2 An Overview of Telecommunications and Networks Telecommunications: the _________ transmission of signals for communications (home net) (home net)

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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

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Transmission Media

• Guided Media– Twisted pair cable– Coaxial cable– _________ optic cable

• Wireless Media– Microwave transmission– Cellular transmission– _________ transmission

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Networks

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

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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

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Basic Processing Strategies

• Centralized processing:

• _________ processing:

• Distributed processing:– Terminal-to-host: “dumb” terminal– File server:– Client/server:

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Client Requests & ParametersRequests & Parameters

Disks for Storage

Server

Response & ResultsResponse & Results

TCP/IPHTTP

URLDatabase Query

Client/Server Architecture

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Network Types

• Personal area network (PAN)

• Local area network (LAN)

• Metropolitan area network (MAN)

• Wide area network (WAN)

• International network

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Network Types (continued)

Figure 4.7: A Typical LAN

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Network Types (continued)

Figure 4.8: A Wide Area Network

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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).

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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

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How the Internet Works warrior

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Accessing the Internet

Figure 4.10: Several Ways to Access the Internet

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The World Wide Web

Figure 4.11: Sample Hypertext Markup Language

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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

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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 -

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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 _________

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Use Extranets for:

• Product Development

• Purchasing and Stocks

• Production

• Orders and Delivery

• Customer Relationships

• Collaborative Working– Supply chain

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Intranets and Extranets (continued)

Figure 4.12: Virtual Private Network

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Net Issues

• Management issues

• Service and speed issues

• Privacy– Spyware: – Cookie:

– Fraud• Phishing

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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

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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.

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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

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Firewall CapabilityFirewall 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

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FIREWALLS

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