Computer Science Networks and Topologies

Introduction to Computer Science Networks Lecture c This material (Comp 4 Unit 6) was developed by Oregon Health & Science University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number 90WT0001. This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/4.0/.

Learning Objectives - 1 Define what a communication network is (Lecture a) Explain the purposes and benefits of a communication network. (Lecture a) Explain the Internet and World Wide Web, their histories, and their structures. (Lecture a) Describe different ways of connecting to the Internet. (Lecture a) 2

Learning Objectives - 2 Explain the basics of network addressing Internet Protocol (IP) addresses Domain names Lease vs. purchase from an Internet service provider (Lecture b) Introduce network classification by the coverage size. (Lecture b) 3

Learning Objectives - 3 Describe different network topologies. (Lecture c) Outline different standards and protocols that govern wired and wireless communications. (Lecture c) 4

Learning Objectives - 4 Describe benefits and disadvantages of wireless communication. (Lecture d) Describe a typical wireless network setup. (Lecture d) Describe network hardware. (Lecture d) Introduce networking logical models and discuss Open Systems Interconnection (OSI) model. (Lecture e) 5

Network Topologies Refers to network layout Two types exist Physical: How devices in the network are connected with wires and cables Logical: How devices appear connected to the user, i.e. how data flow through the network regardless of physical design 6

Main Types of Physical Topologies (Malyszkz, 2011, PD-US 7

Physical Topologies - Bus Host is connected to other host by a single network cable with connectors If cable breaks, whole network goes down! Not in use since late 1990s (Foobaz, 2006, PD-US) 8

Physical Topologies Fully Connected and Mesh Each host is connected to every other host, usually by a switch or direct connection Some networks are partial not full mesh topologies (Foobaz, 2006, PD-US) 9

Physical Topologies - Ring Each host is connected to the network in a closed loop or ring Found in highly secure environments Typically utilize a token passing scheme, Only one machine can transmit on the network at a time (Foobaz, 2006, PD-US) 10

Physical Topologies - Star Each network host is connected to a central switch Most common type Easiest type to set up and maintain All traffic passes through the switch (Foobaz, 2006, PD-US) 11

Network Standards and Protocols - 1 Institute of Electrical and Electronics Engineers (IEEE) Creates and publishes networking and many other standards Wired network governed by IEEE 802.3 standard Wireless network governed by IEEE 802.11 standard Standards ensure compatibility of products from various vendors 12

Network Standards and Protocols - 2 Protocols govern communications Example: You install an Intel NIC on your computer and your friend installs a 3Com NIC on her computer. Both computers can communicate flawlessly because both NICs adhere to IEEE standards for network communication. 13

Standardized Communications IPs are a global standard IP addressing is required to function properly IP addressing allows any device with Internet access to communicate with another TCP/IP transports HTTP across the Internet for delivery to its destination Protocols such as HTTP allow any browser to talk to any Web server 14

Network Standards Ethernet Token ring Wi-Fi WiMAX WAP (Wireless Application Protocol) RFID (Radio frequency Identification) Bluetooth 15

Ethernet Network Standard Concepts developed 1973-1975 IEEE Standard 802.3 Defines standards for wiring and signaling Standard defines frame formats, etc. Widely used today 16

Token Ring Network Standard Concepts developed in 1985 IEEE 802.5 standard Named after its logical topology Communicating devices need to possess the digital token that is passed around the ring Put out of business by Ethernet 17

Wi-Fi Network Standard Concepts evolved 1997 today IEEE 802.11 standard for wireless LANs Family of wireless protocols Standard defines throughput, frame formats, etc. Uses frequencies (channels) for wireless communication 802.11 A uses 5.0 GHz wireless band 802.11 B/G uses 2.4 GHz wireless band 802.11 N uses both bands 18

WiMAX Network Standard Developed in 2001 IEEE 802.16 standard for WAN wireless Telecommunications protocol provides fixed and fully mobile internet access Example WiMAX access was used to assist with communications in Aceh, Indonesia, after the tsunami in December 2004. WiMAX provided broadband access that helped regenerate communication to and from Aceh. 19

Wireless Application Protocol (WAP) Open international standard for application-layer network communications in a wireless-communication environment Standard describes a protocol suite allowing the interoperability of WAP equipment and software Concept developed ca. 1997 Most use involves accessing mobile web from a mobile phone or from a PDA 20

Radio-Frequency Identification (RFID) Tag incorporated into an object, communicates using radio waves Most contain at least two parts Integrated circuit stores information Antenna for sending/receiving signals Many organizations govern standard International Organization for Standardization (ISO) International Electrotechnical Commission (IEC) 21

Bluetooth IEEE 802.15 standard Concept developed ca. 1994 to present Open wireless technology standard for exchanging data over short distances Used by Medical implants Keyboard/mouse Cell phone headsets A Bluetooth USB dongle with a 100 m range. (Mmckinley, 2009, PD-US) 22

Networks Summary Lecture c Describe different network topologies List and describe different network standards and protocols 23

Networks References 1 Lecture c References Wikipedia. Computer network. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Computer_network. Wikipedia. Local area network. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Local_area_network. Wikipedia. Metropolitan area networks. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Metropolitan_area_network. Wikipedia. Network topology. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Network_topology. Wikipedia. Institute of Electrical and Electronics Engineers. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/IEEE. Wikipedia. Communications protocol. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Network_protocol. Wikipedia. Ethernet. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Ethernet. 24

Networks References 2 Lecture c References Wikipedia. IEEE 802.11. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/IEEE_802.11. Wikipedia. Wi-Fi. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Wi-Fi. Wikipedia. WiMAX. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Wi-max. Wikipedia. Wireless Application Protocol. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/Wireless_Application_Protocol. Wikipedia. Radio-frequency identification. [Internet].2010 [cited 2011 Nov 07]. Available from: http://en.wikipedia.org/wiki/RFID. Images Slide 5: Screenshot of Computer Name/Domain Changes window. (PD-US, 2011) Slide 7: Network Topologies [image on the Internet]. Maksim (24 April 20144) [cited 2017 March 01]. Retrieved March 2017 from: https://commons.wikimedia.org/wiki/File:NetworkTopologies.svg. (PD-US, 2011) Slide 8: Bus Network [image on the Internet]. Myself, (19 February 2008) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https://commons.wikimedia.org/wiki/File:BusNetwork.svg. (PD-US, 2011) 25

Networks References 3 Lecture c Images Slide 9: NetworkTopology - Mesh [image on the Internet]. Foobaz, (6 February 2014) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https://en.wikipedia.org/wiki/File:NetworkTopology-Mesh.svg. (PD-US, 2011) Slide 9: NetworkTopology Fully Connected [image on the Internet]. Foobaz, (16 October 2016) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https://en.wikipedia.org/wiki/File:NetworkTopology-FullyConnected.png. (PD-US, 2011) Slide 10: Ring Network [image on the Internet]. Foobaz, (19 February 2008) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https://en.wikipedia.org/wiki/File:RingNetwork.svg. (PD-US, 2011) Slide 11: Star Network [image on the Internet]. Foobaz, (19 February 2008) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https://en.wikipedia.org/wiki/File:StarNetwork.svg. (PD-US, 2011) Slide 22: Bluetooth USB Dongle [image on the Internet]. Mmckinley (01 January 2009) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https://commons.wikimedia.org/wiki/File:Drone_4.jpg. (PD-US, 2011) 26

Introduction to Computer Science Networks Lecture c This material was developed by Oregon Health & Science University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number 90WT0001. 27