11 Networks The Great Information Exchange

2 Networking Fundamentals Computer network: Two or more computers connected together Each is a Node Benefits of a network: Sharing resources Transferring files Computer network: Two or more computers connected together Each is a Node Benefits of a network: Sharing resources Transferring files

3 Network Architecture Network designs: Individual PC controlled: Peer-to-peer (P2P) Centrally controlled: Client/server Network designs: Individual PC controlled: Peer-to-peer (P2P) Centrally controlled: Client/server Peer-to-peer Client/ server

4 Peer-to-Peer Networks Nodes communicate with each other: Peers Share peripheral devices: Printers Scanners Home and small office networks Nodes communicate with each other: Peers Share peripheral devices: Printers Scanners Home and small office networks

5 Client/Server Networks Client computers: Users Server computers: Provide resources to clients Central network control Internet A large, multi-server, multi-client network. Client computers: Users Server computers: Provide resources to clients Central network control Internet A large, multi-server, multi-client network.

6 LANs and WANs Local area network (LAN): Nodes are within a small geographic region: Homes Schools Small businesses Wide area network (WAN): LANs connected over long distances: A few miles to thousands of miles Use telecommunications lines Local area network (LAN): Nodes are within a small geographic region: Homes Schools Small businesses Wide area network (WAN): LANs connected over long distances: A few miles to thousands of miles Use telecommunications lines

7 Network Components Transmission media Network adapters Navigation devices Network software Transmission media Network adapters Navigation devices Network software

8 Transmission Media Provides communications channel between nodes Forms of media: Telephone wire: Twisted pair Coaxial cable Fiber-optic cable Radio waves: Wireless Bandwidth: Data transfer rate Throughput Provides communications channel between nodes Forms of media: Telephone wire: Twisted pair Coaxial cable Fiber-optic cable Radio waves: Wireless Bandwidth: Data transfer rate Throughput

9 Network Adapters Devices connected to or installed in nodes: Network interface cards (NIC) External network adapter Enable communication between nodes Devices connected to or installed in nodes: Network interface cards (NIC) External network adapter Enable communication between nodes

10 Network Navigation Devices Devices that help make data flow possible Routers: Route data between networks Switches: Receive data and retransmit it to nodes on the network Devices that help make data flow possible Routers: Route data between networks Switches: Receive data and retransmit it to nodes on the network

11 Networking Software Peer-to-peer Software: Built into operating systems that support networking Windows Mac OS Client/server Software Network operating system (NOS) software Windows XP Professional Windows Server 2003 Novell Netware Peer-to-peer Software: Built into operating systems that support networking Windows Mac OS Client/server Software Network operating system (NOS) software Windows XP Professional Windows Server 2003 Novell Netware

12 Ethernet Networks Ethernet network adapters are used to connect nodes NIC card PC Card USB adapter Computers are connected to each other using unshielded twisted pair cable Ethernet network adapters are used to connect nodes NIC card PC Card USB adapter Computers are connected to each other using unshielded twisted pair cable RJ-45 Phoneline

13 Ethernet Switches Keep track of data packets Amplify and retransmit signals Keep the network running efficiently Keep track of data packets Amplify and retransmit signals Keep the network running efficiently

14 Ethernet Routers Transfer packets from one network to another Home Internet routers transfer data from the Internet to the home network. Transfer packets from one network to another Home Internet routers transfer data from the Internet to the home network. Router

15 Wireless Networks Use radio waves to connect nodes Basically an Ethernet network that uses radio waves instead of wires Each node requires a wireless network adapter: Transceiver Use radio waves to connect nodes Basically an Ethernet network that uses radio waves instead of wires Each node requires a wireless network adapter: Transceiver

16 The Internet: The Basics Origin of the Internet The Web vs. the Internet Clients and servers Connecting to the Internet Origin of the Internet The Web vs. the Internet Clients and servers Connecting to the Internet

17 The Origin of the Internet ARPANET: Advanced Research Projects Agency Network Funded by the US Government in the 1960s Allowed computers at leading universities and research organizations to communicate with each other over great distances ARPANET: Advanced Research Projects Agency Network Funded by the US Government in the 1960s Allowed computers at leading universities and research organizations to communicate with each other over great distances

18 The Internet vs. The Web Internet – part of the system that is primarily hardware infrastructure (telecommunications, routers, servers, disk drives, etcetera) Web - part of the system that contains intellectual property in many multimedia formats (test files, graphic files, sound files, video files, etcetera) Internet – part of the system that is primarily hardware infrastructure (telecommunications, routers, servers, disk drives, etcetera) Web - part of the system that contains intellectual property in many multimedia formats (test files, graphic files, sound files, video files, etcetera) INTERNET WWW

19 Client and Server Client computer: Users connect to the Internet Request data and Web pages Server computers Store Web pages and data Return the requested data to the client Client computer: Users connect to the Internet Request data and Web pages Server computers Store Web pages and data Return the requested data to the client Server Client

20 Connecting to the Internet Dial-up connections: Uses standard telephone line Least costly connection Requires a modem Converts analog and digital signals Slowest connection speed (56kbps) Dial-up connections: Uses standard telephone line Least costly connection Requires a modem Converts analog and digital signals Slowest connection speed (56kbps)

21 Broadband Connections Digital Subscriber Lines Faster than dial-up Upstream (16Kbps -640kbps) Downstream (1.5 Mbps – 9 Mbps) Requires special DSL modem Digital Subscriber Lines Faster than dial-up Upstream (16Kbps -640kbps) Downstream (1.5 Mbps – 9 Mbps) Requires special DSL modem DSL modem

22 Broadband Connections Cable: Uses TV coaxial cable Fast connection speed (300kbps – 4mbps) Speed depends on number of users Not available in all areas Requires a cable modem Cable: Uses TV coaxial cable Fast connection speed (300kbps – 4mbps) Speed depends on number of users Not available in all areas Requires a cable modem Coaxial cable

23 Satellite Connections Uses a satellite dish and coaxial cable Download speed 500kbps Upload speed 100kbps Signal is affected by location and weather Uses a satellite dish and coaxial cable Download speed 500kbps Upload speed 100kbps Signal is affected by location and weather

24 Comparing Internet Connection Options Connection Option Maximum Upload Data Transfer Rate (approximate) Maximum Download Data Transfer Rate (approximate) Dial-Up56kbps DSL (ADSL)300 kbps1 Mbps DSL (SDSL)1.5mbps Cable500 kbps6 mbps Satellite100kbps400kbps

25 Internet Service Providers ISP: Internet service provider Provide user access to the Internet National, regional or local companies ISP: Internet service provider Provide user access to the Internet National, regional or local companies OSP: Online service provider Provide online proprietary content as well as Internet access AOL, CompuServe, MSN OSP: Online service provider Provide online proprietary content as well as Internet access AOL, CompuServe, MSN

26 Choosing an ISP Factors to consider: Customer service Local access numbers options Cost Trial period Factors to consider: Customer service Local access numbers options Cost Trial period