CT320: Network and System Administration

Fall 2019

Definitions

Show Lecture.Definitions as a slide show.

CT320 Definitions

Definition: definition

Definition: host

A host is a thing on a network; anything with an IP address. My house contains these hosts:

  • my library Linux laptop
  • my CSU Linux/Windows laptop
  • my Android phone
  • desktop Linux/Windows system
  • NAS
  • wife’s Windows laptop
  • wife’s Android tablet
  • wife’s Android phone
  • Wi-Fi DD-WRT router
  • Wi-Fi DD-WRT repeater
  • cable modem
  • TV
  • DVR
  • Blu-ray player
  • Wi-Fi thermostat

Definition: medium

Singular: “medium”
Plural: “media”

Definition: network

A network is hosts connected by a single medium. Your laptop and eBay are not on the same network.

    ┌────────┐           ┌────────┐          ┌─────────┐
    │        │           │        │          │         │
    │ laptop │···········│ router │··········│ Blu-Ray │
    │        │   Wi-Fi   │        │   Wi-Fi  │         │
    └────────┘           └────────┘          └─────────┘

Definition: LAN

Variations on a theme

Definition: internet

What is a (lower-case “i”) internet(work)? It’s a collection of connected networks.

    ┌────────┐           ┌────────┐              ┌─────────┐
    │        │           │        │              │         │
    │ laptop │···········│ router │··············│ printer │
    │        │   Wi-Fi   │        │   ethernet   │         │
    └────────┘           └────────┘              └─────────┘

Definition: Internet

    ┌────────┐           ┌────────┐              ┌──────┐
    │        │           │        │              │      │
    │ laptop │···········│ router │··············│ eBay │
    │        │   Wi-Fi   │        │   Internet   │      │
    └────────┘           └────────┘              └──────┘

or, more simply:

    ┌────────┐              ┌──────┐
    │        │              │      │
    │ laptop │··············│ eBay │
    │        │   Internet   │      │
    └────────┘              └──────┘

Definition: World-Wide-Web

What is the (World-Wide-)Web? It’s a use of the Internet.

Definition: End system

    ┌────────┐              ┌──────┐
    │ laptop │··············│ eBay │
    └────────┘   Internet   └──────┘

Definition: Client/Server

    ┌────────┐              ┌──────┐
    │ laptop │··············│ eBay │
    └────────┘   Internet   └──────┘

End systems may be clients, servers, both, or neither.

Client vs. server depends on what programs the end system is running. A given host may be both. Most hosts are DNS clients.