Chapter 1: Introduction to Data Communications (Video Notes)

A set of practice flashcards covering key concepts from Chapter 1: Introduction to Data Communications.

What are the three fundamental questions this book answers?

1) How does the Internet work? (Chapters 1–5) 2) How do I design a network? (Chapters 6–10) 3) How do I manage my network to ensure security, performance, and cost? (Chapters 11–12)

Define data communications.

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

What are the three basic hardware components of a data communications network?

Server (stores data/software), Client (input–output device at the user end), and Circuit (the pathway messages travel).

What is a peer-to-peer network?

A network without a dedicated server.

What is a Local Area Network (LAN)?

A network with several client computers connected by switches and cables, possibly wireless via an access point, with a router connecting to other networks or the Internet.

What is a backbone network (BN)?

A central network linking LANs and other networks (BNs, MANs, WANs) with typical speeds around 100–1,000 Mbps and over varying distances.

What is an intranet?

A LAN using Internet technologies but open only to inside the organization; may be served by a separate Web server hidden from the Internet.

What is an extranet?

A LAN using Internet technologies provided to invited external users (customers, suppliers) who access it over the Internet.

What are the two most important network models?

The Open Systems Interconnection (OSI) reference model and the Internet model.

How many layers does the OSI model have and what are they from top to bottom?

Seven layers: Application, Presentation, Session, Transport, Network, Data Link, and Physical.

Who developed the OSI model, when, and is it commonly used today?

Developed by ISO in 1984; widely referenced but rarely used commercially in North America; some European networks still use it.

What are the five layers of the Internet model?

Physical, Data Link, Network, Transport, and Application.

How do the OSI and Internet models differ in layer grouping?

OSI has seven layers; the Internet model has five. Some group Data Link with Physical (hardware layer) and Transport with Network (internetwork layers); such groupings vary by convention.

What is encapsulation in layered networking?

The process of placing a higher-layer PDU inside a lower-layer PDU as data moves down the stack; each layer adds its own header/trailer; PDUs are often called packets.

What is a Protocol Data Unit (PDU)?

A unit of data at a given layer (e.g., packet, segment, frame) used by that layer's protocol.

Why are standards important in networking?

To ensure interoperability among hardware and software from different vendors and prevent vendor lock-in; enables layer-by-layer development.

What is the difference between de jure and de facto standards?

De jure standards are formal, official standards; de facto standards emerge in the marketplace without formal status and gain widespread support.

Name some standard-making organizations.

ISO, ITU-T, ANSI, IEEE, and IETF.

What are some common data communications standards by layer?

Application: HTTP, HTML, MPEG, H.323, SMTP/IMAP/POP; Transport: TCP; Network: IP; Data Link: Ethernet, Frame Relay, WAN/LAN links; Physical: T1, RS-232C, Category 5, V.92.

What are the core IT capabilities in organizational settings?

Storing and retrieving data; analyzing and visualizing data; automating data operations; protecting data.

What future trends are mentioned in Chapter 1?

Wireless LAN and BYOD (bring your own device); Internet of Things (IoT) and the Network of Things (NoT); massively online activities (games and education).

What are the cybersecurity implications discussed?

Networks and the Internet enable many devices to connect; increasing demand for secure storage, secure transfer of data, and secure servers as capacity grows.

Name some common server types described in the notes.

File server (stores data/software); Web server (serves documents/graphics); Mail server (handles and delivers email).