CMPE 257: Wireless and Mobile Networking
|
|
|
- Henry Snow
- 5 years ago
- Views:
Transcription
1 CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 3 CMPE 257 Spring'15 1
2 Next week Announcements April 14: ICN (Spencer Sevilla) April 16: DTN (Aloizio Silva) Projects Project ideas Project proposal Student presentations Class calendar updated CMPE 257 Spring'15 2
3 Today Medium access control (MAC). CMPE 257 Spring'15 3
4 Medium Access Control MAC protocols. Aka, multiple access protocols. CMPE 257 Spring'15 4
5 When do we need MAC? 2 types of links: Point-to-point. Shared. shared wire (e.g., cabled Ethernet) shared RF (e.g., WiFi) shared RF (satellite) humans at a cocktail party (shared air, acoustical) CMPE 257 Spring'15 5
6 Shared Links If more than 1 node transmits at the same time: Collision at receiver! MAC protocol: Arbitrate access to medium. Determine who can transmit when. CMPE 257 Spring'15 6
7 Expanded Data Link Layer Sublayers of data link layer: Logical Link Control (LLC): framing, flow and error control. Medium Access Control (MAC): multiple access resolution. CMPE 257 Spring'15 7
8 Types of MAC Who makes decision? Centralized versus distributed MACs. Channel access policy. CMPE 257 Spring'15 8
9 Types of MAC Channel Access Policy Random access (or contention-based) No scheduled time for transmissions. No order for transmissions. Controlled access Stations coordinate access to channel. Station only transmits when it has right to send. Channelization (channel partitioning) Bandwidth of channel is statically partitioned. CMPE 257 Spring'15 9
10 Another way to look at it Control: Distributed. Centralized. How they coordinate access to medium: Round-robin. Scheduled-access. Contention-based. A-priori channel partitioning. CMPE 257 Spring'15 10
11 Contention-Based Protocols Aka, Random-Access MAC: ALOHA Slotted Aloha CSMA CSMA/CD (Ethernet IEEE 802.3) CSMA/CA (WiFi IEEE ) CMPE 257 Spring'15 11
12 CSMA Carrier sense: Stations listen first whether another transmission is in progress. If medium in use, wait. If not, transmit. Can collisions still occur? CMPE 257 Spring'15 12
13 CSMA Variants 1-persistent (IEEE 802.3): If medium idle, transmit. If medium busy, keep listening; when medium idle, transmit with probability 1. p-persistent: Same as above but with probability p. Non-presistent: If medium idle, transmit. If medium busy, wait a random period before retrying. CMPE 257 Spring'15 13
14 CSMA/CD CSMA + collision detection. Performance improvement over CSMA. How? Listen while transmitting. If collision, transmit brief jamming signal and abort transmission. How does this improve performance? Wait random time and try again. CMPE 257 Spring'15 14
15 Collision Avoidance (CA) CSMA/CD assumes stations can detect collision. Not valid in all contexts (e.g., wireless): Attenuation too great to detect collision at all stations. Hard for transmitter to distinguish its own transmission from incoming weak signals and noise. Radios are usually half-duplex ($$$). CSMA/CA tries to avoid collisions. CMPE 257 Spring'15 15
16 CSMA/CA Tries to avoid collisions by avoiding the hidden terminal problem. CMPE 257 Spring'15 16
17 Hidden-Terminal Problem CMPE 257 Spring'15 17
18 Hidden- and Exposed Terminals Hidden Terminals Exposed Terminals CMPE 257 Spring'15 18
19 CSMA/CA: RTS-CTS Solution Channel reservation With collision avoidance, stations exchange small control packets to determine which sender can transmit to a receiver. CMPE 257 Spring'15 19
20 CSMA-CA CSMA/CA means both physical- and virtual carrier sensing. Physical: CS. Virtual: CA. CMPE 257 Spring'15 20
21 How does CSMA-CA work? CMPE 257 Spring'15 21
22 IEEE Provides 2 types of medium access: DCF: distributed coordination function. PCF: point coordination function. DCF is contention-based. PCF is polling-based. Collision free. PCF Implemented atop DCF. DCF CMPE 257 Spring 15 22
23 IEEE DCF Physical carrier sensing: Stations listen to channel before transmitting (CS of CSMA/CA). Virtual carrier sensing: CA OF CSMA/CA. Reserve channel for transmission. Use RTS/CTS handshake. CMPE 257 Spring'15 Spring'12 23
24 IEEE MAC Protocol: CSMA (no sender CA) 1 if sense channel idle for DIFS then transmit entire frame (no CD) 2 if sense channel busy then start random backoff time timer counts down while channel idle transmit when timer expires if no ACK, increase random backoff interval, repeat receiver DIFS sender data ACK receiver SIFS - if frame received OK return ACK after SIFS (ACK needed due to hidden terminal problem) CMPE 257 Spring'15 24
25 IEEE MAC Protocol: CSMA/CA Physical CS + virtual CS. Sense channel for DIFS. RTS/CTS handshake before sending data. RTS is 20 bytes and CTS is 16 bytes. Maximum data frame is 2,346 bytes. Note: This is only for unicast transmissions. Broadcast transmissions do not use virtual carrier sensing. CMPE 257 Spring'15 Spring'12 25
26 CSMA-CA Examples D A C B Scenario: A wants to transmit to C.. A sends RTS.. D defers.. C sends CTS.. B defers. CMPE 257 Spring'15 26
27 IEEE Wireless LAN b GHz unlicensed spectrum up to 11 Mbps direct sequence spread spectrum (DSSS) in physical layer all hosts use same chipping code a 5-6 GHz range up to 54 Mbps g GHz range up to 54 Mbps n: multiple antennae GHz range up to 200 Mbps all use CSMA/CA for multiple access all have base-station and ad-hoc network modes. CMPE 257 Spring'15 27
28 MAC: A Bird s Eye View CMPE 257 Spring'15 28
29 Solutions to Hidden/Exposed Nodes in CSMA Use control packets: RTS/CTS (Request-To-Send/Clear-To-Send) Used by MACA (Multiple Access Control Avoidance) and MACAW (MACA for Wireless LANs). Use both control packets and carrier sense: CSMA/CA, IEEE CMPE 257 Spring'15 29
30 Dynamic Reservation Approaches: Sender- vs. Receiver-initiated Sender-initiated: A node wanting to send data takes the initiative of setting up the reservation. Most existing schemes. Receiver-initiated: A receiving node polls a potential transmitting node for data. A node can send data after being polled. E.g., MACA-By Invitation. CMPE 257 Spring'15 30
31 Single vs. Multiple Channel Protocols Single channel protocols: control and data use the same channel. Multiple channel protocols: separate channels for control & data transmission; data transmission on separate channels. CMPE 257 Spring'15 31
32 Other criteria for classification Power-aware. E.g., PAMAS. Directional or omnidirectional antennas. QoS-aware End-to-end (E2E) delay Packet loss rate (or the probability) Available bandwidth Challenges: lack of centralized control, limited bandwidth, node mobility, power/computational constraints, error-prone nature of wireless media. CMPE 257 Spring'15 32
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.
CMPE 257: Wireless and Mobile Networking
CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 5 CMPE 257 Winter'11 1 Announcements Project proposals. Student presentations. 10 students so
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
Unit 7 Media Access Control (MAC)
Unit 7 Media Access Control (MAC) 1 Internet Model 2 Sublayers of Data Link Layer Logical link control (LLC) Flow control Error control Media access control (MAC) access control 3 Categorization of MAC
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
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
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
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
High Level View. EE 122: Ethernet and Random Access protocols. Medium Access Protocols
High Level View EE 122: Ethernet and 802.11 Ion Stoica September 18, 2002 Goal: share a communication medium among multiple hosts connected to it Problem: arbitrate between connected hosts Solution goals:
CSE 461: Wireless Networks
CSE 461: Wireless Networks Wireless IEEE 802.11 A physical and multiple access layer standard for wireless local area networks (WLAN) Ad Hoc Network: no servers or access points Infrastructure Network
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,
EE 122: Ethernet and
EE 122: Ethernet and 802.11 Ion Stoica September 18, 2002 (* this talk is based in part on the on-line slides of J. Kurose & K. Rose) High Level View Goal: share a communication medium among multiple hosts
CSE 461: Multiple Access Networks. This Lecture
CSE 461: Multiple Access Networks This Lecture Key Focus: How do multiple parties share a wire? This is the Medium Access Control (MAC) portion of the Link Layer Randomized access protocols: 1. Aloha 2.
Mohamed Khedr.
Mohamed Khedr http://webmail.aast.edu/~khedr Tentatively Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12 Week 13 Week 14 Week 15 Overview Packet Switching IP addressing
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
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
Lecture 6. Data Link Layer (cont d) Data Link Layer 1-1
Lecture 6 Data Link Layer (cont d) Data Link Layer 1-1 Agenda Continue the Data Link Layer Multiple Access Links and Protocols Addressing Data Link Layer 1-2 Multiple Access Links and Protocols Two types
Computer Network Fundamentals Spring Week 3 MAC Layer Andreas Terzis
Computer Network Fundamentals Spring 2008 Week 3 MAC Layer Andreas Terzis Outline MAC Protocols MAC Protocol Examples Channel Partitioning TDMA/FDMA Token Ring Random Access Protocols Aloha and Slotted
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
Chapter 12 Multiple Access 12.1
Chapter 12 Multiple Access 12.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12.2 Figure 12.1 Data link layer divided into two functionality-oriented sublayers
Aloha and slotted aloha
CSMA 2/13/06 Aloha and slotted aloha Slotted aloha: transmissions are synchronized and only start at the beginning of a time slot. Aloha sender A sender B collision sender C t Slotted Aloha collision sender
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
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
Chapter 4. The Medium Access Control Sublayer. Points and Questions to Consider. Multiple Access Protocols. The Channel Allocation Problem.
Dynamic Channel Allocation in LANs and MANs Chapter 4 The Medium Access Control Sublayer 1. Station Model. 2. Single Channel Assumption. 3. Collision Assumption. 4. (a) Continuous Time. (b) Slotted Time.
Computer Communication III
Computer Communication III Wireless Media Access IEEE 802.11 Wireless LAN Advantages of Wireless LANs Using the license free ISM band at 2.4 GHz no complicated or expensive licenses necessary very cost
Logical Link Control (LLC) Medium Access Control (MAC)
Overview of IEEE 802.11 Data Link layer Application Presentation Session Transport LLC: On transmission, assemble data into a frame with address and CRC fields. On reception, disassemble frame, perform
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
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
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
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
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
Lecture 16: QoS and "
Lecture 16: QoS and 802.11" CSE 123: Computer Networks Alex C. Snoeren HW 4 due now! Lecture 16 Overview" Network-wide QoS IntServ DifServ 802.11 Wireless CSMA/CA Hidden Terminals RTS/CTS CSE 123 Lecture
CS 348: Computer Networks. - WiFi (contd.); 16 th Aug Instructor: Sridhar Iyer IIT Bombay
CS 348: Computer Networks - WiFi (contd.); 16 th Aug 2012 Instructor: Sridhar Iyer IIT Bombay Clicker-1: Wireless v/s wired Which of the following differences between Wireless and Wired affect a CSMA-based
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
The MAC layer in wireless networks
The MAC layer in wireless networks The wireless MAC layer roles Access control to shared channel(s) Natural broadcast of wireless transmission Collision of signal: a /space problem Who transmits when?
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
MAC. Fall Data Communications II 1
802.11 MAC Fall 2005 91.564 Data Communications II 1 RF Quality (ACK) Fall 2005 91.564 Data Communications II 2 Hidden Terminal (RTS/CTS) Fall 2005 91.564 Data Communications II 3 MAC Coordination Functions
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
CMPE 257: Wireless and Mobile Networking
CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 4 1 Announcements Project proposals. Due April 17 th. Submit by e-mail to katia@soe.ucsc.edu.
Topics. Link Layer Services (more) Link Layer Services LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS. flow control: error detection:
1 Topics 2 LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS Multiple access: CSMA/CD, CSMA/CA, token passing, channelization LAN: characteristics, i basic principles i Protocol architecture Topologies
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
Data Link Layer -2- Network Access
EITF25 Internet: Technology and Applications Data Link Layer -2- Network Access 2015, Lecture 03 Kaan Bür Previously on EITF25 Logical Link Control Sublayer Flow control Send data Wait for ACK Error control
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
ICE 1332/0715 Mobile Computing (Summer, 2008)
ICE 1332/0715 Mobile Computing (Summer, 2008) Medium Access Control Prof. Chansu Yu http://academic.csuohio.edu/yuc/ Simplified Reference Model Application layer Transport layer Network layer Data link
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
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
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
CSE 6811 Ashikur Rahman
Data Link layer Application Overview of IEEE 802.11 LLC: On transmission, assemble data into a frame with address and CRC fields. On reception, disassemble frame, perform address recognition and CRC validation.
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
CS118 Discussion 1A, Week 9. Zengwen Yuan Dodd Hall 78, Friday 10:00 11:50 a.m.
CS118 Discussion 1A, Week 9 Zengwen Yuan Dodd Hall 78, Friday 10:00 11:50 a.m. 1 Outline Wireless: 802.11 Mobile IP Cellular Networks: LTE Sample final 2 Wireless and Mobile Network Wireless access: WIFI
CMPE 150/L : Introduction to Computer Networks. Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 16
CMPE 150/L : Introduction to Computer Networks Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 16 1 Final project demo Please do the demo next week to the TAs. So basically you may need
Wireless MACs: MACAW/802.11
Wireless MACs: MACAW/802.11 Mark Handley UCL Computer Science CS 3035/GZ01 Fundamentals: Spectrum and Capacity A particular radio transmits over some range of frequencies; its bandwidth, in the physical
MAC Sublayer(1) Principal service of the Medium Access Control Sublayer: Allocating a single broadcast channel (mostly a LAN) among competing users
MAC Sublayer(1) Principal service of the Medium Access Control Sublayer: Allocating a single broadcast channel (mostly a LAN) among competing users Static Channel Allocation: Frequency Division Multiplexing
Data Link Layer -2- Network Access
EITF25 Internet: Technology and Applications Data Link Layer -2- Network Access 2013, Lecture 03 Kaan Bür, Stefan Höst Previously on EITF25 Logical Link Control Sublayer Flow control Send data Wait for
Lecture 25: CSE 123: Computer Networks Alex C. Snoeren. HW4 due NOW
Lecture 25: 802.11 CSE 123: Computer Networks Alex C. Snoeren HW4 due NOW Lecture 25 Overview 802.11 Wireless PHY layer overview Hidden Terminals Basic wireless challenge RTS/CTS Virtual carrier sense
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
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)
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
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
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
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
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
IEEE , Token Rings. 10/11/06 CS/ECE UIUC, Fall
IEEE 802.11, Token Rings 10/11/06 CS/ECE 438 - UIUC, Fall 2006 1 Medium Access Control Wireless channel is a shared medium Need access control mechanism to avoid interference Why not CSMA/CD? 10/11/06
Wireless Challenges : Computer Networking. Overview. Routing to Mobile Nodes. Lecture 25: Wireless Networking
Wireless Challenges 15-441: Computer Networking Lecture 25: Wireless Networking Force us to rethink many assumptions Need to share airwaves rather than wire Don t know what hosts are involved Host may
Wireless & Mobile Networking
Wireless & Mobile Networking CS 752/852 - Spring 2011 Lec #3: Medium Access Control - I Tamer Nadeem Dept. of Computer Science Data Link Layer (DLL) Main Task of the data link layer: Provide error-free
Redes de Computadores. Medium Access Control
Redes de Computadores Medium Access Control Manuel P. Ricardo Faculdade de Engenharia da Universidade do Porto 1 » How to control the access of computers to a communication medium?» What is the ideal Medium
IEEE Medium Access Control. Medium Access Control
IEEE 802.11 Medium Access Control EECS3214 3 April 2018 Medium Access Control reliable data delivery access control MAC layer covers three functional areas: security 2 1 MAC Requirements To avoid interference
CSE/EE 461 Wireless and Contention-Free Protocols
CSE/EE 461 Wireless and Contention-Free Protocols Last Time The multi-access problem Medium Access Control (MAC) sublayer Random access protocols: Aloha CSMA variants Classic Ethernet (CSMA/CD) Application
ECEN 5032 Data Networks Medium Access Control Sublayer
ECEN 5032 Data Networks Medium Access Control Sublayer Peter Mathys mathys@colorado.edu University of Colorado, Boulder c 1996 2005, P. Mathys p.1/35 Overview (Sub)networks can be divided into two categories:
The MAC layer in wireless networks
The MAC layer in wireless networks The wireless MAC layer roles Access control to shared channel(s) Natural broadcast of wireless transmission Collision of signal: a time/space problem Who transmits when?
Review. Error Detection: CRC Multiple access protocols. LAN addresses and ARP Ethernet. Slotted ALOHA CSMA/CD
Review Error Detection: CRC Multiple access protocols Slotted ALOHA CSMA/CD LAN addresses and ARP Ethernet Some slides are in courtesy of J. Kurose and K. Ross Overview Ethernet Hubs, bridges, and switches
Multiple Access Technique. Media Access Control (Intro.) Outline. Multiple Access Technique. Designing Issues of MAC protocols. Protocols examples
Wireless Ad Hoc & Sensor Networks Medium Access Control Outline Multiple Access Technique Application Transport Protocol Network Protocol Media Access Protocol Physical Channel (Radio) WS 2010/2011 Prof.
Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks -IV
Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks -IV CS: 647 Advanced Topics in Wireless Networks Drs. Baruch Awerbuch & Amitabh Mishra Department of Computer Science Johns Hopkins University
Wireless Protocols. Training materials for wireless trainers
Wireless Protocols Training materials for wireless trainers Goals The goal of this lecture is to introduce: IEEE wireless protocols coverage 802.11 radio protocols terminology WiFi modes of operation details
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
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
Topics for Today. More on Ethernet. Wireless LANs Readings. Topology and Wiring Switched Ethernet Fast Ethernet Gigabit Ethernet. 4.3 to 4.
Topics for Today More on Ethernet Topology and Wiring Switched Ethernet Fast Ethernet Gigabit Ethernet Wireless LANs Readings 4.3 to 4.4 1 Original Ethernet Wiring Heavy coaxial cable, called thicknet,
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
Lecture 24: CSE 123: Computer Networks Stefan Savage. HW4 due NOW
Lecture 24: 802.11 CSE 123: Computer Networks Stefan Savage HW4 due NOW About the final Similar in style to midterm Some combination of easy questions, short answer and more in-depth questions Sample final
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
Computer Networks. Today. Principles of datalink layer services Multiple access links Adresavimas, ARP LANs Wireless LANs VU MIF CS 1/48 2/48
Computer Networks VU MIF CS 1/48 Today Principles of datalink layer services Multiple access links Adresavimas, ARP LANs Wireless LANs 2/48 1 Link layer: introduction terminology: hosts and routers: nodes
CC451 Computer Networks
CC451 Computer Networks Lecture 9 Link Layer 5: DataLink Layer 5-1 Chapter 5 Link Layer and LANs A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students,
Outline. EEC-484/584 Computer Networks. Multiple Access Protocols. Wireless LAN Protocols. Lecture 9. Wenbing Zhao
EEC-484/584 Computer Networks Lecture 9 wenbing@ieee.org (Lecture nodes are based on materials supplied by Dr. Louise Moser at UCSB and Prentice-Hall) Outline Review Multiple access protocols IEEE 802
EEC-484/584 Computer Networks
EEC-484/584 Computer Networks Lecture 9 wenbing@ieee.org (Lecture nodes are based on materials supplied by Dr. Louise Moser at UCSB and Prentice-Hall) Outline 2 Review Multiple access protocols IEEE 802
Computer Networks. Wireless LANs
Computer Networks Wireless LANs Mobile Communication Technology according to IEEE (examples) Local wireless networks WLAN 802.11 Personal wireless nw WPAN 802.15 WiFi 802.11a 802.11b 802.11h 802.11i/e/
Chapter 6 Medium Access Control Protocols and Local Area Networks
Chapter 6 Medium Access Control Protocols and Local Area Networks 802.11 Wireless LAN CSE 3213, Winter 2010 Instructor: Foroohar Foroozan Wireless Data Communications Wireless communications compelling
Wireless Communications
4. Medium Access Control Sublayer DIN/CTC/UEM 2018 Why do we need MAC for? Medium Access Control (MAC) Shared medium instead of point-to-point link MAC sublayer controls access to shared medium Examples:
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
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
Introduction to Wireless Networking CS 490WN/ECE 401WN Winter Lecture 4: Wireless LANs and IEEE Part II
Introduction to Wireless Networking CS 490WN/ECE 401WN Winter 2007 Lecture 4: Wireless LANs and IEEE 802.11 Part II This lecture continues the study of wireless LANs by looking at IEEE 802.11. I. 802.11
Medium Access Control. CSCI370 Lecture 5 Michael Hutt New York Institute of Technology
Medium Access Control CSCI370 Lecture 5 Michael Hutt New York Institute of Technology The Data Link Layer Logical Link Control (LLC) IEEE 802.2 Standard RFC 1042 Provides three service options Unreliable
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
CHAPTER 7 MAC LAYER PROTOCOLS. Dr. Bhargavi Goswami Associate Professor & Head Department of Computer Science Garden City College
CHAPTER 7 MAC LAYER PROTOCOLS Dr. Bhargavi Goswami Associate Professor & Head Department of Computer Science Garden City College MEDIUM ACCESS CONTROL - MAC PROTOCOLS When the two stations transmit data
Overview. Wireless networks basics IEEE (Wi-Fi) a/b/g/n ad Hoc MAC protocols ad Hoc routing DSR AODV
Wireless networks 1 Overview Wireless networks basics IEEE 802.11 (Wi-Fi) a/b/g/n ad Hoc MAC protocols ad Hoc routing DSR AODV 2 Wireless Networks Autonomous systems of mobile hosts connected by wireless
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
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 5.4: Multiple Access Protocols Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527
CS 716: Introduction to communication networks. - 9 th class; 19 th Aug Instructor: Sridhar Iyer IIT Bombay
CS 716: Introduction to communication networks - 9 th class; 19 th Aug 2011 Instructor: Sridhar Iyer IIT Bombay Contention-based MAC: ALOHA Users transmit whenever they have data to send Collisions occur,
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/
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
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