Attack & Defense in Wireless Networks

Size: px
Start display at page:

Download "Attack & Defense in Wireless Networks"

Transcription

1 Attack & Defense in Wireless Networks John M. Shea April 22, 2008

2 Overview Wireless networks fundamentals vulnerabilities WING testbed Demonstration of Denial-of-Service Attack and Defense

3 Classification: Topology Infrastructure: communication controlled by base station (cellular), access point (WiFi), master (Bluetooth) Ad hoc: nodes communicate directly with peers (currently used for tactical radio networks) Mesh: hybrid of above (option for WiMax wireless municipal area network)

4 Classification: Frequency Band Licensed: cellular phone, TV, radio, satellite Unlicensed: wireless LAN, bluetooth, cordless phones unlicensed wireless networks use the Industrial, Scientific and Medical (ISM) bands MHz (centre frequency 915 MHz) GHz (centre frequency GHz) GHz (centre frequency GHz)... low spectral mask (limit on power spectral density) to reduce interference

5 IEEE a/b/g/n The IEEE a/b/g/n standards are for wireless local are networks (WLANs) Commonly referred to as WiFi b/g operates in 2.4 GHz ISM band a operates in 5.8 GHz ISM band n (draft) operates in either 2.4 GHz or 5.8 GHz bands

6 Classification: Medium Access Medium access is how the system resources are allocated to the users Frequency Division (analog cellular for users, cellular and WLAN for base stations/access points) Time Division (GSM digital cellular) Code Division (CDMA digital cellular, cdma2000, WCDMA) Space Division reuse frequencies over space (cellular), use directional antennas (cellular)

7 Medium Access In cellular networks, mobile stations synchronize their clocks closely with the base stations In wireless LANs, this is not the case Frequency division is used to allocate channel among access points

8 WiFi Channels at 2.4 GHz US 2.4 GHz ISM band divided into 11 overlapping channels: From

9 Medium Access Distributed protocol (DCF) to allocate time among users Protocol based on carrier-sense multiple access with collision avoidance (CSMA/CA) carrier sense => check if channel is busy before accessing it (same as Ethernet) collision avoidance => use control packets to reserve channel for duration of transmission Ethernet is CSMA/CD, where CD=collision detection. CD is not possible for wireless because radios cannot simultaneously transmit and receive on same channel

10 !"#"$"%&'())*+,&-+.&/(0())*+,&)1(&234 CSMA/CA $%&'()*+*,-,./(0(-01,2(3)04*('5011(67208*(85*,)(9&:(;,85(85*(,.3<)408,<.()*+*,-*2(,.(85*(=6)08,<.(3,*12(3<)(01 ;5*)*(85*(A&(,'(*B601(8<(85*()*+*,-,./($%&C'(D&E(022)*''F(G7<.()*+*,78(<3(0(H$IH<11(3)04*>(0($%&(' *(,8'(9&:('*88,./'(0'(077)<7),08*(6.2*)(85*(2080()08*('*1*+8,<.()61*'(6',./(0(26)08,<.(-016*(*B601(8<(85* Sending a packet requires up to 4 different types of transmissions 9&:( -016*(,'( /)*08*)( 850.( 85*( +6))*.8( 9&:( -016*F( K3( 85*( *2( 26)08,<.(,.+162*'( 0( 3)0+8,<.0 4,+)<'*+<.2>(8508(-016*(,'()<6.2*2(67(85*(.*?8(5,/5*)(,.8*/*)F(:0),<6'(022,8,<.01(+<.2,8,<.'(40M('*8(<)()*'* 85*(9&:>(0'(2*'+),@*2(,.(NFOF!F!F(P5*.(85*(9&:(,'()*'*8>(0(HQRIEE&AS$S%F)*B6*'8('5011(@*(,''6*2F Each transmission unit is called a frame L,/6)* NIT(,.2,+08*'(85*(9&:(3<)($%&'(8508(40M()*+*,-*(85*(A%$(3)04*>(;5,1*(<85*)($%&'(40M(<.1M()*+*,-* 85*(E%$(3)04*>()*'618,./(,.(85*(1<;*)(9&:(@0)(0'('5<;.(U;,85(85*(*?+*78,<.(<3(85*($%&(8<(;5,+5(85*(A%$(;0' 022)*''*2VF Full CSMA/CA looks like this: RTS = Request to Send ACK=acknowledgment CTS=Clear To Send

11 L,/6)* NIT(,.2,+08*'(85*(9&:(3<)($%&'(8508(40M()*+*,-*(85*(A%$(3)04*>(;5,1*(<85*)($%&'(40M(<.1M()*+*,- 022)*''*2VF CSMA/CA If CTS is not received or ACK is not received, transmitter assumes loss due to collision with other transmissions Backoff timer is started to try to prevent future collisions &( $%&( 8508( 6'*2(,.3<)408,<.( 3)<4( 0.( A%$( 3)04*( 0'( 85*( 4<'8( 8<( 67208*(,8'( 9&:( '*88,./( 7*)4,88*2(8<()*'*8(,8'(9&:(,3(.<(HQRIAW$%&A%F,.2,+08,<.(,'(2*8*+8*2(3)<4(85*(HQR(26),./(0(7*),<2(;,85 26)08,<.( <3( U!( ( 0$KL$%,4*V( X( UE%$Y%,4*V( X( 0HQRIAWI$%&A%I=*10M( X( U!( ( 0$1<8%,4*V('80)8,./( 08( 85 HQRIAWS9=F,.2,+08,<.( +<))*'7<.2,./( 8<( 85*( 2*8*+8,<.( <3( 85*( A%$( 3)04*F( %5*( ZE%$Y%,4*[(

12 WiFi Vulnerabilities Interference ISM bands are unlicensed many users: microwave ovens cordless phones bluetooth headsets Nearby access points need to be on different nonoverlapping channels Only 3 non-overlapping channels available: 1, 6, 11

13 WiFi Vulnerabilities Avoiding interference can be hard: Not all base stations advertise their presence (broadcast their SSID) these won t show up on the list your computer displays Use channel monitors (kismet, kismac, netstumbler, istumbler) to detect traffic on all channels Interference from cordless phones can be very intermittent (some phones use frequency hopping)

14 WiFi Vulnerabilities Controlling access Password-based methods WEP = Wired Equivalent Privacy badly broken, easily hackable even when configured correctly made worse by manufacturers not implementing properly do not use unless you have legacy devices that do not support newer techniques

15 WiFi Vulnerabilities Controlling access Password-based methods WPA/WPA2 = Wireless Protected Access based on IEEE i standard much, much harder to hack

16 WiFi Vulnerabilities Controlling access Hardware access lists Allow only devices with certain hardware (MAC) IDs to access network Most wireless cards allow the MAC address to be changed in software So, this is easy to defeat by an attacker with a little knowledge

17 !""" #$%&'()*++,)((- WiFi Vulnerabilities!"#"$"%&'())*+,&-+.&/(0())*+,&)1(&234 Denial-of-Service (DoS) attacks Jamming (intentional interference) can be used to shut down wireless communications A smart jammer can shut down communications with minimum energy expenditure Consider the basic protocol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

18 !""" #$%&'()*++,)((- WiFi Vulnerabilities./01.&123&4"56/7/.!512&16"1&2"58/69#:#7"0!;!0&6"<=!6"4"!"#"$"%&'())*+,&-+.&/(0())*+,&)1(&234 Denial-of-service attacks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mart jammer attacks the ACK to fool transmitter into thinking packet was not successful Full transmission time & energy is wasted L,/6)* NIT(,.2,+08*'(85*(9&:(3<)($%&'(8508(40M()*+*,-*(85*(A%$(3)04*>(;5,1*(<85*)($%&'(40M(<.1M()*+ 022)*''*2VF Transmitter will think collision occured and increase backoff window

19 WING Testbed Linux/WiFi Machines 10 Fujitsu Lifebook Laptops 20 NETGEAR WGT634U 108 Mbps Wireless Media Routers

20 Linux/WiFi Machines WING Testbed 15 ZipIt Wireless Instant Messengers

21 WING Testbed Laptops and routers use Atheros chipsets allow good control of hardware Software development based on open source drivers MadWiFi/Ath5k Perl/TK for user interaction and graphical display

22 Demo: Capture Current Signal Levels Kernel module that allows access to hardware physical-layer received signal strength indicator (RSSI) Monitor.pl program allows complete control and inspection of capture

23 Example: Full Protocol in Operation Reduced RTS threshold on my home router Captured during download -30 Received Signal Strength, Channel RTS CTS DATA ACK RTS CTS DATA ACK RTS CTS DATA ACK COLLISION BACKOFF RSSI Data Time (ms)

24 Defenses Against DoS Attacks Can use the same degrees of freedom that are available for multiple access to defend against DoS attacks: Frequency: change channels to avoid jammer Time: change protocol to prevent jammer from being able to attack so selectively (for instance, attach ACKs to Data packets) Space: use directional antennas to communicate around jammer Coding: spread signal over wider frequency band or add additional error protection

25 Demo: Defense Against DoS Attacks in Wireless Networks Use cordless phone as jammer (transmits in Channel 1) 2 Linux laptops set to switch channels if they lose too many packets

26 One More Demo: Multi-path Fading Wireless channels can vary rapidly with small changes in position because of multi-path fading multiple copies of transmitted signal bounce off objects and add together in channel copies can add constructively or destructively

27 Current & Future Work Implementing smart DoS jammer Implementing better channel-switching techniques Add directional antennas and implement spatial jamming avoidance Develop and implement new protocols to avoid jamming

6.9 Summary. 11/20/2013 Wireless and Mobile Networks (SSL) 6-1. Characteristics of selected wireless link standards a, g point-to-point

6.9 Summary. 11/20/2013 Wireless and Mobile Networks (SSL) 6-1. Characteristics of selected wireless link standards a, g point-to-point Chapter 6 outline 6.1 Introduction Wireless 6.2 Wireless links, characteristics CDMA 6.3 IEEE 802.11 wireless LANs ( wi-fi ) 6.4 Cellular Internet Access architecture standards (e.g., GSM) Mobility 6.5

More information

Wireless LAN. Access Point. Provides network connectivity over wireless media

Wireless LAN. Access Point. Provides network connectivity over wireless media LAN Technologies 802.11 Wireless LAN Network connectivity to the legacy wired LAN Access Point Desktop with PCI 802.11 LAN card Laptop with PCMCIA 802.11 LAN card Provides network connectivity over wireless

More information

ECE 4450:427/527 - Computer Networks Spring 2017

ECE 4450:427/527 - Computer Networks Spring 2017 ECE 4450:427/527 - Computer Networks Spring 2017 Dr. Nghi Tran Department of Electrical & Computer Engineering Lecture 5.6: Wireless Networks - MAC Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527

More information

Wireless Networking based on Chapter 15 of CompTIA Network+ Exam Guide, 4th ed., Mike Meyers

Wireless Networking based on Chapter 15 of CompTIA Network+ Exam Guide, 4th ed., Mike Meyers Wireless Networking 802.11 based on Chapter 15 of CompTIA Network+ Exam Guide, 4th ed., Mike Meyers topics Standards Technical Concepts Implementation Troubleshooting 802.11 timeline source: Anandtech

More information

Wireless and WiFi. Daniel Zappala. CS 460 Computer Networking Brigham Young University

Wireless and WiFi. Daniel Zappala. CS 460 Computer Networking Brigham Young University Wireless and WiFi Daniel Zappala CS 460 Computer Networking Brigham Young University Wireless Networks 2/28 mobile phone subscribers now outnumber wired phone subscribers similar trend likely with Internet

More information

Last Lecture: Data Link Layer

Last Lecture: Data Link Layer Last Lecture: Data Link Layer 1. Design goals and issues 2. (More on) Error Control and Detection 3. Multiple Access Control (MAC) 4. Ethernet, LAN Addresses and ARP 5. Hubs, Bridges, Switches 6. Wireless

More information

EE 597: Wireless Networks (Spring 12)

EE 597: Wireless Networks (Spring 12) EE 597: Wireless Networks (Spring 12) Intro to Cellular and WiFi Networks Bhaskar Krishnamachari= Acknowledgement These slides were prepared by Dr. Kyuho Son, kyuhoson@usc.edu, visiting scholar at USC.

More information

Wireless Communication and Networking CMPT 371

Wireless Communication and Networking CMPT 371 Wireless Communication and Networking CMPT 371 Wireless Systems: AM, FM Radio TV Broadcast Satellite Broadcast 2-way Radios Cordless Phones Satellite Links Mobile Telephony Systems Wireless Local Loop

More information

Topic 2b Wireless MAC. Chapter 7. Wireless and Mobile Networks. Computer Networking: A Top Down Approach

Topic 2b Wireless MAC. Chapter 7. Wireless and Mobile Networks. Computer Networking: A Top Down Approach Topic 2b Wireless MAC Chapter 7 Wireless and Mobile Networks Computer Networking: A Top Down Approach 7 th edition Jim Kurose, Keith Ross Pearson/Addison Wesley April 2016 7-1 Ch. 7: Background: # wireless

More information

Wireless Local Area Networks. Networks: Wireless LANs 1

Wireless Local Area Networks. Networks: Wireless LANs 1 Wireless Local Area Networks Networks: Wireless LANs 1 Wireless Local Area Networks The proliferation of laptop computers and other mobile devices (PDAs and cell phones) created an obvious application

More information

CSC 4900 Computer Networks: Wireless Networks

CSC 4900 Computer Networks: Wireless Networks CSC 4900 Computer Networks: Wireless Networks Professor Henry Carter Fall 2017 Last Time Mobile applications are taking off! What about current platforms is fueling this? How are an application s permission

More information

Lecture 23 Overview. Last Lecture. This Lecture. Next Lecture ADSL, ATM. Wireless Technologies (1) Source: chapters 6.2, 15

Lecture 23 Overview. Last Lecture. This Lecture. Next Lecture ADSL, ATM. Wireless Technologies (1) Source: chapters 6.2, 15 Lecture 23 Overview Last Lecture ADSL, ATM This Lecture Wireless Technologies (1) Wireless LAN, CSMA/CA, Bluetooth Source: chapters 6.2, 15 Next Lecture Wireless Technologies (2) Source: chapter 16, 19.3

More information

Shared Access Networks Wireless. 1/27/14 CS mywireless 1

Shared Access Networks Wireless. 1/27/14 CS mywireless 1 Shared Access Networks Wireless 1 Wireless and Mobile Networks Background: # wireless (mobile) phone subscribers now exceeds # wired phone subscribers (5-to-1)! # wireless Internet-connected devices equals

More information

MSIT 413: Wireless Technologies Week 8

MSIT 413: Wireless Technologies Week 8 MSIT 413: Wireless Technologies Week 8 Michael L. Honig Department of EECS Northwestern University November 2017 The Multiple Access Problem How can multiple mobiles access (communicate with) the same

More information

Chapter 6 Wireless and Mobile Networks

Chapter 6 Wireless and Mobile Networks Chapter 6 Wireless and Mobile Networks Computer Networking: A Top Down Approach Featuring the Internet, 3 rd edition. Jim Kurose, Keith Ross Addison-Wesley, July 2004. 6: Wireless and Mobile Networks 6

More information

Wireless technology Principles of Security

Wireless technology Principles of Security Wireless technology Principles of Security 1 Wireless technologies 2 Overview This module provides an introduction to the rapidly evolving technology of wireless LANs (WLANs). WLANs redefine the way the

More information

Wireless Networks. CSE 3461: Introduction to Computer Networking Reading: , Kurose and Ross

Wireless Networks. CSE 3461: Introduction to Computer Networking Reading: , Kurose and Ross Wireless Networks CSE 3461: Introduction to Computer Networking Reading: 6.1 6.3, Kurose and Ross 1 Wireless Networks Background: Number of wireless (mobile) phone subscribers now exceeds number of wired

More information

Wireless Local Area Networks (WLANs)) and Wireless Sensor Networks (WSNs) Computer Networks: Wireless Networks 1

Wireless Local Area Networks (WLANs)) and Wireless Sensor Networks (WSNs) Computer Networks: Wireless Networks 1 Wireless Local Area Networks (WLANs)) and Wireless Sensor Networks (WSNs) Computer Networks: Wireless Networks 1 Wireless Local Area Networks The proliferation of laptop computers and other mobile devices

More information

Multiple Access Links and Protocols

Multiple Access Links and Protocols Multiple Access Links and Protocols Two types of links : point-to-point PPP for dial-up access point-to-point link between Ethernet switch and host broadcast (shared wire or medium) old-fashioned Ethernet

More information

MULTIPLE ACCESS PROTOCOLS 2. 1

MULTIPLE ACCESS PROTOCOLS 2. 1 MULTIPLE ACCESS PROTOCOLS AND WIFI 1 MULTIPLE ACCESS PROTOCOLS 2. 1 MULTIPLE ACCESS LINKS, PROTOCOLS Two types of links : point-to-point broadcast (shared wire or medium) POINT-TO-POINT PPP for dial-up

More information

Wireless and Mobile Networks 7-2

Wireless and Mobile Networks 7-2 Wireless and Mobile Networks EECS3214 2018-03-26 7-1 Ch. 6: Wireless and Mobile Networks Background: # wireless (mobile) phone subscribers now exceeds # wired phone subscribers (5-to-1)! # wireless Internet-connected

More information

WiFi Networks: IEEE b Wireless LANs. Carey Williamson Department of Computer Science University of Calgary Winter 2018

WiFi Networks: IEEE b Wireless LANs. Carey Williamson Department of Computer Science University of Calgary Winter 2018 WiFi Networks: IEEE 802.11b Wireless LANs Carey Williamson Department of Computer Science University of Calgary Winter 2018 Background (1 of 2) In many respects, the IEEE 802.11b wireless LAN (WLAN) standard

More information

CS 332 Computer Networks Wireless Networks

CS 332 Computer Networks Wireless Networks CS 332 Computer Networks Wireless Networks Professor Szajda Chapter 6: Wireless and Mobile Networks Background: # wireless (mobile) phone subscribers now exceeds # wired phone subscribers! computer nets:

More information

Multiple Access in Cellular and Systems

Multiple Access in Cellular and Systems Multiple Access in Cellular and 802.11 Systems 1 GSM The total bandwidth is divided into many narrowband channels. (200 khz in GSM) Users are given time slots in a narrowband channel (8 users) A channel

More information

Overview : Computer Networking. Spectrum Use Comments. Spectrum Allocation in US Link layer challenges and WiFi WiFi

Overview : Computer Networking. Spectrum Use Comments. Spectrum Allocation in US Link layer challenges and WiFi WiFi Overview 15-441 15-441: Computer Networking 15-641 Lecture 21: Wireless Justine Sherry Peter Steenkiste Fall 2017 www.cs.cmu.edu/~prs/15-441-f17 Link layer challenges and WiFi WiFi Basic WiFi design Some

More information

COMP 3331/9331: Computer Networks and Applications

COMP 3331/9331: Computer Networks and Applications COMP 3331/9331: Computer Networks and Applications Week 10 Reading Guide: Chapter 6: 6.1 6.4 1 Ch. 6: Wireless and Mobile Networks Background: v # wireless (mobile) phone subscribers now exceeds # wired

More information

Wireless Local Area Networks (WLANs) Part I

Wireless Local Area Networks (WLANs) Part I Wireless Local Area Networks (WLANs) Part I Raj Jain Professor of CSE Washington University in Saint Louis Saint Louis, MO 63130 Jain@cse.wustl.edu These slides are available on-line at: http://www.cse.wustl.edu/~jain/cse574-08/

More information

02/21/08 TDC Branch Offices. Headquarters SOHO. Hot Spots. Home. Wireless LAN. Customer Sites. Convention Centers. Hotel

02/21/08 TDC Branch Offices. Headquarters SOHO. Hot Spots. Home. Wireless LAN. Customer Sites. Convention Centers. Hotel TDC 363 Introductions to LANs Lecture 7 Wireless LAN 1 Outline WLAN Markets and Business Cases WLAN Standards WLAN Physical Layer WLAN MAC Layer WLAN Security WLAN Design and Deployment 2 The Mobile Environment

More information

Wireless Communication and Networking CMPT 371

Wireless Communication and Networking CMPT 371 Wireless Communication and Networking CMPT 371 Wireless Systems: AM, FM Radio TV Broadcast Satellite Broadcast 2-way Radios Cordless Phones Satellite Links Mobile Telephony Systems Wireless Local Loop

More information

Wireless Networking Basics. Ed Crowley

Wireless Networking Basics. Ed Crowley Wireless Networking Basics Ed Crowley 2014 Today s Topics Wireless Networking Economic drivers and Vulnerabilities IEEE 802.11 Family WLAN Operational Modes Wired Equivalent Privacy (WEP) WPA and WPA2

More information

CSC344 Wireless and Mobile Computing. Department of Computer Science COMSATS Institute of Information Technology

CSC344 Wireless and Mobile Computing. Department of Computer Science COMSATS Institute of Information Technology CSC344 Wireless and Mobile Computing Department of Computer Science COMSATS Institute of Information Technology Wireless Local Area Networks (WLANs) Part I Almost all wireless LANs now are IEEE 802.11

More information

based on Chapter 15 of CompTIA Network+ Exam Guide, 4th ed., Mike Meyers

based on Chapter 15 of CompTIA Network+ Exam Guide, 4th ed., Mike Meyers Wireless Networking 802.11 based on Chapter 15 of CompTIA Network+ Exam Guide, 4th ed., Mike Meyers topics History Standards Technical Concepts Implementation Troubleshooting 1 HISTORY AND STANDARDS History

More information

Wireless Local Area Networks (WLANs) and Wireless Sensor Networks (WSNs) Primer. Computer Networks: Wireless LANs

Wireless Local Area Networks (WLANs) and Wireless Sensor Networks (WSNs) Primer. Computer Networks: Wireless LANs Wireless Local Area Networks (WLANs) and Wireless Sensor Networks (WSNs) Primer 1 Wireless Local Area Networks (WLANs) The proliferation of laptop computers and other mobile devices (PDAs and cell phones)

More information

Mobile and Sensor Systems

Mobile and Sensor Systems Mobile and Sensor Systems Lecture 2: Mobile Medium Access Control Protocols and Wireless Systems Dr Cecilia Mascolo In this lecture We will describe medium access control protocols and wireless systems

More information

Medium Access Control. MAC protocols: design goals, challenges, contention-based and contention-free protocols

Medium Access Control. MAC protocols: design goals, challenges, contention-based and contention-free protocols Medium Access Control MAC protocols: design goals, challenges, contention-based and contention-free protocols 1 Why do we need MAC protocols? Wireless medium is shared Many nodes may need to access the

More information

Getting Connected (Chapter 2 Part 4) Networking CS 3470, Section 1 Sarah Diesburg

Getting Connected (Chapter 2 Part 4) Networking CS 3470, Section 1 Sarah Diesburg Getting Connected (Chapter 2 Part 4) Networking CS 3470, Section 1 Sarah Diesburg Five Problems Encoding/decoding Framing Error Detection Error Correction Media Access Five Problems Encoding/decoding Framing

More information

Wireless Technologies

Wireless Technologies Wireless Technologies Networking for Home and Small Businesses Chapter 7 Manju. V. Sankar 1 Objectives Describe wireless technologies. Describe the various components and structure of a WLAN Describe wireless

More information

Wireless Networking. Chapter The McGraw-Hill Companies, Inc. All rights reserved

Wireless Networking. Chapter The McGraw-Hill Companies, Inc. All rights reserved Wireless Networking Chapter 23 Overview In this chapter, you will learn how to Discuss wireless networking components Analyze and explain wireless networking standards Install and configure wireless networks

More information

Wireless LAN -Architecture

Wireless LAN -Architecture Wireless LAN -Architecture IEEE has defined the specifications for a wireless LAN, called IEEE 802.11, which covers the physical and data link layers. Basic Service Set (BSS) Access Point (AP) Distribution

More information

Wireless LANs. The Protocol Stack The Physical Layer The MAC Sublayer Protocol The Frame Structure Services 802.

Wireless LANs. The Protocol Stack The Physical Layer The MAC Sublayer Protocol The Frame Structure Services 802. Wireless LANs The 802.11 Protocol Stack The 802.11 Physical Layer The 802.11 MAC Sublayer Protocol The 802.11 Frame Structure Services 56 802.11 The 802.11 Working Group The IEEE 802.11 was formed in July

More information

Computer Networks. Wireless and Mobile Networks. László Böszörményi Computer Networks Mobile - 1

Computer Networks. Wireless and Mobile Networks. László Böszörményi Computer Networks Mobile - 1 Computer Networks Wireless and Mobile Networks László Böszörményi Computer Networks Mobile - 1 Background Number of wireless (mobile) phone subscribers now exceeds number of wired phone subscribers! Computer

More information

CMPE 257: Wireless and Mobile Networking

CMPE 257: Wireless and Mobile Networking CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 3 CMPE 257 Spring'15 1 Next week Announcements April 14: ICN (Spencer Sevilla) April 16: DTN

More information

04/11/2011. Wireless LANs. CSE 3213 Fall November Overview

04/11/2011. Wireless LANs. CSE 3213 Fall November Overview Wireless LANs CSE 3213 Fall 2011 4 November 2011 Overview 2 1 Infrastructure Wireless LAN 3 Applications of Wireless LANs Key application areas: LAN extension cross-building interconnect nomadic access

More information

CS263: Wireless Communications and Sensor Networks

CS263: Wireless Communications and Sensor Networks CS263: Wireless Communications and Sensor Networks Matt Welsh Lecture 5: The 802.11 Standard October 7, 2004 2004 Matt Welsh Harvard University 1 All about 802.11 Today's Lecture CSMA/CD MAC and DCF WEP

More information

Lecture 4: Wireless MAC Overview. Hung-Yu Wei National Taiwan University

Lecture 4: Wireless MAC Overview. Hung-Yu Wei National Taiwan University Lecture 4: Wireless MAC Overview Hung-Yu Wei National Taiwan University Medium Access Control Topology 3 Simplex and Duplex 4 FDMA TDMA CDMA DSSS FHSS Multiple Access Methods Notice: CDMA and spread spectrum

More information

Institute of Electrical and Electronics Engineers (IEEE) IEEE standards

Institute of Electrical and Electronics Engineers (IEEE) IEEE standards HW Institute of Electrical and Electronics Engineers (IEEE) IEEE 802.11 standards WLAN Standard (IEEE 802.11) The IEEE 802.11 is a family of standards that governs the operations and functions of WLANs.

More information

CS 43: Computer Networks. 27: Media Access Contd. December 3, 2018

CS 43: Computer Networks. 27: Media Access Contd. December 3, 2018 CS 43: Computer Networks 27: Media Access Contd. December 3, 2018 Last Class The link layer provides lots of functionality: addressing, framing, media access, error checking could be used independently

More information

Announcements / Wireless Networks and Applications Lecture 9: Wireless LANs Wireless. Regular Ethernet CSMA/CD.

Announcements / Wireless Networks and Applications Lecture 9: Wireless LANs Wireless. Regular Ethernet CSMA/CD. Announcements 18-452/18-750 Wireless Networks and Applications Lecture 9: Wireless LANs 802.11 Wireless Peter Steenkiste Homework 1 should be out by tomorrow Project 1 by Friday Schedule:» Thursday lecture

More information

Wireless and Mobile Networks Reading: Sections 2.8 and 4.2.5

Wireless and Mobile Networks Reading: Sections 2.8 and 4.2.5 Wireless and Mobile Networks Reading: Sections 2.8 and 4.2.5 Acknowledgments: Lecture slides are from Computer networks course thought by Jennifer Rexford at Princeton University. When slides are obtained

More information

ECE 435 Network Engineering Lecture 8

ECE 435 Network Engineering Lecture 8 ECE 435 Network Engineering Lecture 8 Vince Weaver http://web.eece.maine.edu/~vweaver vincent.weaver@maine.edu 26 September 2016 HW#3 was posted Announcements note the warnings you were getting on toupper()

More information

Guide to Wireless Communications, Third Edition. Objectives

Guide to Wireless Communications, Third Edition. Objectives Guide to Wireless Communications, Third Edition Chapter 7 Low-Speed Wireless Local Area Networks Objectives Describe how WLANs are used List the components and modes of a WLAN Describe how an RF WLAN works

More information

Wireless Router at Home

Wireless Router at Home Wireless Router at Home 192.168.1.2 192.168.1.1 Modem 192.168.1.3 120.6.46.15 telephone line to ISP 192.168.1.4 Internet connection with public IP internal LAN with private IPs 192.168.1.5 Wireless All-in-one

More information

Data Communication & Networks G Session 5 - Main Theme Wireless Networks. Dr. Jean-Claude Franchitti

Data Communication & Networks G Session 5 - Main Theme Wireless Networks. Dr. Jean-Claude Franchitti Data Communication & Networks G22.2262-001 Session 5 - Main Theme Wireless Networks Dr. Jean-Claude Franchitti New York University Computer Science Department Courant Institute of Mathematical Sciences

More information

Chapter 7. Basic Wireless Concepts and Configuration. Part I

Chapter 7. Basic Wireless Concepts and Configuration. Part I Chapter 7 Basic Wireless Concepts and Configuration Part I CCNA3-1 Chapter 7-1 Note for Instructors These presentations are the result of a collaboration among the instructors at St. Clair College in Windsor,

More information

CS 43: Computer Networks Media Access. Kevin Webb Swarthmore College November 30, 2017

CS 43: Computer Networks Media Access. Kevin Webb Swarthmore College November 30, 2017 CS 43: Computer Networks Media Access Kevin Webb Swarthmore College November 30, 2017 Multiple Access Links & Protocols Two classes of links : point-to-point dial-up access link between Ethernet switch,

More information

Lecture 6. Reminder: Homework 2, Programming Project 2 due on Thursday. Questions? Tuesday, September 13 CS 475 Networks - Lecture 6 1

Lecture 6. Reminder: Homework 2, Programming Project 2 due on Thursday. Questions? Tuesday, September 13 CS 475 Networks - Lecture 6 1 Lecture 6 Reminder: Homework 2, Programming Project 2 due on Thursday. Questions? Tuesday, September 13 CS 475 Networks - Lecture 6 1 Outline Chapter 2 - Getting Connected 2.1 Perspectives on Connecting

More information

COMP 3331/9331: Computer Networks and Applications

COMP 3331/9331: Computer Networks and Applications COMP 3331/9331: Computer Networks and Applications Week 10 Wireless Networks Reading Guide: Chapter 6: 6.1 6.3 Wireless Networks + Security 1 Wireless and Mobile Networks Background: # wireless (mobile)

More information

Mohammad Hossein Manshaei 1393

Mohammad Hossein Manshaei 1393 Mohammad Hossein Manshaei manshaei@gmail.com 1393 Wireless Links, WiFi, Cellular Internet Access, and Mobility Slides derived from those available on the Web site of the book Computer Networking, by Kurose

More information

CMPE 257: Wireless and Mobile Networking

CMPE 257: Wireless and Mobile Networking CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 3 CMPE 257 Winter'11 1 Announcements Accessing secure part of the class Web page: User id: cmpe257.

More information

Wireless Networks. CSE 3461: Introduction to Computer Networking Reading: , Kurose and Ross ( 6th ed.); , Kurose and Ross (7th ed.

Wireless Networks. CSE 3461: Introduction to Computer Networking Reading: , Kurose and Ross ( 6th ed.); , Kurose and Ross (7th ed. Wireless Networks CSE 3461: Introduction to Computer Networking Reading: 6.1 6.3, Kurose and Ross ( 6th ed.); 7.1 7.3, Kurose and Ross (7th ed.) 1 Questions How do you use wireless network technology in

More information

CSMC 417. Computer Networks Prof. Ashok K Agrawala Ashok Agrawala. Fall 2018 CMSC417 Set 1 1

CSMC 417. Computer Networks Prof. Ashok K Agrawala Ashok Agrawala. Fall 2018 CMSC417 Set 1 1 CSMC 417 Computer Networks Prof. Ashok K Agrawala 2018 Ashok Agrawala Fall 2018 CMSC417 Set 1 1 The Medium Access Control Sublayer November 18 Nov 6, 2018 2 Wireless Networking Technologies November 18

More information

Data and Computer Communications. Chapter 13 Wireless LANs

Data and Computer Communications. Chapter 13 Wireless LANs Data and Computer Communications Chapter 13 Wireless LANs Wireless LAN Topology Infrastructure LAN Connect to stations on wired LAN and in other cells May do automatic handoff Ad hoc LAN No hub Peer-to-peer

More information

Medium Access Control

Medium Access Control Medium Access Control All material copyright 1996-2009 J.F Kurose and K.W. Ross, All Rights Reserved 5: DataLink Layer 5-1 Link Layer Introduction and services Multiple access protocols Ethernet Wireless

More information

Ethernet. Lecture 6. Outline. Ethernet - Physical Properties. Ethernet - Physical Properties. Ethernet

Ethernet. Lecture 6. Outline. Ethernet - Physical Properties. Ethernet - Physical Properties. Ethernet Lecture 6 Ethernet Reminder: Homework 2, Programming Project 2 due on 9/20/12. Thick-net Thin-net Twisted Pair Thursday, September 13 CS 475 Networks - Lecture 6 1 Thursday, September 13 CS 475 Networks

More information

Link Layer: Retransmissions

Link Layer: Retransmissions Link Layer: Retransmissions Context on Reliability Where in the stack should we place reliability functions? Application Transport Network Link Physical CSE 461 University of Washington 2 Context on Reliability

More information

Module 6: Wireless Mobile Networks

Module 6: Wireless Mobile Networks Module 6: Wireless Mobile Networks SMD123 Computer Communications Kaustubh Phanse Department of Computer Science and Electrical Engineering Luleå University of Technology Lecture Objectives Wireless links

More information

Wireless Terms. Uses a Chipping Sequence to Provide Reliable Higher Speed Data Communications Than FHSS

Wireless Terms. Uses a Chipping Sequence to Provide Reliable Higher Speed Data Communications Than FHSS How to Set Up a Secure Home Wireless Network What you don t know about setting up a home wireless network can hurt you. 2008 APCUG Convention Session Tom Jones, P.E., RCDD-NTS CQS-CWLSS AGENDA Some Terms

More information

Analysis of IEEE e for QoS Support in Wireless LANs

Analysis of IEEE e for QoS Support in Wireless LANs Analysis of IEEE 802.11e for QoS Support in Wireless LANs Stefan Mangold, Sunghyun Choi, Guido R. Hiertz, Ole Klein IEEE Wireless Communications, December 2003 Presented by Daeseon Park, Student No.2005-30231

More information

Data Communications. Data Link Layer Protocols Wireless LANs

Data Communications. Data Link Layer Protocols Wireless LANs Data Communications Data Link Layer Protocols Wireless LANs Wireless Networks Several different types of communications networks are using unguided media. These networks are generally referred to as wireless

More information

Multiple Access Links and Protocols

Multiple Access Links and Protocols Multiple Access Links and Protocols Two types of links : point-to-point PPP for dial-up access point-to-point link between Ethernet switch and host broadcast (shared wire or medium) old-fashioned Ethernet

More information

Local Area Networks NETW 901

Local Area Networks NETW 901 Local Area Networks NETW 901 Lecture 4 Wireless LAN Course Instructor: Dr.-Ing. Maggie Mashaly maggie.ezzat@guc.edu.eg C3.220 1 Contents What is a Wireless LAN? Applications and Requirements Transmission

More information

CSCI-1680 Wireless Chen Avin

CSCI-1680 Wireless Chen Avin CSCI-1680 Wireless Chen Avin Based on slides from Computer Networking: A Top Down Approach - 6th edition Administrivia TCP is due on Friday Final Project is out (fun, two weeks) Wireless and Mobile Networks

More information

Wireless LANs and Ad-hoc networks. IFI Master - Ubinet G. Urvoy-Keller

Wireless LANs and Ad-hoc networks. IFI Master - Ubinet G. Urvoy-Keller 802.11 Wireless LANs and Ad-hoc networks IFI Master - Ubinet G. Urvoy-Keller Sources of document Matthew Guast, 802.11 Wireless Networks, the definitive guide O'Reilly 2005. Matti Siekkinen, Aalto University

More information

Strengthening Unlicensed Band Wireless Backhaul

Strengthening Unlicensed Band Wireless Backhaul be in charge Strengthening Unlicensed Band Wireless Backhaul Use TDD/TDMA Based Channel Access Mechanism WHITE PAPER Strengthening Unlicensed Band Wireless Backhaul: Use TDD/TDMA Based Channel Access Mechanism

More information

standard. Acknowledgement: Slides borrowed from Richard Y. Yale

standard. Acknowledgement: Slides borrowed from Richard Y. Yale 802.11 standard Acknowledgement: Slides borrowed from Richard Y. Yang @ Yale IEEE 802.11 Requirements Design for small coverage (e.g. office, home) Low/no mobility High data rate applications Ability to

More information

Naveen Kumar. 1 Wi-Fi Technology

Naveen Kumar. 1 Wi-Fi Technology Naveen Kumar 1 Contents 2 Introduction Need of Purpose History How a Wi-Fi Network Works Topologies & Configurations Applications Wi-Fi Security Advantages & Limitations Innovations Introduction 3 Wireless

More information

Outline / Wireless Networks and Applications Lecture 9: Wireless LANs Aloha and 802 Wireless. Regular Ethernet CSMA/CD

Outline / Wireless Networks and Applications Lecture 9: Wireless LANs Aloha and 802 Wireless. Regular Ethernet CSMA/CD Page 1 Outline 18-452/18-750 Wireless Networks and Applications Lecture 9: Wireless LANs Aloha and 802 Wireless Peter Steenkiste Data link fundamentals» And what changes in wireless Aloha Ethernet Wireless-specific

More information

Public Wireless LAN Service.

Public Wireless LAN Service. Public Wireless LAN Service touch@coe.psu.ac.th Radio Wave Wave Frequency Amplitude Wave Length Radio Wave Band Frequency Wavelength VLF 3-30 khz > 10 km LF 30-300 khz 1-10 km MF 300-3,000 khz 100-1000

More information

WNC-0300USB. 11g Wireless USB Adapter USER MANUAL

WNC-0300USB. 11g Wireless USB Adapter USER MANUAL WNC-0300USB 11g Wireless USB Adapter USER MANUAL Contents 1. Introduction...3 1.1 Product Feature...3 1.2 System Requirement...3 2. Getting Start...3 2.1 LED Indicators...3 2.2 Install the 54Mbps Wireless

More information

Wireless and Mobile Networks

Wireless and Mobile Networks Wireless and Mobile Networks Raj Jain Washington University in Saint Louis Saint Louis, MO 63130 Jain@wustl.edu Audio/Video recordings of this lecture are available on-line at: http://www.cse.wustl.edu/~jain/cse473-11/

More information

1. INTRODUCTION. Wi-Fi 1

1. INTRODUCTION. Wi-Fi 1 Wi-Fi 1 1. INTRODUCTION Wi-Fi, or Wireless Fidelity, is freedom: it allows you to connect to the Internet from your home, a bed in a hotel room or at a conference room at work without wires. How? Wi-Fi

More information

INTRODUCTION TO WIRELESS LAN, MAC PROTOCOLS and INTERFERENCE. Choong Seon Hong, KHU

INTRODUCTION TO WIRELESS LAN, MAC PROTOCOLS and INTERFERENCE. Choong Seon Hong, KHU INTRODUCTION TO WIRELESS LAN, MAC PROTOCOLS and INTERFERENCE cshong@khu.ac.kr, Choong Seon Hong, KHU Outline 2 Introduction Wireless LAN Architecture Wireless LAN standards Media Access Problem The IEEE

More information

CSCD 433 Network Programming Fall Lecture 7 Ethernet and Wireless

CSCD 433 Network Programming Fall Lecture 7 Ethernet and Wireless CSCD 433 Network Programming Fall 2016 Lecture 7 Ethernet and Wireless 802.11 1 Topics 802 Standard MAC and LLC Sublayers Review of MAC in Ethernet MAC in 802.11 Wireless 2 IEEE Standards In 1985, Computer

More information

Wireless LANs: outline. wireless and WiFi security: WEP, i, WPA, WPA2. networking security wireless ad-hoc and mesh networks

Wireless LANs: outline. wireless and WiFi security: WEP, i, WPA, WPA2. networking security wireless ad-hoc and mesh networks Wireless LANs: outline wireless 802.11 and WiFi. 802.11 security: WEP, 802.11i, WPA, WPA2. networking security wireless ad-hoc and mesh networks ISM bands to operate most radios, a license is needed from

More information

Wireless# Guide to Wireless Communications. Objectives

Wireless# Guide to Wireless Communications. Objectives Wireless# Guide to Wireless Communications Chapter 7 Low-Speed Wireless Local Area Networks Objectives Describe how WLANs are used List the components and modes of a WLAN Describe how an RF WLAN works

More information

3.1. Introduction to WLAN IEEE

3.1. Introduction to WLAN IEEE 3.1. Introduction to WLAN IEEE 802.11 WCOM, WLAN, 1 References [1] J. Schiller, Mobile Communications, 2nd Ed., Pearson, 2003. [2] Martin Sauter, "From GSM to LTE", chapter 6, Wiley, 2011. [3] wiki to

More information

Wireless Networks. Authors: Marius Popovici Daniel Crişan Zagham Abbas. Technical University of Cluj-Napoca Group Cluj-Napoca, 24 Nov.

Wireless Networks. Authors: Marius Popovici Daniel Crişan Zagham Abbas. Technical University of Cluj-Napoca Group Cluj-Napoca, 24 Nov. Wireless Networks Authors: Marius Popovici Daniel Crişan Zagham Abbas Technical University of Cluj-Napoca Group 3250 Cluj-Napoca, 24 Nov. 2003 Presentation Outline Wireless Technology overview The IEEE

More information

Chapter 10: Wireless LAN & VLANs

Chapter 10: Wireless LAN & VLANs Chapter 10: Wireless LAN & VLANs Abdullah Konak School of Information Sciences and Technology Penn State Berks Wireless Transmission for LAN Radio Frequency Transmission (RF) Infrared Transmission 2 1

More information

IEEE Wireless LANs Part I: Basics

IEEE Wireless LANs Part I: Basics IEEE 802.11 Wireless LANs Part I: Basics Raj Jain Professor of Computer Science and Engineering Washington University in Saint Louis Saint Louis, MO 63130 Jain@cse.wustl.edu Audio/Video recordings of this

More information

Advanced Computer Networks WLAN

Advanced Computer Networks WLAN Advanced Computer Networks 263 3501 00 WLAN Patrick Stuedi Spring Semester 2014 1 Oriana Riva, Department of Computer Science ETH Zürich Last week Outlook Medium Access COPE Short Range Wireless Networks:

More information

Wireless LANs. ITS 413 Internet Technologies and Applications

Wireless LANs. ITS 413 Internet Technologies and Applications Wireless LANs ITS 413 Internet Technologies and Applications Aim: Aim and Contents Understand how IEEE 802.11 wireless LANs work Understand what influences the performance of wireless LANs Contents: IEEE

More information

Wireless Internet Routing. Review of Wireless Networking (with Routing in Mind)

Wireless Internet Routing. Review of Wireless Networking (with Routing in Mind) Wireless Internet Routing Review of Wireless Networking (with Routing in Mind) 1 Review of Wireless Networking Architecture of wireless networks Wireless PHY Wireless MAC o 802.11 PHY: physical layer /

More information

IEEE Wireless LAN draft Standard

IEEE Wireless LAN draft Standard IEEE 802.11 Wireless LAN draft Standard Keith B. Amundsen Wireless Solutions 508-470-9483 keith_b_amundsen@raytheon.com October 24, 1996 Worcester Polytechnic Institute Introduction IEEE 802.11 Draft 5.0

More information

M06:Wireless and Mobile Networks. Corinna Schmitt

M06:Wireless and Mobile Networks. Corinna Schmitt M06:Wireless and Mobile Networks Corinna Schmitt corinna.schmitt@unibas.ch Acknowledgement 2016 M06 2 Background q # wireless (mobile) phone subscribers now exceeds # wired phone subscribers (5-to-1)!

More information

WIRELESS-NETWORK TECHNOLOGIES/PROTOCOLS

WIRELESS-NETWORK TECHNOLOGIES/PROTOCOLS 3 WIRELESS-NETWORK TECHNOLOGIES/PROTOCOLS Dr. H. K. Verma Distinguished Professor (EEE) Sharda University, Greater Noida (Formerly: Deputy Director and Professor of Instrumentation Indian Institute of

More information

CEN 538 Wireless LAN & MAN Networks

CEN 538 Wireless LAN & MAN Networks King Saud University College of Computer and Information Sciences Department of Computer Engineering CEN 538 Wireless LAN & MAN Networks Dr. Ridha OUNI rouni@ksu.edu.sa LMS web site References Text book

More information

Rahman 1. Application

Rahman 1. Application Data Link layer Overview of IEEE 802.11 Application Presentation Session Transport LLC: On transmission, assemble data into a frame with address and CRC fields. On reception, disassemble frame, perform

More information

Home Area Networks. Outline

Home Area Networks. Outline Home Area Networks CS 687 University of Kentucky Fall 2015 Acknowledgment: Some slides are adapted from the slides distributed with the book Computer Networking: A Top Down Approach, 5th edition. Jim Kurose,

More information

15-441: Computer Networking. Wireless Networking

15-441: Computer Networking. Wireless Networking 15-441: Computer Networking Wireless Networking Outline Wireless Challenges 802.11 Overview Link Layer Ad-hoc Networks 2 Assumptions made in Internet Host are (mostly) stationary Address assignment, routing

More information

Medium Access Control Sublayer Chapter 4

Medium Access Control Sublayer Chapter 4 Medium Access Control Sublayer Chapter 4 Channel Allocation Problem Multiple Access Protocols Ethernet Wireless LANs Broadband Wireless Bluetooth RFID Data Link Layer Switching Revised: August 2011 & February

More information