S305 Technology Infrastructure - Network Model & Application Layer Flashcards

Vocabulary flashcards covering fundamental concepts in data communications, network models (OSI and Internet), standards, application architectures, cloud computing models, and application protocols based on Chapters 1-2 and Lectures 1-2.

Data Communications

The movement of computer information from one point to another via electrical or optical transmission.

Local Area Network (LAN)

A network spanning a single floor, work area, or building, typically operating at speeds of around $100\,\text{Mbps}$.

Backbone Network (BN)

A high-speed network operating from hundreds of feet to several miles ($100\,\text{Mbps} - 1,000\,\text{Mbps}$) that connects other networks together.

Wide Area Network (WAN)

A network spanning hundreds or thousands of miles ($64\,\text{Kbps} - 10\,\text{Gbps}$), often utilizing leased circuits from Interexchange Carriers (IXCs).

Intranet

A private network restricted exclusively to organization insiders that uses Internet technologies such as HTTP and HTML internally.

Extranet

A network accessible via the Internet that allows invited outside users with authentication logins to access specified company resources.

OSI Model

A formal 7-layer theoretical network model (Physical, Data Link, Network, Transport, Session, Presentation, Application) primarily used for teaching and certification exams.

Internet Model

The dominant 5-layer network model actually used in real-world networking, consisting of Physical, Data Link, Network, Transport, and Application layers.

Protocol

A standardized set of rules, functionality, and message structures that define communication at a specific network layer.

Protocol Data Unit (PDU)

The specific message format or unit added by a network layer (such as Frame, Packet, or Segment) as data travels down the stack.

Encapsulation

The process of wrapping a higher-layer Protocol Data Unit (PDU) inside a lower-layer PDU as a message moves down through the network layers.

De Jure Standard

An official, formal standard established by a recognized industry or government organization (e.g., IEEE 802.3 Ethernet, HTTP).

De Facto Standard

A standard that emerges informally from marketplace adoption and widespread vendor support without official standing (e.g., TCP/IP).

Application Architecture

The structural design dictating how application logic, data storage, data access logic, presentation logic, and services logic are distributed between clients and servers.

Host-Based Architecture

An application architecture where the server (such as a mainframe) performs all processing, data access, storage, and presentation logic, while the client acts as a dumb terminal.

Client-Based Architecture

An architecture where the client handles presentation, application, and data access logic, leaving the server to handle only data storage.

Client-Server Architecture

An architecture where application work is distributed between clients (handling presentation) and servers (handling data storage and access logic), currently the most common architecture.

Middleware

Software located between client and server applications that translates message formats and routes requests across software from different vendors.

Thin Client

A client architecture containing little to no application logic, making applications easier to manage because software updates only occur on the server.

Thick Client

A client architecture carrying most or all application logic, providing greater local functionality but making software management across multiple machines more difficult.

Software as a Service (SaaS)

A cloud service model where the provider manages the entire application, infrastructure, security, and updates, while the user accesses software via a browser.

Platform as a Service (PaaS)

A cloud service model where the provider manages hardware, operating systems, and database platforms, while the client organization manages only the application logic and data.

Infrastructure as a Service (IaaS)

A cloud service model where the provider manages only raw hardware (servers, storage, network), and the client organization retains control of operating systems, software, and data.

Hybrid Cloud Strategy

A cloud deployment strategy combining public, private, or community cloud infrastructure across an organization for different application requirements.

Hypertext Transfer Protocol (HTTP)

The standard application-layer protocol defining communication and request-response cycles between web browsers and web servers.

Simple Mail Transfer Protocol (SMTP)

The standard plain-text email transmission protocol governing client-to-origin-server and server-to-server mail delivery.

Post Office Protocol (POP3)

An email retrieval protocol that downloads copies of messages to the client device and then deletes them from the mail server.

Internet Message Access Protocol (IMAP)

An email retrieval protocol where messages remain stored on the server after being read, supporting consistent access across multiple devices.

Multipurpose Internet Mail Extension (MIME)

An email utility protocol that encodes non-text files (such as images and attachments) into ASCII text code so they can travel via plain-text SMTP.

Telnet

An early host-based application protocol that enables remote command-line login and access to network servers or devices.

SQL Injection

An application security threat where malicious code is entered into unsecured form fields to execute arbitrary SQL commands and manipulate a back-end database.