IS 410 MIDTERM EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

IS 410 MIDTERM EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 Computer Network - Answers A collection of computing devices connected in various ways to communicate and share resources Protocol - Answers A set of rules that dictate how to format, transmit, and receive data so computers can communicate Protocol Stack - Answers The full set of protocols used together across all layers (e.g., TCP/IP suite) Network Standards - De Jure - Answers Officially approved standards developed by standards bodies (e.g., IEEE, ISO); take years to develop Network Standards - De Facto - Answers Standards that emerge in the marketplace and are widely adopted without official standing (e.g., Windows OS) IEEE - Answers Institute of Electrical and Electronics Engineers; develops networking standards like IEEE 802.3 (Ethernet) and IEEE 802.11 (Wi-Fi) IETF - Answers Internet Engineering Task Force; develops Internet standards through RFCs (Requests for Comments) ITU-T - Answers International Telecommunications Union; develops international telecom/networking standards RFC (Request for Comments) - Answers The process by which Internet standards are proposed, debated, and published by the IETF Circuit - Answers The physical or logical connection between two devices used to transmit data Point-to-Point Circuit - Answers A circuit connecting exactly two devices directly Multipoint Circuit - Answers A circuit connecting more than two devices on the same line Logical Circuit - Answers Refers to transmission characteristics of a connection (e.g., speed) rather than the physical wire Physical Circuit - Answers The actual physical media (wire, fiber, etc.) connecting devices OSI Model - Answers 7-layer framework for network standards created by ISO in 1984; conceptual model, rarely implemented directly today Internet Model (TCP/IP) - Answers 5-layer practical model used to build the Internet; layers are Physical, Data Link, Network, Transport, Application Why the Internet Model replaced OSI - Answers OSI was too complex and took too long to standardize; TCP/IP was already deployed and working OSI Layer 1 - Physical - Answers Transmits raw bits over a medium using electrical, light, or radio signals; specifies cables, connectors, signal types OSI Layer 2 - Data Link - Answers Node-to-node delivery; frames messages, uses MAC addresses, detects errors, controls physical layer access OSI Layer 3 - Network - Answers Routes packets between networks using IP addresses; path selection OSI Layer 4 - Transport - Answers End-to-end delivery between source and destination hosts; segmentation, error detection, retransmission OSI Layer 5 - Session - Answers Establishes, maintains, and terminates sessions (conversations) between systems OSI Layer 6 - Presentation - Answers Translates data formats; handles encryption, decryption, compression, encoding OSI Layer 7 - Application - Answers User-facing; where apps interact with the network (browsers, email clients, APIs) OSI Mnemonic bottom to top - Answers Please Do Not Throw Sausage Pizza Away (Physical, Data Link, Network, Transport, Session, Presentation, Application) PDU - Physical - Answers Bit PDU - Data Link - Answers Frame PDU - Network - Answers Packet PDU - Transport - Answers Segment PDU - Application - Answers Data (or Packet) Encapsulation - Answers Wrapping a higher-layer PDU inside a lower-layer PDU as a message travels down the layers; each layer adds a header Decapsulation - Answers Stripping headers off as a message travels up the layers at the receiving end Routers process up to which layer? - Answers Layer 3 (Network) only — Transport and Application are only involved at the source and destination computers Ethernet frame lifespan - Answers Created and destroyed at each hop; a new frame is made for each next hop. IP packets and above never change in transit. Simplex Transmission - Answers One-way only communication; data flows in one direction only (e.g., TV broadcast, smoke alarm) Half-Duplex Transmission - Answers Two-way communication but only one direction at a time; must take turns (e.g., walkie-talkie) Full-Duplex Transmission - Answers Two-way simultaneous communication; both sides send and receive at the same time (e.g., phone call) Turnaround Time - Answers The time it takes to switch from sending to receiving in half-duplex communication Bandwidth - Answers The maximum capacity of a circuit to carry data; measured in bits per second (bps) Baud Rate - Answers The number of signal changes per second; different from bit rate when each signal carries multiple bits Bit Rate - Answers The number of bits transmitted per second (bps); what we usually mean by "speed" Multiplexing - Answers Combining multiple signals onto one physical circuit to increase efficiency; types include FDM, TDM, WDM FDM (Frequency Division Multiplexing) - Answers Divides the circuit into multiple frequency bands, each carrying a separate signal simultaneously TDM (Time Division Multiplexing) - Answers Divides the circuit into time slots, rotating between signals; each gets its own turn WDM (Wavelength Division Multiplexing) - Answers Used in fiber optics; different wavelengths (colors) of light carry different signals simultaneously Serial Transmission - Answers Bits sent one at a time over a single wire; used in most network communications Parallel Transmission - Answers Multiple bits sent simultaneously over multiple wires; faster but impractical over long distances Guided Media - Answers Physical media that guides signals; twisted-pair cable, coaxial cable, fiber optic cable Wireless (Radiated) Media - Answers Transmits signals through the air; radio, microwave, satellite, infrared Twisted-Pair Cable (UTP/STP) - Answers Most common LAN media; pairs of copper wires twisted to reduce crosstalk; UTP=unshielded, STP=shielded Coaxial Cable - Answers Copper cable with inner conductor, insulator, and outer shield; used in older networks and cable TV Fiber Optic Cable - Answers Transmits data as pulses of light (NOT electrical signals); highest speeds; immune to interference; used in backbones CAT3 - Answers Up to 10 Mbps; used in early 90s office wiring; mostly obsolete for networking CAT5 - Answers Up to 100 Mbps; replaced by CAT5e; uses 100BASE-T CAT5e - Answers Up to 1 Gbps at 100 meters; most common in homes/offices; uses 4 twisted pairs; reduces crosstalk vs CAT5 CAT6 - Answers Up to 10 Gbps (55m) or 1 Gbps (100m); better insulation than CAT5e; used in high-capacity networks CAT7 - Answers Up to 10 Gbps at 100m, 40 Gbps at 50m, 100 Gbps at 15m; fully shielded; not widely adopted Radio Transmission - Answers Wireless; signals broadcast in all directions; used for Wi-Fi, Bluetooth, cellular Microwave Transmission - Answers High-frequency wireless; line-of-sight required; used for long-distance point-to-point links Satellite Transmission - Answers Signals sent to satellites in orbit and back; covers wide areas; high latency; used where cables are impractical Submarine Cables - Answers Undersea fiber optic cables connecting continents; carry most intercontinental Internet traffic Attenuation - Answers The weakening of a signal as it travels over distance; fixed by repeaters or amplifiers Repeater - Answers Regenerates a digital signal exactly; used to extend transmission distance; Layer 1 device Amplifier - Answers Boosts the strength of an analog signal including any noise; does NOT regenerate; used in analog systems Noise - Answers Unwanted signals that distort or corrupt data during transmission Crosstalk - Answers Signal from one circuit bleeds into another nearby circuit; reduced by twisting wire pairs or shielding Impulse Noise - Answers Sudden electrical spikes (lightning, motors, power lines) that corrupt data; hardest to control Gaussian (White) Noise - Answers Random, constant low-level background noise present in all circuits; also called thermal noise Intermodulation Noise - Answers Occurs when two signals combine on a circuit and create new interference frequencies Echo - Answers A signal reflected back toward the transmitting device; can interfere with new transmissions Shielding - Answers Wrapping wires in metallic foil/braid to block external interference; reduces crosstalk, impulse noise, intermodulation Error Detection - Parity Check - Answers Adds a parity bit to make the number of 1-bits even (even parity) or odd (odd parity); detects single-bit errors Error Detection - Checksum - Answers Sums all bytes in a message; receiver recalculates and compares; detects most errors Error Detection - CRC (Cyclic Redundancy Check) - Answers Most powerful error detection; uses polynomial division; nearly eliminates undetected errors; used in Ethernet/TCP Forward Error Correction - Answers Adds enough redundant bits that the receiver can reconstruct corrupted data without retransmission; used in wireless ARQ (Automatic Repeat reQuest) - Answers Error correction method where receiver detects an error and requests retransmission from the sender ACK (Acknowledgement) - Answers Sent by receiver to confirm a packet was received correctly; tells sender to continue NAK / NACK (Negative Acknowledgement) - Answers Sent by receiver when a packet has an error; requests retransmission of that packet Stop-and-Wait ARQ - Answers Sender sends one frame, waits for ACK before sending the next; simple but slow Continuous ARQ / Sliding Window - Answers Sender can transmit multiple frames before receiving ACKs; much more efficient than stop-and-wait Information Bits - Answers Bits that carry the actual user data/message content Overhead Bits - Answers Bits used for error checking, framing, and control; not user data (e.g., headers, parity bits, CRC) Burst Error - Answers Multiple consecutive bits corrupted by a single noise event; harder to detect than single-bit errors Throughput - Answers The actual usable data transfer rate after accounting for overhead, errors, and retransmissions Transmission Efficiency - Answers Ratio of information bits to total bits (including overhead); higher is better Media Access Control (MAC) - Answers The process of deciding when a device is allowed to transmit on a shared medium Controlled Access - Polling - Answers A controller asks each device in turn if it has data to send; orderly but adds overhead Token Passing - Answers A special "token" frame circulates the network; only the device holding the token can transmit Contention - CSMA/CD - Answers Carrier Sense Multiple Access with Collision Detection; used in wired Ethernet; listen before transmit, detect collisions Contention - CSMA/CA - Answers Carrier Sense Multiple Access with Collision Avoidance; used in wireless (Wi-Fi); tries to avoid collisions before transmitting Collision - Answers When two devices transmit simultaneously on a shared medium; corrupts both frames Collision Domain - Answers The set of devices that can cause a collision with each other; switches break up collision domains, hubs do not TCP (Transmission Control Protocol) - Answers Reliable, connection-oriented transport layer protocol; guarantees delivery via acknowledgements and retransmission UDP (User Datagram Protocol) - Answers Fast, connectionless transport layer protocol; no error checking or retransmission; used where speed matters more than reliability TCP Three-Way Handshake (Session Establishment) - Answers SYN → SYN-ACK → ACK; both sides must be ready before data transfers TCP Session Termination - Answers Four-way handshake: FIN → ACK → FIN → ACK; each side independently closes its half of the connection TCP Data Transmission - Answers Error-checked; receiver sends ACK for each segment; sender retransmits if NAK received or timeout occurs Connection-Oriented Messaging - Answers A session is established before data is sent; used by TCP Connectionless Messaging - Answers Data sent without establishing a session first; used by UDP TCP Header Size - Answers 192 bits (24 bytes) of overhead UDP Header Size - Answers 64 bits (8 bytes) of overhead — much smaller, which is why it's faster Port - Answers 16-bit number identifying which application on a computer a message is for; 65,536 total (2^16) Well-Known Ports (0-1023) - Answers Assigned to standard server services: HTTP=80, HTTPS=443, FTP=20/21, SMTP=25, DNS=53 Segmenting - Answers Breaking a large message into smaller segments for transmission; transport layer function; reassembled at destination When to use TCP - Answers File transfer, email, web browsing — anywhere reliability matters When to use UDP - Answers Video/audio streaming, VoIP, online gaming, DNS — anywhere speed matters more than perfect delivery IP Address (IPv4) - Answers 32-bit address in dotted quad notation (e.g., 128.95.155.134); every Internet-connected device must have one IPv4 Address Space - Answers 2^32 = ~4.3 billion addresses; nearly exhausted due to Internet growth IPv6 - Answers 128-bit address (2^128 ≈ 3.4×10^38 addresses); created to solve IPv4 exhaustion; written in hexadecimal with colons How to convert Decimal to Binary - Answers Divide repeatedly by 2; track remainders; read remainders bottom-to-top How to convert Binary to Decimal - Answers Multiply each bit by 2^(position from right, starting at 0); sum the results. E.g., 111101 = 32+16+8+4+0+1 = 61 Excel DEC2BIN - Answers =DEC2BIN(number) — converts decimal to binary Excel BIN2DEC - Answers =BIN2DEC(number) — converts binary to decimal Excel DEC2HEX - Answers =DEC2HEX(number) — converts decimal to hexadecimal Excel HEX2DEC - Answers =HEX2DEC("number") — converts hexadecimal to decimal Dotted Quad - Answers The standard way to write IPv4 addresses: four decimal numbers (0-255) separated by dots DHCP (Dynamic Host Configuration Protocol) - Answers Server automatically leases an IP address to a client for a set time; process: Discover → Offer → Request → Ack Static IP Assignment - Answers Manually assigned permanent IP address; disadvantage: administrative overhead, can't reuse when device offline Dynamic IP Assignment - Answers DHCP assigns IPs automatically from a pool; flexible and efficient; IP may change each session