1. WHAT IS NETWORKING?

2. Networking is … How computers talk to each other

3. Overview of Today Types of Networks Data Processing on Networks Communications Circuits Communications Devices TCP/IP Protocol and Routing

4. Types of Networks LAN (Local Area Network) Local area networks usually occupy a room or building, and typically include a group of PCs that share a circuit. Support data rates of 10 to 100Mbps.

5. Types of Networks MAN (Metropolitan Area Network) Air Force Base San Francisco Executive Airport Sacramento Army Depot Capitol Building Office of Public Works MANs usually span 3-30 miles and can support data rates of 100 – 1000Mbps.

6. Types of Networks WAN (Wide Area Network) Seattle Sacramento Los Angeles Phoenix Chicago New York WANs span hundreds or even thousands of kilometers. Leased circuits or other commercially available services are used to transmit data. Supports data rates of 28.8 Kbps – 2Gbps.

7. These different types of networks are linked together! WAN MAN LAN

8. WANs are interconnected too WAN

9. Example Trace Route to http://www.bbc.co.uk/ IP: 212.58.240.120

10. What a LAN might look like: Print Server Web Server File Server Router Circuit: The pathway through which the messages travel Client Computers HUB

11. Data Processing on Networks Host-Based Architectures Client-Based Architectures Client-Server Architectures

12. Host-Based Architecture Client (user) Terminals Host (Mainframe computer) Presentation Logic Application Logic Data access logic Data storage Problems: -All processing is done by the host which creates a bottleneck -Upgrades require big jumps and are expensive Thin CLIENT

13. Client-based Architecture Client (microcomputer) Server (microcomputer) Data storagePresentation Logic Application Logic Data access logic Problem: All data must travel between server and clients Why is this a problem? It creates network congestion that can cause poor network performance FAT CLIENT

14. Client-Server Architecture More efficient More reliable Allows hardware and software from different servers to be used together. Client (microcomputer) Server (microcomputer) Data Access Logic Data storage Presentation Logic Application Logic

15. Bandwidth WHAT IS IT?

16. Twisted Pair Most Commonly used WHY are they twisted? Two Types –Shielded: Difficult to Install and use More expensive –Unshielded: Easier to Install More susceptible to Interference

17. Twisted Pair Pros and Cons PROS -Inexpensive -Easy to get -Flexible and lightweight -Easy to work with CONS -High interference -Signal weakens over time -Relatively low bandwidth

18. Coaxial Cable Inner Conductor Insulator Wire mesh (ground) Outer protective shell TV companies use coaxial cable between community site out to businesses and telephone poles between users. Coaxial cable was invented in 1929 and first used commercially in 1941 Biggest difference between coaxial and twisted pair is that it is better shielded

19. Coaxial Cable PROS -Higher bandwidth 350-600MHz Up to 10,800 voice conversations -Easy to work with -Less interference than Twisted Pair CONS -Signal strength wanes fairly quickly over distance -Expensive over long distances -Bulky

20. Fiber Optic Cable Plastic JacketGlass CladdingFiber Core

21. Fiber in the real world

22. Fiber Optic Cable PROS -Greater Capacity -Data rates of up to 2Gbps -Strong signal over distance -Small and lightweight -Immune to electromagnetic interference -Good security CONS -EXPENSIVE -Difficult to install

23. Fiber Optic Cable is THE FUTURE! Want to learn more? There are tutorials on the web: http://www.iec.org/online/tutorials/fiber_optic/ http://www.arcelect.com/fibercable.htm

24. Wireless To Internet

25. Wireless Balmer! Popular in LAN use WHY? What are possible cons? Flexibility! Cost: No wires to install! It’s fast! Security More Interference – what does this mean?

26. Satellite Transmission PROS -Can reach a large geographical area -High bandwidth -Cheaper over long distances CONS -High Installation Cost -Interference from lots of factors, including weather

27. Another look at the LAN Router HUB or Switch?

28. HUB Old technology Stupid, why? Broadcasts to all computers on the network, which creates unnecessary traffic Switch Does everything a HUB can do, but it’s smarter Forwarding Tables allow switches to send messages directly to the computer who it’s supposed to go to

29. Switch Kim Ron Meg Amy

30. TCP/IP Transmission Control Protocol/Internet Protocol What is it? A Protocol! Yeah, but what does that mean? A Language that computers use! We use English, they use TCP/IP What does it look like? 111.111.111.111  4 octet number All computer must have an IP address to use the Internet. Why? It’s the address of the computer, just like you have a street address

31. TCP/IP 128.95.230.3 128.95.230.54 128.95.230.80 128.95.230.100 140.142.200.100 140.142.200.95 140.142.200.34

32. OSI Model 7. Application 6. Presentation 5. Session 4. Transport 3. Network 2. Data Link 1. Physical 7. Application 6. Presentation 5. Session 4. Transport 3. Network 2. Data Link 1. Physical 1010001011101000111010 SuzyRachael Application Layer Internetwork Layer Hardware Layer

33. How packets move across the Internet

34. Asynchronous Packet Transfer Out of order How does the computer know what order they should be in? –There is a header on each packet Why is this good? –Each packet can find the fastest way (not necessarily the most direct way) Synchronous Packet Transfer