Computer Networks Chapter 7

2 Overview  This chapter covers:  Common networking and communications applications  Networking concepts and terminology  Technical issues related to networks  general characteristics of data transmission  types of transmission media in use today  Communications protocols and networking standards  Types of hardware used with a computer network

3 What Is a Network?  Define a network  A connected system of objects or people  What is a computer network?  A collection of computers and other hardware devices connected together so users can share hardware, software, and data, and electronically communicate

Understanding Computers: Today and Tomorrow, 13th Edition LAB NETWORK PRINTER SCANNER SERVERS Alejandra CJ Immanuel Rita NETWORK SERVER

Understanding Computers: Today and Tomorrow, 13th Edition CAMPUS NETWORK IT DEPT ADMISSIONS LIBRARY CIS LAB BUSINESS DIVISION CAMPUS POLICE Alejandra CJ Immanuel Rita NETWORK SERVER MONICA Taylor LAURIE Yudhis KEVIN

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Understanding Computers: Today and Tomorrow, 13th Edition WORLDWIDE NETWORK

Understanding Computers: Today and Tomorrow, 13th Edition Why learn about networks?  All around us  Use them all the time  Homes  Jobs  Schools  Airports  Hospitals

9 PHONES, GPS, MONITORING, CONFERENCES, REMOTE CONSULTATIONS

10 NETWORKED HOME

Understanding Computers: Today and Tomorrow, 13th Edition Network Enabled Appliances =WWgy1Y27QnI&feature=share& list=PLF5B F301B

12 SETTING UP A NETWORK  Networking hardware  Network adapter: Used to connect a computer to a network or the Internet  Also called network interface card (NIC) when in the form of an expansion card  Modem: Device that connects a computer to the Internet or to another computer (cable, DSL, etc.)  Wired/Wireless router: Connects wired/wireless devices in a network

13 Network Adapters

14 Networking Hardware for Connecting Devices and Networks  Repeater: Amplifies signals along a network  Range extender: Repeater for a wireless network  Wireless router: Typically connects both wired and wireless devices in a network

15 Networking Hardware for Connecting Devices and Networks  Hub:  Central device that connects all of the devices on the network and sends data to all devices  Switch:  Connects devices in a network like a hub but only sends data to the device for which the data is intended  Wireless access point:  Used to grant network access to wireless client devices  Bridges:  Used to connect two networks together usually on a local network

Understanding Computers: Today and Tomorrow, 13th Edition Network Characteristics  Communication Architecture  Client/server and P2P  Topology  Size/Coverage Area  Transmission Characteristics  Bandwidth  Signal  Transmission Method  Data Organization  Transmission Direction  Delivery Method  Hardware  Connection method  Protocols and Standards

17 Network Communication Architectures  The way networks are designed to communicate  Client-server networks  Peer-to-peer (P2P) networks: All computers at the same level

18 Network Topologies  How the devices in the network (called nodes) are arranged  Star networks  Bus networks  Mesh networks  Ring networks  Tree networks

19 Network Topologies

20 Network Size and Coverage Area  Personal area network (PAN)  Home area network (HAN)  Local area network (LAN)  Campus area network (CAN)  Metropolitan area network (???)  Wide area network (???)  Storage area network (???)  Virtual private network (???)

21 Data Transmission Characteristics  Bandwidth: The amount of data that can be transferred in a given period of time  Measured in bits per second (bps)  Analog (waves) vs. digital Signal (discrete chunks/packets)  Serial vs. parallel transmission method  Serial = 1 bit  Parallel = at least 1 byte at a time = usually 8

Understanding Computers: Today and Tomorrow, 13th Edition Transmission Timing Organization

23 Data Transmission Characteristics  Transmission direction:  Simplex transmission  Half-duplex transmission  Full-duplex transmission

24 Data Transmission Characteristics  Type of delivery method:  Circuit-switched  Packet-switched  Broadcast

25 Network Connection Method  Wired  connected to the network via physical cables  Wireless networks  data is typically sent via radio waves

26 Communications Protocols and Networking Standards  Protocol: A set of rules for a particular situation  Communications protocol: A set of rules that determine how devices on a network communicate  TCP/IP: The most widely used communications protocol – used with the Internet  Standard: A set of criteria or requirements approved by a recognized standards organization  Networking standards: Address how networked computers connect and communicate  Needed to ensure products can work with other products  Communications protocol: A set of rules that determine how devices on a network communicate

HERTZ How communications work

Understanding Computers: Today and Tomorrow, 13th Edition Electro-magnetic Spectrum  The range of all possible frequencies of electromagnetic radiation  Measured in Hertz (Hz)  Consists of the Electromagnetic radiation and frequency bands  Range of Hz (energy – radiation)  Spectrum controls distance, volume, ability to pass through barrier  Wireless Spectrum -  Radio Signals - Frequencies assigned by FCC

29 The Electromagnetic Spectrum

CONNECTIONS  CELLULAR  SATELLITE  WiFi  Ethernet

ETHERNET A wired connection

33 Ethernet (802.3)  Ethernet: Most widely used standard for wired networks  Continually evolving  Original (10Base-T) Ethernet networks run at 10 Mbps  Newer 100 Mbps, 1Gbps, and 10 Gbps versions are common  100 Gbps and Terabit Ethernet are in development  Power over Ethernet: Allows electrical power to be sent along with data on an Ethernet network  Most often used by businesses

34 Power over Ethernet (PoE)

35 Phoneline, Powerline, G.hn, and BPL (802.5)  Phoneline: Allows networking via ordinary telephone wiring  Powerline: Allows networking via ordinary electrical outlets  G.hn: An emerging standard for home networks creating via phone lines, power lines, and coaxial cable  Broadband over powerline (BPL): Uses existing power lines to deliver broadband internet to some homes  Limited areas

Wi-Fi Wireless Fidelity

37 Wi-Fi (802.11)  Wi-Fi (802.11): A family of wireless networking standards using the IEEE standard  Current standard for wireless networks in homes and offices  Designed for medium-range transmission  Wi-Fi hardware built into most notebook computers and many consumer devices today  Wi-Fi hotspots are rapidly multiplying

38 Wi-Fi (802.11)  Speed and distance of Wi-Fi networks depends on:  Standard and hardware being used (continually evolving)  Number of solid objects between the access point and the computer or device  Possible interference

39 WiMAX and Mobile WiMAX  WiMAX (802.16): Fairly new wireless standard for longer range wireless networking connections  Designed to deliver broadband to homes, businesses, other fixed locations  Hotzones close to 2 miles (similar in concept to cell phone towers)  Mobile WiMAX: Mobile version of the standard  Broadband by via mobile phone, portable computer, etc.

40 WiMAX and Mobile WiMAX

CELLULAR Wireless

42 Cellular Standards  Cellular standards: Continually evolving  1 st generation: Analog and voice only  2 nd generation: Digital, both voice and data  3 rd generation: HSDPA/UMTS (high speed downlink, universal mobile,) EV-DO (evolution data optimized)  4 th generation: mobile WiMAX, LTE

43 Short-Range Wireless Standards  Bluetooth: Very short range (less than 10 feet)  For communication between computers or mobile devices and peripheral devices  Bluetooth devices are automatically networked with each other when they are in range (piconets)

44 Cellular Radio Transmissions  Cellular radio: Uses cellular towers within cells  Calls are transferred from cell tower to cell tower as the individual moves  Cell tower forwards call to the MTSO  Data works in similar manner  Cell phone transmission speed depends on the cellular standard being used

45 Cellular Radio Transmissions

MICROWAVE & SATELLITE A wireless connection

47 Microwave and Satellite Transmissions  Microwaves: High-frequency radio signals  Sent and received using microwave stations or satellites  Signals are line of sight, so microwave stations are usually built on tall buildings, towers, mountaintops  Communication satellites are launched into orbit to send and receive microwave signals from earth  Traditional satellites use geosynchronous orbit  Low earth orbit (LEO) satellites were developed to combat delay  Medium earth orbit (MEO) satellites are most often used for GPS systems

48 Microwave and Satellite Transmissions

49 Infrared (IR) Transmissions  IR: Sends data as infrared light  Like an infrared television remote, IR requires line of sight  Because of this limitation, many formerly IR devices (wireless mice, keyboards) now use RF technology  IR is still sometimes used to beam data between portable computers or gaming systems, or send documents from portable computers to printers