1. Local and Wide Area Networks: Understanding the Pieces John H. Porter University of Virginia Coastal Research Center

2. WHY have a LAN (Local Area Network) hooked to the Internet? n Sharing of Resources disksdisks printersprinters n Access to Internet Electronic MailElectronic Mail WWW pagesWWW pages use net resourcesuse net resources n Control of setups of multiple computers

3. Ethernet - How does it work? n Ethernet is the most common system used on LANs n It operates the same way a group discussion works wait for a pausewait for a pause start to talk - but stop if someone else talksstart to talk - but stop if someone else talks in case of “collision” wait for a pause and try againin case of “collision” wait for a pause and try again

4. What are the PARTS you need? n Network Interface Cards (NICs) for computers n Category 5 (CAT5) cables running to n Hubs or Switches n Optical cable to interconnect hubs and switches n Server computers for printing & disk n A router to connect them to the Internet n A high speed telecommunications line to an Internet Service Provider (ISP)

5. Graphical Network Server PC PC PC PC Hub Hub Router InternetServiceProvider CAT5 Cable Optical or CAT5 Cable ISDN,T1 etc.

6. Network Interface Cards n Need one for each PC connected to the network n Most modern MacIntosh computers have Ethernet capabilities built in n Cost: $20-$100

7. CAT 5 Cables n “twisted pair” copper wires n Have a RJ-45 connector at each end looks like an extra-wide modular phone pluglooks like an extra-wide modular phone plug n Run between the computer and its “hub” n Cost: about $250 per installed “drop” 2 wall jacks2 wall jacks

8. Hubs and Switches n Hubs connect PCs together to form a network in a minimal LAN, this might be all you needin a minimal LAN, this might be all you need n Switches are like Hubs but are “smart” enough to optimize network traffic that passes through them n Cost: $50-$200 for most Hubs, $1,000- $3,000 for most switches –Cost depends on number of ports

9. Optical or CAT5 Cabling n Hubs, switches and routers can be connected using optical cables or CAT5 wiring n Optical cables are preferred for connecting buildings due to reduced susceptibility to lightning etc.

10. Server(s) n A server is a “normal” PC usually running Windows NT or Linux that shares disks and printers connected to it with other computers on the net. n It can be configured to provide security so that users only have access to “their” part of the system n Cost: $3,000-$10,000

11. Router n A router is a “very smart” network switch. It calculates the most efficient route for network packets to take. n Cost: $1,000-6,000

12. Internet Connection n A Internet connection to an Internet Service Provider (ISP) can take many forms: modem (56KB/S max) ($20/month)modem (56KB/S max) ($20/month) ISDN (64KB/S or 128KB/S) ($200/month)ISDN (64KB/S or 128KB/S) ($200/month) Leased lineLeased line –T1 (1.5 MB/sec) ($1,000/month) –DSL

13. Cutting Costs: The Ultimate Mini-Net Server PC PC PC PC Hub 56K modem InternetServiceProvider CAT5 Cable Serial Cable Regular phone line Server runs either WinNT or Win98 with Wingate 3.1 software (http://www.wingate.com) Cost: NICs $60+Hub $50+Cables $40+Software $40= $190 Recurrent cost: $20/month for ISP fees