ITGS Networks Based on the textbook “Information Technology in a Global Society for the IB Diploma” by Stuart Gray

Networks Due to computer and smart phone growth, networks are becoming increasingly important due to the wireless options. Computer networks exist in many places; small = at home with a few computers; large = companies with thousands of computers.

Network Components Clients and servers Shared devices Hubs, routers and switches

Network Architecture The way computers are organized on a network and the role each takes. Thin Client Network – computers rely heavily on a server not only for storage but to run software. Peer-to-peer Networks – Every client has equal status and there is no central authority or server.

Firewalls Hardware or software that determines which data is allowed to enter and leave a network. Personal firewall – when a software firewall in installed on a desktop computer versus a server. IP Addresses Domain Names Protocols and Ports Application Program

Proxy Servers Middle step between 2 computers – usually between a computer on a LAN and a web server on the internet. Caching – Process used to speed up activities such as web browsing.

Server Types Local Area Network (LAN) – confined to 1 geographic area ex: home, school campus; can be wireless LANs Personal Area Network (PAN) – when mobile devices are connected to a computer Metropolitan Area Network (MAN) – Covers large areas ex: cities or large campuses

Server Types continued Wide Area Networks (WAN) – Connecting many computers and LANs together ex: internet Storage Area Networks (SAN) – Dedicated to storing data Virtual Private Networks (VPN) – Uses encryption over a public network; Virtual LAN (VLAN)

Network Connections Wired – Fiber optic cables, cable internet access, Dialup, Ethernet Wireless – Wimax, Wi-Fi, Bluetooth, 3G and 4G NOTE: Network speeds are measured in bits per second.

Network Communication MAC Addresses (hardware address) – each is unique. Protocols – Set of rules on how to do something. IP (Internet Protocol) – how devices on the internet are identified and info is routed. TCP (Transmission Control Protocol) – Deals with if data is sent and received. Ports – Identify the services available on networked computers.

How are IP Addresses Assigned? All IP Addresses are managed by IANA – the Internet Assigned Numbers Authority. Dynamic – changes each time you connect. Static – remains the same each time you connect. Geolocation – implications for privacy – impossible to maintain anonymity on the Internet. IP Address Future – 243 million are assigned a year – new standard adopted IPv6 (128 bit addresses).

The Internet The Internet Backbone – series of high speed links which connect major geographical areas. Data routing – infrastructure of the Internet. Domain Name System (DNS) – responsible for translating domain names when people type in their web browsers into IP addresses.

Internet Protocols Hypertext Transfer Protocols (HTTP) – governs communication between web servers and web browsers. Hypertext Transfer Protocol Secure (https) – Designed to keep communication secure through encryption. TLS SSL

Internet Protocols continued When data is transferred between computers: Asynchronous Transfer – the sender and received are not synchronized in terms of time. Synchronous Transfer – the sender and receiver agree on a transfer rate before the start of a transfer = faster data transfer.

Web 2.0 Web sites that allow users to contribute information as well as view it. Sometimes called read/write web: Blogs or microblogs Wikis Social bookmarking Social networks RSS Podcasts and Vodcasts Web 3.0 – the next evolution – what will it look like?