Section 1.1: What Is the Internet?
Description 1: Basic hardwares and softwares make up the Internet.
Description 2: A networking infrastructure that provides services to distributed applications.
Definition of a protocol:
A protocol defines the format and order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event.
Section 1.2: The Network Edge
| bandwidth | shared/dedicated | range | |
|---|---|---|---|
| DSL (digital subscriber line) |
upstream < 2.5Mbps
扫描二维码关注公众号，回复：
3623029 查看本文章
downstream < 24Mbps |
dedicated | |
| HFC (hybrid fiber-coacial cable) |
upstream up to 2Mbps downstream up to 30Mbps |
shared | |
| Ethernet | 10Mbps, 100Mbps, 1Gbps, 10Gbps | ||
| wireless LAN | 11Mbps, 54Mbps (IEEE 802.11) |
100s ft | |
| wide-area wireless access network | 1~10Mbps | 10s km |