01. The Internet — An Overview

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The Internet¶

The Internet is made up of billions of connected computing devices.
A host is an end system running network apps at the Internet’s “edge”. Data only enters/exits the Internet via edges. Internally, no “new” data is generated.
A packet switch forwards packets, which are chunks of data.
Examples of packet switches are routers and switches.
Communication links are the methods which are used to transfer data
Examples of comm links are fiber, copper, radio, satellite.
A network is a collection of devices, routers, and links, managed by an organization.

Really, the Internet is a network of ISP¹s.

Protocols¶

Protocols are the agreed upon rules of communication. They control sending and receiving data.
Examples: HTTP, SSH, TCP, IP, WiFi, 4G, Ethernet

Internet Standards¶

• RFC - Request for Comments
  • A protocol draft
• IETF - Internet Engineering Task Force

Misc. Definitions¶

• Hosts
  • Clients and servers
  • Servers are waiting passively for clients to send requests

802.11b/g/n (WiFi: 11, 54, 450 Mb/s)