Platform Tech Midterms

Network (definition)

A collection of interconnected devices (nodes) that exchange data, resources, or services; connections may use wired media or wireless signals, and devices follow communication protocols

Node

Any device connected to a network, such as a computer, printer, router, or game console

Bandwidth / Data Transfer Rate

The maximum rate at which data can be transmitted

Throughput

The actual data-transfer rate achieved in practice; it may be lower than bandwidth

Client-Server Architecture

A central server provides resources or services to multiple clients; clients request information and the server processes requests and manages data (e.g., a website or learning platform hosted centrally); offers centralized management/consistency, but server availability and capacity matter

Peer-to-Peer (P2P) Architecture

Devices can act as both clients and servers and share resources directly without relying on one dedicated central server (e.g., computers exchanging file segments directly); can be resilient and scalable, but management and security can be harder

OSI Model (overview)

A seven-layer conceptual framework useful for understanding communication and troubleshooting

OSI Layer 7: Application

Network services directly used by applications

OSI Layer 6: Presentation

Data format/translation, encryption, and compression

OSI Layer 5: Session

Establishes and manages sessions between applications

OSI Layer 4: Transport

End-to-end delivery; reliability, error recovery, and flow control

OSI Layer 3: Network

Logical addressing (IP) and routing packets between networks

OSI Layer 2: Data Link

Frames, MAC addressing, and link-level error control

OSI Layer 1: Physical

Transmits raw bits over the physical medium

TCP/IP Model (overview)

A practical four-layer model used for Internet communication

TCP/IP — Application Layer

User-facing network services; broadly combines OSI Application, Presentation, and Session functions

TCP/IP — Transport Layer

End-to-end delivery; TCP emphasizes reliable delivery, while UDP emphasizes lower-overhead/fast delivery

TCP/IP — Internet Layer

IP addressing and packet routing; aligns closely with OSI Network layer

TCP/IP — Network Interface Layer

Access to the network and transmission over the medium; broadly covers link/physical functions

Scenario strategy — OSI/TCP-IP clues

IP addresses and routing → logical addressing (Network/Internet layer); MAC addresses and frames → local-link delivery (Data Link layer); raw signals or bits → physical transmission (Physical layer)

Twisted-Pair Cable

Pairs of copper wires twisted to reduce interference; UTP is affordable and common, STP adds shielding; used in Ethernet LANs and everyday wired connections

Coaxial Cable

Central copper conductor with insulation and shielding; better interference resistance than basic twisted pair; used for cable television and broadband connections

Fiber-Optic Cable

Carries data as light; very high bandwidth, long-distance transmission, minimal signal loss, and immunity to electromagnetic interference; used for backbone links, data centers, undersea cables

Radio Waves (transmission medium)

Wireless transmission through air; supports mobility but can be affected by interference, attenuation, and security risks; used for Wi-Fi, Bluetooth, and cellular networks

Network Interface Card (NIC)

Provides a device's network interface; associated with a unique MAC address

Modem

Modulates/demodulates signals to connect with certain ISP access systems, such as traditional phone-line or cable systems

Switch (network hardware)

Connects devices within a LAN and forwards frames using MAC addresses

Router (network hardware)

Forwards packets between different networks using network-layer information

Access Point (AP)

Allows wireless devices to join a network through Wi-Fi

Firewall (network hardware)

Monitors and filters incoming/outgoing traffic according to security rules; may be hardware or software

Network Operating System (NOS)

Manages network resources such as shared files, printers, and user authentication

Protocols (networking)

Standard rules for formatting, sending, and receiving data; examples include TCP/IP, HTTP/HTTPS, and SMTP

Drivers and Utilities (networking)

Drivers help hardware work with the OS; tools such as ping, traceroute, and Wireshark help test, diagnose, or monitor networks

CIA Triad — Confidentiality

Information is seen only by authorized users; supported by encryption, secure authentication, access control; scenario clue: keeping intercepted information unreadable, preventing unauthorized disclosure

CIA Triad — Integrity

Information remains accurate and is not changed without authorization; supported by hashing, digital signatures, validation and controls; scenario clue: detecting tampering or unauthorized changes

CIA Triad — Availability

Systems, services, and data are accessible when needed; supported by redundancy, load balancing, disaster recovery planning; scenario clue: keeping a service operating despite failures or heavy traffic

Malware (threat)

Malicious software—such as viruses, worms, or ransomware—that damages systems or steals data

Phishing (threat)

Deceptive messages or websites intended to trick people into revealing sensitive information

DoS / DDoS (threat)

Excessive traffic overwhelms a system or network so legitimate users cannot access it; DDoS involves distributed sources

Man-in-the-Middle (MitM)

An attacker intercepts communication between two parties and may steal or manipulate information

Insider Threat

A person inside an organization misuses legitimate access to cause harm or leak data

Shared Responsibility in Cloud Security (principle)

Cloud security is shared between the cloud service provider (CSP) and the customer; using a cloud service does not transfer every security duty to the provider

CSP Responsibilities (cloud security)

Secures underlying infrastructure, including physical data centers, networking, and virtualization layers; maintains the provider-controlled foundation of the service

Customer Responsibilities (cloud security)

Secures what it deploys and configures: applications, data, user access, and cloud settings; must configure permissions and firewalls appropriately, protect sensitive data, and manage access

Scenario method — Cloud security responsibility

Ask what was exposed or misconfigured; if it concerns the provider's physical infrastructure, consider the provider's role; if it concerns customer-created permissions, data access, or application settings, consider the customer's role

Database (definition)

An organized collection of data that can be stored, retrieved, and updated

Database Management System (DBMS)

Software used to create, maintain, and interact with databases

DBMS Function — Data Storage and Retrieval

Stores data and supports queries

DBMS Function — Security

Controls who may access information

DBMS Function — Integrity and Consistency

Applies rules that help keep data accurate and reliable

DBMS Function — Backup and Recovery

Helps restore data or service after failures

DBMS Function — Concurrency Control

Coordinates simultaneous access so users' changes do not conflict

Centralized Database Architecture

Data is stored and managed at one location; simpler administration, but may face scalability and reliability challenges

Distributed Database Architecture

Data is spread across multiple locations; can improve scalability and fault tolerance, but increases consistency and management complexity

Cloud-Based Database Architecture

Database is hosted using cloud services; can provide scalability, flexibility, and less infrastructure maintenance

Relational Databases (SQL/RDBMS) — Data Model

Tables with rows and columns; relationships can be defined between tables

Relational Databases — Typical Fit

Structured records and applications needing defined relationships and reliable transactions

Relational Databases — Strengths

Data integrity, atomic transactions, defined structure, powerful queries; commonly uses SQL

Relational Databases — Limitations

Less flexible for unstructured data; horizontal scaling and complex schema changes can be difficult

Relational Databases — Examples

MySQL, PostgreSQL, Oracle Database; cloud examples include Amazon RDS, Google Cloud SQL, Azure SQL Database

NoSQL Databases — Data Model

Flexible models such as key-value, document, wide-column, and graph

NoSQL Databases — Typical Fit

Large-scale, unstructured or semi-structured data; flexible and high-throughput workloads

NoSQL Databases — Strengths

Flexible schema, high scalability, support for varied data types and horizontal scaling

NoSQL Databases — Limitations

May not provide full ACID compliance in some systems and may be less suited to complex multi-table transactions

NoSQL Databases — Examples

MongoDB and Redis; cloud examples include Amazon DynamoDB, MongoDB Atlas, Google Firestore

Choosing a Database (strategy)

Start with the application's data shape and transaction needs; ask whether records have clear relationships requiring strong transactional consistency, or whether data is varied/changes frequently and needs flexible scaling — justify from the scenario, not by popularity

Managed Cloud Database Service (definition)

The provider handles many operational tasks so the organization can focus more on application development

Cloud Database Benefits

Maintenance relief (less manual hardware management, backups, updates); availability and scalability (remain accessible, adjust resources as workload changes); but security is still a concern — managed hosting doesn't remove the need for access controls, configuration, and data protection

Relational Cloud Databases

SQL-based operations and ACID-compliant transactions; useful when structured relationships and transaction reliability matter

NoSQL Cloud Databases

Flexible data models and high-throughput operations; useful for unstructured or semi-structured cloud-native applications

Horizontal Scaling (Scaling Out)

Adds more database instances or nodes and distributes the workload across them; think horizontal when adding nodes/instances to share work or needing growth across multiple machines

Vertical Scaling (Scaling Up)

Increases the resources of one existing database instance, such as CPU, memory, or storage; think vertical when upgrading the capacity of the current server/instance