9. Computer networks and Internet infrastructure

Basic description of the Internet Independent network made of voluntarily

interconnected networks, Runs on technical standards (RFC) that are also

voluntary, Originally: governmental and academic project,Currently: public use,Commercial use started later

What are components of the Internet? 1)Servers, computers, routers, repeatersServers, computers, routers, repeaters2)Backbone, Wide and Local AreaNetwork 3)people4)servis5)inf-n6)Internet creates information society

Internet connection:

Providers ISP (Internet Service Provider) for a charge

Types of connection Fair User Policy (FUP) Payments per time or data (FUP, Fair User Policy)

IP address (dynamic, public) Way out– creating LAN – local area network, for LAN are 3 segments of IP address reserved Typical Internet connections at households Dial-up analog line via modem (diminishing),DSL (ADSL/VDSL,…) fixed line telephone network, Wireless connection, Optical fibre connection Internet Service Provider (ISP) In common: provider of internet connection (line, IP address, routing), In practice: provides e-mail box, web hosting Services on the Internet Based on technical communication protocols E-mail On of the oldest, but most used services, SMTP protocol, Mail box at „my“ server (@ = “at”,World Wide Web (WWW) Main standards of the Web HTML-Hypertext Markup Language what? URL-Uniform Resource Locator where?HTTP-Hypertext Transfer Protocol,Tells how Domain Name System (DNS) IP address is very difficult to memorize,Words or shortcuts are better, Name system for domain – DNS TCP/IP – brief description of purpose and function Transfer Control Protocol / Internet Protocol, Every computer or network device connected to network must have own unique address, IP address – 32 bits number – 4 bytes

IP address Way out creating LAN – local area network, for LAN are 3 segments of IP address reserved IP version 4 vs. IP version 6 Currently IPv6 is being established,Larger a ddress range than IPv4, 2 ¹²⁸ – more and more IP addresses History of the Internet development Cold war between USA and USSR, In 1964 – 4 computers, Better if all of them could work simultaneously. Heavy computing – nuclear warhead, balistics characteristic for weapons, ...Idea – all computers are connected in one net, 1996 – Internet in CZ (Czech Technical University in Prague since 1992) Basic network hardware: server (Computing power,Searching, WWW servers, repeater(Amplifies data signal, for wi-fi) and router (Governs all internet traffic,speed,latency)