3DX7X Vol 1: Unit 5

The most common wireless networking standard is 802.11. This standard is widely used for wireless local area networks (WLANs) and provides high-speed internet access and network connectivity. It is commonly known as Wi-Fi and is used in various devices such as smartphones, laptops, and routers.

A Local Area Network (LAN) is a network that connects computers and devices within a small geographic area, such as a home, office, or building. It allows for the sharing of resources, such as files, printers, and internet connections, among the connected devices. LANs typically use Ethernet cables or Wi-Fi to establish the network connection. In contrast to LANs, a Metropolitan Area Network (MAN) covers a larger geographic area, a Wide Area Network (WAN) covers an even larger area, and a Virtual Private Network (VPN) is a secure network that allows remote access to a private network over the internet.

A Metropolitan Area Network (MAN) is a type of network that interconnects users with computer resources within a specific geographic area or region, such as a city. It covers a larger area than a Local Area Network (LAN) but is smaller than a Wide Area Network (WAN). MANs are typically used by organizations or institutions to connect multiple LANs together, allowing for efficient communication and resource sharing within a specific metropolitan area.

A modem is a device that modulates and demodulates data signals. Modulation refers to the process of converting digital data into analog signals that can be transmitted over a communication channel. Demodulation, on the other hand, involves converting the analog signals back into digital data. Therefore, a modem enables the transmission of data over communication networks by converting the signals between digital and analog formats.

The design of a communications network is known as network architecture. Network architecture refers to the overall structure and organization of a network, including the arrangement of its components, protocols, and technologies. It involves determining the network's layout, connectivity, and functionality, as well as selecting the appropriate hardware and software components. Network architecture plays a crucial role in ensuring efficient and reliable communication between devices and systems within a network.

The correct answer is Physical. Physical topology refers to the physical arrangement of devices and media in a network. It defines how the devices are connected and the physical layout of the network, including the cables, connectors, and devices such as switches and routers. This topology determines how the data flows through the network and how devices communicate with each other physically.

Twisted pair cable is the primary carrier of voice communications because it is a type of copper cable that consists of two insulated wires twisted together. This design helps to minimize electromagnetic interference and crosstalk, ensuring clear and reliable transmission of voice signals. Twisted pair cable is widely used in telephone networks and is capable of carrying analog voice signals efficiently over long distances. It is also cost-effective and easy to install, making it a popular choice for voice communication systems.

802.11n is the correct answer because it is the only standard among the given options that is designed to operate at both 2.4GHz and 5 GHz. 802.11a operates only at 5 GHz, 802.11b operates only at 2.4GHz, and 802.11g operates at 2.4GHz but not at 5 GHz. 802.11n, on the other hand, is a dual-band standard that can operate at both frequencies, providing greater flexibility and compatibility with different devices and networks.

A star topology consists of cable segments from each computer connected to a centralized component, usually a switch or hub. In this topology, each computer has its own dedicated cable that connects directly to the central component, forming a star-like shape. This centralized component manages the communication between the computers, allowing them to transmit data to each other. This topology is commonly used in Ethernet networks and provides better performance and reliability compared to other topologies like bus or ring.

The given answer, "Transporting information groups (packets) through an internetwork," is the correct explanation because it accurately describes one of the basic routing activities. Routing involves the process of forwarding packets from a source to a destination through an internetwork, which can include multiple networks and routers. This process ensures that information is successfully transported across the internetwork, allowing communication between different devices and networks.

Dynamic routing automatically calculates the best path between two nodes. This means that the routing algorithm determines the most efficient route for data packets to travel from the source node to the destination node in a network. The algorithm takes into consideration factors such as network congestion, link quality, and other metrics to determine the optimal path. Therefore, the correct answer is 2.

Coaxial cable is associated with the original designs of the Ethernet standard. This type of cable consists of a central conductor surrounded by an insulating layer, a metallic shield, and an outer insulating layer. It was commonly used in early Ethernet networks to transmit data signals. Coaxial cable provides good transmission quality and can support high data rates, making it suitable for Ethernet connections. However, it has been largely replaced by twisted-pair cables, such as shielded twisted-pair (STP) and unshielded twisted-pair (UTP), due to their lower cost and easier installation.

A bridge is a Data Link Layer network device that logically separates a single network into two segments or collision domains in Ethernet networks. It operates by examining the MAC addresses of incoming frames and making forwarding decisions based on the destination address. By doing so, it reduces collisions and improves network performance by creating separate collision domains. Unlike a hub, which simply broadcasts all incoming frames to all connected devices, a bridge selectively forwards frames to the appropriate segment, thereby improving network efficiency.

ISDN (Integrated Services Digital Network) is a digital telecommunications network that can transmit voice, video, and data simultaneously over a single pair cable. It operates at a transmission rate of 144 Kbps (Kilobits per second), which is the correct answer. This speed is sufficient for basic internet browsing, email, and low-quality video streaming. However, it is relatively slow compared to modern broadband connections, which offer much higher speeds in Mbps (Megabits per second). Hence, the correct answer is 144 Kbps.

Link encryption is the type of encryption applied to each end of a communications line in a distributed network, ensuring that all information flowing through the line is unintelligible to unauthorized intruders. This type of encryption specifically focuses on securing the communication link itself, protecting the data as it travels between different points in the network. It is an important security measure to prevent eavesdropping and unauthorized access to sensitive information.

The correct answer is 802.11b. This standard has a throughput of 11 Mbps and operates at the 2.4 GHz frequency. It was one of the earliest Wi-Fi standards and provided a significant improvement over the previous 802.11a standard in terms of cost and compatibility. However, it has since been surpassed by newer standards such as 802.11g and 802.11n, which offer faster speeds and better performance.