220-1201 Practice Questions

A power-redundant server has two or more power supply units (PSUs). To achieve true redundancy, each PSU should be connected to an independent power source. The best practice is to connect the PSUs to different Uninterruptible Power Supplies (UPSs), which are ideally connected to separate electrical circuits or power distribution units (PDUs). This ensures that the server remains operational even if one UPS, PDU, or entire circuit fails.

A. Connecting to only one power outlet creates a single point of failure, defeating the purpose of having redundant power supplies.

B. A redundant power supply must be connected and active to take over instantly in case of a failure; leaving it disconnected is incorrect.

D. Connecting both PSUs to a single battery backup still represents a single point of failure if that backup unit fails.

1. Dell Inc. (2022). PowerEdge R750 Installation and Service Manual. Dell Support Documentation. Section: Power supply unit specifications, p. 89. (This type of manual details connecting redundant PSUs for high availability).

2. Hewlett Packard Enterprise. (2019). HPE ProLiant DL380 Gen10 Server User Guide. HPE Support Center. Section: Cabling, p. 82. (Illustrates connecting redundant power supplies to separate PDUs).

3. Massachusetts Institute of Technology (MIT). (n.d.). IS&T Data Center Colocation Service Level Description. MIT Information Systems & Technology. Section: Power. (Describes best practices for power in a data center environment, including A/B power feeds for redundant equipment).

A mobile hotspot is a feature that allows a smartphone or other mobile device to share its cellular data connection (e.g., LTE, 5G) with other nearby devices. The host device acts as a portable Wi-Fi router, creating a small, localized wireless network. Other devices, like laptops or tablets, can then connect to this Wi-Fi network to access the internet. This process is also commonly referred to as "tethering."

A. Bluetooth can be used for tethering, but it offers much lower speeds and range than a Wi-Fi hotspot, which is the primary method.

B. NFC (Near Field Communication) is a very short-range technology used for tasks like mobile payments and data exchange, not for sharing an internet connection.

C. Cellular is the type of internet connection being shared, not the method used to share it with other devices.

1. Google. (n.d.). Share a mobile connection by tethering or hotspot on Android. Android Help. This official vendor documentation explicitly defines using a "Wi-Fi hotspot" to share a phone's mobile data with up to 10 other devices.

2. Apple Inc. (n.d.). Share your internet connection with Personal Hotspot. Apple Support. This official vendor documentation describes how to set up "Personal Hotspot" to share the cellular data connection of an iPhone or iPad.

3. Federal Communications Commission (FCC). (n.d.). Wireless Connections and Bluetooth. In its consumer guides, the FCC describes Wi-Fi hotspots as a way for devices to "share a single mobile broadband connection with other devices."

Virtual Desktop Infrastructure (VDI) is a technology that hosts desktop operating systems on a centralized server in a data center. Users connect to their desktop instances remotely using a network connection from a thin client or any other endpoint device. This model allows an organization to provide a full desktop experience to users without issuing them individual physical workstations, as all the processing and data storage occurs on the central server. This centralizes management, improves security, and supports remote work.

A. RMM (Remote Monitoring and Management) is software used by administrators to manage existing physical or virtual endpoints, not to provide them.

B. SaaS (Software as a Service) delivers specific software applications over the internet, not a complete desktop operating system.

D. Containers are a lightweight virtualization method for deploying and running applications in isolated environments, not for providing interactive desktop sessions to users.

- Mell, P., & Grance, T. (2011). The NIST Definition of Cloud Computing (NIST Special Publication 800-145). National Institute of Standards and Technology. While not defining VDI directly, it defines the service models. VDI is a primary example of Desktop as a Service (DaaS), a cloud service where a virtual desktop is delivered to a user.

- VMware, Inc. (n.d.). What is VDI (Virtual Desktop Infrastructure)?. Official vendor documentation from VMware, a leading VDI provider, defines VDI as "the hosting of desktop environments on a central server." It explicitly states this is a form of desktop virtualization.

- Armbrust, M., et al. (2009). Above the Clouds: A Berkeley View of Cloud Computing (Technical Report No. UCB/EECS-2009-28). University of California, Berkeley. This foundational paper on cloud computing discusses virtualization as a key enabling technology, the principles of which are applied in VDI to abstract the desktop OS from the physical hardware.

A loopback plug is a diagnostic tool used to test the functionality of a physical port on a device like a network interface card (NIC) or a switch. It redirects outgoing data signals from the transmit pins directly back to the receive pins of the same port. This allows diagnostic software to run a test, sending data and verifying it is received correctly, which confirms that the port's circuitry is working properly. It is a direct and definitive method for testing port hardware.

A. A network tap is a passive monitoring device used to capture and analyze traffic; it does not test the functionality of a port.

B. A crimper is a tool used to attach connectors, such as RJ45, to the ends of a cable. It is used for cable creation, not port testing.

C. A patch panel is a passive wiring component used to organize and connect network cables; it is not a diagnostic tool.

- University of Chicago, IT Services. (n.d.). Troubleshooting Network Connections. In guides for network technicians, the use of a loopback adapter is described as a standard procedure to test whether a network interface card is dispatching and receiving data correctly, isolating the port as a point of failure.

- Intel Corporation. (2021). Intel® Ethernet Adapters — Identify Your Wired Intel® Ethernet Adapter and Drivers. Vendor documentation for network adapters often includes troubleshooting steps that specify using a loopback plug to perform diagnostics on the physical port.

Cable internet service is delivered to a location via a coaxial cable. The standard connector used on coaxial cables for this purpose, connecting the wall jack to the cable modem, is an F-type connector. This is a threaded connector that screws on to provide a secure and reliable connection for the radio frequency (RF) signals carrying the internet data. It is the same type of connector commonly used for cable television (CATV) installations.

LC (Lucent Connector) is a small form-factor connector used for fiber optic cables, typically for fiber-to-the-home (FTTH) internet service.

RJ45 (Registered Jack 45) is the standard connector for Ethernet cables (twisted-pair) and is used to connect devices to a LAN, not for the ISP's coaxial signal.

Lightning is a proprietary connector developed by Apple Inc. for its mobile devices and has no application in network or ISP connections.

1. Federal Communications Commission (FCC). (n.d.). Types of Broadband Connections. Retrieved from fcc.gov. The "Cable" section describes the service as being delivered through the same coaxial cables that deliver cable television, which utilize F-type connectors.

2. Society of Cable Telecommunications Engineers (SCTE). (2017). ANSI/SCTE 123 2017: F Connector, Male, Feed-Through. This standard specifies the physical and mechanical characteristics of the F-type connector used in cable telecommunications systems.

3. Comcast Xfinity. (2023). Self-Installation Guide for Xfinity Internet. Official customer support documentation consistently shows diagrams and instructions for connecting the coaxial cable from the wall outlet to the modem using a screw-on F-type connector.

The user is describing keystone distortion, a common issue when a projector is not aligned perpendicularly to the screen. This causes the image to be a trapezoid shape (wider at the top and narrower at the bottom, or vice versa). The "keystone" adjustment feature on the projector is specifically designed to digitally correct this distortion, making the image rectangular. Restarting the device or changing the cable will not fix a physical projection angle issue.

A. A faulty HDMI cable would likely cause signal loss, flickering, or color issues, not a consistent geometric distortion of the image.

B. Power cycling the projector might resolve a temporary glitch but will not correct a persistent image shape problem caused by physical alignment.

D. Increasing the resolution affects the image's clarity and detail (pixel count), not its fundamental geometric shape on the screen.

1. Epson. (2021). PowerLite 1781W/1785W/1795F User's Guide. Page 51, Section: "Correcting Image Shape with Keystone". "If your projected image is wider at the top or bottom (keystone distortion), you can use the projector's keystone correction feature to correct the shape."

2. University of Wisconsin-Madison, Division of Information Technology. (n.d.). General Classroom (GAC) - Projector Image is Distorted (Keystoning). KnowledgeBase. Retrieved from kb.wisc.edu. The document explicitly states: "This distortion of the projector image is known as 'keystoning'. To fix this, you will need to adjust the keystone settings on the projector."

The digitizer is the component of a touch screen assembly responsible for sensing and converting physical touch into a digital signal. When a phone's screen displays an image correctly but does not respond to touch, it indicates a failure in this specific layer. Since a restart did not resolve the issue, a software glitch is less likely, and the next logical step is to suspect a hardware failure of the digitizer itself. The digitizer is often fused with the display screen but is a distinct functional component.

A. A faulty battery would cause power-related issues, such as the device not turning on or shutting down, not a non-responsive touch screen.

B. The screen (e.g., LCD/OLED panel) is responsible for displaying the image. The user did not report a display issue, only a touch issue.

C. A stylus is an external input device. Its failure would not prevent the screen from responding to a finger touch.

1. Layton, J., & Valdes, R. (2006). How the iPhone Works. HowStuffWorks. Updated by C. Lampton. Section: "iPhone Touch Screen". "The screen is a capacitive touch screen... The layer that does the sensing is the digitizer." This principle applies to modern smartphones.

2. Samsung Electronics. (2019). Galaxy S10 Service Manual (SM-G973F). Section 4: "Disassembly and Reassembly," p. 4-15. The manual identifies the "Front OCTA (On-Cell Touch AMOLED)" as a single assembly containing the display and touch sensor (digitizer), which must be replaced for touch failures.

3. Walker, G. R. (2012). A review of technologies for sensing contact location on the surface of a display. Journal of the Society for Information Display, 20(8), 413-440. (DOI: 10.1002/jsid.100). This academic review details the function of various digitizer technologies (e.g., capacitive, resistive) used in touch screens.

A Virtual Private Network (VPN) creates a secure, encrypted tunnel over a public network, such as the internet. This allows workstations in different physical locations to communicate as if they were on the same private network. VPNs use protocols like IPsec or SSL/TLS to secure the connection and require user credentials (e.g., username/password, digital certificates) for authentication, ensuring that only authorized users can access the network.

A. DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses to devices on a local network; it does not create secure channels between locations.

B. A CNAME (Canonical Name) record is a type of DNS entry that maps an alias name to a true or canonical domain name.

C. A VLAN (Virtual Local Area Network) segments a single physical network into multiple logical networks but does not secure communication between different geographic locations.

1. Microsoft Corporation. (2023). What is VPN?. Microsoft Azure Documentation. In the "How does a VPN work?" section, it states, "A VPN works by creating an encrypted connection over the internet from a device to a network... This secure connection helps ensure that sensitive data is safely transmitted."

2. Cisco. (n.d.). What Is a VPN?. Cisco Documentation. The "How a VPN works" section explains that a VPN establishes a secure and encrypted connection and that "To ensure data remains secure, a remote worker may need to be authenticated using a VPN".

3. Fall, K. R., & Stevens, W. R. (2011). TCP/IP Illustrated, Volume 1: The Protocols (2nd ed.). Addison-Wesley Professional. Chapter 30 discusses security protocols like IPsec, which are fundamental to many VPN implementations.

The scenario describes a situation where the physical connections and the laptop's display settings are confirmed to be correct. The most common cause for a projector not displaying an image under these circumstances is a configuration error on the projector itself. Projectors often have multiple input ports (e.g., HDMI 1, HDMI 2, VGA). The user must manually select the correct active input source using the projector's remote or on-device controls to match the physical port where the HDMI cable is connected.

A. The presence of an HDMI port and the ability to connect the cable makes it unlikely the projector does not support HDMI at all.

B. "Duplicate" mode is a valid setting for mirroring the laptop screen. While "Extend" is another option, "Duplicate" not working points to a connectivity or source issue.

C. While a port failure is possible, it is a hardware fault. Standard troubleshooting methodology dictates checking simple configuration issues, like the input source, before assuming hardware failure.

1. Dell Inc. (2023). How to Troubleshoot Dell Projector issues. Dell Knowledge Base, Article ID: 000125849. In the troubleshooting steps for "No Video," the guide explicitly lists "Check if the correct input source is selected on the projector (HDMI, VGA, S-video, Composite, and so on)."

2. Epson. (2022). Projector User's Guide - PowerLite Series. In the "Troubleshooting" section for "No image is projected," a primary solution provided is "Press the [Source Search] button on the projector or remote control to select the correct input source."

For a device to communicate with the internet, its default gateway must be on the same logical subnet. The user's computer has an IP address of 192.168.223.15 and a subnet mask of 255.255.255.0. This configuration places the computer on the 192.168.223.0/24 network. However, the configured gateway is 192.168.233.1, which is on a completely different subnet (192.168.233.0/24). Because the gateway is not on the same local network, the computer cannot send traffic to it, thus preventing any access to the internet. The gateway setting must be changed to an address within the 192.168.223.x range (e.g., 192.168.223.1).

A. Tertiary DNS: The DNS servers are valid public resolvers; the issue is with routing at the IP layer, not name resolution.

B. Secondary DNS: Same as the tertiary DNS, this is not the source of the routing problem.

C. Primary DNS: Same as the other DNS options, the configured server (8.8.8.8) is correct and reachable if routing were working.

D. IP Address: While the IP could be changed, the gateway is definitively on the wrong subnet relative to the IP, making the gateway the incorrect setting.

F. Subnet mask: The /24 mask is standard for this IP class. Altering it to an unconventional mask is less likely than a simple typo in the gateway address.

1. Microsoft. (2021, March 31). Core network guide. Microsoft Learn. "For TCP/IP to work correctly, you need to configure each computer with... an IP address, a subnet mask, and a default gateway." It further explains these components must be logically consistent.

2. Comer, D. E. (2018). Computer Networks and Internets (6th ed.). Pearson. Chapter 19, "Internet Addressing," explains the principle that a host's IP address and its default router's (gateway's) IP address must share the same network prefix as defined by the subnet mask.

3. Massachusetts Institute of Technology (MIT). (n.d.). IP Address, Subnet Mask, and Default Gateway for a Wireless Connection in Windows 10. MIT Information Systems & Technology Knowledge Base, Article 66331. "The Default Gateway is the IP address of the router that connects your network to the Internet... It must be on the same subnet as your computer's IP address."