E-LEARNING

Point 1. The internet structure
The main stages of Internet development:
ARPANET (Advanced Research Projects Agency net)
NFSNET (National Fond for Science net)
NFSNET Backboon - INTERNET
Internet is a global net.

Point 1. The internet structure
Structure:
Internet consists of local nets.
There are 3 categories of computers:
Hosts (nodes) handle the client access.
Servers provide information.
Clients use information.

Point 1. The internet structure
Every host or host group of Internet is served by some organization (provider).
Servers
WEB (World Wide Web)- for work with WWW
Mail – for receiving and transmitting the mail
FTP (file transfer protocol) – for file storage which are used for client download
NNTP (network news transfer protocol) – for teleconferencing- and news service
DNS (domain name system) – for converting the letter (domain) addresses into IP-addresses

Point 2. The main principles of network
No rules and limits to presentation of information
Information interchange between all the computers
No limits to computer type and OS
No hierarchy between PC connected to the Internet

Point 2. The main principles of network
IP-addressing
Every computer connected has its IP-address.
IP-address is a group of numbers (dotted decimal or octat). A dotted decimal is 1 byte of 32-bits address and cannot be more then 255.
The 32-bits address has 2 parts: net number and host number.

Point 2. The main principles of network
Dynamic address is an IP-address given automatic and used during limited time period.
For example, 108.25.17.100

Point 2. The main principles of network
Domain addressing
Domain address (URL – uniform resource locater) is a symbol (letter) group of domains with points.
There is a hierarchy. The 1.st level domain is the last one. It is an organization type or country. The 2.nd level domain is often an organization activity character. The 3.d level domain is a computer name (gov, mil, edu, com, org, net)