Computers: Information Technology in Perspective By Long and Long Copyright 2002 Prentice Hall, Inc. Networks & Networking Jaana Holvikivi 2012

Quit 6.2Connectivity Seeking ways to interface, or connect, a diverse set of hardware, software, and databases.

Quit 6.3 Cooperative Processing  Internally (for company resources) via Intracompany networking Intracompany networking Intranets Intranets  Externally (for world competition) via Intercompany networking Intercompany networking Business-to-business (B2B) Business-to-business (B2B) E-commerce (electronic commerce) E-commerce (electronic commerce) Extranets Extranets Companies must cooperate

Quit 6.4 Types of Networks Wide Area Network WANWAN Wireless Local Area Network WLANWLAN Local Area Network LANLAN PANS & BANs & NFC Potentially any / personal area network service

Quit 6.5 Sharing Resources on a LAN  Applications software & groupware  Links to other LANs: campus networks  Communications capabilities: within LAN, internet, remote computers  I/O devices - printers  Storage devices - file servers, central back-ups  Data base servers  Security Courtesy of Orbital Sciences Corporation

Quit 6.6 LAN Overview  One node at a time can send Token Access Method Token Access Method Ethernet protocols Ethernet protocols  Transmission media Twisted-pair, coax, and fiber optic cable Twisted-pair, coax, and fiber optic cable Wi-Fi Wi-Fi  LAN Servers File Server File Server Print Server Print Server Communications Server Communications Server

Quit 6.7 LAN Overview  Workstations PC, NIC (integrated), software PC, NIC (integrated), software  LAN Servers computer, NIC, software computer, NIC, software LAN operating system LAN operating system management of resources management of resources access control access control  Protection Firewall, UTM (Unified Threat Management) Firewall, UTM (Unified Threat Management)

Quit 6.8 LAN Software  Operating Systems Peer to Peer LANs Peer to Peer LANs LANs with dedicated servers: Novell Netware, Windows Server LANs with dedicated servers: Novell Netware, Windows Server  Applications Software Shared software Shared software Groupware Groupware  Networks on the Fly Portable networks Portable networks

Quit LAN storage options 6.9 Network Access storage

Quit 6.10 Data Communications Channel Data Communications Channel  Same as line, link or pipe  Special hardware transmits the digital information between computers

Quit 6.11 Transmission Media   Bandwidth is channel capacity # of bits channel can transmit/second 56 K bps (bits per second) to over 100T bps Bps nearly same as baud   High bandwidth = Broadband   Low bandwidth = Narrowband   Broadband Access is high-speed Internet access

Quit 6.12 Transmission speed  Sending photos to be printed  The upload speed is 512 kbps  One file is about 1 MB  There are 41 photos  How long does it take?

Quit 6.13 Transmission speed 2  Downloading security software  The download speed is max 2 Mbps  Realistic maximum is 210 kB/s (achieved 70% time)  The update size kB  How long does it take at least?

Quit 6.14 Transmission Media Twisted-pair wire Wireless Coaxial cable Fiber optic cable

Quit 6.15 Twisted-Pair Wire  POTS (Plain old telephone service) 56 K bps 56 K bps  ISDN (Integrated Services Digital Network) Line & Modem 128 K bps Line & Modem 128 K bps  DSL (Digital Subscriber Line) Line & Modem 1.5 to 24 M bps Line & Modem 1.5 to 24 M bps Transmission Media Telephone company services

Quit 6.16 Coaxial Cable  Minimum signal distortion  Hundreds of times faster than POTS  100 times faster than ISDN  Ethernet standard 10Base-T in 1990  100Base-Tx in 1995 (100Mbits)

Quit 6.17 Fiber Optic Cable  Carries data as laser-generated pulses of light  Foundation transmission medium for Internet backbone  Better for data security  40 and 100 Gb Ethernet standards in 2010  max bandwidth 14 Tb/s over 1,2 km

Quit 6.18 Wireless Communications  Carries data via microwave or radio signals  Transmission is line-of-sight  Use transceivers/repeater stations  Satellites Eliminate line-of-sight limitation Eliminate line-of-sight limitation Geosynchronous orbit Geosynchronous orbit Everyone has satellite access Everyone has satellite access Need dish and modem Need dish and modem Somewhat slower than DSL and Cable Somewhat slower than DSL and Cable  Carries data via microwave or radio signals  Transmission is line-of-sight  Use transceivers/repeater stations  Satellites Eliminate line-of-sight limitation Eliminate line-of-sight limitation Geosynchronous orbit Geosynchronous orbit Everyone has satellite access Everyone has satellite access Need dish and modem Need dish and modem Somewhat slower than DSL and Cable Somewhat slower than DSL and Cable

Quit 6.19 Communications Protocols  Rules that govern the way data are transmitted  TCP/IP (Transmission Control Protocol/Internet Protocol

Quit 6.20Routers  Hardware and software used to ease the problems of linking incompatible networks  Routes messages to proper destinations  Backbone is a system of routers and transmission media that link computers.

Quit 6.21 Network Topologies Network Topology is a description of the possible physical connections within a network. It is a configuration of hardware and it shows which pairs of nodes can communicate. Networks

Quit 6.22 Network Topologies Ring Star Bus

Quit Cloud  Services distributed over network  Google applications, Youtube, Facebook, etc.  Servers, data and applications  Case NYTimes archives 4tB TIFF-files > 11 mil. PDFs 4tB TIFF-files > 11 mil. PDFs Using Amazon EC2 servers: 100 servers, 24 hours, cost 240$ Using Amazon EC2 servers: 100 servers, 24 hours, cost 240$ 6.23

Computers: Information Technology in Perspective By Long and Long Copyright 2002 Prentice Hall, Inc. Networks & Networking The End