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

What is the difference between telecommunications and a network? TELECOMMUNICATIONS - the electronic movement of information over public or private networks NETWORK – two or more computers connected together using standards/protocols so that they can work together. What are the benefits of a network? The ability to communicate with others email is the most popular form of network communications The ability to share Data and Information Software Peripheral devices and other resources Processing power

What is the most basic way to differentiate networks? By Proximity Local Area Network (LAN) --Connects computers in relatively close proximity Wide Area Networks (WAN) -- Connects computers dispersed among a number of buildings, or even in different cities. Biggest WAN = the Internet Personal Area Network (PAN) --Wirelessly connecting small personal devices, really short distance

Wireless Topology Computers are connected by radio waves to a wireless access point (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) 22 20 20 20

Comparing Wired to Wireless Wired Network Wireless Network Communications occur using a wired media. Faster Tends to be more secure Limited location and hard to move around (bound to the wire). Limited by walls, furniture, infrastructure. Should be able to easily handle multiple users Fixed work location All of the work tools that you need probably are available Communication occurs using radio signals and line-of-sight base station. Limited by obstructions. Slower: rarely reaches max speeds that could be available Inherently insecure: security features not turned on: easier to have data packets captured. Mobile. 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 set up where needed, but work tools needed may not be available when needed.

Bluetooth vs Wi-Fi (802.11) Bluetooth 802.11 Business networks use 802.11 (Wi-Fi/Wireless Fidelity) while individuals might create their own short range network using Bluetooth Bluetooth Allows for wireless communications within a limited distance: 2 megabits per second, up to 30 feet. Less expensive than Wi-Fi chips, consume less power, 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. 802.11 802.11b Provides transmission speeds of up to 11 mbps, 300 feet inside, 800 feet outside. 802.11g Provides transmission speeds of up to 54 mbps, at a 35 foot indoor range 802.11a Uses a different radio frequency than standards b & g and other electronic devices (kinda like taking a less crowded route: it will be faster since no one is using it) 802.11n Still being developed: expected to provide transmission speeds over 100 mbps using MIMO technology (multiple wireless signals and antennas):

802.11 wireless standards explained 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

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.

What are Protocols and what is the difference between them? Protocol - a standard that specifies the format of data as well as the rules to be followed during transmission Following a certain protocol/standard/set of rules, 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 using perhaps different technologies. Two primary communications protocols are TCP/IP and Ethernet TCP/IP is used for Internet communications Ethernet is used by computers in a LAN to communicate Why is interoperability so important in today's world? With so many different worldwide manufactures of computer components it is imperative that all of the devices work together

Ethernet Ethernet - a physical and data layer technology for LAN networking Are you are using a cable to connect to the Internet? If so, is it Ethernet?

Ethernet Defines the wiring and signaling standards used in a LAN. Used to describe the hardware layer of a LAN Wiring Technology Used (Co-axial, twisted-pair, fiber-optic) How bits are physically transmitted using those media Access control rules Data transmission speeds Details multiple user communications and works on the principle of collision avoidance and collision detection. Helps insure the compatibility of different devices so that many people can attach to a common cable.

Transmission Control Protocol/ Internet Protocol Transmission Control Protocol/Internet Protocol (TCP/IP) - provides the technical foundation for the public Internet as well as for large numbers of private network The TCP/IP protocol suite is made up of over 100 different protocols. The two most important are TCP and IP TCP provides for data transport functions IP provides the addressing and routing mechanism Do you use TCP/IP? If you are on the Internet, yes, you are using TCP/IP.

TRANSMISSION CONTROL PROTOCOL / INTERNET PROTOCOL (TCP / IP) Allows computers to exchange messages regardless of their operating system 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 identify a specific computer 209.1.144.212 Organizations use diverse network technologies that may not be compatible with the technologies of other organizations. Because so many different networks are connected, they must have a common protocol to communicate. The protocol of the Internet is TCP/IP. TCP control s the packets. IP controls the addressing of individual machines. Packets travel independently to their destination, sometimes following different paths and arriving out of order. The destination computer uses TCP to reassemble the packets based on their identification and sequencing information. Every computer that uses the Internet must run IP software. The IP defines how a packet must be formed and how a router must forward each packet. TCP helps guarantee delivery of the packets.

TCP/IP’s four-layer reference model The application layer allows users and applications to access network services File transfer protocol (FTP) Simple mail transfer protocol (SMTP) Telnet provides terminal emulation that allows a “dumb terminal with no processing capability” to be able to connect to a host computer (which will control everything). Hypertext transfer protocol (HTTP) Simple network management Protocol (SNMP) Do you use TCP/IP? If you are on the Internet, yes, you are using TCP/IP.

TCP/IP’s four-layer reference model The Transport layer handles end-to-end packet transportation. The Internet layer handles the packets (creation, labeling and addressing, etc.) The Network Interface layer details how data is physically sent through the networking hardware. Do you use TCP/IP? If you are on the Internet, yes, you are using TCP/IP.

How Does the Internet Work?? http://www.howstuffworks.com/web-server.htm #1 Browser breaks URL into 3 parts #2 Browser communicates with name server to get IP address 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.

What is a VPN? You can build your own wired network or you can lease lines from a national provider. Virtual private network (VPN) - a way to use the public telecommunication infrastructure (e.g., Internet) to provide secure access to an organization’s network Tunneling software is used to create a private connection between two different servers or between a server and individual computers (made when needed and terminated when transmission is completed). Data packets are encrypted for security.

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 packets. Network operating system at the source uses a communications protocol to label and address each packet. 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 identifies and reassembles the packets of the message by looking at the communication protocol information. Requests retransmission of any missing data. 34

Connecting Networks LAN WAN or Backbone Router LAN The connection between a LAN and a larger network is usually accomplished using a device called a router. Routers are used to connect computers in a network. They also “sit” between your network and other networks (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 LAN WAN or Backbone Router LAN Routers are responsible for determining the path that messages take from the sending computer to the destination computer. Router

Wide Area Network Packet Switched Network Data is packaged in Packet-switching occurs 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 packets for transmission. R R R R R R R R R R R R R Each packet follows it’s own path through the network.

WANs Once a network is linked to a backbone, it becomes part of the Internet community. High Speed Backbone Backbone is usually a type of network that has a larger size limit and is relatively high speed.

Internet Backbone on the Ocean Floor

What are the different types of LANs? Peer-to-Peer Each user can share a portion their computer’s hard drive with other LAN users Client/Server Only resources on specific computers called “servers” can be shared

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 BitTorrent is an excellent example of peer-to-peer Discuss the Apply Your Knowledge project on BitTorrent (AYK project 7 – Contemplating Sharing)

Peer-to-Peer LAN Advantages Control is distributed to the LAN users Users who own data have control over who accesses it (often through the use of passwords). Inexpensive and easy to install You just need A network card A network operating system on both computers, like Windows XP or Vista (any version of Windows since 95). Network Cabling Network resources are distributed A disaster on one user’s computer doesn’t destroy all the data on the network

Peer-to-Peer LAN Disadvantages Control is distributed to the LAN users No one person or group can know what resources are available. No one person or group is in charge of security. Each user is responsible for sharing resources on their own computer. Performance is poor Since the computers share resources and some computers can even access the hard drives of other computers, the result is that network performance is usually slow. The performance of a PC also slows down when someone on the network accesses it. As a result, peer-to-peer networks are typically small.

Client/Server Networks Client - a computer that is designed to request information 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 bulk of the back-end processing takes place on a server, while the front-end processing is handled by the clients Is your PC a client or a server? Chances are most student computers are clients on the universities network Can your PC be a client or a server? Both, any PC can be used as a server – you simply install the server operating system

The Client/Server Model Storage and management of the data needed by the application (the database) Data Management Business Logic Actual business rules implemented as software (how you implement your software to get the job done and what are the processing steps) Presentation The user’s interface to the application (how the application appears to the user, including the formatting)

Client/Server Model: A Business View The different Client/server implementations differ according to: Where the processing for the presentation of information occurs Where the processing of logic or business rules occurs Where the data management component (DBMS) and information (database) are located

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

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

Client/Server Advantages Application can be structured to match organizational requirements since it is both flexible and scalable Can change the implementation of this model as the organization changes in size since the Client/Server model provides the flexibility to mold information systems to whatever business model is most appropriate for an organization. Data access is transparent to the user regardless of where the data is stored. Separate programs are more easily maintained and can be reused. One central location to go to for all of the sharing and easier to control the entire network.

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, no one can use the network Expensive Usually require expensive hardware and extra staff to manage Only 30% of client/server costs are tied up in hardware and software. The remaining 70% is in the form of labor - both IT professionals and knowledge workers.

Current Events in Information Technology

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 “clean slate” approach. Security 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 authenticated

Ubiquity (also called Pervasive Computing) 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: Reconfigure the IP address system 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 addresses to fewer devices 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 will not be cheap (expected to cost millions and billions of dollars as computer hardware and software and Internet infrastructure are replaced)