An Overview of Telecommunications and Networks • Telecommunications: the _________ transmission of signals for communications (home net) • Telecommunications medium: anything that _________ an electronic signal and interfaces between a sending device and a receiving device 2 Transmission Media • Guided Media – Twisted pair cable – Coaxial cable – _________ optic cable • Wireless Media – Microwave transmission – Cellular transmission – _________ transmission 3 Networks • Computer network: the _________ media, devices, and software needed to connect two or more computer systems or devices 4 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 5 Basic Processing Strategies • Centralized processing: • _________ processing: • Distributed processing: – Terminal-to-host: “dumb” terminal – File server: – Client/server: 6 Client/Server Architecture URL Database Query Client Server Requests & Parameters TCP/IP HTTP Response & Results Disks for Storage 7 Network Types • • • • • Personal area network (PAN) Local area network (LAN) Metropolitan area network (MAN) Wide area network (WAN) International network 8 Network Types (continued) Figure 4.7: A Typical LAN 9 Network Types (continued) Figure 4.8: A Wide Area Network 10 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 802.3 (Ethernet), and FireWire. Bluetooth & 802.11b (Wi-Fi). 11 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 12 How the Internet Works warrior 13 Accessing the Internet Figure 4.10: Several Ways to Access the Internet 14 The World Wide Web Figure 4.11: Sample Hypertext Markup Language 15 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 16 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 17 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 _________ 18 Use Extranets for: • Product Development • Purchasing and Stocks • Production • Orders and Delivery • Customer Relationships • Collaborative Working – Supply chain 19 Intranets and Extranets (continued) Figure 4.12: Virtual Private Network 20 Net Issues • Management issues • Service and speed issues • Privacy – Spyware: – Cookie: – Fraud • Phishing 21 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 22 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. 23 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 24 Firewall Capability Firewall can _________ decisions Enforce _________ policy Log internet activity Limit Focus for _________ keeps one section of intranet separate from another Firewall can not _________ insiders Protect against _________ that do not go through it Protect against Protect against new threats Protect against viruses 25 FIREWALLS • Sample firewall architecture connecting systems located in Chicago, New York, and Boston 26