Question 1

A router forwards packets by always placing each incoming packet on the output link with the shortest queue. Which routing approach is being used?

Accepted Answer

Introduction / Context: Routing strategies can optimize for path length, delay, or local queueing conditions. The described behavior prefers the least waiting time, pushing packets out of the router as quickly as possible versus calculating global shortest paths. Given Data / Assumptions: Decision metric: choose the output with the shortest queue (lowest immediate delay). No mention of global topology knowledge or fixed tables. Goal: minimize local residence time per packet. Concept / Approach: Hot potato routing (deflection routing) forwards a packet to whatever acceptable outgoing link currently appears best locally (e.g., shortest queue, lowest delay), avoiding buffering. It does not necessarily send the packet along a precomputed shortest path; it 'gets rid of the packet fast.' Step-by-Step Solution: Identify key heuristic: shortest output queue ⇒ local delay minimization.Relate to known strategy: hot potato/deflection routing uses immediate local criteria to choose an egress.Eliminate alternatives: flooding sends copies on all links; static uses fixed tables; delta routing adapts by delay differences but is not simply 'shortest queue now' in its textbook form.Conclude that the described behavior matches hot potato routing. Verification / Alternative check: Architectures for deflection routing in buffer-limited networks prioritize any free output port with minimal contention, consistent with picking the shortest queue. Why Other Options Are Wrong: Flooding: Replicates to multiple outputs; not queue-based selection. Static routing: Fixed next hops; ignores queue lengths. Delta routing: Uses measured delay deltas across paths, not the simple per-port queue heuristic in the stem. None of the above: Incorrect because hot potato matches. Common Pitfalls: Confusing shortest-path (global) with shortest-queue (local). The stem clearly states a local queue heuristic. Final Answer: Hot potato routing

Question 2

You have Class A network 10.0.0.0. There are already 40 subnets and 60 more will be added soon (total ≥ 100). To maximize host IDs per subnet, which subnet mask should you choose?

Accepted Answer

Introduction / Context: Subnetting trades bits between the subnet field and the host field. Here, you must support at least 100 subnets while keeping the host space per subnet as large as possible. The address is a Class A (default /8) private block: 10.0.0.0. Given Data / Assumptions: Base: Class A ⇒ default mask /8 (255.0.0.0). Required subnets: at least 100 (40 existing + 60 new). Maximize hosts per subnet. Assume traditional subnet count uses 2^b - 2 (for historical reserved all-0/all-1), but even with modern practice, choosing the smallest b meeting ≥100 is optimal. Concept / Approach: Let b = subnet bits needed. Need 2^b - 2 ≥ 100 ⇒ b = 7 (since 2^7 = 128, 128 - 2 = 126).New prefix length = 8 + 7 = /15./15 in dotted decimal is 255.254.0.0. Step-by-Step Solution: Compute b from requirement: b = 7.Compute new mask length: 8 (Class A) + 7 = 15.Convert to dotted decimal: /15 ⇒ 255.254.0.0.Hosts per subnet = 2^(32 − 15) − 2 = 2^17 − 2 ≈ 131072 − 2, very large. Verification / Alternative check: Any mask longer than /15 (e.g., /16+/) would reduce hosts per subnet without increasing needed subnets beyond the minimum. /15 is the smallest prefix that meets ≥100 subnets from a Class A block while maximizing hosts. Why Other Options Are Wrong: 255.240.0.0 (/12), 255.248.0.0 (/13), 255.252.0.0 (/14): Provide fewer than 100 usable subnets under 2^b − 2 convention. 255.255.255.255: /32, no host space. Common Pitfalls: Forgetting to add subnet bits to the classful /8 or confusing the requirement (≥100) with exactly 100. Choosing /15 satisfies with maximum host space. Final Answer: 255.254.0.0

Question 3

In an IEEE 802.5 token ring network, which component houses the internal switching and connects stations in a star-wired ring topology?

Accepted Answer

Introduction / Context: Token ring (IEEE 802.5) physically uses a star-wired topology but logically forms a ring. Understanding the central device that internally relays the token and data frames helps distinguish token ring from Ethernet hubs/switches. Given Data / Assumptions: Token ring uses a Multistation Access Unit (MAU). Stations connect to the MAU and are inserted into or bypassed from the ring. The MAU is not an Ethernet switch; it maintains ring continuity. Concept / Approach: A MAU (or MSAU) provides the physical wiring concentration and the internal relays to pass the token from one port to the next, creating the logical ring. NICs reside in hosts; transceivers/connector types are passive/physical and do not implement the ring logic. Step-by-Step Solution: Identify device that 'houses the switches' (internal relays) in token ring.Recall token ring star-wired ring uses MAUs/MSAUs.Select MAU as the central component ensuring ring continuity and insertion/bypass.Confirm others are not ring concentrators. Verification / Alternative check: Vendor literature for 802.5 shows MAU ports with lobe cables to stations; the MAU manages insertion and wrap-around when a station is offline. Why Other Options Are Wrong: Transceiver: Media interface only; does not form the ring. Nine-pin connector: A connector type, not a concentrator device. NIC: Host interface; not the hub of the ring. None of the above: Incorrect because MAU is correct. Common Pitfalls: Confusing token ring MAUs with Ethernet hubs/switches; their operation and purpose differ. Final Answer: MAU

Question 4

Which of the following does NOT enable multiple users/devices to share a single communications line?

Accepted Answer

Introduction / Context: Sharing a single high-capacity line among many lower-rate users is fundamental in telecom and networking. Devices designed for multiplexing or traffic concentration combine streams; other devices merely manage or interface without providing true line sharing. Given Data / Assumptions: We interpret 'share one communications line' as combining multiple input channels onto a single aggregated link. Standard devices: multiplexers (FDM/TDM/StatMux) and concentrators provide sharing. Controllers manage or interface but are not inherently multiplexing devices. Concept / Approach: A multiplexer combines multiple signals onto one line using time, frequency, code, or statistical methods. A concentrator aggregates many low-duty-cycle devices onto a higher-capacity trunk. A controller (e.g., terminal/line controller) administers connections or protocols but does not itself multiplex signals onto a single line by design. Step-by-Step Solution: Identify devices that explicitly perform sharing: Multiplexer, Concentrator.Evaluate 'Controller': provides control/management; not the sharing mechanism.Note that 'Doubleplexer' is not a standard multiplexing device; however, by elimination and textbook usage, 'Controller' clearly does not perform sharing.Select 'Controller' as the option that does not allow multiple users to share one line. Verification / Alternative check: Typical WAN diagrams show CSU/DSU + MUX/Concentrator feeding one T1/E1 or higher line. Controllers appear on edges but do not perform the combining. Why Other Options Are Wrong: Multiplexer: Purpose-built for line sharing (TDM/FDM/CDM/statistical multiplexing). Concentrator: Aggregates many inputs to one trunk, enabling sharing. Doubleplexer: Nonstandard term; but in the context of the question, the only clearly non-sharing role is 'Controller.' None of the above: Incorrect because a controller is not a sharing device. Common Pitfalls: Assuming any device in a WAN rack performs multiplexing; roles differ between control and aggregation. Final Answer: Controller

Question 5

To connect a computer with a nearby device in the same room (short distance, point-to-point), which option is most appropriate?

Accepted Answer

Introduction / Context: Short-distance connections inside a room are typically direct, simple, and point-to-point—think computer-to-instrument or computer-to-printer cabling. The goal is to select the option that best characterizes this local connection style. Given Data / Assumptions: Endpoints are in the same room (meters apart). No carrier services or satellite links are needed. Point-to-point dedicated connectivity is intended. Concept / Approach: A 'dedicated line' in this context denotes a private, exclusive link between two devices. Although the physical medium may be coaxial, twisted pair, or USB, the defining property is the direct dedicated connection, not a shared or carrier-provisioned service. Ground stations are satellite infrastructures and are irrelevant for in-room links. Step-by-Step Solution: Recognize that same-room connectivity implies simple point-to-point wiring.Choose the answer that emphasizes exclusivity and directness: 'A dedicated line.'Note that 'coaxial cable' is a type of medium, but the question asks for what you would be likely to use—conceptually a dedicated connection, not satellite or carrier gear.Eliminate options involving satellite (ground station) or an indiscriminate 'All of the above.' Verification / Alternative check: Common lab setups use direct dedicated cabling (USB/serial/Ethernet patch) between a computer and a device in the same room, matching the dedicated-line concept. Why Other Options Are Wrong: A coaxial cable: Possible physical medium, but the broader, more accurate choice is a dedicated line. A ground station: Satellite infrastructure; irrelevant indoors. All of the above: Incorrect; ground station is not applicable. None of the above: Incorrect because a dedicated line is appropriate. Common Pitfalls: Confusing the concept (dedicated link) with a specific cable type; many media can implement a dedicated line. Final Answer: A dedicated line

Question 6

Which statements correctly describe packet switching in data networks?

Accepted Answer

Introduction / Context: Packet switching is the foundation of modern networks (e.g., the Internet). It segments data into packets and forwards them independently, exploiting statistical multiplexing and adaptive routing to improve efficiency and resilience. Given Data / Assumptions: Networks support addressing of packets to their destinations. Routers/switches make per-packet forwarding decisions. Trunk links can carry many flows simultaneously. Concept / Approach: Three key advantages: (1) alternate routing around failures/congestion, (2) in-network control for reliability and flow management, and (3) cost efficiency by sharing high-capacity trunks among many bursty sources (statistical multiplexing). Step-by-Step Solution: Evaluate statement (a): Packets can follow different paths; dynamic routing adapts to faults/congestion ⇒ True.Evaluate statement (b): Network nodes implement error checks, retransmissions (on some links), and link management ⇒ True in many packet networks.Evaluate statement (c): Sharing wide trunks among many users increases utilization and reduces cost per bit ⇒ True.If (a), (b), and (c) are all true, choose 'All of the above.' Verification / Alternative check: Operational Internet behavior (e.g., BGP/IGP reroutes, per-hop CRC/ECN/QoS, and statistical multiplexing on backbone links) exemplifies all three benefits. Why Other Options Are Wrong: Each individual statement is correct; picking only one would ignore the comprehensive nature of packet switching. None of the above: False because all three are valid. Common Pitfalls: Confusing packet switching with circuit switching, which uses fixed dedicated paths and lacks per-packet routing flexibility. Final Answer: All of the above

Question 7

In data communications, the term ‘‘full duplex’’ refers to simultaneous two-way transmission. In a full-duplex link, what can the sender and receiver do at the same time?

Accepted Answer

Introduction / Context: Link directionality is a foundational networking concept that determines how two endpoints exchange information. Terms like simplex, half duplex, and full duplex describe whether data flows in one direction, alternates directions, or flows both ways at once. Understanding full duplex helps explain performance differences in Ethernet switching, serial links, and wireless systems that may be half duplex. Given Data / Assumptions: We are discussing link behavior between exactly two endpoints (sender and receiver). ‘‘Full duplex’’ is being contrasted with half duplex and simplex. No special protocols or media are assumed; the concept is medium-agnostic. Concept / Approach: In full duplex, both endpoints transmit and receive at the same time over logically separate directions (two wires, two frequencies, two time slots, or echo cancellation on a single pair). This is different from half duplex, where only one station transmits at a time and the other must wait, and from simplex, where data flows only in one direction. Step-by-Step Solution: Identify the definition: full duplex = simultaneous bidirectional communication.Map to behavior: sender can transmit while receiver transmits back.Eliminate alternatives that imply alternation (half duplex) or one-way flow (simplex).Select the statement that explicitly says ‘‘receive and send simultaneously’’. Verification / Alternative check: Modern switched Ethernet at 1 Gbps and above operates full duplex, allowing frames to be sent and received concurrently without collisions. In contrast, traditional hub-based Ethernet was half duplex and relied on collision detection or avoidance. Why Other Options Are Wrong: ‘‘can send or receive data one at a time’’ describes half duplex, not full duplex. ‘‘cannot talk at once’’ also implies half duplex. ‘‘one-way data transmission only’’ defines simplex. ‘‘None of the above’’ is incorrect since one option is exactly right. Common Pitfalls: Assuming wireless links are always full duplex; many Wi-Fi links are effectively half duplex due to shared medium constraints. Also, users sometimes conflate full duplex with ‘‘twice the speed’’; actual throughput depends on workload symmetry and protocol overhead. Final Answer: can receive and send data simultaneously

Question 8

In satellite communications, which statements are true for a geostationary satellite used by communication systems?

Accepted Answer

Introduction / Context: Geostationary Earth Orbit (GEO) satellites are the backbone of many broadcast and telecommunications services. Their unique orbital characteristics allow ground antennas to point at a fixed position in the sky, simplifying deployment and maintenance. Knowing the defining properties of GEO satellites is essential for understanding coverage, latency, and link budgeting. Given Data / Assumptions: The term ‘‘geostationary’’ refers to a satellite that appears motionless to a ground observer. We consider standard GEO altitude and orbital plane characteristics. We are not discussing Medium Earth Orbit (MEO) or Low Earth Orbit (LEO) constellations. Concept / Approach: A geostationary satellite orbits at approximately 35,786 km above mean sea level in the equatorial plane. It has an orbital period equal to the Earth’s rotational period (sidereal day). Because it orbits in the same direction as Earth’s rotation and at the correct altitude and inclination (0 degrees), it maintains a constant position relative to the Earth’s surface. Step-by-Step Solution: Confirm synchronous rotation: orbital period matches Earth’s rotation → appears fixed.Check relative stationarity: from the ground, the satellite’s azimuth/elevation remain constant.Verify geometry: orbit must lie over the equator (inclination ~0°) to avoid north–south drift.Therefore, all listed statements are true. Verification / Alternative check: Observe fixed satellite TV dishes: they are not motorized because GEO satellites remain in a fixed sky position. Coverage maps also show GEO satellites centered above the equator with footprints spanning large regions. Why Other Options Are Wrong: Picking any single statement ignores other equally true properties. ‘‘None of the above’’ is incorrect since each statement reflects GEO fundamentals. Common Pitfalls: Confusing ‘‘geosynchronous’’ with ‘‘geostationary’’: geosynchronous matches Earth’s period but may have inclination or eccentricity, causing figure-8 ground tracks. Geostationary is the special case with zero inclination and circular orbit over the equator. Final Answer: All of the above

Question 9

Data transmission scenario: A firm needs to send information from 1,000 punched cards to a remote computer. Which type of terminal would typically be used for this bulk, non-interactive transfer of data?

Accepted Answer

Introduction / Context: Punched cards represent historical batch data entry. When an organization wants to transmit a large stack of cards (for example, 1,000 cards) to a host, the workflow is non-interactive and scheduled. This question tests understanding of terminal types and when batch versus interactive methods are appropriate in data communications. Given Data / Assumptions: A stack of 1,000 punched cards must be transmitted. The destination is a remote computer, not a local processor. The process emphasizes volume transfer over real-time interaction. Legacy data-entry and telecom concepts apply (terminals, host links). Concept / Approach: Punched card workflows are classically aligned with batch operations. A batch processing terminal is designed to collect a large dataset offline and then transmit it as a block at predetermined times or on demand. This minimizes line usage and operator interaction during transmission, which fits the punched-card context. Step-by-Step Solution: Recognize that 1,000 cards imply bulk, non-interactive traffic.Map bulk, scheduled transfer to batch processing methods.Identify the terminal type that supports off-line preparation and on-line submission: batch processing terminal.Conclude that batch processing terminal best meets the scenario. Verification / Alternative check: Operationally, older data centers used card readers connected to communication front-ends. Data would be staged and then shipped to the host in blocks. This confirms that batch transfer mechanisms, rather than interactive point-of-sale or conversational terminals, were the norm for such workloads. Why Other Options Are Wrong: POS terminal: Optimized for retail transactions, not bulk card stacks. Data collection terminal: May capture data, but does not specifically emphasize batch transmission to a remote host. Intelligent terminal: Provides local processing, usually interactive; not necessary for card-batch transmission. None of the above: Incorrect because batch processing terminal matches precisely. Common Pitfalls: Confusing data collection (gathering) with batch transmission (scheduled, bulk send). Also, assuming that any terminal with local logic is optimal; in this use case, the workload pattern is the key determinant. Final Answer: batch processing terminal

Question 10

Windows NT network assessment: You manage eight NT servers and plan to move them to different network segments. Which tool on each server best measures which server generates the most network traffic?

Accepted Answer

Introduction / Context: When planning network segmentation or server relocation, administrators need visibility into traffic volumes per host. Windows NT offered several TCP/IP tools, but only some are suitable for measuring packet flows and bandwidth usage. This question evaluates knowledge of the correct utility for network traffic analysis in an NT environment. Given Data / Assumptions: Eight Windows NT servers are involved. Goal is to determine which server generates the most traffic. Measurement must be done on each server before re-segmenting the network. Classic NT toolset applies (no third-party analyzers assumed). Concept / Approach: Windows NT includes Network Monitor (and an agent) that captures and analyzes packets, showing per-host traffic statistics and protocols. While Performance Monitor can show interface counters, Network Monitor provides protocol-level visibility and capture capabilities, making it preferable for identifying the top talkers and understanding traffic composition. Step-by-Step Solution: Identify the need: quantify per-server traffic and analyze packets.Match need to tool: Network Monitor captures and summarizes network frames.Confirm alternatives: PerfMon counters are coarse, not packet-centric.Select Network Monitor as the best fit for measuring which server generates the most traffic. Verification / Alternative check: Cross-check by enabling Performance Monitor counters (Bytes Total/sec) on NICs to validate trends, then use Network Monitor to capture a representative interval for detailed confirmation of the highest traffic generator. Why Other Options Are Wrong: NBTSTAT: Focused on NetBIOS over TCP/IP name tables and sessions, not traffic quantification. NETSTAT.EXE: Displays connections and listening ports; limited for traffic volume analysis. Performance Monitor: Helpful but less granular than a protocol analyzer for per-conversation traffic. ARP.EXE: Manipulates the ARP cache; irrelevant to traffic measurement. Common Pitfalls: Assuming open connections imply high traffic; a single idle TCP session may contribute little. Always measure bytes or frames over time. Ensure captures occur during peak windows to avoid misleading off-peak data. Final Answer: Network Monitor

Question 11

Voiceband communications: Which medium is commonly referred to as a voiceband channel suitable for ordinary speech-frequency transmission?

Accepted Answer

Introduction / Context: Voiceband refers to the frequency range used for standard telephone audio (roughly 300 Hz to 3.4 kHz). Data communications historically leveraged this range with modems over public switched telephone networks. This question checks recognition of the voiceband medium. Given Data / Assumptions: Voiceband implies the conventional telephony audio band. We are selecting the medium that natively supports that band. Focus is on classical telephony and data-over-voice techniques (for example, analog modems). Concept / Approach: Traditional analog telephone lines are engineered for voiceband frequencies. While data can move across them via modulation, the physical medium and switching were designed around human speech frequencies, defining the concept of a voiceband channel. Step-by-Step Solution: Recall voiceband definition: about 300–3400 Hz.Map to medium: PSTN analog telephone line supports that band.Exclude higher-frequency media (coaxial, microwave) that are broadband or carrier systems.Choose Telephone line as the correct answer. Verification / Alternative check: Historically, modems (for example, V.32, V.34) transmitted within the voiceband over telephone lines. This validates that the PSTN voice channel is the canonical voiceband medium. Why Other Options Are Wrong: Telegraph line: Associated with low-speed signaling, not a standard voiceband telephony path. Coaxial cable: Supports wideband services, not limited to voiceband. Microwave systems: High-frequency, wide-area backhaul; not voiceband-limited. None of the above: Incorrect because telephone line is correct. Common Pitfalls: Equating any copper medium with voiceband. Coax can carry TV and broadband; voiceband is a functional bandwidth concept tied to PSTN analog loops, not just copper presence. Final Answer: Telephone line

Question 12

Communications quality metric: In data transmission, how is the error rate formally defined?

Accepted Answer

Introduction / Context: Error rate quantifies the reliability of a communication channel. It is commonly expressed as bit error rate (BER) or block/frame error rate, depending on the unit of measurement. This question asks for the general definition regardless of the specific unit chosen. Given Data / Assumptions: We consider error rate in a generic sense. Data units could be bits, bytes, frames, or packets. The definition must be ratio-based for comparability. Concept / Approach: Error rate = errors observed divided by total units transmitted, over a defined interval or sample. For BER, units are bits. For block error rate, units are blocks. The ratio provides a normalized measure independent of absolute traffic volume. Step-by-Step Solution: Identify that error rate is a ratio metric.Specify numerator: number of data units received in error.Specify denominator: total number of data units sent or received.Therefore, option describing this ratio is correct. Verification / Alternative check: Standards and textbooks define BER as errors / total bits. Lab tests use known patterns, count mismatches, and compute the ratio to characterize channel quality at various signal-to-noise ratios. Why Other Options Are Wrong: Summation code and check bit options describe parity or checksum mechanisms, not the metric definition. Construction rule codes describe error-detecting code properties (for example, codes with invalid combinations), not the error rate formula. None of the above: Incorrect since the ratio definition is correct. Common Pitfalls: Confusing error detection methods (parity, checksums, CRC) with the measure of errors observed. The mechanism detects errors; the rate quantifies frequency. Final Answer: The ratio of the number of data units in error to the total number of data units

Question 13

Messaging software: What type of software package enables users to send and receive electronic mail over a network of computers and workstations?

Accepted Answer

Introduction / Context: Electronic mail (email) is a foundational network application that predates the modern web. It involves client software, server components, and protocols that enable message composition, transport, storage, and retrieval. This question checks recognition of the correct software category for email functionality. Given Data / Assumptions: Users need to send messages over a network. Workstations and computers are interconnected. We focus on the end-user application category rather than the underlying protocols. Concept / Approach: An electronic mail package provides the features needed for composing, sending, receiving, and managing email messages. It may use SMTP for sending and POP3/IMAP for retrieval. The package may include address books, attachments, and filtering. Other software categories do not provide the specific messaging functions described. Step-by-Step Solution: Identify the user task: email messaging over a network.Map to application category: electronic mail package (mail client or groupware).Exclude unrelated categories such as project management or generic comms suites without mail features.Select Electronic mail package as the correct answer. Verification / Alternative check: Classic examples include Eudora, Outlook, Thunderbird, and groupware like Lotus Notes. All center on email composition and transport via standard mail protocols, confirming the category match. Why Other Options Are Wrong: Memory resident package: Describes TSRs or resident utilities, not mail. Project management package: Focuses on scheduling and tasks, not messaging. Data communication package: May provide terminal emulation or file transfer but not necessarily integrated email services. None of the above: Incorrect because an electronic mail package is exactly correct. Common Pitfalls: Confusing generic communication software (for example, terminal emulators) with full email clients. While both run on networks, only the email package implements mail protocol workflows. Final Answer: Electronic mail package

Question 14

Local Area Network scope: Which kinds of devices are typically interconnected by a LAN within an organization?

Accepted Answer

Introduction / Context: A Local Area Network (LAN) connects resources within a limited geographic area such as an office, building, or campus. Understanding what can be attached to a LAN clarifies the scope of shared services and traffic patterns in enterprise networks. Given Data / Assumptions: The network spans a local environment. We consider both endpoints (users, peripherals) and interconnection devices. Modern Ethernet and switching are assumed, but the concept applies broadly. Concept / Approach: LANs link user devices (PCs, terminals), shared peripherals (printers, plotters, network-attached storage), and networking infrastructure (bridges, switches, routers, gateways). The objective is resource sharing, collaboration, and local service delivery with low latency and high throughput compared to wide-area links. Step-by-Step Solution: List device categories: user computers and terminals.Include shared peripherals: printers, plotters, mass storage (NAS/SAN gateways).Include interconnect devices: bridges and gateways for segmentation and connectivity.All categories belong on a LAN, so choose 'All of the above'. Verification / Alternative check: Enterprise network diagrams show PCs, printers, storage arrays, and network devices connected at the access, distribution, and core layers within a LAN. This validates the inclusive nature of LAN attachment. Why Other Options Are Wrong: Each single category is true but incomplete; the best comprehensive answer is 'All of the above'. None of the above: Incorrect because LANs commonly include all listed device types. Common Pitfalls: Overlooking infrastructure nodes as LAN members. Bridges, gateways, and switches are integral to segmentation, security, and routing between VLANs or to external networks. Final Answer: All of the above

Question 15

Radio spectrum knowledge: Which frequency band contains commercial FM broadcast radio transmissions?

Accepted Answer

Introduction / Context: FM broadcasting uses a specific portion of the radio spectrum defined internationally, though exact allocations vary by region. Knowing the correct band helps in understanding propagation characteristics, antenna design, and interference considerations for broadcast and communications systems. Given Data / Assumptions: FM means frequency-modulated broadcast radio for the general public. We are identifying the parent band, not the narrow sub-band allocation. Standard ITU band names and ranges are assumed. Concept / Approach: Commercial FM broadcast typically occupies 88 MHz to 108 MHz, which lies entirely within the Very High Frequency (VHF) band of 30 MHz to 300 MHz. VHF propagation characteristics suit local to regional coverage with line-of-sight tendencies and moderate antenna sizes. Step-by-Step Solution: Recall FM broadcast allocation: approximately 88–108 MHz.Map 88–108 MHz to the broader band: VHF (30–300 MHz).Select the option naming VHF with the correct numeric range.Confirm that other named bands do not include 88–108 MHz. Verification / Alternative check: Radio reference material and regulator tables (for example, ITU, FCC) list FM broadcast as part of the VHF band, cementing the classification. Why Other Options Are Wrong: VLF and LF: Far below FM frequencies; used for navigation and specialized communications. HF: 3–30 MHz; used for shortwave and skywave propagation, not FM broadcast. None of the above: Incorrect because VHF is correct. Common Pitfalls: Confusing HF (shortwave) with FM due to historical radio terminology. Remember that FM broadcast sits well above HF in the VHF band. Final Answer: Very High Frequency (30 MHz to 300 MHz)

Question 16

Partner connectivity: Internet-like private networks linking a company with external business partners are best described as which of the following?

Accepted Answer

Introduction / Context: Organizations extend selected internal resources to suppliers, distributors, and customers using web technologies and secure access controls. This controlled external sharing is architected differently from purely internal networks. The question probes the correct naming convention for such networks. Given Data / Assumptions: Connectivity is Internet-like (TCP/IP, web protocols). Participants include outside business partners, not only internal staff. Security, authentication, and limited resource exposure are assumed. Concept / Approach: An extranet is an extension of an organization's intranet selectively opened to external parties. It uses the same technologies as intranets (HTTP/S, VPNs, directory services) but enforces strict access control to protect sensitive assets while enabling collaboration and data exchange across firm boundaries. Step-by-Step Solution: Recognize external partner involvement.Match to terminology: extranet (external access to intranet resources).Exclude intranet, which is strictly internal.Select Extranets as the correct choice. Verification / Alternative check: Reference standard enterprise architectures where supplier portals and customer portals are implemented as extranets providing controlled access to ERP, ordering, and support systems. Why Other Options Are Wrong: Bandwidth alternatives / Switching alternating: Not recognized architectural terms for partner networks. Inter organizational networks: Descriptive but not the canonical term; extranet is the accepted name. Intranets: Strictly internal networks, not extended to partners. Common Pitfalls: Using intranet as a catch-all. The distinction hinges on whether external entities authenticate into the organization's environment. Final Answer: Extranets

Question 17

Secure connectivity term: Within enterprises, intranets and extranets often use firewalls and security features to create protected links over the public Internet. What is the standard term for such secure tunnels?

Accepted Answer

Introduction / Context: Organizations commonly link sites, remote users, and partners securely over the Internet. Rather than private leased lines, they build encrypted tunnels that provide confidentiality, integrity, and often authentication. This question asks for the widely accepted term for that technology class. Given Data / Assumptions: Communication rides over the public Internet. Security controls include encryption and authentication. Endpoints are enterprise networks (intranets/extranets) and remote peers. Concept / Approach: A Virtual Private Network (VPN) uses protocols such as IPsec or TLS to create secure tunnels over untrusted networks. VPNs can be site-to-site or remote access. They complement firewalls and directory services to enforce policy while providing private connectivity semantics on public infrastructure. Step-by-Step Solution: Identify need: secure links across the Internet.Map to solution: VPN creates encrypted tunnels between endpoints.Recognize that VPN is the established umbrella term.Select Virtual Private Network as the correct answer. Verification / Alternative check: Common deployments include IPsec site-to-site VPNs between data centers and SSL/TLS-based remote access VPNs for users. Both fulfill the described requirement. Why Other Options Are Wrong: Network Server: A role, not a secure tunnel technology. Network operating system: Software class, not the tunneling method. OSI: A reference model, not a product or feature. Secure Sockets Layer (SSL): A protocol component; modern TLS can underpin VPNs, but the overall solution is called a VPN. Common Pitfalls: Equating a single protocol (for example, SSL/TLS) with the broader deployment concept. The accepted umbrella term for secure site or user tunnels across the Internet is VPN. Final Answer: Virtual Private Network

Question 18

Communication modes: Which mode supports two-way communication but only one direction at a time (that is, alternating send and receive)?

Accepted Answer

Introduction / Context: Communication systems are classified by directionality: one-way only, two-way simultaneously, or two-way but not at the same time. Correctly naming these modes is fundamental for designing links, protocols, and media access strategies. Given Data / Assumptions: Two-way communication is required. Only one direction can use the channel at any instant. The link alternates between sending and receiving. Concept / Approach: Half duplex allows bidirectional traffic, but transmissions do not overlap in time on the same channel. Classic examples include push-to-talk radios and older Ethernet hubs with collision domains where stations take turns. Full duplex, by contrast, allows simultaneous send and receive, and simplex allows only one fixed direction. Step-by-Step Solution: Determine that two-way capability exists.Note the time-sharing constraint: only one direction at a time.Map to the term half duplex.Select 'half duplex' accordingly. Verification / Alternative check: Review protocol and media examples: walkie-talkies (half duplex), modern Ethernet on switches (full duplex), and broadcast TV (simplex). The alternating talk-listen model confirms half duplex. Why Other Options Are Wrong: Simplex: Supports only a single fixed direction, not two-way. Duplex (full duplex): Supports simultaneous bidirectional transfer, unlike the scenario. Multiplex: Refers to combining multiple signals on one medium, not directionality. None of the above: Incorrect because half duplex fits exactly. Common Pitfalls: Confusing multiplexing (a bandwidth sharing technique) with duplex modes (directionality). Also, assuming duplex always means full duplex; half duplex is a distinct, important category. Final Answer: half duplex

Question 19

Computer networks – transmission media categories: Which types of data transmission channels are commonly recognized for carrying information from one location to another (by bandwidth classification and typical use cases)?

Accepted Answer

Introduction / Context: Data communication channels are often grouped by their usable bandwidth and the applications they serve. Understanding the common categories helps you choose the right medium for telemetry, telephony, and high-speed data networking. This question checks recognition of the standard classifications: narrowband, voiceband, and broadband. Given Data / Assumptions: Narrowband refers to very small bandwidth channels, typically used for low-rate telemetry or control signals. Voiceband typically refers to the traditional telephone channel bandwidth around 300 Hz to 3.4 kHz and technologies designed to operate in that band (for example, dial-up modems). Broadband refers to wideband channels capable of supporting high data rates, frequency division, or multiple services (for example, cable, fiber, microwave). Concept / Approach: Classification is not about the exact medium (copper, fiber, wireless) but about the bandwidth and services supported. If all three categories exist in practice for carrying data between locations, then the comprehensive answer is that all listed categories are viable channels. Step-by-Step Solution: Identify each option as an established channel classification.Narrowband: low-rate channels for signaling/telemetry; still used in SCADA and IoT LPWAN contexts.Voiceband: the PSTN voice channel; historically used by modems to carry data via tones.Broadband: high-capacity channels such as DOCSIS, xPON, and microwave backhaul.Since all are valid data-carrying channels, the correct choice aggregates them. Verification / Alternative check: Cross-check with standard networking texts which consistently define these three categories based on bandwidth and typical use. Each has well-known technologies and protocols built to operate within their constraints. Why Other Options Are Wrong: a: Narrowband alone is incomplete; it omits voiceband and broadband. b: Voiceband alone ignores other valid categories. c: Broadband alone omits legacy and low-rate channels which still carry data. e: Incorrect because all three are legitimate channel types used to carry data. Common Pitfalls: Equating classification strictly with medium (for example, copper vs fiber) rather than bandwidth; assuming legacy channels like voiceband can no longer carry data (they can, albeit at lower rates); or thinking broadband is the only modern option. Final Answer: All of the above

Question 20

TCP/IP basics: What is HMP (Host Monitoring Protocol) primarily used for in an internetworking context?

Accepted Answer

Introduction / Context: Networking stacks include many protocols with specific roles. The Host Monitoring Protocol (HMP) is an older Internet protocol intended for host status monitoring. Distinguishing it from address resolution, file transfer, and control-message protocols demonstrates basic fluency with the TCP/IP suite. Given Data / Assumptions: HMP is not used for data file transfer like FTP. HMP is not used to resolve IP to MAC addresses (that is ARP). HMP is not the network control message protocol (that is ICMP). Concept / Approach: Map each distractor to the well-known protocol that actually performs the described function. Then identify HMP by elimination and by its historical purpose as a host status monitoring protocol designed to report and query machine health or state. Step-by-Step Solution: Option a describes ARP, which resolves IP addresses to link-layer hardware addresses.Option b describes FTP or similar application protocols (not HMP).Option d describes ICMP, which carries error and control messages (for example, echo request/reply).Therefore, HMP aligns with option c: a protocol used to monitor hosts. Verification / Alternative check: Review canonical lists of TCP/IP protocols; HMP appears as a host monitoring protocol, distinct from ARP (address resolution), FTP (file transfer), and ICMP (control messages). Why Other Options Are Wrong: a: ARP, not HMP, performs dynamic IP-to-MAC mapping. b: FTP/TFTP/HTTP perform file transfer, not HMP. d: ICMP provides network diagnostics and error reporting. e: Not applicable because c correctly states HMP’s role. Common Pitfalls: Confusing protocol roles due to similar acronyms; assuming any monitoring function is handled by ICMP; or believing HMP is a widely used modern protocol (it is largely historical/legacy today). Final Answer: A protocol used to monitor computers (host status reporting)

Networking Questions