2 An Overview of Telecommunications and Networks Telecommunications: the _________ transmission of signals for communications (home net) (home net) Telecommunications medium: anything that _________ an electronic signal and interfaces between a sending device and a receiving device

3 Transmission Media Guided Media –Twisted pair cable –Coaxial cable –_________ optic cable Wireless Media –Microwave transmission –Cellular transmission –_________ transmission

4 Networks Computer network: the _________ media, devices, and software needed to connect two or more computer systems or devices

5 Advantages of Networks streamline work _________ and cut costs allow people within organizations to collaborate share hardware, software, and processing power enable _________ distant work groups to communicate with each other allow _________ to share information with external groups such as suppliers shorten _________ lead times and response times support electronic commerce NBC

6 Basic Processing Strategies Centralized processing: _________ processing: Distributed processing: –Terminal-to-host: “dumb” terminal –File server: –Client/server:

7 Client Requests & Parameters Disks for Storage Server Response & Results TCP/IP HTTP URL Database Query Client/Server Architecture

8 Network Types Personal area network (PAN) Local area network (LAN) Metropolitan area network (MAN) Wide area network (WAN) International network

9 Network Types (continued) Figure 4.7: A Typical LAN

10 Network Types (continued) Figure 4.8: A Wide Area Network

11 Communications Software and Protocols Communications software: software that provides a number of important functions in a network, such as error checking and data security –Network operating system (NOS) –Network management software Communications protocol: a standard set of rules that controls a telecommunications connection –Transmission Control Protocol/Internet Protocol (TCP/IP), IEEE (Ethernet), and FireWire. Bluetooth & b (Wi-Fi).

12 Use and Functioning of the Internet Internet: a _________ of interconnected networks, all freely exchanging information –ARPANET The ancestor of the Internet A project started by the U.S. Department of Defense (DoD) in 1969 –Internet Protocol (IP): _________ standard that enables traffic to be routed from one network to another as needed

13 How the Internet Works warrior warrior

14 Accessing the Internet Figure 4.10: Several Ways to Access the Internet

15 The World Wide Web Figure 4.11: Sample Hypertext Markup Language

16 Intranets Intranet –_________ corporate network built using Internet and World Wide Web standards and products –Used by employees to gain access to corporate information –Intranets can benefit all kinds of organizations

17 Benefits of Intranets –Reduced costs –improved communication –shared software, –Improved productivity –Increased security –Better customer service Scalability –More cost effective IT spend –Increased competitiveness –Streamlined administration –Easier training of new employees –Calendar and diary sharing working –Extranet-ready -

18 Extranets Extranet –A _________ based on Web technologies that links selected resources of a company’s intranet with its customers, suppliers, or other business partners Virtual private network (VPN): a secure connection _________ two points across the Internet Tunneling: the process by which VPNs transfer information by encapsulating traffic in IP packets over the _________

19 Use Extranets for: Product Development Purchasing and Stocks Production Orders and Delivery Customer Relationships Collaborative Working –Supply chain

20 Intranets and Extranets (continued) Figure 4.12: Virtual Private Network

21 Net Issues Management issues Service and speed issues Privacy –Spyware: –Cookie: –Fraud Phishing

22 Net Issues (continued) Security with encryption and firewalls –Cryptography: _________ a message into a secret code and changing the encoded message back to regular text –Digital signature: encryption technique used to verify the identity of a message sender for processing online _________ transactions –Firewall: a device that sits between an internal network and the Internet, limiting _________ into and out of a network based on access policies

23 Net Issues (continued) Figure 4.13: Cryptography is the process of converting a message into a secret code and changing the encoded message back into regular text.

24 FIREWALLS One of the most common defenses for preventing a security breach is a firewall –Firewall – hardware and/or software that guards a private network by analyzing the _________ leaving and entering the network

25 Firewall Capability Firewall can Focus for _________ decisions Enforce _________ policy Log internet activity Limit _________ keeps one section of intranet separate from another Firewall can not Protect against _________ insiders Protect against _________ that do not go through it Protect against new threats Protect against viruses

26 FIREWALLS Sample firewall architecture connecting systems located in Chicago, New York, and Boston