Data Communications Networking and Telecommunications topics for the Business Student

1. Data Communications Networking and Telecommunications topics for the Business Student

2. What is the difference between telecommunications and a network? • TELECOMMUNICATIONS - the of over public or private networks • NETWORK– t connected together using /protocols so that they can work together. What are the benefits of a network? • The ability to with others is the most popular form of network communications • The ability to shareD Software Peripheral devices and other resources Processing power

3. What is the most basic way to differentiate networks? By • L Network (LAN) --Connects computers in relatively • W Networks (WAN) -- Connects computers dispersedamong a number of buildings, oreven in different cities.Biggest WAN = • P Network (PAN) --Wirelessly connecting smallpersonal devices, really

4. Wireless Topology • Computers are connected by to a wireless (which is directly connected to a wired LAN) • Must be within a certain number of feet from the access point to communicate wirelessly (35-300 feet depending on the technology being used)

5. Comparing Wired to Wireless Wired Network Wireless Network Communication occurs using signals and base station. Limited by obstructions. S : rarely reaches max speeds that could be available Inherently : security features not turned on: easier to have data packets captured. M . Relatively easy to connect to. Must be within range of hotspot (base station) One person could monopolize the base station with huge data transfers: slowness for everyone. Computer can be , but work tools needed may not be available when needed. • Communications occur using a wired media. • F • Tends to be more • L and hard to move around (bound to the wire). Limited by walls, furniture, infrastructure. • Should be able to easily handle multiple users • F work • All of the work tools that you need probably are available

6. Bluetooth vs Wi-Fi (802.11) • Business networks use (Wi-Fi/Wireless Fidelity) while individuals might create their own network using B Bluetooth • Allows for wireless communications within a : 2 megabits per second, up to 30 feet. • Less expensive than Wi-Fi chips, , easier to build into small devices than run on batteries such as cell phones, palm-top computers, and other PDAs. • Called a “personal area network” (PAN) technology.

7. Walt Mossberg Chief Technology columnist for the WallStreet Journal Q: I’m wondering about wireless specs for a laptop. I suspect the “n” version of Wi-Fi is best but “g” is adequate. Any advice would be appreciated. A. It depends on how and where you intend to use your laptop’s wireless connectivity. The “n” version of Wi-Fi can be much faster than “g” and can have much greater range. However, the speed difference won’t matter much if your sole use is connecting to the Internet with a typical home or public hotspot service, since the maximum speed of these services is almost always well below “g” and “n” capabilities. But if you are streaming video at home or backing up large files wirelessly among computers and networked hard disks on a home network, you’d be much better off with “n,” assuming all devices involved support it. The same goes for range. In a small apartment, it likely won’t matter. In a large home, it could. 802.11 wireless standards explained http://compnetworking.about.com/cs/wireless80211/a/aa80211standard.htm http://info.cba.ksu.edu/bkovar/wireless.htm

8. 802.11 standards • 802.11b: can provide transmission speeds of up to 11 mbps, 300 feet inside, 800 feet outside. • 802.11g: can provide transmission speeds of up to 54 mbps, at a 35 foot indoor range. • Both the “b” and “g” standards use the same radio frequency, or wavelength. • 802.11a: same transmission speeds as the “g” standard, but it uses a different radio frequency (not used by other Wi-Fi users, microwave ovens and cordless phones) • Good for use in high density/population areas, such as apartment complexes. • 802.11n is currently being developed (in use, but not finalized) . • Expected to provide transmission speeds over 100 mbps using MIMO technology (multiple wireless signals and antennas): signal intensity will also help increase range.

9. What are Protocols and what is the difference between them? • Protocol - a that specifies the as well as the during transmission • Following a certain , allows for interoperability • Interoperability - the capability of two or more computer systems to share data and resources, even though they are made by different manufacturers • Two primary communications protocols are TCP/IP and Ethernet • TCP/IP is used for • Ethernet is used by computers in a to communicate

10. Ethernet • Ethernet - a physical and data layer technology for LAN networking

11. Ethernet • Defines the standards used in a LAN. • Used to describe the • W (Co-axial, twisted-pair, fiber-optic) • How bits are physically transmitted using those media • Access control rules • Data transmission speeds • Details and works on the principle of and • Helps insure the compatibility of different devices so that many people can attach to a common cable.

12. Transmission Control Protocol/ Internet Protocol • Transmission Control Protocol/Internet Protocol (TCP/IP) - provides the technical as well as for large numbers of private network • The TCP/IP protocol suite is made up of over protocols. • The two are TCP and IP • TCP provides for • IP provides the mechanism

13. TRANSMISSION CONTROL PROTOCOL / INTERNET PROTOCOL (TCP / IP) • Allows computers to regardless of their or hardware. • Transmission Control Protocol • Breaks information into data packets • Reassembles packets when received • Checks for lost packets • Internet Protocol • Each computer given a unique IP address • Used to • 209.1.144.212

14. TCP/IP’s four-layer reference model • The layer allows users and applications to access • F protocol (FTP) • Simple protocol (SMTP) • T provides terminal emulation that allows a “ terminal with ” to be able to connect to a host computer (which will control everything). • H protocol (HTTP) • Simple network management Protocol (SNMP)

15. TCP/IP’s four-layer reference model • The layer handles • The layer handles the packets ( , etc.) • The layer details how is through the networking

16. How Does the Internet Work?? http://www.howstuffworks.com/web-server.htm #1 #2 Browser communicates with to get 209.1.144.212 #3 Browser connects to specific server, uses GET request to ask for file you wish to see. #4 Server sends HTML text to your browser. HTML tags are read and page displayed.

17. What is a VPN? • You can build your own wired network or you can from a national provider. • Virtual private network (VPN) - a way to use the telecommunication infrastructure (e.g., ) to provide secure access to an organization’s network • T software is used to create a connection between two different servers ( ). • Data packets are

18. Network Data Transfer Process: How does it happen? • Network operating system at the source divides the message to be sent into segments of predetermined length called • Network operating system at the source uses a communications protocol to • Network Operating System at the source sends packets over the network. • Packets are routed as necessary through the network depending on the transmission mediums, transmission signal characteristics and access control methods. • Network Operating system at the destination receives packets over the network. • Network Operating system at the destination by looking at the communication protocol information. Requests retransmission of any missing data.

19. The connection between a LAN and a larger network is usually accomplished using a device called a . Routers are used to . They also “sit” (serving as a gatekeeper both into and out of your network). They are intelligent connecting devices that examine each packet of data it receives and then decides which way to send it onward toward its destination Connecting Networks LAN WAN or Backbone Router LAN Router Routers are responsible for that messages take from the sending computer to the destination computer.

20. Wide Area Network Poccurs when the sending computer divides a message into a number of efficiently sized units called packets, each of which contains the address of the destination computer. Packet Switched Network Data is packaged in for transmission. R R R R R R R R R R R R R Each packet follows through the network.

21. WANs Once a network is linked to a , it becomes part of the Internet community. Backbone is usually a type of network that has High Speed Backbone

23. Internet Backbone on the Ocean Floor

24. What are the different types of LANs? P Each user can share a portion their computer’s with other LAN users • C • Only resources on specific computers called “servers”can be shared

25. Peer-to-Peer Networks • Peer-to-peer (P2P) network - any network without a central file server and in which all computers in the network have access to the public files located on all other workstations

27. Client/Server Networks • Client- a computer that is designed to from a server • Server - a computer that is dedicated to providing information in response to external requests • Client/server network -model for applications in which the takes place on a , while the is handled by the

28. Business Logic Presentation The Client/Server Model Data Management Storage and management of the data needed by the application Actual business rules implemented The to the application

29. Client/Server Model: A Business View The different Client/server implementations differ according to: • Where the processing for the • Where the processing of occurs • Where the (DBMS) and are located

30. Data Management Data Management Presentation Business Logic Business Logic Presentation Flexible Applications Server Client Business Logic

31. Any Combination is Possible Client Data Management Business Logic Design Server Presentation Data Management Business Logic Production Server

33. Client/Server Advantages • Application can be structured to match organizational requirements since it is both • Can change the implementation of this model as the organization changes in size since the Client/Server model provides the to whatever is • Data access is regardless of where the data is stored. • Separate programs are more easily maintained and can be reused. • One for all of the and easier to

34. Client/Server Disadvantages • All shared resources reside on computers call “servers” • If a disaster occurs on the server all the data is in jeopardy • If the server malfunctions, • Expensive • Usually require expensive hardware and extra staff to manage • Only of client/server costs are tied up in • The remaining is in the form of - both IT professionals and knowledge workers.

35. Current Events in Information Technology

36. Researchers explore scrapping and rebuilding the Internet • In order to address the problems that were not envisioned when the Internet was initially created, some are suggesting rebuilding the Internet using a approach. • S • The Internet was designed to be open and flexible and all users were assumed to be trustworthy. Internet protocols were not designed to authenticate users and their data. Firewalls and spam filters are now being used to control security. • Solution: data not passed along until

37. Mobility • Initially, computers were fixed in location so IP addresses were assigned to devices in a fixed location. Wireless mobile computing is presenting challenges related to data flow. • Solution: R so that addresses are based on the device, rather than the location. • Ubiquity (also called Pervasive Computing) • When the Internet was first designed, there were relatively few computers connected to it. The addressing system has become strained due to the proliferation of personal computers and mobile devices. • Solution: assign and have those same devices connected to an addressed gateway, which is then connected to routers and the rest of the Internet • Result is fewer devices to keep track of and improved efficiency. • These changes may happen over the next 10-15 years. They (expected to cost as computer hardware and software and Internet infrastructure are replaced)