2

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

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 & ParametersRequests & Parameters

Disks for Storage

Server

Response & ResultsResponse & Results

TCP/IPHTTP

URLDatabase 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 802.3 (Ethernet), and FireWire. Bluetooth & 802.11b (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

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 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

26

FIREWALLS

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