The Basics of Wireless Communication. Octav Chipara

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "The Basics of Wireless Communication. Octav Chipara"

Transcription

1 The asics of Wireless ommunication Octav hipara

2 genda hannel model: the protocol model High-level media access TM, SM hidden/exposed terminal problems WLN Fundamentals of routing proactive on-demand 2

3 hannel models hannel models - document assumptions of wireless properties the basis upon which we build and analyze network protocols good model is one that is simple - reason effectively about the properties of protocols accurate - capture prevalent properties of wireless channels these requirements are often conflicting Must provide insight into fundamental problems media access routing congestion Today, simple channel model..., next lecture more realistic models 3

4 Protocol model Network is modeled as a graph vertices - all nodes in a graph edges - connect nodes that may communicate Properties: captures connectivity information packet collisions (collisions happen only at the receiver) radios are half-duplex 4

5 Protocol model Network is modeled as a graph vertices - all nodes in a graph edges - connect nodes that may communicate Properties: captures connectivity information packet collisions (collisions happen only at the receiver) radios are half-duplex 4

6 Protocol model Network is modeled as a graph vertices - all nodes in a graph edges - connect nodes that may communicate Properties: captures connectivity information packet collisions (collisions happen only at the receiver) radios are half-duplex 4

7 Media ccess and ontrol (M) Problem: multiple nodes want to transmit concurrently nodes transmitting concurrently packet collisions Metrics for characterizing M performance throughput - number of packets delivered per second latency - time to deliver a packet energy efficiency - energy consumed for tx and rx fairness - each node gets its fair share of the channel flexibility - how does the M handle changes in workload pproaches SM - arrier Sense Multiple ccess TM - Time ivision Multiple ccess 5

8 SM SM - arrier Sense Multiple ccess pproach: 1: node will attempt to transmit after a random delay t W 2: check if channel is available free perform packet transmission busy W = W * 2, go to step 1 Notes: nodes operate independently! the underlying performance is highly dependent on selecting W W - reflects the expected number of contenders for the channel W increases exponentially [the rate depends on protocol] assumption: the sender can accurately check if channel is free/busy usually holds because: receiver sensibility << channel quality required for communication 6

9 SM SM - arrier Sense Multiple ccess pproach: 1: node will attempt to transmit after a random delay t W 2: check if channel is available free perform packet transmission busy W = W * 2, go to step 1 Notes: nodes operate independently! the underlying performance is highly dependent on selecting W W - reflects the expected number of contenders for the channel W increases exponentially [the rate depends on protocol] assumption: the sender can accurately check if channel is free/busy usually holds because: receiver sensibility << channel quality required for communication 6

10 Signal propagation ranges Transmission range communication possible low error rate etection range detection of the signal possible no communication possible Interference range signal may not be detected signal adds to the background noise sender transmission detection interference distance 7

11 TM TM - Time ivision Multiple ccess pproach: 1: construct a frame in which each node gets a slot to transmit F - frame size, fn - slot in which node n is assigned to transmit 2: a node n will transmit at time (t mod F) = fn Notes: time synchronization is required frame construction requires a global agreement among nodes underlying performance depends on matching a node s workload demand with its slot allocations hard to do due to dynamic workloads and channel properties assumption: only one successful transmission per slot 8

12 TM TM - Time ivision Multiple ccess pproach: 1: construct a frame in which each node gets a slot to transmit F - frame size, fn - slot in which node n is assigned to transmit 2: a node n will transmit at time (t mod F) = fn Notes: time synchronization is required frame construction requires a global agreement among nodes underlying performance depends on matching a node s workload demand with its slot allocations hard to do due to dynamic workloads and channel properties assumption: only one successful transmission per slot 8

13 Single-hop vs. multiple hops Single-hop networks both SM and TM protocols are easy to implement Multi-hop networks important challenges arise due to asymmetrical views of the networks hidden-terminal problem exposed-terminal problem 9

14 Hidden terminal problem Node and are hidden (edge () is not in the graph) they cannot sense their packet transmissions onsequences for M protocols SM protocols will never increase W TM protocols will have to agree on a frame over multiple hops 10

15 Hidden terminal problem Node and are hidden (edge () is not in the graph) they cannot sense their packet transmissions onsequences for M protocols SM protocols will never increase W TM protocols will have to agree on a frame over multiple hops 10

16 Hidden terminal problem undetected collisions Node and are hidden (edge () is not in the graph) they cannot sense their packet transmissions onsequences for M protocols SM protocols will never increase W TM protocols will have to agree on a frame over multiple hops 10

17 Exposed terminal problem Node and can communicate () and () can occur currently (collisions at receivers) onsequences for M protocols SM will increase W unnecessarily 11

18 Exposed terminal problem false positives Node and can communicate () and () can occur currently (collisions at receivers) onsequences for M protocols SM will increase W unnecessarily 11

19 RTS/TS a solution for SM protocols dd two additional messages to the TM protocol RTS - request to send TS - clear to send lgorithm node n wants to send packet to m transmit RTS(n, m) node a1, a2,..., an, m receive RTS(n, m) node m replies with TS(n, m) if its channel is free node b1, b2,..., bn, n receives TS(n, m) node n transmits the data packet The algorithm signals access requests over 2-hops 12

20 Hidden terminal problem 13

21 Hidden terminal problem send RTS(,) 13

22 Hidden terminal problem recv RTS(,) send RTS(,) 13

23 Hidden terminal problem recv RTS(,) send RTS(,) send TS(,) 13

24 Hidden terminal problem recv RTS(,) send RTS(,) recv TS(,) send TS(,) recv TS(,) 13

25 Exposed terminal problem send RTS(,) 14

26 Exposed terminal problem send RTS(,) send TS 14

27 Exposed terminal problem send RTS(,) ready to tx send TS 14

28 Exposed terminal problem send RTS(,) ready to tx send TS send RTS(, ) ready to tx 14

29 Exposed terminal problem send RTS(,) ready to tx send TS send RTS(, ) ready to tx send TS ready to tx 14

30 Exposed terminal problem send RTS(,) ready to tx send TS send RTS(, ) ready to tx send TS ready to tx ready to tx 14

31 WLN technology Protocol soup: Local wireless networks WLN WiFi a h i/e/ /w b g Goals: seamless operation leverage on existing wired infrastructure low-power operation on stations Two architectures: infrastructure + ad-hoc 15

32 802.11: rchitecture of an infrastructure network ST 1 ESS SS LN ccess Point istribution System SS 2 ccess Point 802.x LN Portal ST LN ST 3 Station (ST) terminal with wireless access mechanisms to contact the access point asic Service Set (SS) group of stations using the same radio frequency ccess Point station integrated into the wireless LN and the distribution system Portal bridge to other (wired) networks istribution System interconnection network to/form one logical network 16

33 802.11: rchitecture of an ad-hoc network SS 1 ST LN ST 3 irect communication within a limited range Station (ST): terminal with access mechanisms to the wireless medium Independent asic Service Set (ISS): group of stations using the same radio frequency When no direct link is feasible between two station, a third station may act as a relay (multihop communications) ST LN 17

34 802.11b - istributed oordination Function Exponential back-off hosen for uniformly from (0, W-1), W increase exponentially with the number of failed attempts Wmin minimum contention window Wmax = 2 m Wmin maximum contention window 18

35 802.11b - istributed oordination Function Message resent when the backoff counter reaches zero ackoff counter decremented only when the channel is idle ackoff counter is reset to zero after a successful transmission 19

36 Routing Routing consists of two fundamental steps Forwarding packets to the next hop (from an input interface to an output interface in a traditional wired network) etermining how to forward packets (building a routing table or specifying a route) Forwarding packets is easy, but knowing where to forward packets (especially efficiently) is hard Reach the destination Minimize the number of hops (path length) Minimize delay Minimize packet loss Minimize cost 20

37 Routing ecision Point Source routing Sender determines a route and specifies it in the packet header Hop-by-hop (datagram) routing routing decision is made at each forwarding point (at each router) Standard routing scheme for IP Virtual circuit routing etermine and configure a path prior to sending first packet Used in TM (and analogous to voice telephone system) 21

38 Routing Table routing table contains information to determine how to forward packets Source routing: Routing table is used to determine route to the destination to be specified in the packet Hop-by-hop routing: Routing table is used to determine the next hop for a given destination Virtual circuit routing: Routing table used to determine path to configure through the network 22

39 Routing pproaches Reactive (On-demand) protocols discover routes when needed source-initiated route discovery Proactive protocols traditional distributed shortest-path protocols based on periodic updates. High routing overhead Tradeoff state maintenance traffic vs. route discovery traffic route via maintained route vs. delay for route discovery

40 istance Vector lgorithms (1) istance of each link in the network is a metric that is to be minimized each link may have distance 1 to minimize hop count algorithm attempts to minimize distance The routing table at each node specifies the next hop for each destination specifies the distance to that destination Neighbors can exchange routing table information to find a route (or a better route) to a destination 24

41 istance Vector lgorithms (2) est Next Metric est Next Metric est Next Metric est Next Metric

42 istance Vector lgorithms (3) Node will learn of Node s shorter path to Node and update its routing table est Next Metric est Next Metric

43 Reactive Routing Source initiated Source floods the network with a route request packet when a route is required to a destination flood is propagated outwards from the source pure flooding = every node transmits the request only once estination replies to request reply uses reversed path of route request sets up the forward path 27

44 Route iscovery RREQ FORMT G Initiator Initiator seq # estination I Partial Route E H -- Route Request (RREQ) F -- Route Reply (RREP) 28

45 Route iscovery RREQ FORMT G Initiator Initiator seq # estination I Partial Route -- E H Route Request (RREQ) F -- Route Reply (RREP) 28

46 Route iscovery RREQ FORMT - G Initiator Initiator seq # estination I Partial Route -- E H Route Request (RREQ) F -- Route Reply (RREP) 28

47 Route iscovery RREQ FORMT - G Initiator Initiator seq # estination I Partial Route -- E H Route Request (RREQ) - -- F Route Reply (RREP) 28

48 Route iscovery RREQ FORMT - G Initiator Initiator seq # estination I Partial Route --E -- - E --E --E H Route Request (RREQ) -- F Route Reply (RREP) 28

49 Route iscovery RREQ FORMT - -- G Initiator Initiator seq # estination I Partial Route --E -- - E --E --E H Route Request (RREQ) -- F Route Reply (RREP) 28

50 Route iscovery RREQ FORMT - --E -- G --E-H Initiator Initiator seq # estination I Partial Route -- - E --E --E H Route Request (RREQ) -- F Route Reply (RREP) 28

51 Route iscovery RREQ FORMT ---G - ---G ---G --E -- G --E-H Initiator Initiator seq # estination I Partial Route -- - E --E --E H Route Request (RREQ) -- F Route Reply (RREP) 28

52 Route iscovery: at source need to send to G Lookup ache for route to G Start Route iscovery Protocol wait uffer packet ontinue normal processing yes no Route found? yes Write route in packet header Route iscovery finished Packet in buffer? no done Send packet to next-hop 29

53 Route iscovery: t an intermediate node ccept route request packet <src,id> in recent requests list? yes iscard route request no ppend myddr to partial route Store <src,id> in list no Host already in partial route no myddr =target Send route reply packet yes iscard route request roadcast packet done 30

54 Route iscovery Route Reply message containing path information is sent back to the source either by the destination, or intermediate nodes that have a route to the destination reverse the order of the route record, and include it in Route Reply. unicast, source routing Each node maintains a Route ache which records routes it has learned and overheard over time 31

55 Route Maintenance Route maintenance performed only while route is in use Error detection: monitors the validity of existing routes by passively listening to data packets transmitted at neighboring nodes When problem detected, send Route Error packet to original sender to perform new route discovery Host detects the error and the host it was attempting; Route Error is sent back to the sender the packet original src 32

Review of Networking Concepts. Part 1: Switching Networks

Review of Networking Concepts. Part 1: Switching Networks Review of Networking oncepts Part 1: Switching Networks The first few lectures of this course cover basic, but important, concepts of computer networking Summary of Topics Taxonomy of switching networks

More information

Advanced Computer Networks

Advanced Computer Networks Introduction to Mobile Ad hoc Networks (MANETs) Advanced Computer Networks Outline Ad hoc networks Differences to other networks Applications Research areas Routing Other research areas Enabling Technologies

More information

CSMA/CA. Information Networks p. 1

CSMA/CA. Information Networks p. 1 Information Networks p. 1 CSMA/CA IEEE 802.11 standard for WLAN defines a distributed coordination function (DCF) for sharing access to the medium based on the CSMA/CA protocol Collision detection is not

More information

6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches?

6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches? TUTORIAL 2 (EKT 332) 6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches? Why broadcast network? -The computers in a LAN are separated by a short

More information

Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks - III

Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks - III Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks - III CS: 647 Advanced Topics in Wireless Networks Drs. Baruch Awerbuch & Amitabh Mishra Department of Computer Science Johns Hopkins

More information

Star topology. Ethernet. Ethernet Frame Structure (more) Ethernet Frame Structure. Ethernet uses CSMA/CD. Unreliable, connectionless service

Star topology. Ethernet. Ethernet Frame Structure (more) Ethernet Frame Structure. Ethernet uses CSMA/CD. Unreliable, connectionless service thernet dominant wired LN technology: cheap $0 for 00Mbs! first widely used LN technology Simpler, cheaper than token LNs and TM Kept up with speed race: 0 Mbps 0 bps Star topology us topology popular

More information

MAC Addresses and ARP. Mac Addressing, Ethernet, and Interconnections. LAN Addresses and ARP. LAN Address (more) ARP protocol: Same LAN (network)

MAC Addresses and ARP. Mac Addressing, Ethernet, and Interconnections. LAN Addresses and ARP. LAN Address (more) ARP protocol: Same LAN (network) M ddresses and RP Mac ddressing, thernet, and Interconnections 32-bit IP address: network-layer address used to get datagram to destination IP subnet M (or LN or physical or thernet) address: used to get

More information

A Comparison Study of Qos Using Different Routing Algorithms In Mobile Ad Hoc Networks

A Comparison Study of Qos Using Different Routing Algorithms In Mobile Ad Hoc Networks A Comparison Study of Qos Using Different Routing Algorithms In Mobile Ad Hoc Networks T.Chandrasekhar 1, J.S.Chakravarthi 2, K.Sravya 3 Professor, Dept. of Electronics and Communication Engg., GIET Engg.

More information

Infrastructure Components: Hub & Repeater. Network Infrastructure. Switch: Realization. Infrastructure Components: Switch

Infrastructure Components: Hub & Repeater. Network Infrastructure. Switch: Realization. Infrastructure Components: Switch Network Infrastructure or building computer networks more complex than e.g. a short bus, some additional components are needed. They can be arranged hierarchically regarding their functionality: Repeater

More information

Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc

Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc (International Journal of Computer Science & Management Studies) Vol. 17, Issue 01 Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc Dr. Khalid Hamid Bilal Khartoum, Sudan dr.khalidbilal@hotmail.com

More information

Lecture 12: Computer Networks Review

Lecture 12: Computer Networks Review Lecture : omputer s Review Yuan Xue Suppose you want to build a computer network. What technologies would serve as the underlying building blocks, what kind of software architecture would you design to

More information

Behavior Analysis of TCP Traffic in Mobile Ad Hoc Network using Reactive Routing Protocols

Behavior Analysis of TCP Traffic in Mobile Ad Hoc Network using Reactive Routing Protocols Behavior Analysis of TCP Traffic in Mobile Ad Hoc Network using Reactive Routing Protocols Purvi N. Ramanuj Department of Computer Engineering L.D. College of Engineering Ahmedabad Hiteishi M. Diwanji

More information

Lecture 2.1 : The Distributed Bellman-Ford Algorithm. Lecture 2.2 : The Destination Sequenced Distance Vector (DSDV) protocol

Lecture 2.1 : The Distributed Bellman-Ford Algorithm. Lecture 2.2 : The Destination Sequenced Distance Vector (DSDV) protocol Lecture 2 : The DSDV Protocol Lecture 2.1 : The Distributed Bellman-Ford Algorithm Lecture 2.2 : The Destination Sequenced Distance Vector (DSDV) protocol The Routing Problem S S D D The routing problem

More information

DSR: The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks

DSR: The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks DSR: The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks David B. Johnson David A. Maltz Josh Broch Computer Science Department Carnegie Mellon University Pittsburgh, PA 15213-3891

More information

Communication Networks Chapter 5. Switching Technology

Communication Networks Chapter 5. Switching Technology Communication Networks Chapter 5. Switching Technology o Circuit Switching o Message Switching o Virtual Circuit / Virtual Connection o Datagram Recapitulation: Telecommunications Network LAN 1 Backbone

More information

Optimization of AODV routing protocol in mobile ad-hoc network by introducing features of the protocol LBAR

Optimization of AODV routing protocol in mobile ad-hoc network by introducing features of the protocol LBAR Optimization of AODV routing protocol in mobile ad-hoc network by introducing features of the protocol LBAR GUIDOUM AMINA University of SIDI BEL ABBES Department of Electronics Communication Networks,

More information

Attenuation (amplitude of the wave loses strength thereby the signal power) Refraction Reflection Shadowing Scattering Diffraction

Attenuation (amplitude of the wave loses strength thereby the signal power) Refraction Reflection Shadowing Scattering Diffraction Wireless Physical Layer Q1. Is it possible to transmit a digital signal, e.g., coded as square wave as used inside a computer, using radio transmission without any loss? Why? It is not possible to transmit

More information

CS263: Wireless Communications and Sensor Networks

CS263: Wireless Communications and Sensor Networks CS263: Wireless Communications and Sensor Networks Matt Welsh Lecture 4: Medium Access Control October 5, 2004 2004 Matt Welsh Harvard University 1 Today's Lecture Medium Access Control Schemes: FDMA TDMA

More information

28 Networks and Communication Protocols

28 Networks and Communication Protocols 113 28 Networks and ommunication Protocols Trend in computer systems: personal computing. Reasons why: ost: economies of scale. lso, avoids large initial investment in timesharing system. Performance:

More information

CS6956: Wireless and Mobile Networks Lecture Notes: 2/11/2015. IEEE 802.11 Wireless Local Area Networks (WLANs)

CS6956: Wireless and Mobile Networks Lecture Notes: 2/11/2015. IEEE 802.11 Wireless Local Area Networks (WLANs) CS6956: Wireless and Mobile Networks Lecture Notes: //05 IEEE 80. Wireless Local Area Networks (WLANs) CSMA/CD Carrier Sense Multi Access/Collision Detection detects collision and retransmits, no acknowledgement,

More information

Multi Channel, Multi Radio

Multi Channel, Multi Radio Multi Channel, Multi Radio Lecture Outline What is multi channel, multi radio Why use multi channel, multi radio? Design Issues in using multi channel, multi radio. Examples of protocols MMAC HMCP Link

More information

An Efficient QoS Routing Protocol for Mobile Ad-Hoc Networks *

An Efficient QoS Routing Protocol for Mobile Ad-Hoc Networks * An Efficient QoS Routing Protocol for Mobile Ad-Hoc Networks * Inwhee Joe College of Information and Communications Hanyang University Seoul, Korea iwj oeshanyang.ac.kr Abstract. To satisfy the user requirements

More information

Local Area Networks (LANs)

Local Area Networks (LANs) Local Area Networks (LANs) Broadcast Networks Multiple Access Protocols Ethernet (IEEE 802.3) Token Ring (IEEE 802.5, FDDI) Introduction So far, we have dealt with switched communication networks. Recall

More information

Medium Access Control (MAC) protocol

Medium Access Control (MAC) protocol Medium Access ontrol (MA) protocol omputers DNS Shared medium Point-to-Point. R R. WLAN AP R LAN. Shared medium AP DNS DNS: Domain Name System Figure 1: Different components of a network The Internet consists

More information

ESSENTIALS. Understanding Ethernet Switches and Routers. April 2011 VOLUME 3 ISSUE 1 A TECHNICAL SUPPLEMENT TO CONTROL NETWORK

ESSENTIALS. Understanding Ethernet Switches and Routers. April 2011 VOLUME 3 ISSUE 1 A TECHNICAL SUPPLEMENT TO CONTROL NETWORK VOLUME 3 ISSUE 1 A TECHNICAL SUPPLEMENT TO CONTROL NETWORK Contemporary Control Systems, Inc. Understanding Ethernet Switches and Routers This extended article was based on a two-part article that was

More information

Telecommunication Systems

Telecommunication Systems PUF-HCM Master Informatics Telecommunication Systems RTEL 1 Team teaching Responsible Team: Email Rami Langar Rami Langar (Courses) Su Tam Nguyen (TD) Rami.Langar@lip6.fr guitar1911@yahoo.com RTEL 2 Organisation

More information

Wide Area Networks. Learning Objectives. LAN and WAN. School of Business Eastern Illinois University. (Week 11, Thursday 3/22/2007)

Wide Area Networks. Learning Objectives. LAN and WAN. School of Business Eastern Illinois University. (Week 11, Thursday 3/22/2007) School of Business Eastern Illinois University Wide Area Networks (Week 11, Thursday 3/22/2007) Abdou Illia, Spring 2007 Learning Objectives 2 Distinguish between LAN and WAN Distinguish between Circuit

More information

Wireless LAN Concepts

Wireless LAN Concepts Wireless LAN Concepts Wireless LAN technology is becoming increasingly popular for a wide variety of applications. After evaluating the technology, most users are convinced of its reliability, satisfied

More information

06/02/ Local & Metropolitan Area Networks. Overview. Medium Access Sublayer (1) ACOE322

06/02/ Local & Metropolitan Area Networks. Overview. Medium Access Sublayer (1) ACOE322 1 Local & Metropolitan Area Networks ACOE322 Lecture 2 Medium Access Control and Logical Link Control 1 Overview The architecture of a LAN is best described in terms of a layering of protocols that organize

More information

Layering. Jingwen Chen Dept. of Electronics and Information Engineering

Layering. Jingwen Chen   Dept. of Electronics and Information Engineering Network Architecture and Layering Jingwen Chen Email: jwchen@hust.edu.cn Web: http://itec.hust.edu.cnhust edu cn Dept. of Electronics and Information Engineering Huazhong University of Science and Technology

More information

802.11 standard. Acknowledgement: Slides borrowed from Richard Y. Yang @ Yale

802.11 standard. Acknowledgement: Slides borrowed from Richard Y. Yang @ 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

CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING

CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING CHAPTER 6 CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING 6.1 INTRODUCTION The technical challenges in WMNs are load balancing, optimal routing, fairness, network auto-configuration and mobility

More information

Security in Ad Hoc Network

Security in Ad Hoc Network Security in Ad Hoc Network Bingwen He Joakim Hägglund Qing Gu Abstract Security in wireless network is becoming more and more important while the using of mobile equipments such as cellular phones or laptops

More information

Dynamic Source Routing in Ad Hoc Wireless Networks

Dynamic Source Routing in Ad Hoc Wireless Networks Dynamic Source Routing in Ad Hoc Wireless Networks David B. Johnson David A. Maltz Computer Science Department Carnegie Mellon University 5000 Forbes Avenue Pittsburgh, PA 15213-3891 dbj@cs.cmu.edu Abstract

More information

IRMA: Integrated Routing and MAC Scheduling in Multihop Wireless Mesh Networks

IRMA: Integrated Routing and MAC Scheduling in Multihop Wireless Mesh Networks IRMA: Integrated Routing and MAC Scheduling in Multihop Wireless Mesh Networks Zhibin Wu, Sachin Ganu and Dipankar Raychaudhuri WINLAB, Rutgers University 2006-11-16 IAB Research Review, Fall 2006 1 Contents

More information

Local Area Networks transmission system private speedy and secure kilometres shared transmission medium hardware & software

Local Area Networks transmission system private speedy and secure kilometres shared transmission medium hardware & software Local Area What s a LAN? A transmission system, usually private owned, very speedy and secure, covering a geographical area in the range of kilometres, comprising a shared transmission medium and a set

More information

William Stallings Data and Computer Communications. Chapter 15 Internetwork Protocols

William Stallings Data and Computer Communications. Chapter 15 Internetwork Protocols William Stallings Data and Computer Communications Chapter 15 Internetwork Protocols Internetworking Terms (1) Communications Network Facility that provides data transfer service An internet Collection

More information

CSE331: Introduction to Networks and Security. Lecture 6 Fall 2006

CSE331: Introduction to Networks and Security. Lecture 6 Fall 2006 CSE331: Introduction to Networks and Security Lecture 6 Fall 2006 Open Systems Interconnection (OSI) End Host Application Reference model not actual implementation. Transmits messages (e.g. FTP or HTTP)

More information

Study And Comparison Of Mobile Ad-Hoc Networks Using Ant Colony Optimization

Study And Comparison Of Mobile Ad-Hoc Networks Using Ant Colony Optimization Study And Comparison Of Mobile Ad-Hoc Networks Using Ant Colony Optimization 1 Neha Ujala Tirkey, 2 Navendu Nitin, 3 Neelesh Agrawal, 4 Arvind Kumar Jaiswal 1 M. Tech student, 2&3 Assistant Professor,

More information

Introduction to Local Area Networks

Introduction to Local Area Networks For Summer Training on Computer Networking visit Introduction to Local Area Networks Prepared by : Swapan Purkait Director Nettech Private Limited swapan@nettech.in + 91 93315 90003 Introduction A local

More information

Ethernet. Ethernet Frame Structure. Ethernet Frame Structure (more) Ethernet: uses CSMA/CD

Ethernet. Ethernet Frame Structure. Ethernet Frame Structure (more) Ethernet: uses CSMA/CD Ethernet dominant LAN technology: cheap -- $20 for 100Mbs! first widely used LAN technology Simpler, cheaper than token rings and ATM Kept up with speed race: 10, 100, 1000 Mbps Metcalfe s Etheret sketch

More information

Data Communications & Computer Networks. Circuit and Packet Switching

Data Communications & Computer Networks. Circuit and Packet Switching Data Communications & Computer Networks Chapter 9 Circuit and Packet Switching Fall 2008 Agenda Preface Circuit Switching Softswitching Packet Switching Home Exercises ACOE312 Circuit and packet switching

More information

MEDIA ACCESS CONTROL

MEDIA ACCESS CONTROL MEDIA ACCESS CONTROL Random Access & Token Rings 18 The Data Link Layer Simplest way to create a network of nodes Ø Connect the nodes directly with a physical medium Point-to-point links: Ø Choice of Media

More information

DIN 2012 Tutorial. physical links between primary and secondary stations: Synchronous Connection Oriented (SCO); Asynchronous Connection Link (ACL).

DIN 2012 Tutorial. physical links between primary and secondary stations: Synchronous Connection Oriented (SCO); Asynchronous Connection Link (ACL). DIN 2012 Tutorial (Q1a) In the IEEE 802.15 standard (Bluetooth), describe the following two types of : physical links between primary and secondary stations: (i) (ii) Synchronous Connection Oriented (SCO);

More information

ECE 358: Computer Networks. Homework #3. Chapter 5 and 6 Review Questions 1

ECE 358: Computer Networks. Homework #3. Chapter 5 and 6 Review Questions 1 ECE 358: Computer Networks Homework #3 Chapter 5 and 6 Review Questions 1 Chapter 5: The Link Layer P26. Let's consider the operation of a learning switch in the context of a network in which 6 nodes labeled

More information

ssumathy@vit.ac.in upendra_mcs2@yahoo.com

ssumathy@vit.ac.in upendra_mcs2@yahoo.com S. Sumathy 1 and B.Upendra Kumar 2 1 School of Computing Sciences, VIT University, Vellore-632 014, Tamilnadu, India ssumathy@vit.ac.in 2 School of Computing Sciences, VIT University, Vellore-632 014,

More information

Introduction to Metropolitan Area Networks and Wide Area Networks

Introduction to Metropolitan Area Networks and Wide Area Networks Introduction to Metropolitan Area Networks and Wide Area Networks Chapter 9 Learning Objectives After reading this chapter, you should be able to: Distinguish local area networks, metropolitan area networks,

More information

Formal Measure of the Effect of MANET size over the Performance of Various Routing Protocols

Formal Measure of the Effect of MANET size over the Performance of Various Routing Protocols Formal Measure of the Effect of MANET size over the Performance of Various Routing Protocols Er. Pooja Kamboj Research Scholar, CSE Department Guru Nanak Dev Engineering College, Ludhiana (Punjab) Er.

More information

LAN Switching. 15-441 Computer Networking. Switched Network Advantages. Hubs (more) Hubs. Bridges/Switches, 802.11, PPP. Interconnecting LANs

LAN Switching. 15-441 Computer Networking. Switched Network Advantages. Hubs (more) Hubs. Bridges/Switches, 802.11, PPP. Interconnecting LANs LAN Switching 15-441 Computer Networking Bridges/Switches, 802.11, PPP Extend reach of a single shared medium Connect two or more segments by copying data frames between them Switches only copy data when

More information

Ad hoc On Demand Distance Vector (AODV) Routing Protocol

Ad hoc On Demand Distance Vector (AODV) Routing Protocol Ad hoc On Demand Distance Vector (AODV) Routing Protocol CS: 647 Advanced Topics in Wireless Networks Dr. Baruch Awerbuch & Dr. Amitabh Mishra Department of Computer Science Johns Hopkins 4-1 Reading Chapter

More information

Final for ECE374 05/06/13 Solution!!

Final for ECE374 05/06/13 Solution!! 1 Final for ECE374 05/06/13 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam taker -

More information

Final Exam. Route Computation: One reason why link state routing is preferable to distance vector style routing.

Final Exam. Route Computation: One reason why link state routing is preferable to distance vector style routing. UCSD CSE CS 123 Final Exam Computer Networks Directions: Write your name on the exam. Write something for every question. You will get some points if you attempt a solution but nothing for a blank sheet

More information

Chapter 2 Network Devices

Chapter 2 Network Devices Chapter 2 Network Devices Objectives Explain the uses, advantages, and disadvantages of repeaters, hubs, wireless access points, bridges, switches, and routers Define the standards associated with wireless

More information

Fast and Secure Data Transmission by Using Hybrid Protocols in Mobile Ad Hoc Network

Fast and Secure Data Transmission by Using Hybrid Protocols in Mobile Ad Hoc Network Middle-East Journal of Scientific Research 15 (9): 1290-1294, 2013 ISSN 1990-9233 IDOSI Publications, 2013 DOI: 10.5829/idosi.mejsr.2013.15.9.11514 Fast and Secure Data Transmission by Using Hybrid Protocols

More information

ECE 333: Introduction to Communication Networks Fall 2001

ECE 333: Introduction to Communication Networks Fall 2001 ECE 333: Introduction to Communication Networks Fall 2001 Lecture 17: Medium Access Control V Perfectly scheduled approaches Token ring networks 1 We have categorized channel allocation techniques as either

More information

Multiple Access Techniques PROF. MICHAEL TSAI 2011/12/8

Multiple Access Techniques PROF. MICHAEL TSAI 2011/12/8 Multiple Access Techniques PROF. MICHAEL TSAI 2011/12/8 Multiple Access Scheme Allow many users to share simultaneously a finite amount of radio spectrum Need to be done without severe degradation of the

More information

Switches and Bridges. COS 461: Computer Networks Spring 2009 (MW 1:30-2:50 in COS 105) Guest Lecture Jennifer Rexford 1

Switches and Bridges. COS 461: Computer Networks Spring 2009 (MW 1:30-2:50 in COS 105) Guest Lecture Jennifer Rexford 1 Switches and Bridges COS 461: Computer Networks Spring 2009 (MW 1:30-2:50 in COS 105) Guest Lecture Jennifer Rexford 1 Goals of Todayʼs Lecture Devices that shuttle data at different layers Repeaters and

More information

RT-QoS for Wireless ad-hoc Networks of Embedded Systems

RT-QoS for Wireless ad-hoc Networks of Embedded Systems RT-QoS for Wireless ad-hoc Networks of Embedded Systems Marco accamo University of Illinois Urbana-hampaign 1 Outline Wireless RT-QoS: important MA attributes and faced challenges Some new ideas and results

More information

APPENDIX 1 USER LEVEL IMPLEMENTATION OF PPATPAN IN LINUX SYSTEM

APPENDIX 1 USER LEVEL IMPLEMENTATION OF PPATPAN IN LINUX SYSTEM 152 APPENDIX 1 USER LEVEL IMPLEMENTATION OF PPATPAN IN LINUX SYSTEM A1.1 INTRODUCTION PPATPAN is implemented in a test bed with five Linux system arranged in a multihop topology. The system is implemented

More information

ALOHA Class of Multiple Access Protocols

ALOHA Class of Multiple Access Protocols ALOHA Class of Multiple Access Protocols ALOHA, also called pure ALOHA: Whenever a user has a frame to send, it simply transmits the frame. If collision occurs, it waits for a random period of time and

More information

Express Forwarding : A Distributed QoS MAC Protocol for Wireless Mesh

Express Forwarding : A Distributed QoS MAC Protocol for Wireless Mesh Express Forwarding : A Distributed QoS MAC Protocol for Wireless Mesh, Ph.D. benveniste@ieee.org Mesh 2008, Cap Esterel, France 1 Abstract Abundant hidden node collisions and correlated channel access

More information

EEC-484/584 Computer Networks

EEC-484/584 Computer Networks EEC-484/584 Computer Networks Lecture 8 wenbing@ieee.org (Lecture nodes are based on materials supplied by Dr. Louise Moser at UCSB and Prentice-Hall) Outline 2 Homework #1 Review Protocol verification

More information

MPLS. Packet switching vs. circuit switching Virtual circuits

MPLS. Packet switching vs. circuit switching Virtual circuits MPLS Circuit switching Packet switching vs. circuit switching Virtual circuits MPLS Labels and label-switching Forwarding Equivalence Classes Label distribution MPLS applications Packet switching vs. circuit

More information

Transport Layer Protocols

Transport Layer Protocols Transport Layer Protocols Version. Transport layer performs two main tasks for the application layer by using the network layer. It provides end to end communication between two applications, and implements

More information

COMP 631: COMPUTER NETWORKS. Internet Routing. Jasleen Kaur. Fall 2014. Forwarding vs. Routing: Local vs. Distributed

COMP 631: COMPUTER NETWORKS. Internet Routing. Jasleen Kaur. Fall 2014. Forwarding vs. Routing: Local vs. Distributed OMP 3: OMPUTER NETWORKS // OMP 3: OMPUTER NETWORKS Internet Routing Jasleen Kaur Fall 0 Forwarding vs. Routing: Local vs. istributed oth datagram and virtual-circuit based networks need to know how to

More information

Routing in packet-switching networks

Routing in packet-switching networks Routing in packet-switching networks Circuit switching vs. Packet switching Most of WANs based on circuit or packet switching Circuit switching designed for voice Resources dedicated to a particular call

More information

Edges = communication links Vertices = computers, switches, routers, etc. For packet inbound at a particular vertex, determine what output edge to use

Edges = communication links Vertices = computers, switches, routers, etc. For packet inbound at a particular vertex, determine what output edge to use IP Routing Networks as Graphs Networks are graphs Edges = communication links Vertices = computers, switches, routers, etc For packet inbound at a particular vertex, determine what output edge to use Routers

More information

Multiplexing, Circuit Switching and Packet Switching. Circuit Switching

Multiplexing, Circuit Switching and Packet Switching. Circuit Switching Multiplexing, Circuit Switching and Packet Switching Circuit Switching Old telephone technology For each connection, physical switches are set in the telephone network to create a physical circuit That

More information

Achieving Energy Efficiency in MANETs by Using Load Balancing Approach

Achieving Energy Efficiency in MANETs by Using Load Balancing Approach International Journal of Computer Networks and Communications Security VOL. 3, NO. 3, MARCH 2015, 88 94 Available online at: www.ijcncs.org E-ISSN 2308-9830 (Online) / ISSN 2410-0595 (Print) Achieving

More information

EECS 122: Introduction to Computer Networks Multiaccess Protocols. ISO OSI Reference Model for Layers

EECS 122: Introduction to Computer Networks Multiaccess Protocols. ISO OSI Reference Model for Layers EECS 122: Introduction to Computer Networks Multiaccess Protocols Computer Science Division Department of Electrical Engineering and Computer Sciences University of California, Berkeley Berkeley, CA 94720-1776

More information

Introduction to LAN Protocols

Introduction to LAN Protocols CHAPTER 2 Chapter Goals Learn about different LAN protocols. Understand the different methods used to deal with media contention. Learn about different LAN topologies. This chapter introduces the various

More information

DESIGN AND DEVELOPMENT OF LOAD SHARING MULTIPATH ROUTING PROTCOL FOR MOBILE AD HOC NETWORKS

DESIGN AND DEVELOPMENT OF LOAD SHARING MULTIPATH ROUTING PROTCOL FOR MOBILE AD HOC NETWORKS DESIGN AND DEVELOPMENT OF LOAD SHARING MULTIPATH ROUTING PROTCOL FOR MOBILE AD HOC NETWORKS K.V. Narayanaswamy 1, C.H. Subbarao 2 1 Professor, Head Division of TLL, MSRUAS, Bangalore, INDIA, 2 Associate

More information

INTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND TECHNOLOGY

INTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND TECHNOLOGY INTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND TECHNOLOGY A PATH FOR HORIZING YOUR INNOVATIVE WORK AN OVERVIEW OF MOBILE ADHOC NETWORK: INTRUSION DETECTION, TYPES OF ATTACKS AND

More information

Communication Networks. MAP-TELE 2011/12 José Ruela

Communication Networks. MAP-TELE 2011/12 José Ruela Communication Networks MAP-TELE 2011/12 José Ruela Network basic mechanisms Introduction to Communications Networks Communications networks Communications networks are used to transport information (data)

More information

CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012

CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012 CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012 Important: The solutions to the homework problems from the course book have been provided by the authors.

More information

III. Our Proposal ASOP ROUTING ALGORITHM. A.Position Management

III. Our Proposal ASOP ROUTING ALGORITHM. A.Position Management Secured On-Demand Position Based Private Routing Protocol for Ad-Hoc Networks Ramya.R, Shobana.K, Thangam.V.S ramya_88@yahoo.com, k shobsi@yahoo.co.in,thangam_85@yahoo.com Department of Computer Science,

More information

Wireless Networks. Reading: Sec5on 2.8. COS 461: Computer Networks Spring 2011. Mike Freedman

Wireless Networks. Reading: Sec5on 2.8. COS 461: Computer Networks Spring 2011. Mike Freedman 1 Wireless Networks Reading: Sec5on 2.8 COS 461: Computer Networks Spring 2011 Mike Freedman hep://www.cs.princeton.edu/courses/archive/spring11/cos461/ 2 Widespread Deployment Worldwide cellular subscribers

More information

Medium Access Sublayer

Medium Access Sublayer Medium Access Sublayer Topology of the Network Bus, Ring, Tree Protocols IEEE 802.3 for bus topology IEEE 802.4 for token bus IEEE 802.5 for token ring FDDI for fibre ring IEEE 802.11 for wireless networks

More information

ECE/CS 372 introduction to computer networks. Lecture 13

ECE/CS 372 introduction to computer networks. Lecture 13 ECE/CS 372 introduction to computer networks Lecture 13 Announcements: HW #4 hard copy due today Lab #5 posted is due Tuesday June 4 th HW #5 posted is due Thursday June 6 th Pickup midterms Acknowledgement:

More information

m p k A E N 1..N 6 A E k = 5m, 1m, 15m, 2m Φ Φ minbe Operating Mode Current (mah) ATMega1281V, full operation 6 (7.37 MHz) ATMega1281V, sleep.1 Radio, receive 16 Radio, transmit (1 mw

More information

SIMULATION STUDY OF BLACKHOLE ATTACK IN THE MOBILE AD HOC NETWORKS

SIMULATION STUDY OF BLACKHOLE ATTACK IN THE MOBILE AD HOC NETWORKS Journal of Engineering Science and Technology Vol. 4, No. 2 (2009) 243-250 School of Engineering, Taylor s University College SIMULATION STUDY OF BLACKHOLE ATTACK IN THE MOBILE AD HOC NETWORKS SHEENU SHARMA

More information

Chapter 8 Directional and Smart Antennas

Chapter 8 Directional and Smart Antennas Chapter 8 Directional and Smart Antennas Prof. Yuh-Shyan Chen Department of Computer Science and Information Engineering National Taipei University Dec. 2007 Advanced Techniques of Mobile Ad Hoc and Wireless

More information

PERFORMANCE OF MOBILE AD HOC NETWORKING ROUTING PROTOCOLS IN REALISTIC SCENARIOS

PERFORMANCE OF MOBILE AD HOC NETWORKING ROUTING PROTOCOLS IN REALISTIC SCENARIOS PERFORMANCE OF MOBILE AD HOC NETWORKING ROUTING PROTOCOLS IN REALISTIC SCENARIOS Julian Hsu, Sameer Bhatia, Mineo Takai, Rajive Bagrodia, Scalable Network Technologies, Inc., Culver City, CA, and Michael

More information

Local & Metropolitan Area Networks

Local & Metropolitan Area Networks Local & Metropolitan Area Networks CS455 Yonshik Choi, Ph.D. Department of Computer Science Illinois Institute of Technology Rice Campus Local Area Networks Characteristic Smaller geographical area a

More information

PEDAMACS: Power efficient and delay aware medium access protocol for sensor networks

PEDAMACS: Power efficient and delay aware medium access protocol for sensor networks PEDAMACS: Power efficient and delay aware medium access protocol for sensor networks Sinem Coleri and Pravin Varaiya Department of Electrical Engineering and Computer Science University of California,

More information

Lecture 17: 802.11 Wireless Networking"

Lecture 17: 802.11 Wireless Networking Lecture 17: 802.11 Wireless Networking" CSE 222A: Computer Communication Networks Alex C. Snoeren Thanks: Lili Qiu, Nitin Vaidya Lecture 17 Overview" Project discussion Intro to 802.11 WiFi Jigsaw discussion

More information

Real-Time Traffic Support in Heterogeneous Mobile Networks

Real-Time Traffic Support in Heterogeneous Mobile Networks Real-Time Traffic Support in Heterogeneous Mobile Networks Yuan Sun Elizabeth M. Belding-Royer Department of Computer Science University of California, Santa Barbara {suny, ebelding}@cs.ucsb.edu Xia Gao

More information

July 13, Copyright 2015 Thread Group, Inc. All rights reserved.

July 13, Copyright 2015 Thread Group, Inc. All rights reserved. July 13, 2015 This Thread Technical white paper is provided for reference purposes only. The full technical specification is available to Thread Group Members. To join and gain access, please follow this

More information

College 5, Routing, Internet. Host A. Host B. The Network Layer: functions

College 5, Routing, Internet. Host A. Host B. The Network Layer: functions CSN-s 5/1 College 5, Routing, Internet College stof 1 Inleiding: geschiedenis, OSI model, standaarden, ISOC/IETF/IRTF structuur Secties: 1.2, 1.3, 1.4, 1.5 2 Fysieke laag: Bandbreedte/bitrate Secties:

More information

Wiereless LAN 802.11

Wiereless LAN 802.11 Tomasz Kurzawa Wiereless LAN 802.11 Introduction The 802.11 Architecture Channels and Associations The 802.11 MAC Protocol The 802.11 Frame Introduction Wireless LANs are most important access networks

More information

4. MAC protocols and LANs

4. MAC protocols and LANs 4. MAC protocols and LANs 1 Outline MAC protocols and sublayers, LANs: Ethernet, Token ring and Token bus Logic Link Control (LLC) sublayer protocol Bridges: transparent (spanning tree), source routing

More information

CHAPTER 8 CONCLUSION AND FUTURE ENHANCEMENTS

CHAPTER 8 CONCLUSION AND FUTURE ENHANCEMENTS 137 CHAPTER 8 CONCLUSION AND FUTURE ENHANCEMENTS 8.1 CONCLUSION In this thesis, efficient schemes have been designed and analyzed to control congestion and distribute the load in the routing process of

More information

Enhanced Power Saving for IEEE 802.11 WLAN with Dynamic Slot Allocation

Enhanced Power Saving for IEEE 802.11 WLAN with Dynamic Slot Allocation Enhanced Power Saving for IEEE 802.11 WLAN with Dynamic Slot Allocation Changsu Suh, Young-Bae Ko, and Jai-Hoon Kim Graduate School of Information and Communication, Ajou University, Republic of Korea

More information

802.11. Markku Renfors. Partly based on student presentation by: Lukasz Kondrad Tomasz Augustynowicz Jaroslaw Lacki Jakub Jakubiak

802.11. Markku Renfors. Partly based on student presentation by: Lukasz Kondrad Tomasz Augustynowicz Jaroslaw Lacki Jakub Jakubiak 802.11 Markku Renfors Partly based on student presentation by: Lukasz Kondrad Tomasz Augustynowicz Jaroslaw Lacki Jakub Jakubiak Contents 802.11 Overview & Architecture 802.11 MAC 802.11 Overview and Architecture

More information

CMPT 165: The Internet, Part 3

CMPT 165: The Internet, Part 3 CMPT 165: The Internet, Part 3 Tamara Smyth, tamaras@cs.sfu.ca School of Computing Science, Simon Fraser University September 15, 2011 1 Basic Communication Technology Packet Switching (sharing a tranmission

More information

The Wireless Network Road Trip

The Wireless Network Road Trip The Wireless Network Road Trip The Association Process To begin, you need a network. This lecture uses the common logical topology seen in Figure 9-1. As you can see, multiple wireless clients are in

More information

IEEE P Wireless Personal Area Networks

IEEE P Wireless Personal Area Networks IEEE P802.15 Wireless Personal Area Networks Project Title Date Submitted Source Re: Abstract Purpose Notice IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Managing the performance

More information

Second Midterm for ECE374 04/16/12 Solution!!

Second Midterm for ECE374 04/16/12 Solution!! ECE374: Second Midterm 1 Second Midterm for ECE374 04/16/12 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the

More information

Scenario based Performance Analysis of AODV and OLSR in Mobile Ad hoc Networks

Scenario based Performance Analysis of AODV and OLSR in Mobile Ad hoc Networks Scenario based Performance Analysis of AODV and OLSR in Mobile Ad hoc Networks Scenario based Performance Analysis of AODV and OLSR in Mobile Ad hoc Networks S. Gowrishankar, T.G. Basavaraju, M. Singh,

More information

EETS 8316 Wireless Networks Fall 2013

EETS 8316 Wireless Networks Fall 2013 EETS 8316 Wireless Networks Fall 2013 Lecture: WiFi Discovery, Powersave, and Beaconing http://lyle.smu.edu/~skangude/eets8316.html Shantanu Kangude skangude@lyle.smu.edu Discovery and Beaconing Discovery?

More information