Introduction to Computer Science Networks Lecture c This

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 90 WT 0001. This work is licensed under the Creative Commons Attribution-Non. Commercial-Share. Alike 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 1990 s (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 3 Com 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 Wi. MAX 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 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

Wi. MAX Network Standard • Developed in 2001 • IEEE 802. 16 standard for WAN wireless • Telecommunications protocol provides fixed and fully mobile internet access • Example – Wi. MAX access was used to assist with communications in Aceh, Indonesia, after the tsunami in December 2004. Wi. MAX 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. Wi. MAX. [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: Network. Topologies. svg. (PD-US, 2011) Slide 8: Bus Network [image on the Internet]. Myself, (19 February 2008) [cited 2011 Nov 07]. Retrieved Jan 2012 from: 25 https: //commons. wikimedia. org/wiki/File: Bus. Network. svg. (PD-US, 2011)

Networks References – 3 – Lecture c Images Slide 9: Network. Topology - Mesh [image on the Internet]. Foobaz, (6 February 2014) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https: //en. wikipedia. org/wiki/File: Network. Topology-Mesh. svg. (PD-US, 2011) Slide 9: Network. Topology – Fully Connected [image on the Internet]. Foobaz, (16 October 2016) [cited 2011 Nov 07]. Retrieved Jan 2012 from: https: //en. wikipedia. org/wiki/File: Network. Topology-Fully. Connected. 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: Ring. Network. 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: Star. Network. 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 90 WT 0001. 27