Computer Networks Notes Review

Vocabulary flashcards covering core concepts from Session 1 and Session 2 notes: network types, topologies, OSI/TCP-IP models, encoding techniques, framing and data-link practices.

Computer Network

A collection of interconnected computers and devices that communicate and share resources.

Resource Sharing

Using network resources such as printers, files, and storage across multiple devices.

Communication

Methods for exchanging information over a network (e.g., email, chat, video conferencing).

Data Sharing

Transfer or access of data between systems over a network.

Remote Access

Accessing a computer or network from a distant location.

E-commerce

Online banking, shopping, and other services that rely on networks.

Entertainment over Networks

Online gaming and streaming services delivered via networks.

LAN

Local Area Network; network covering a small geographic area, typically a building.

MAN

Metropolitan Area Network; spans a city or campus.

WAN

Wide Area Network; covers broad geographic areas, often using public or leased lines.

Topology

The layout or arrangement of devices and cables in a network.

Bus Topology

Devices connect to a single main cable; pros: simple and cheap; cons: a fault in the cable can bring down the entire network.

Star Topology

All nodes connect to a central hub or switch; pros: easy to manage; cons: hub failure can disrupt the network.

Ring Topology

Devices connected in a circle; pros: equal access; cons: a break disrupts the network.

Mesh Topology

Each device connected to every other device; pros: high reliability; cons: expensive and complex.

Hybrid Topology

Combination of two or more topologies.

Client-Server Network

A network where a central server controls and provides resources to clients.

Peer-to-Peer Network

All computers are equal and share resources directly without a central server.

OSI Reference Model

Open Systems Interconnection model; a 7-layer framework for standardizing network communications.

Application Layer (OSI)

User interface and applications (e.g., email, web).

Presentation Layer (OSI)

Data translation, encryption, and compression.

Session Layer (OSI)

Establish, manage, and end sessions between communicating parties.

Transport Layer (OSI)

Provides reliable delivery of data (TCP/UDP).

Network Layer (OSI)

Routing of packets between networks (IP).

Data Link Layer (OSI)

Error detection and framing on a data link.

Physical Layer (OSI)

Transmission media and signals.

TCP/IP Reference Model

A four-layer model used for internet communications.

Application Layer (TCP/IP)

Protocols such as HTTP, FTP, SMTP used by applications.

Transport Layer (TCP/IP)

Provides process-to-process data transport (TCP/UDP).

Internet Layer

Addresses and routes packets (IP addressing, routing).

Network Access Layer

Physical and data link functions in TCP/IP model.

Unipolar Encoding

Uses only one polarity (+ voltage); simple but inefficient.

Bipolar Encoding

Uses +, 0, – voltages with alternate polarity.

NRZ (Non-Return-to-Zero)

Encoding where the signal does not return to baseline between bits.

RZ (Return-to-Zero)

Encoding with a return-to-zero level within bit intervals.

Manchester Encoding

Bi-phase encoding with a transition in the middle of each bit for clocking.

Bit Stuffing

Inserting an extra bit to distinguish data from a frame delimiter (as used in HDLC).

Framing

Dividing data into frames for transmission.

Byte Count Framing

Framing method where the first field indicates the number of bytes in the frame.

Byte Stuffing

Inserting a special byte (ESC) to avoid confusion with the frame delimiter.