331: STUDY DATA COMMUNICATIONS AND NETWORKS

 1. Discuss computer networks (5 hrs)  2. Discuss data communications (15 hrs)

 PERFORMANCE STANDARD ◦ Identify the benefits and classify a given network  Objectives ◦ Define Computer Network ◦ Discuss types & class of networks ◦ Explain reasons for networks ◦ Discuss the effects of computer networking on our society ◦ Discuss latest trend in the networking

 If we consider networks in general, rather than computer networks, then a good broad definition is: ◦ “a group or system of interconnected people or things” (Source:

 Networking involves connecting computers and other electronic devices for the purpose of sharing information and resources and for communication.  Computer networks represent an important advance from what a single computer can do alone.

 A basic network could consist of two computers or more, connected by a transmission medium that allows signals to pass between them.  Anything from a small PDA or Smartphone to a supercomputer can be networked

 But there is no need to limit it to 2 computers. ◦ Even in a single office it makes sense to add more devices to the network:  More computers  Peripheral devices (printers, etc).

 Local Area Network (LAN)  Wide Area Network (WAN)  Metropolitan Area Network (MAN)  Personal Area Network (PAN)  Internet  Intranet  Extranet

 Local Area Network (LAN) ◦ Physically close, such as a company site or college campus ◦ Usually using a single overall technology (Ethernet) ◦ Usually owned and run by one organization ◦ E.g. your college network or a home network

 Wide Area Network (WAN) ◦ Physically large distances, between sites or even countries ◦ May use a range of connection technologies, such as Asynchronous Transfer Mode (ATM) ◦ Links often operated by specialist suppliers ◦ Links often provided these days over the “public” Internet ◦ E.g. the Internet

 Metropolitan Area Network (MAN) ◦ Spans a city, large campus or other geographical area ◦ i.e. between a LAN and a WAN in size ◦ Single company or co-operatively managed ◦ E.g. Net North West provides Internet services to academic institutions in North West England ◦ See

 Personal Area Network ◦ Connects computer technology close to (within physical reach of) one person ◦ Connecting PC, PDA, smartphone and peripherals ◦ Typically using Bluetooth wireless technology or USB/Firewire

 The Internet: ◦ Technically a WAN ◦ It is a vast public wide area internetwork that makes it possible for any computer in the world to communicate with any other computer in the world using standard technologies and protocols. ◦ Global communications system with access to virtually anywhere in the world  and even off world, e.g. the international space station

 Intranet ◦ A private computer network that uses Internet technology (usually TCP/IP and HTTP) to deliver documents and services within an organization ◦ Often a website that is only accessible within a company or via a company login ◦ “Intra” means “within” or “inside”

Extranet  An extension to an intranet allowing (restricted) access to people outside the company  Allows business-to-business (B2B) and possible business-to-customer (B2C) transactions  Does not grant whole company network access to those outside the company

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 Why do we need networks? There would be no point building networks if there was no demand for them. The vast majority of computers these days are networked. Figures of networked computers difficult to obtain, but probably over 95%

Can you think of a computer system that is NOT networked? Computers connected together to:  Share resources  Disk space  Data  printers  Internet connections  Provide communications  , chat

 Internet Access ◦ Finding a new job ◦ Up-to-date information ◦ Facebooking? ◦ Online game. ◦ Etc.

 Area of the effects of computer networking on society. ◦ Personal Impact ◦ Community Impact ◦ National Impact ◦ Global Impact ◦ Future Impact

 Personal Impact ◦ privacy and personal rights ◦ data banks, computer terminals, data security ◦ Employment ◦ job opportunities, new careers, the need for retraining ◦ business transactions ◦ automated billing, credit cards, consumer spending ◦ the replacement of people through automation ◦ robots, word processing ◦ the impact that a machine has on a human - ergonomics

 Community Impact ◦ Employment ◦ traffic control ◦ urban planning ◦ law enforcement

 National Impact ◦ communications media ◦ the use of information for control ◦ vote counting ◦ electronic funds transfer ◦ stock-market transactions ◦ Defense ◦ Surveillance ◦ national data banks ◦ Etc…

 Global Impact ◦ reporting of current events ◦ communications media ◦ world government ◦ international standards ◦ exploration of space and sea ◦ world wide access to data

 Future Impact ◦ computers in the home ◦ gaming ◦ learning ◦ electronic mail ◦ shopping ◦ business transactions ◦ information processing, storage and retrieval ◦ the home as a work center ◦ Etc…

 40- and 100-Gigabit Ethernet (GE): Virtualized servers will generate more traffic than 10 gigabits per second (Gbps) connections can handle.  Internet security: Zombies – compromised computers ready to act as robot attack systems – are ticking time bombs throughout the Internet. For example, the recent attacks on the WikiLeaks servers in Sweden demonstrate network vulnerability.

 IPv4/IPv6 co-existence: On 1 February 2011, the Internet Assigned Numbers Authority (IANA) allocated the last freely-available block of IPv4 addresses, pushing IPv6 addresses to the forefront. Service providers and enterprise are under the gun to prepare their networks for the influx of IPv6 traffic.

 Rich Media: A perfect storm is developing for network operators. Smartphone users use information and entertainment almost 24 hours a day, in full living color. Wireless data usage will continue along its anticipated exponential growth curve, and nowadays, large amounts of inexpensive bandwidth are no longer available.

 3G/4G: Many users can have their individual networking connection through mobile phone. Recently, the usage of 3G device is expanding and can be used as a GPS (Global Positioning System) map for the latest car.