Computer Networks

Cisco, Brocade (acquired by Broadcom), and QLogic are major Fibre Channel switch manufacturers. D-Link primarily produces consumer networking equipment and is not a significant player in enterprise Fibre Channel switching.

A modem (modulator-demodulator) converts digital signals from a computer into analog signals for transmission over telephone lines, and converts incoming analog signals back to digital form. ISDN, DSL, and HDSL are digital communication technologies that don't perform this conversion - they transmit digital signals directly. The modem's core function is this digital-analog conversion, which is essential for traditional analog phone line communications.

Statement D is false because applications CAN be shared over a LAN. Local Area Networks are specifically designed to allow resource sharing including applications, files, and printers. Statements A, B, and C are all true statements about networks.

In networking, attenuation (signal weakening over distance) determines the maximum number of nodes per segment because each node adds cable length and signal degradation. Once signal strength drops below threshold, the segment becomes unreliable. Bandwidth and throughput affect data speed, regeneration is the solution (adding repeaters), not the limiting factor.

Circuit-switched networks (like traditional telephone networks) establish a dedicated communication path with reserved resources (bandwidth, buffers) for the entire circuit duration. This guarantees quality but wastes resources when idle. This fundamental characteristic distinguishes circuit switching from packet switching, which shares resources dynamically.

Thicknet refers to the thick coaxial cable standard in Ethernet, officially designated as 10Base5 by IEEE. The '10' means 10 Mbps, 'Base' means baseband transmission, and '5' indicates 500 meter maximum segment length. 10Base2 is Thinnet (thin coaxial), and 10BaseT uses twisted-pair copper.

Early Ethernet networks (like 10Base5 Thicknet and 10Base2 Thinnet) did transmit data over thick, heavy coaxial cables. These cables were bulky, difficult to work with, and had limited bandwidth compared to modern twisted-pair and fiber alternatives.

A router acts as a 'traffic cop' by directing data packets between different networks based on IP addresses and routing tables. It makes intelligent decisions about the best path for packets, unlike a hub (which broadcasts to all ports) or a switch (which forwards based on MAC addresses within a network).

Android networking is NOT principally handled by ConnectivityManager for actual network operations. ConnectivityManager monitors network connectivity state and availability, but actual network requests use HttpURLConnection, OkHttp, or other HTTP libraries. The statement confuses connectivity monitoring with network communication.

getNetworkInfo() and getActiveNetworkInfo() are both valid ConnectivityManager methods for retrieving network details. getNetworkStatus() is not a standard Android API method. Both getNetworkInfo() (deprecated) and getActiveNetworkInfo() provide information about network state and connectivity.

WifiManager is the correct Android service class for WiFi connectivity management. It provides methods for scanning, connecting, and managing WiFi networks. ConnectivityManager handles overall network connectivity state, not specifically WiFi.

In messaging systems, ST (possibly referring to Secure Transport or similar technologies) can communicate externally through a Gateway component. Gateways typically serve as intermediaries that enable secure external communication for internal systems.

Cable internet uses coaxial or fiber-optic cables to deliver high-speed data, classifying it as broadband. 28.8k and 56k are dial-up modem speeds (narrowband), and Modem is the device, not a connection type.

Peer-to-peer relationship in UML is a type of association where two classes interact as equals, neither containing the other. Unlike aggregation (whole-part) or composition (strong ownership), peer-to-peer represents a collaborative relationship where both classes have comparable status.