to operate above 28 and below 38 MHz.

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Explanation

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62. What is committed information rate (CIR)?

Is a guaranteed rate of throughput when using frame relay.

Is based on five classes of service, which provides control over how much information a node can place on the network.

Is equal to total throughput added to the Br and Be values.

Is not allowed by some carriers, who limit the maximum throughput to the bursting rate.

CIR stands for committed information rate and it refers to a guaranteed rate of throughput when using frame relay. This means that when using frame relay, the network provider ensures a minimum level of bandwidth for the user, regardless of the network conditions or other traffic. This ensures that the user will always have a certain level of performance and can rely on a consistent data transfer rate.

Explanation

CIR stands for committed information rate and it refers to a guaranteed rate of throughput when using frame relay. This means that when using frame relay, the network provider ensures a minimum level of bandwidth for the user, regardless of the network conditions or other traffic. This ensures that the user will always have a certain level of performance and can rely on a consistent data transfer rate.

63. A digital subscriber line (DSL)

Accommodates ordinary analog telephone calls over a different wire connection that uses the "D" channel.

Cannot be implemented on most of the existing copper infrastructure.

Supports a wide variety of high-bandwidth applications including virtual private networking and streaming multimedia content.

Uses a line-sharing technique that is a simplified form of old-fashioned time division multiplexing.

DSL supports a wide variety of high-bandwidth applications including virtual private networking and streaming multimedia content. This means that DSL can handle the demands of these applications, allowing users to access high-quality video streaming and connect securely to private networks.

Explanation

DSL supports a wide variety of high-bandwidth applications including virtual private networking and streaming multimedia content. This means that DSL can handle the demands of these applications, allowing users to access high-quality video streaming and connect securely to private networks.

64. The zero span and max hold features of a spectrum analyzer allow accurate measurement of which of the following impairments?

Service interruptions from laser clipping.

Fluctuations in thermal noise.

Six MHz intermodulation beats due to common path distortion.

Fast transient signals such as impulse noise.

The zero span and max hold features of a spectrum analyzer allow accurate measurement of fast transient signals such as impulse noise. These features freeze the display and capture the maximum signal level, allowing the user to analyze and measure the characteristics of these transient signals. This is useful in identifying and troubleshooting issues related to impulse noise in a system.

Explanation

The zero span and max hold features of a spectrum analyzer allow accurate measurement of fast transient signals such as impulse noise. These features freeze the display and capture the maximum signal level, allowing the user to analyze and measure the characteristics of these transient signals. This is useful in identifying and troubleshooting issues related to impulse noise in a system.

65. Which of the following mitigation devices provide filtering on sub-split return frequencies as described?

Window filters act on specific frequencies from 5-42 MHz.

Window filters act on specific frequencies above 5-42 MHz.

Step attenuators provide 100 dB of attenuation on frequencies from 5-42 MHz.

High-pass filters block all frequencies above 108 MHz.

The correct answer is "Window filters act on specific frequencies from 5-42 MHz." This answer states that window filters are designed to work on frequencies within the range of 5-42 MHz. This implies that window filters provide filtering on sub-split return frequencies within this range.

Explanation

The correct answer is "Window filters act on specific frequencies from 5-42 MHz." This answer states that window filters are designed to work on frequencies within the range of 5-42 MHz. This implies that window filters provide filtering on sub-split return frequencies within this range.

66. A local area network (LAN)

Uses the bus topology to put the secondary station in control of all communication on the bus.

Uses the star topology to place the secondary station at the center, allowing connection to all primary stations.

Uses the peer-to-peer bus topology to enable any station to initiate communication with any other station through a primary station.

Uses the ring topology to eliminate the problems with contention found on peer-to-peer bus networks.

A local area network (LAN) uses the ring topology to eliminate the problems with contention found on peer-to-peer bus networks. In a ring topology, each station is connected to its adjacent stations in a closed loop, forming a ring. This eliminates the need for a central hub or server and allows each station to directly communicate with its neighboring stations. This arrangement reduces the chances of collisions and contention, as only one station can transmit data at a time. Therefore, the ring topology is ideal for LANs as it ensures efficient and reliable communication between stations.

Explanation

A local area network (LAN) uses the ring topology to eliminate the problems with contention found on peer-to-peer bus networks. In a ring topology, each station is connected to its adjacent stations in a closed loop, forming a ring. This eliminates the need for a central hub or server and allows each station to directly communicate with its neighboring stations. This arrangement reduces the chances of collisions and contention, as only one station can transmit data at a time. Therefore, the ring topology is ideal for LANs as it ensures efficient and reliable communication between stations.

67. Which statement is true for frame relay?

Frame relay uses error checking at every node and continual message exchange regarding the progress of packets.

Frame relay uses a technique called distributed queue on a dual bus, which distributes the network requests of users into queues to handle information transfer.

Frame relay was designed to ensure guaranteed data delivery and integrity because its circuits have analog error rates of 10-sto 10-6.

Each node on the network only checks the address but never verifies the payload and passes the frame along a predetermined path.

Frame relay is a packet-switching technology that operates at the data link layer of the OSI model. The correct answer states that each node on the network only checks the address but never verifies the payload and passes the frame along a predetermined path. This means that frame relay does not perform error checking at every node and does not involve continual message exchange regarding the progress of packets. Instead, it relies on the addressing information to determine the path for packet forwarding, which makes it a more efficient and faster technology compared to other protocols like X.25.

Explanation

Frame relay is a packet-switching technology that operates at the data link layer of the OSI model. The correct answer states that each node on the network only checks the address but never verifies the payload and passes the frame along a predetermined path. This means that frame relay does not perform error checking at every node and does not involve continual message exchange regarding the progress of packets. Instead, it relies on the addressing information to determine the path for packet forwarding, which makes it a more efficient and faster technology compared to other protocols like X.25.

68. Which of the following methods is employed to reduce traffic congestion on a hybrid fiber/coax (HFC) network?

Installing separate drops for high-speed data (HSD), cable telephony, and cable television service.

Splitting the distribution legs into separate optical return paths.

Funneling in more distribution legs into a single optical node.

Reducing the number of cable modem termination system (CMTS) ports in the headend.

Splitting the distribution legs into separate optical return paths is a method employed to reduce traffic congestion on a hybrid fiber/coax (HFC) network. By separating the distribution legs, the network can handle more traffic and reduce congestion. This allows for better performance and faster speeds for high-speed data (HSD), cable telephony, and cable television service.

Explanation

Splitting the distribution legs into separate optical return paths is a method employed to reduce traffic congestion on a hybrid fiber/coax (HFC) network. By separating the distribution legs, the network can handle more traffic and reduce congestion. This allows for better performance and faster speeds for high-speed data (HSD), cable telephony, and cable television service.

69. Transmission control protocol/Internet protocol (TCP/IP)

Has become the least accepted set of protocols in the telecommunications industry.

Was the result of a development effort to reach heterogeneous connectivity in packet-switched networks.

Uses session and presentation layers for all of its standard services.

Is a true international standard (not a de facto standard) for global educational and government industries.

TCP/IP was developed to achieve connectivity between different types of networks in a packet-switched environment. It was designed to be compatible with various types of hardware and software, allowing for seamless communication between different systems. This development effort was necessary to ensure that data could be transmitted effectively and reliably across diverse networks, making TCP/IP a widely accepted set of protocols in the telecommunications industry.

Explanation

TCP/IP was developed to achieve connectivity between different types of networks in a packet-switched environment. It was designed to be compatible with various types of hardware and software, allowing for seamless communication between different systems. This development effort was necessary to ensure that data could be transmitted effectively and reliably across diverse networks, making TCP/IP a widely accepted set of protocols in the telecommunications industry.

70. Why are maintenance practices for two-way broadband cable systems more complex than for one-way systems?

Noise funneling the accumulation of noise from different sources, travels downstream from the customer premises to the headend.

Ingress that appears in the upstream frequencies, which is of no consequence in the downstream, must be identified and eliminated.

Ingress that appears in the downstream frequencies, which is of no consequence in the upstream, must be identified and eliminated.

Noise funneling the accumulation of noise from different sources, travels downstream from the headend to the customer premises.

In two-way broadband cable systems, there is both upstream and downstream communication. This means that noise and interference can occur in both directions. However, the ingress that appears in the upstream frequencies, which is of no consequence in the downstream, must be identified and eliminated. This adds complexity to the maintenance practices because it requires specific measures to identify and eliminate the ingress in the upstream frequencies without affecting the downstream communication.

Explanation

In two-way broadband cable systems, there is both upstream and downstream communication. This means that noise and interference can occur in both directions. However, the ingress that appears in the upstream frequencies, which is of no consequence in the downstream, must be identified and eliminated. This adds complexity to the maintenance practices because it requires specific measures to identify and eliminate the ingress in the upstream frequencies without affecting the downstream communication.

71. The voice over IP (VoIP)

Resource reservation protocol lets all applications share a path across an IP network, even when resources are inadequate to provide the required level of service.

Real-time transport protocol is implemented in applications that do not need much bandwidth, but is unable to compensate for any packet loss.

H.323 protocol is the recommended standard for multimedia transmission on wide area and packet networks that have a guaranteed bandwidth.

Open settlement protocol involves a dedicated server to handle authentication, authorization, call routing, and call detail over IP networks.

The Open settlement protocol is a protocol that involves a dedicated server to handle various tasks such as authentication, authorization, call routing, and call detail over IP networks. This means that it provides a centralized system for managing these functions, ensuring that they are handled efficiently and effectively. By using a dedicated server, the protocol can ensure that these tasks are performed reliably and securely, allowing for smooth communication over IP networks.

Explanation

The Open settlement protocol is a protocol that involves a dedicated server to handle various tasks such as authentication, authorization, call routing, and call detail over IP networks. This means that it provides a centralized system for managing these functions, ensuring that they are handled efficiently and effectively. By using a dedicated server, the protocol can ensure that these tasks are performed reliably and securely, allowing for smooth communication over IP networks.

72. Why is data throughput an effective measurement of the network's technical integrity?

Because data throughput is an obscure measurement that the customer is unable to relate to their service.

Because the data throughput measurement is derived from data packets traveling downstream only, separating downstream issues from upstream issues.

Because data throughput is an easy measurement that can be accurately obtained by the customer going to a generic speed test site on the Internet.

Because data throughput can be compromised by traffic congestion and errors introduced during transport through the network.

Data throughput is an effective measurement of the network's technical integrity because it reflects the actual speed at which data is being transferred through the network. It takes into account factors such as traffic congestion and errors during transport, which can significantly impact the network's performance. By monitoring data throughput, network administrators can identify and address any issues that may be affecting the network's efficiency and reliability.

Explanation

Data throughput is an effective measurement of the network's technical integrity because it reflects the actual speed at which data is being transferred through the network. It takes into account factors such as traffic congestion and errors during transport, which can significantly impact the network's performance. By monitoring data throughput, network administrators can identify and address any issues that may be affecting the network's efficiency and reliability.

73. Digital FDMA technology.

Can carry data along with voice by digitizing the voice, expanding it, and then transmitting the voice interspersed with other conversations.

Was rejected as the access technique for the global system for mobile communications (GSM) system.

Allocates only two time slots per 30 kHz channel.

Digital technology is designed to coexist with the analog AMPS.

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Explanation

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74. If a customer already has cable television service and is adding high-speed data service, what should be checked on the digital television channels?

Intermittent operation which is a symptom of noise or interference in the downstream.

Intermittent operation which is a symptom of noise or interference in the upstream.

Buzzing audio and horizontal lines, which become quite obvious on digital channels.

The video and audio carrier levels to make sure that they are on frequency and that their respective levels are 15 dB, plus or minus 2 dB.

When a customer adds high-speed data service to their existing cable television service, it is important to check for intermittent operation on the digital television channels. This can be a symptom of noise or interference in the downstream, which may affect the quality of the signal. By identifying and addressing any issues with noise or interference, the customer can ensure a smooth and uninterrupted viewing experience.

Explanation

When a customer adds high-speed data service to their existing cable television service, it is important to check for intermittent operation on the digital television channels. This can be a symptom of noise or interference in the downstream, which may affect the quality of the signal. By identifying and addressing any issues with noise or interference, the customer can ensure a smooth and uninterrupted viewing experience.

75. How does a cable modem know what frequency and carrier level it should transmit upstream?

When powered on and connected to cable system, the cable modem receives an upstream channel descriptor (UCD) which contains upstream transmission parameters, including frequency and carrier level.

After it is authorized for service, the cable modem receives an upstream channel descriptor (UCD) which contains upstream transmission parameters, including frequency and carrier level.

The installer enters the modem's upstream transmission parameters, including frequency and carrier level, into the modem's configuration file during its activation.

During initialization the cable modem receives upstream transmission parameters, including frequency and carrier level, that were entered for the modem's location in the system.

The cable modem knows what frequency and carrier level it should transmit upstream after it is authorized for service because it receives an upstream channel descriptor (UCD) which contains the necessary transmission parameters. This UCD is sent to the modem once it is connected to the cable system and powered on.

Explanation

The cable modem knows what frequency and carrier level it should transmit upstream after it is authorized for service because it receives an upstream channel descriptor (UCD) which contains the necessary transmission parameters. This UCD is sent to the modem once it is connected to the cable system and powered on.

76. Which statement is true for asynchronous transfer mode (ATM)?

The ATM layer adds a 53-byte header with connection and QoS information to each cell and passes the cell to the application layer.

An ATM cell consists of 155 8-bit bytes, with the 155-byte cell size resulting from a compromise between voice and video communications.

ATM is a connectionless protocol that requires a single virtual path to be set up for all flows.

ATM's ability to create virtual paths and channels means that multiple customers' traffic can be carried on a single network without security concerns or encryption overhead.

ATM's ability to create virtual paths and channels allows for the consolidation of multiple customers' traffic onto a single network without the need for security concerns or encryption overhead. This means that different customers can share the same network infrastructure while maintaining their own separate virtual paths, ensuring privacy and security for each customer's data. Additionally, the use of virtual paths and channels allows for efficient utilization of network resources and effective management of traffic flows.

Explanation

ATM's ability to create virtual paths and channels allows for the consolidation of multiple customers' traffic onto a single network without the need for security concerns or encryption overhead. This means that different customers can share the same network infrastructure while maintaining their own separate virtual paths, ensuring privacy and security for each customer's data. Additionally, the use of virtual paths and channels allows for efficient utilization of network resources and effective management of traffic flows.

77. Packet over SONET

Requires ATM to map IP packets directly onto SONET frames.

Makes a network that uses a combination of T-1 and T-3 lines for voice and data a prime candidate for redesign.

Transfers packets with less efficiency of bandwidth than over ATM on an OC-3 link.

Protocols are optimized for fixed-length packets rather than variable length ATM cells.

The given answer states that using Packet over SONET makes a network that uses a combination of T-1 and T-3 lines for voice and data a prime candidate for redesign. This implies that Packet over SONET may not be the most efficient or suitable solution for a network that uses T-1 and T-3 lines. The answer suggests that redesigning the network may be necessary to improve its efficiency and effectiveness.

Explanation

The given answer states that using Packet over SONET makes a network that uses a combination of T-1 and T-3 lines for voice and data a prime candidate for redesign. This implies that Packet over SONET may not be the most efficient or suitable solution for a network that uses T-1 and T-3 lines. The answer suggests that redesigning the network may be necessary to improve its efficiency and effectiveness.

78. Internet protocol (IP)

Consists of end-to-end error checking and acknowledgement, making it a highly reliable protocol.

Segments and packetizes data for transmission and then applies a header for delivery.

Headers include the source address but not the destination address, enabling an end-to-end data flow.

Routing specifies that IP datagrams travel through internetworks with the entire route known at the outset of the journey.

The correct answer is "Segments and packetizes data for transmission and then applies a header for delivery." This is because the given information states that the Internet Protocol (IP) segments and packetizes data, which means it breaks the data into smaller units called packets. It then applies a header, which contains information such as the source address, to each packet for delivery. This process allows for the efficient and reliable transmission of data over the internet.

Explanation

The correct answer is "Segments and packetizes data for transmission and then applies a header for delivery." This is because the given information states that the Internet Protocol (IP) segments and packetizes data, which means it breaks the data into smaller units called packets. It then applies a header, which contains information such as the source address, to each packet for delivery. This process allows for the efficient and reliable transmission of data over the internet.

79. Quality of service in an IP network

Is the focus of two protocols, DiffServ and multiprotocol label switching.

Is not affected by changes in network traffic load.

Gives all packets equal priority in a congested network.

Uses multiprotocol services switching, which works with IP, ATM, and frame relay protocols by forwarding packets at Layer 3 rather than Layer 2.

Quality of service in an IP network is the main concern of two protocols, DiffServ and multiprotocol label switching. These protocols aim to enhance the performance and efficiency of network traffic by prioritizing certain packets over others. They achieve this by implementing various mechanisms such as traffic classification, packet marking, and traffic shaping. By focusing on quality of service, these protocols ensure that critical data, such as real-time video or voice, receives higher priority and is delivered with minimal delay and loss, thus improving the overall network performance.

Explanation

Quality of service in an IP network is the main concern of two protocols, DiffServ and multiprotocol label switching. These protocols aim to enhance the performance and efficiency of network traffic by prioritizing certain packets over others. They achieve this by implementing various mechanisms such as traffic classification, packet marking, and traffic shaping. By focusing on quality of service, these protocols ensure that critical data, such as real-time video or voice, receives higher priority and is delivered with minimal delay and loss, thus improving the overall network performance.

80. The high-level data link control (HDLC) frame format

Uses five bytes (24 bits) of control information to describe the type of HDLC frame, routing parameters, and other packet identifiers.

Is specified as the standard protocol for Layer 15 in the OSI model.

Consists of raw data or information and an overhead that envelops the raw data.

Allows every device to send (but not receive) information without being controlled by any other device.

The HDLC frame format consists of raw data or information and an overhead that envelops the raw data. This means that the frame not only carries the actual data but also includes additional information such as control information, routing parameters, and packet identifiers. The overhead is necessary for the proper functioning and interpretation of the data being transmitted.

Explanation

The HDLC frame format consists of raw data or information and an overhead that envelops the raw data. This means that the frame not only carries the actual data but also includes additional information such as control information, routing parameters, and packet identifiers. The overhead is necessary for the proper functioning and interpretation of the data being transmitted.

81. An asynchronous transfer mode-passive optical network (ATM-PON)

Is an optical-access architecture that facilitates broadband communications over an active optical distribution network.

Provides a dedicated optical connection that is secure all the way to the central office.

Architecture has a minimum of 32 ONUs that can share the capacity of a single fiber using passive optical splitter/ combiner technology.

Applies a framing structure to the upstream signals to support multimode operation.

The correct answer is "Provides a dedicated optical connection that is secure all the way to the central office." This means that the ATM-PON architecture ensures that the optical connection from the user to the central office is dedicated and secure, without any interference or sharing with other users. This is important for maintaining the privacy and security of the data being transmitted over the network.

Explanation

The correct answer is "Provides a dedicated optical connection that is secure all the way to the central office." This means that the ATM-PON architecture ensures that the optical connection from the user to the central office is dedicated and secure, without any interference or sharing with other users. This is important for maintaining the privacy and security of the data being transmitted over the network.

82. What are some considerations when seeking a power source for the cable modem?

The cable modem power supply should be plugged into a dedicated electrical outlet that will not be switched off and has no other appliances or devices plugged into it.

The cable modem power supply should be plugged into an electrical outlet that will not be switched off, near the customer's computer, and in a well-ventilated area so that it remains cool.

The cable modem power supply should be plugged into an electrical outlet that will not be switched off and because of its size is not likely to be unplugged.

The cable modem power supply should be plugged into an electrical outlet that will be switched off and because of its size is not likely to be unplugged.

The cable modem power supply should be plugged into an electrical outlet that will not be switched off and because of its size is not likely to be unplugged. This is important because if the power source is switched off, the cable modem will lose power and the internet connection will be disrupted. Additionally, if the power supply is unplugged, the cable modem will also lose power. Therefore, it is necessary to have a dedicated electrical outlet that will remain on and ensure the cable modem stays connected to the power source.

Explanation

The cable modem power supply should be plugged into an electrical outlet that will not be switched off and because of its size is not likely to be unplugged. This is important because if the power source is switched off, the cable modem will lose power and the internet connection will be disrupted. Additionally, if the power supply is unplugged, the cable modem will also lose power. Therefore, it is necessary to have a dedicated electrical outlet that will remain on and ensure the cable modem stays connected to the power source.

83. The TCP/IP-based application

That sends standard, interoperable text messages from one computer system to another is called the simple mail transfer protocol.

Post office protocol (POP) provides a store-and-forward mechanism that ensures clients connected to the network are able to retrieve e-mail via the Internet.

FTP can tolerate packet loss, but TELNET cannot because it is bandwidth-intensive.

Known as point-to-point protocol (PPP) was designed to route a single protocol over always-on links through point-to-point separations.

The TCP/IP-based application that sends standard, interoperable text messages from one computer system to another is called the simple mail transfer protocol (SMTP). SMTP is commonly used for sending and receiving emails over the internet. It provides a reliable and efficient method for transferring email messages between mail servers. SMTP ensures that the messages are delivered to the intended recipients by following a set of protocols and standards that allow different mail systems to communicate with each other.

Explanation

The TCP/IP-based application that sends standard, interoperable text messages from one computer system to another is called the simple mail transfer protocol (SMTP). SMTP is commonly used for sending and receiving emails over the internet. It provides a reliable and efficient method for transferring email messages between mail servers. SMTP ensures that the messages are delivered to the intended recipients by following a set of protocols and standards that allow different mail systems to communicate with each other.

84. Each version of the Data Over Cable Service Interface Specification (DOCSIS) adds features and improvements over the previous version. What features does DOCSIS 2.0 add?

Increased bandwidth of the upstream and advanced access systems so that higher orders of modulation (and higher data rates) are possible.

Increased bandwidth of the upstream and advanced access systems so that lower orders of modulation (and higher data rates) are possible.

Increased bandwidth of the upstream so that enhanced security and adaptive equalization in the upstream path for improved data throughput are possible.

Increased bandwidth of the downstream with advanced access systems so that higher orders of modulation (and higher data rates) are possible.

DOCSIS 2.0 adds increased bandwidth to the upstream and advanced access systems, allowing for higher orders of modulation and higher data rates. This means that data can be transmitted at faster speeds and with more efficient use of the available spectrum. This improvement in bandwidth enables better performance and increased capacity for data transmission in the upstream direction.

Explanation

DOCSIS 2.0 adds increased bandwidth to the upstream and advanced access systems, allowing for higher orders of modulation and higher data rates. This means that data can be transmitted at faster speeds and with more efficient use of the available spectrum. This improvement in bandwidth enables better performance and increased capacity for data transmission in the upstream direction.

85. How does IP multicast differ from IP broadcast?

IP multicast traffic is only sent to specific modem addresses on the network; IP broadcast traffic is sent to all modems on the network.

IP multicast traffic is only sent to one modem at a time on the network; IP broadcast traffic is sent to all modems on the network all the time.

IP multicast traffic is sent to all modems on the network; IP broadcast traffic is only sent to specific modem addresses on the network.

IP multicast traffic is only sent to a maximum of 100 modem addresses on the network; IP broadcast traffic is sent to all modems on the network.

IP multicast traffic is different from IP broadcast traffic because multicast traffic is only sent to specific modem addresses on the network, while broadcast traffic is sent to all modems on the network. This means that multicast traffic is targeted and intended for a specific group of recipients, whereas broadcast traffic is intended for all devices on the network.

Explanation

IP multicast traffic is different from IP broadcast traffic because multicast traffic is only sent to specific modem addresses on the network, while broadcast traffic is sent to all modems on the network. This means that multicast traffic is targeted and intended for a specific group of recipients, whereas broadcast traffic is intended for all devices on the network.

86. Which of the following describes long-loop automatic gain control (AGC)?

Long-loop AGC adjusts the transmit levels of the customer premises equipment.

Long-loop AGC adjusts the receive levels of the customer premises equipment.

Long-loop AGC adjusts the transmit levels from the headend to the customer premises equipment.

Long-loop AGC adjusts the receive levels from the headend to the customer premises equipment.

Long-loop automatic gain control (AGC) is a mechanism that adjusts the transmit levels of the customer premises equipment. This means that it regulates the power of the signal being sent from the customer premises equipment to ensure that it is at an optimal level. By adjusting the transmit levels, long-loop AGC helps to maintain a consistent and reliable signal quality for communication between the customer premises equipment and the network.

Explanation

Long-loop automatic gain control (AGC) is a mechanism that adjusts the transmit levels of the customer premises equipment. This means that it regulates the power of the signal being sent from the customer premises equipment to ensure that it is at an optimal level. By adjusting the transmit levels, long-loop AGC helps to maintain a consistent and reliable signal quality for communication between the customer premises equipment and the network.

87. How do media access control (MAC) protocols increase the efficiency of upstream transmissions from the cable modems?

When an upstream transmission request is received, the MAC protocols instruct the cable modem termination system (CMTS) when to transmit, its bandwidth, and its transmission interval to prevent or decrease the number of upstream packet collisions. The reduction of collisions increases the upstream transmission efficiency since colliding packets need not be resent.

When a downstream transmission request is received, the MAC protocols instruct the cable modem termination system (CMTS) when to transmit, its bandwidth, and its transmission interval to prevent or decrease the number of downstream packet collisions. The reduction of collisions increases the upstream transmission efficiency since colliding packets need not be resent.

When a downstream transmission request is received, the MAC protocols instruct the cable modem when to transmit, its bandwidth, and its transmission interval to prevent or decrease the number of upstream packet collisions. The reduction of collisions increases the upstream transmission efficiency since colliding packets need not be resent.

When an upstream transmission request is received, the MAC protocols instruct the cable modem when to transmit, its bandwidth, and its transmission interval to prevent or decrease the number of upstream packet collisions. The reduction of collisions increases the upstream transmission efficiency since colliding packets need not be resent.

MAC protocols increase the efficiency of upstream transmissions from the cable modems by instructing the cable modems when to transmit, its bandwidth, and its transmission interval. This prevents or decreases the number of upstream packet collisions. By reducing collisions, the efficiency of upstream transmission is increased because colliding packets do not need to be resent.

Explanation

MAC protocols increase the efficiency of upstream transmissions from the cable modems by instructing the cable modems when to transmit, its bandwidth, and its transmission interval. This prevents or decreases the number of upstream packet collisions. By reducing collisions, the efficiency of upstream transmission is increased because colliding packets do not need to be resent.

88. Asynchronous transfer mode (ATM)

Cannot accept real-time traffic, such as voice and video, because it introduces too much latency and jitter while serving as a statistical multiplexer.

Provides seven service classes, one for each layer of the OSI.

Will give traffic access to a virtual circuit regardless of whether a contracted Qo5 standard can be ensured.

Cells consisting of 53 bytes are too small for efficient data transfer since a minimum IP data packet is 64 bytes.

The given answer states that cells consisting of 53 bytes are too small for efficient data transfer since a minimum IP data packet is 64 bytes. This means that the size of the cells used in ATM is not optimal for transferring IP data packets, which can result in inefficiency. The minimum size requirement of IP data packets being larger than the size of the cells used in ATM can lead to unnecessary overhead and decreased efficiency in data transfer.

Explanation

The given answer states that cells consisting of 53 bytes are too small for efficient data transfer since a minimum IP data packet is 64 bytes. This means that the size of the cells used in ATM is not optimal for transferring IP data packets, which can result in inefficiency. The minimum size requirement of IP data packets being larger than the size of the cells used in ATM can lead to unnecessary overhead and decreased efficiency in data transfer.

89. Why was the Data Over Cable Service Interface Specification (DOCSIS) designed to operate in a shared services environment?

The shared services environment makes optimum use of the network to efficiently transport the continuous data traffic to and from the modems.

The shared services environment follows the same model for television content distribution. Instead of the customer choosing which channel to watch, the cable modem chooses which data packet to receive and then decode.

The shared services environment is a less expensive alternative than dedicated connections, which is most efficient for transporting the intermittent data traffic to and from the modems.

The shared services environment makes optimum use of the network to efficiently transport the intermittent data traffic to and from the modems.

DOCSIS was designed to operate in a shared services environment because it allows for the efficient transportation of intermittent data traffic to and from the modems. This shared services environment optimizes the use of the network, making it a cost-effective alternative to dedicated connections. In this environment, the cable modem selects and decodes the data packets, similar to how television content distribution works. By utilizing the shared services environment, DOCSIS ensures that data traffic is transported efficiently and effectively.

Explanation

DOCSIS was designed to operate in a shared services environment because it allows for the efficient transportation of intermittent data traffic to and from the modems. This shared services environment optimizes the use of the network, making it a cost-effective alternative to dedicated connections. In this environment, the cable modem selects and decodes the data packets, similar to how television content distribution works. By utilizing the shared services environment, DOCSIS ensures that data traffic is transported efficiently and effectively.

90. In a Data Over Cable Service Interface Specification (DOCSIS) network, why is the data throughput over the return or upstream path typically less than the throughput of data over the forward or downstream path?

Compared to the downstream path, the narrower bandwidths and lower orders of modulation used to transport data over the return path cause the downstream and upstream data throughput to be unequal or asymmetrical.

Compared to the downstream path, the narrower bandwidths and lower transmit power of the modems used to transmit data over the return path cause the downstream and upstream data throughput to be unequal or asymmetrical.

Compared to the downstream path, the narrower bandwidths and higher orders of modulation used to transport data over the return path cause the downstream and upstream data throughput to be unequal or asymmetrical.

Compared to the downstream path, the higher bandwidths and lower orders of modulation used to transport data over the return path cause the downstream and upstream data throughput to be unequal or asymmetrical.

In a DOCSIS network, the data throughput over the return or upstream path is typically less than the throughput of data over the forward or downstream path because the narrower bandwidths and lower orders of modulation are used to transport data over the return path. This results in asymmetry in the downstream and upstream data throughput.

Explanation

In a DOCSIS network, the data throughput over the return or upstream path is typically less than the throughput of data over the forward or downstream path because the narrower bandwidths and lower orders of modulation are used to transport data over the return path. This results in asymmetry in the downstream and upstream data throughput.