CDC 3DX5X (Edit Code 02) Volume 2, Unit 2

A scanner is a device that optically reads an image, printed text, or an object and converts it to a digital image. It uses a light source and a photosensitive element to capture the image and then converts it into a digital format that can be stored, manipulated, and displayed on a computer. Unlike a printer, which produces physical copies of digital images, a scanner takes physical copies and converts them into digital files. A monitor and camera lens are not devices specifically designed for converting physical images to digital format.

A virtual private network (VPN) provides a private tunnel through the Internet. It allows users to securely connect to a remote network over the Internet by encrypting their data and routing it through a virtual tunnel. This ensures that the data remains private and protected from unauthorized access. VPNs are commonly used by individuals and organizations to access resources on a private network remotely while maintaining the security and privacy of their data.

The characteristic of "Cost to install and train technicians" is not an advantage of fiber optic cable. Fiber optic cable installation and technician training can be expensive compared to other types of cables. However, fiber optic cables have other advantages such as electromagnetic immunity, low attenuation, and security.

The logical link control (LLC) sub layer is a part of the Data Link layer in the OSI model. The Data Link layer is responsible for providing reliable and error-free transmission of data between adjacent network nodes. The LLC sub layer specifically handles flow control, error control, and framing of data packets. It ensures that data is properly encapsulated and delivered to the correct destination.

Linear is another name for a bus topology. In a bus topology, all devices are connected to a single cable called the bus. The devices share the same communication medium and can transmit data in both directions. The linear topology refers to the physical arrangement of devices in a straight line along the bus. This topology is commonly used in Ethernet networks and is known for its simplicity and ease of installation.

A local area network (LAN) is a network of computers and devices that are connected together within a small geographic area, such as a home, office, or building. In a LAN, the computers and devices are connected to a common communications line, allowing them to share resources such as files, printers, and internet access. LANs are typically used in small-scale settings where the distance between devices is relatively short. Examples of LANs include home networks, office networks, and school networks.

Wireless local area network (WLAN) uses Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) to avoid collisions while transmitting data. CSMA/CA is a protocol used in wireless networks where devices listen to the wireless medium before transmitting data. If the medium is busy, the device waits for a random amount of time before attempting to transmit again, thus reducing the chances of collisions. This method is necessary in wireless networks where multiple devices share the same wireless channel and collisions can occur if multiple devices transmit at the same time.

When star networks are interconnected, the central node acts as a hub for all the connected devices. If the central node fails, it will result in large portions of the network becoming isolated. This means that communication between those isolated portions and the rest of the network will be disrupted. Therefore, the negative effect of interconnecting star networks is that a failure in the central node can cause significant network isolation and communication breakdown.

The correct answer is "Header Checksum". The Header Checksum portion in the IP Datagram allows IP to detect data-grams with corrupted headers and discard them. The Header Checksum is a 16-bit field that contains a checksum value calculated over the IP header. When a data-gram is received, the receiver recalculates the checksum and compares it with the value in the Header Checksum field. If the values do not match, it indicates that the header has been corrupted during transmission, and the data-gram is discarded to maintain data integrity.

The Defense Information System Agency (DISA) is the correct answer because it is the governing body responsible for information technology (IT) communications within the Department of Defense (DOD). DISA oversees every level of IT communication from the DOD information network to the war fighter under their scope of control. DISA ensures the secure and reliable operation of the DOD's IT infrastructure and provides IT services and capabilities to support the DOD's mission.

End-to-end encryption provides the greatest degree of protection since it fully encodes the information from the network to the users' own end terminals. This means that the data is encrypted at the source and remains encrypted until it reaches the intended recipient, preventing any unauthorized access or interception along the way. This type of encryption ensures that only the sender and the recipient have access to the decrypted data, providing a high level of security and privacy.

The correct answer is Data Transport and Application. The OSI reference model consists of seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The Data Transport layer is responsible for reliable and efficient data transfer between network devices, while the Application layer provides services for user applications to access the network.

A media converter is a device that converts the electrical signal used in copper unshielded twisted pair (UTP) network cabling to light waves used for fiber optic cabling. It allows for the seamless integration of different types of network media, such as copper and fiber, by converting the signals between them. This enables the transmission of data over longer distances and at higher speeds, making it an essential component in network infrastructure where copper and fiber optic cables are used together. A modem, switch, and router are all different types of networking devices that serve different purposes and do not perform the specific function of converting signals between copper and fiber optic cables.

A peripheral device is not a main component of a computer and can be either internal or external. This means that it is not essential for the basic functioning of a computer, but rather serves as an additional device that enhances the computer's capabilities. Peripheral devices can include items such as printers, scanners, keyboards, and mice, which can be connected to the computer either internally or externally to perform specific tasks.

The kernel is the UNIX system software that interacts most closely with the hardware. It is the core component of the operating system that manages the system's resources, such as memory, processes, and input/output devices. The kernel provides an interface between the hardware and the user programs, allowing them to access and utilize the system's resources efficiently. The shell, user programs, and dynamic-link library are all important components of the UNIX system, but they do not directly interact with the hardware like the kernel does.

Access is a Microsoft application that allows users to create a desktop database. It provides a user-friendly interface for designing and managing databases, enabling users to store, organize, and manipulate data efficiently. With Access, users can create tables, forms, queries, and reports to meet their specific database needs. It is widely used for small to medium-sized projects and is particularly popular among businesses and organizations for managing and analyzing data effectively.

The seven layers of the Open Systems Interconnection (OSI) reference model specify different functions related to networking. The Network layer specifically deals with the routing and forwarding of data packets between different networks. It is responsible for establishing connections, addressing, and controlling the flow of data. This layer ensures that data is properly delivered from the source to the destination across multiple networks.

In 1999, the Institute of Electrical and Electronics Engineers (IEEE) ratified the use of gigabit Ethernet (GbE). This means that in 1999, the IEEE officially approved and standardized the use of GbE, which allowed for faster data transmission speeds over Ethernet networks.

The star topology offers centralized management of a network. In a star topology, all devices are connected to a central hub or switch, which acts as a central point of control and management for the network. This allows for easier monitoring, troubleshooting, and administration of the network, as all communication flows through the central hub. Additionally, if one device fails in a star topology, it does not affect the rest of the network, making it a reliable and manageable option for network management.

Outlook is a personal information manager developed by Microsoft. It is commonly used as an email client, but it also includes features such as a calendar, task manager, contact manager, and note-taking. Outlook allows users to organize and manage their personal information in one place, making it an effective tool for managing emails, appointments, tasks, and contacts.

Class D address is reserved for multicast addressing. In IP addressing, multicast is a method of sending data packets to a group of devices simultaneously. Class D addresses range from 224.0.0.0 to 239.255.255.255 and are used for multicast group communication. These addresses are not assigned to specific devices but are used to identify a group of devices that are interested in receiving the multicast data.

Standardized Tactical Entry Point (STEP) terminals offer 7 T1 Defense Switched Network (DSN) access circuits.

The word "topology" typically refers to the physical arrangement or structure of a network. This includes the layout of devices, cables, and connections in a network. It does not refer to the transport topology, which is related to how data is routed and delivered in a network. It also does not refer to the physical medium, which is the actual material used for data transmission. Finally, it does not refer to the logical topology, which describes how devices are logically connected in a network. Therefore, the correct answer is physical topology.

A wide area network (WAN) is a network that connects local area networks (LAN) and metropolitan area networks (MAN) by using long-distance communication links leased or purchased from a telecommunications company. Unlike LANs and MANs, which cover smaller geographical areas, WANs cover larger areas and allow for the transmission of data over longer distances. This makes WANs suitable for connecting remote locations and facilitating communication between different LANs and MANs. Therefore, the correct answer is wide area network (WAN).

The logical link control (LLC) sub layer of the data link layer manages communications between devices over a single link of a network. This sub layer is responsible for error control, flow control, and framing of data packets. It ensures that data is properly transmitted and received between devices connected by a single link, providing a reliable and efficient communication channel.

Encryption is the best described method for hiding a message in a service code. Encryption involves the process of converting plaintext into ciphertext, making it unreadable to anyone without the proper decryption key. By encrypting the message, it becomes hidden within the service code and can only be accessed by authorized individuals with the correct decryption key. This method ensures the security and confidentiality of the message being transmitted over the wireless local area network (WLAN).

The correct answer is Five GB/S. USB 3.0 SuperSpeed transfer mode has a maximum data transfer rate of 5 gigabits per second (GB/S). This means that it can transfer data at a speed of 5 billion bits per second, which is significantly faster than the previous USB 2.0 standard. This high speed allows for faster file transfers and improved performance when using USB 3.0 devices.

Exterior Gateway Protocol (EGP) is a network routing protocol that allows multiple autonomous systems to connect together. It is specifically designed for interconnecting different autonomous systems and exchanging routing information between them. EGP enables the exchange of routing information and the determination of the best path for data to travel between different autonomous systems, ensuring efficient and reliable communication across interconnected networks.

Class C addresses allow for a maximum of 254 hosts per network. In IPv4, the address space is divided into different classes based on the number of network and host bits. Class C addresses have a default subnet mask of 255.255.255.0, which means that there are 24 network bits and 8 host bits. With 8 host bits, we can have 2^8 - 2 = 254 usable host addresses per network. Class A and Class B addresses have more network bits and fewer host bits, resulting in larger networks but fewer available host addresses. Class D addresses are used for multicast and do not have a specific number of hosts per network.

Well known port numbers range from 0 to 1023. These are the port numbers that are commonly used by well-known protocols such as HTTP (port 80), FTP (port 21), and SSH (port 22). These port numbers are reserved for specific services and are often used by popular applications and protocols.

A TCP socket is a combination of a port number and an IP address that is used by a process to request network services and is passed as an argument between layers. This means that when a process wants to communicate over a network, it uses a TCP socket to specify which port and IP address it wants to communicate with. The TCP socket acts as a unique identifier for the process and allows it to establish a connection and exchange data with another process on a different machine.

The media access control (MAC) sub layer of the data link layer manages the protocol access to the physical network medium. This means that it governs how devices on a network access and use the physical medium, such as Ethernet cables or wireless frequencies, to send and receive data. The MAC sub layer ensures that devices take turns accessing the medium to avoid collisions and manage the flow of data.

A slide window in Transmission Control Protocol (TCP) is used to regulate the amount of information that can pass over a TCP connection before the receiving host must send an acknowledgement. This helps in controlling the flow of data and prevents network congestion by ensuring that transmitting devices do not overwhelm receiving devices with data.

The main purpose of system cache is to reduce central processing unit (CPU) access time to stored data. System cache stores frequently accessed data and instructions from the main memory, allowing the CPU to quickly retrieve this data without having to access the slower main memory. This helps to improve overall system performance by reducing the time it takes for the CPU to access the data it needs.

The major difference between Random Access Memory (RAM) and Read Only Memory (ROM) is that ROM is non-volatile, meaning that the data stored in ROM is retained even when the power is turned off. On the other hand, RAM is volatile, meaning that the data stored in RAM is lost when the power is turned off.

In Internet Protocol version 4 (IPv4), an octet is a group of 8 bits. Each bit can have a value of either 0 or 1, giving a total of 256 possible combinations (2^8). However, since the values range from 0 to 255, the maximum value for an octet in IPv4 is 255.

A network bridge is a Data Link layer network device or software set that logically separates a single network into multiple segments or collision domains in Ethernet networks. It allows for the division of a network into smaller parts, reducing network congestion and improving overall performance. By separating segments, a bridge prevents collisions and allows for better communication between devices within each segment. This helps to improve network efficiency and maintain data integrity.

A gateway is a network device that provides connectivity between different networks. It acts as an entry and exit point for data packets traveling between a remote network and a host network. It translates protocols, manages data flow, and ensures seamless communication between the two networks. Therefore, a gateway is the correct answer as it enables connectivity between a remote network and a host network.

There are generally six operating system task categories.