Introduction to Information and Computer Science Networks Lecture d This material (Comp4_Unit7d) was developed by Oregon Health and Science University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number IU24OC000015.
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Introduction to Information and Computer Science Networks Lecture d This material (Comp4_Unit7d) was developed by Oregon Health and Science University,
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Introduction to Information and Computer Science
Networks
Lecture d
This material (Comp4_Unit7d) was developed by Oregon Health and Science University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number
IU24OC000015.
NetworksLearning Objectives
• List and describe the various types of network communications and network addressing (Lecture a and b)
• List and define the different types of networks (Lecture c)• Describe different network topologies (Lecture c)• List and describe different network standards and
protocols (Lecture c and e)• Describe wireless communication (Lecture d)• List and describe network hardware (Lecture d)
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Introduction to Information and Computer Science Networks
Lecture d
Wireless Communications
• Wireless devices communicate without cabling.• Signals sent via:
• Infrared light – laptop to laptop• Microwave – requires clear line of sight• Radio frequency - most common method
• Governed by IEEE 802.11 standard.• Seems to be available everywhere!
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Introduction to Information and Computer Science Networks
Lecture d
Wireless – The Good, The Bad, & The Ugly
• Good:• No cables needed to connect devices to network.• Cleaner work environment without cables.• Devices can be easily moved about.• Easy for users to connect.
• Bad:• Can be slower than wired networks.• Limited signal range.
• Ugly:• Security issues.
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Introduction to Information and Computer Science Networks
Lecture d
How Does Wireless Function
• Home wireless communication is done by radio frequency.• Radio frequencies are mapped to channel numbers.• In North America, channels are 1-13 for 802.11 a/b/g
• Need the following for typical home setup:• Computers need wireless NICs
– Facilitates connection to a wireless router.
• Network needs a wireless router– Also known as a wireless access point (WAP).
• Wireless router needs to connect to a wired device– To get Internet access, wireless router needs wired connection to
the ISP device (cable modem router).
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Introduction to Information and Computer Science Networks
Lecture d
Wireless Network Setup
• WAP:• SSID – name for wireless network.• Change WAP default password since globally known.• IP address and subnet mask.• Configure WPA2 and record the code/phrase created.• Cable WAP so it somehow connects to ISP device.
• Each wireless client:• SSID configured same as WAP.• IP address and subnet mask in same range as WAP.• Configure WPA2 using code/phrase from WAP.
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Introduction to Information and Computer Science Networks
Lecture d
Wireless Network Setup (cont’d)
• Standards are backwards compatible• 802.11g NICs work in 802.11 a/b device-controlled
WLANs.
• Wireless RF channels• WAPs and clients must use same channel.• Different channels cannot communicate.• Channel numbers correspond to an RF range.• Channels 1, 6, and 11 RF do not overlap. Use one of
these!– Channel 5 uses the RF range of 2.421–2.443 GHz.– Channel 6 uses the RF range of 2.426–2.448 GHz.
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Introduction to Information and Computer Science Networks
Lecture d
Wireless Components Example
• The notebook is connected to the wireless access point using a PC card.
PC card (wireless NIC)
Wireless Access Point (WAP)
Network cable connection to wired network.
(Porao, 2005, CC BY-SA 3.0)
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Introduction to Information and Computer Science Networks
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Introduction to Information and Computer Science Networks
Lecture d
Network Hardware – ISP Device
• Connects SOHO and Office networks to Internet.• Can lease from ISP with Internet service.
• Sometimes available for purchase too.• Usually has one Internet port to connect to a wall port.• Usually has one switch port to connect one device using
Ethernet cable.• Can use that port to connect to a switch, which can
connect to other devices or other switches to extend network.
• All devices then share the one Internet connection.
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Introduction to Information and Computer Science Networks
Lecture d
ISP Device Examples• The image on the left
shows a Motorola cable modem. This router uses the ISP’s coaxial cable to provide Internet connectivity.
• The image on the right shows a wireless D-Link router/modem used as a residential DSL gateway. This router uses the ISP’s Ethernet cable to provide Internet connectivity.
(Larocomp, 2010, PD-US)
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Introduction to Information and Computer Science Networks
Network Hardware - Server• Computer with specialized OS installed.
• Windows Server 2008
• Ubuntu Server
• Novell Open Enterprise Server
• Creates ‘gated community’ of devices and users.• Server maintains database of objects, restricts access to authorized
devices/users, and manages them.
• Can provide various functions: Domain controller Print server DHCP server DNS server File server Certificate server NAP server
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Introduction to Information and Computer Science Networks
Lecture d
Network Hardware – Surge Protector
• Protects devices from spikes in power usually originating with the power company.• Some power strips are also surge protectors – need
to carefully read product information to differentiate.• Devices need to be plugged in to gain protection.• Power surge can destroy a devices circuitry.• Protection measured in Joules.
• Joules define how much electricity the surge protector can absorb without failure.
• Should consult electrician to protect hardware.
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Introduction to Information and Computer Science Networks
Lecture d
Network Hardware - UPS
• Uninterruptible power supply (UPS) provides emergency power to attached devices when power fails.
• Short battery power time (5-30 min.) depending on attached devices.• Computer and monitor – portable unit okay.• Whole building – need large (site) solution.
• Never plug laser printer into UPS.• Due to power requirements, will instantly drain
available UPS battery power.Health IT Workforce Curriculum Version 3.0/Spring 2012
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Introduction to Information and Computer Science Networks
Lecture d
Surge Protector & UPS Examples
(Amakuru, 2006, CC BY-SA 3.0)
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Introduction to Information and Computer Science Networks
•Describe wireless communication•List and describe network hardware
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Lecture d
NetworksReferences – Lecture d
References • Wikipedia. Medical Implant Communication Service. [Internet]. 2011 Jun [cited 2011 Nov 07]. Available from:
http://en.wikipedia.org/wiki/Medical_Implant_Communication_Service. • Wikipedia. Wireless LAN. [Internet]. 2011 Jun [cited 2011 Nov 07]. Available from:
http://en.wikipedia.org/wiki/Wireless_LAN. • Wikipedia. Network switch. [Internet]. 2011 Jun [cited 2011 Nov 07]. Available from:
http://en.wikipedia.org/wiki/Network_switch. • Wikipedia. Surge protector. [Internet]. 2011 Jun [cited 2011 Nov 07]. Available from:
http://en.wikipedia.org/wiki/Surge_protector. • Wikipedia. Uninterruptible power supply. [Internet]. 2011 Jun [cited 2011 Nov 07]. Available from:
Images • Slide 8: Wireless Network Components [image on the Internet]. (Porao, 2005, CC BY-SA 3.0) [cited 2011 Nov
07]. Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/File:Wireless_network.jpg. • Slide 11: Network Interface Card [image on the Internet]. (Helix84, 2005, CC BY-SA 3.0) [cited 2011 Nov 07].
Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/Network_interface_card. • Slide 11: Wireless Interface Card [image on the Internet]. (Wheeler, 2007, CC BY-SA 3.0) [cited 2011 Nov 07].
Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/File:WLAN_PCI_Card_cleaned.png. • Slide 12: Network Switch [image on the Internet]. (Sub, 2007, PD-US) [cited 2011 Nov 07]. Retrieved Jan 2012
from: http://en.wikipedia.org/wiki/File:Ethernet_switch_Atlantis_A02-F5P_5_ports_backend.jpg. • Slide 13: Cisco Linksys Wireless Router [image on the Internet]. c2008 [cited 2011 Nov 07]. Retrieved Jan 2012
from: http://en.wikipedia.org/wiki/File:Linksys_WRT54GL.jpg. • Slide 14: SOHO Wireless Network [image on the Internet]. (Feval, 2006, CC BY-SA 3.0) [cited 2011 Nov 07].
Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/File:SPOF.png. • Slide 16: Motorola Cable Modem Router [image on the Internet]. (Larocomp, 2010, PD-US) [cited 2011 Nov 07].
Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/Cable_modem. • Slide 16: D-Link Wireless Router [image on the Internet]. (Macic7, 2007, CC BY 3.0) [cited 2011 Nov 07].
Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/File:Wirelessadsl2%2Brouter.dlink.dslg684t.JPG. • Slide 20: Large UPS Device [image on the Internet]. (Cgxke, 20087, PD-US) [cited 2011 Nov 07]. Retrieved Jan
2012 from: http://en.wikipedia.org/wiki/File:500kVA-UPS.jpg. • Slide 20: Small UPS Device [image on the Internet]. (Amakuru, 2006, CC BY-SA 3.0) [cited 2011 Nov 07].
Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/File:UPSRearView.jpg. • Slide 20: Multi-outlet Surge Protector [image on the Internet]. (Amakuru, 2006, CC BY-SA 3.0) [cited 2011 Nov
07]. Retrieved Jan 2012 from: http://en.wikipedia.org/wiki/File:Surge_protector.jpg.
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Introduction to Information and Computer Science Networks