ITGS Types of network ITGS Local Area Networks

ITGS Types of network

ITGS • Local Area Networks (LAN) – A network confined to one geographical area, such as a home, an office building, or a school campus. • All computers belong to one organization • LANS provide many advantages: – Users can log in from anywhere in the organization – Easy sharing of peripherals, files, appications

ITGS • Wireless LAN’s (WLAN) – A local network in which some or all devices connect wirelessly • Common in businesses and schools for desktops to have wired Ethernet access, while laptops and PDA’s connect using Wi-Fi • Personal Area Networks (PAN) – Created when devices such as mobile phones or PDAs are connected to a computer • PANS cover a small area • Normally used to transfer data or synchronize devices • PANs are created using bluetooth, USB cables and Infrared

ITGS • MANs and WANs (Metropolitan Area Networks/ Wide Area Networks) – MANs cover relatively large areas like very large university campuses or cities • Series of LANs connected together – WANs - even larger networks covering multiple cities or countries • The internet is a WAN, formed by connecting many computers and LANs together to form a nework of networks • Storage Area Networks (SAN) – A specialized network dedicated to storing data • Contain multiple hard disks which are attached to a LAN using high speed optical fiber connections

ITGS • SAN storage appears to client computers as local storage (like a hard disk inside the client computer) – Advantage: all storage is maintained in a single location » Backup tasks are much easier » Easier to add storage and distribute it across network clients • Virtual Private Networks (VPN) – Wide area networks like the Internet are insecure because of how data travels across them – VPN - uses encryption to create an encrypted tunnel from one computer to a local network in another location • For example: a businessman traveling in a London hotel can use a VPN to connect to his company’s LAN in the main New York office, allowing him to access the LAN’s files and printers

ITGS • the VPN software automatically encrypts all data sent backwards and forwards through the tunnel, meaning transactions are secure from eavesdroppers • Virtual LAN (VLAN) • Connects geographically separated computers or LANs into one virtual network • Similar to a VPN, except entire networks connect with eachother, rather than just individual computers

ITGS • Network connections – Wired connections • Fiber optic cables – Transfer data by sending light down an extremely thin glass tube – Connections are extremely fast, able to transfer data at well over 40 gbps (gigabits per second) – Each cable is able to contain multiple indpendent optical fibers – Extremely expensive » Slow to catch on with home and small business users » Mostly used for high speed backbone connections which deal with huge volumes of traffic

ITGS • Cable internet access – One of the most common forms of broadband internet access in homes • Cable uses existing cable TV network to transfer data, removing the need to have additional cable installed • DSL (digital subscriber line) – Connections use existing telephone network • Cable modem is used to convert data for use over the network • Unlike fiber optics, the main advantage of cable and DSL connections is that high speed connections can be achieved without having to lay additional networks. – Disadvantage of cable networks: users in the same area share the network, reducing bandwidth

ITGS • Dialup – Relatively old technology that connects using a standard telephone line • Because computers are digital and phone lines are analog, the computer must be connected to a Modem to use the phone network – Common before broadband became popular – Slow speed: up to 56 Kbps » Phone line can’t be used for anything else while connected » Dialup connections must be paid for by the minute • Ethernet – LAN cables that can transfer data at high speeds over short distances