Chapter 8 LAN Topologies

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Chapter 8 LAN Topologies"

Transcription

1 Chapter 8 LAN Topologies Point-to-Point Networks In a Point-to-Point network, each wire connects exactly two computers Point To Point Link Machine A Machine B Figure 1: Each line connects two machines Advantages Univ. of Kentucky CS 471, Spring Jim Griffioen 1

2 P-t-P Networks: (continued) Disadvantages Univ. of Kentucky CS 471, Spring Jim Griffioen 2

3 Multiaccess Networks Problem: P-t-P networks have many lines => high cost Solution: IDEA: the computers must take turns we need an allocation strategy to determine who s turn it is (TDM, FDM, Statistical Multiplexing) Shared lines reduce cost But it means you only get a fraction of the line s bandwidth Univ. of Kentucky CS 471, Spring Jim Griffioen 3

4 LAN Topologies Networks are typically classified by their shape There are three popular shapes: Univ. of Kentucky CS 471, Spring Jim Griffioen 4

5 Bus Topologies Shared Bus Connector Wire Figure 2: Example Bus Topology Must solve the Channel Allocation Problem. Univ. of Kentucky CS 471, Spring Jim Griffioen 5

6 Ring Topologies Computers are connected in a closed loop/ring Packets Travel Around The Ring in Some Direction Figure 3: Example Ring Topology Univ. of Kentucky CS 471, Spring Jim Griffioen 6

7 All computers connect to Star Topologies If it is a multiaccess star, hosts must synchronize their sending. If hub does store-n-forwarding of messages, then hosts do not need to synchronize. Hub Figure 4: Example Star Topology Univ. of Kentucky CS 471, Spring Jim Griffioen 7

8 Why Multiple Topologies Each topology has advantages and disadvantages Advantages Bus: Ring: Star: Ring: Disadvantages Bus: Ring: Ring: Star: Univ. of Kentucky CS 471, Spring Jim Griffioen 8

9 Ethernet: A Bus Network is probably most popular LAN technology developed at Xerox PARC by R. Metcalf and D. Boggs 1976 DEC, Intel, and Xerox developed the DIX ethernet standard later IEEE defined the ethernet standard first versions ran at 3 Mbps current versions run at 10 Mbps and 100 Mbps is a multiaccess network technology is a broadcast-based technology is inexpensive because it uses a passive cable only provides best-effort service higher level protocols do all the real work comes in three varietys: thick net, thin net, twisted pair Univ. of Kentucky CS 471, Spring Jim Griffioen 9

10 Ethernet Basics Sending Animation Univ. of Kentucky CS 471, Spring Jim Griffioen 10

11 CSMA/CD Carrier Sense, Multiple Access with Collision Detection Ethernet is just one example of a CSMA/CD protocol The goal is to There is no THE BASIC IDEA of CSMA/CD protocols is: CSMA/CD Animation Univ. of Kentucky CS 471, Spring Jim Griffioen 11

12 Ethernet Collision Detection Note that CSMA does not prohibit two machines from sending at the same time! Consequently, their signals may collide How do you detect collisions? (Short Packet Animation) Univ. of Kentucky CS 471, Spring Jim Griffioen 12

13 Two Short Packets that will collide When Packets Collide, Garbage Results (see green line below) Red host sends: Blue host sends: Wire sees: Figure 5: Short Packets might not detect collision Univ. of Kentucky CS 471, Spring Jim Griffioen 13

14 Collision Detection: (continued) What should the minimum Length Packet be? (See min-length animation) What is the Round Trip Delay of and Ethernet? if we transmit for 51.2 usecs, we will have seen the first few bits of a colliding host before we get done transmitting thus the minimum transmission time = 51.2 usec minimum packet size = Univ. of Kentucky CS 471, Spring Jim Griffioen 14

15 Ethernet Transmission Algorithm wait till idle line, send immediately, and monitor you may only send 1500 bytes. Why? you must wait 9.6 usec before sending again if you detect a collision, continue sending a jam signal until the end of the 51.2 usec interval (the minimum packet length) to make sure everyone sees the collision. wait a certain (with slight randomness) amount of time and try again if you collide again, double the wait time, then try again, etc. called exponential backoff Univ. of Kentucky CS 471, Spring Jim Griffioen 15

16 Receiever Algorithm the ethernet card sees all packets sent over the ether the ethernet card runs in one of two modes: Univ. of Kentucky CS 471, Spring Jim Griffioen 16

17 LocalTalk LAN technology that uses bus topology Interface included with all Macintosh computers Relatively low speed (230.4 Kbps) Low cost ( free with a Macintosh); easy to install and connect Univ. of Kentucky CS 471, Spring Jim Griffioen 17

18 CSMA/CA LocalTalk uses collision avoidance rather than collision detection CA = Collision Avoidance Transmitting computer sends very short message to reserve bus If reservation succeeds, transmitter can use bus without conflict Univ. of Kentucky CS 471, Spring Jim Griffioen 18

19 Two popular examples: IBM Token Ring FDDI Example Ring Networks Univ. of Kentucky CS 471, Spring Jim Griffioen 19

20 IBM Token Ring network manages access to the shared ring via a token Univ. of Kentucky CS 471, Spring Jim Griffioen 20

21 forward packet s Token Ring Access Points Receiver Sender copy packet and forward Figure 6: (Left) Abstract Ring (Right) Ring in Operation Token Ring Animation Univ. of Kentucky CS 471, Spring Jim Griffioen 21

22 The Token The token is There is only A computer must hold the token Univ. of Kentucky CS 471, Spring Jim Griffioen 22

23 Token Passing Algorithm Univ. of Kentucky CS 471, Spring Jim Griffioen 23

24 Token Ring Failures What kinds of problems/failurs can occur? Univ. of Kentucky CS 471, Spring Jim Griffioen 24

25 FDDI (Fiber Distributed Data Interface) FDDI was a very popular ring technology Ran at 100 Mbps Still used in some places, but has been largely replaced by other technologies. Gigabit ring networks (follow-ons to FDDI) have also been developed (CSMA/RN) Univ. of Kentucky CS 471, Spring Jim Griffioen 25

26 Physical Characteristics runs over fiber an alternative version called CDDI runs over copper the attachment stations form a Dual, Counter-Rotating Ring Concentrator DAS SAS SAS Dual Attachment Station (Concentrator) 2 fibers in / 2 fibers out SAS hang off it expensive/complex To a To a Figure 7: Rings, DAS, and SAS only use the outer ring, the inner ring is idle until a failure occurs Univ. of Kentucky CS 471, Spring Jim Griffioen 26

27 Physical Characteristics: (continued) two types of attachments Dual Attachment Stations (DAS) Single Attachment Stations (SAS) the network is said to be self-healing a DAS has an optical by-pass that fixes SAS failures each DAS monitors connectivity and reverses the ring if a failure occurs X X X Figure 8: Self-Healing Capability Univ. of Kentucky CS 471, Spring Jim Griffioen 27

28 Physical Characteristics: (continued) has a bandwidth of 100 Mbps, latency depends on ring size max ring size is 100 Kilometers (really 200 Km / 2 rings) max dist between stations is 2 Km max of 500 stations each station adds a 50 ns delay because of an elasticity buffer. uses 4B/5B encoding max packet length is approx 4500 bytes Univ. of Kentucky CS 471, Spring Jim Griffioen 28

29 Token Rotation Algorithm you are allowed to send data as long as you hold the token How long can you hold the token? Univ. of Kentucky CS 471, Spring Jim Griffioen 29

30 Setting THT if (THT is small) if (THT is large) TTRT (Target Token Rotation Time) want a TTRT Target Token Rotation Time for the ring that is as big as possible to get the best efficiency, but small enough so that everyone is happy FDDI selects the minimum of all hosts desired TRT s as the ring s TTRT (vie a bidding algorithm) each machine tries to keep the token rotating at the TTRT speed Univ. of Kentucky CS 471, Spring Jim Griffioen 30

31 Setting THT: (continued) each hosts measures the last rotation time MTRT (Measured Token Rotation Time) if (MTRT < TTRT) the token is moving faster than it needs to you are allowed to hold the token for a maximum of THT = (TTRT - MTRT) if (MTRT >= TTRT) the token is behind schedule you must forfeit your turn and send the token on immediately Univ. of Kentucky CS 471, Spring Jim Griffioen 31

32 When do you send the token? Token Token Packet Packet Figure 9: When to send the Token? Univ. of Kentucky CS 471, Spring Jim Griffioen 32

33 Univ. of Kentucky CS 471, Spring Jim Griffioen 33

34 ATM (Asynchronous Transfer Mode) does not stand for Automated Teller Machine is a packet switching system spans the physical, data link, and network levels standards are still in development (CCITT and ATM forum) highly influenced by the Telephone industry a goal of ATM was to be able to send voice, data, and video over the same network (merge computer and voice networks) also need to carry control information (things needed to support new telephone services like call forwarding, call-waiting, discount dialing plans, etc) In the past this information ran over a parallel network to the voice network. Univ. of Kentucky CS 471, Spring Jim Griffioen 34

35 Goals and Assumptions 1. ATM networks will be organized as a two-level hierarchy consisting of user and network level machines/switches we need a network-network interface (NNI) and we need a user-network interface (UNI) 2. should provide connection-oriented service; set up a channel to communicate 3. should be run over fiber and have very low error rates subgoal is to provide Quality-of-Service such as guaranteed bandwidth, latency, interpacket arrival times, etc. can only do this is the communication links do not introduce errors 4. should allow low cost attachements (ATM telephone devices) standards body decided to prohibit cell reordering cells must arrive at the receiver in order across the link Univ. of Kentucky CS 471, Spring Jim Griffioen 35

36 this means end-point devices can be made with much simpler bufferring schemes in particular, they can use FIFO memory instead of RAM memory ATM telephones can just play the samples as they arrive ATM typically carried over some fiber-based data link layer like SONET uses cells (really just another term for packet) Univ. of Kentucky CS 471, Spring Jim Griffioen 36

37 What is a Cell? Recall that Packets can be any size (i.e., they adjust their size to fit the data) A Cell is just a fixed length packet (usually a small packet) Cells are always the same size (even if you want to send a single bit or byte) ATM uses 53 byte cells : 48 bytes of payload and 5 bytes of header Univ. of Kentucky CS 471, Spring Jim Griffioen 37

38 small packet caught behind big packet big packet divided into cells Time Packets can cause wasted bandwidth Figure 10: Cells have small queueing delays Univ. of Kentucky CS 471, Spring Jim Griffioen 38

39 Characteristics of ATM each switch is a star topology switches can by hooked together uses connection-oriented communication between machines destination identified by a connection id ATM ATM Figure 11: Example ATM Network Univ. of Kentucky CS 471, Spring Jim Griffioen 39

40 Pictures of Real ATM Switches Each machine uses two fiber optic lines to connect to the switch Typically multimode fiber is used running at 155 Mbps Figure 12: Fibers into back of a Sparc IPC Univ. of Kentucky CS 471, Spring Jim Griffioen 40

41 Pictures of Real ATM Switches Univ. of Kentucky CS 471, Spring Jim Griffioen 41

42 Univ. of Kentucky CS 471, Spring Jim Griffioen 42

Lecture 4b. Local Area Networks and Bridges

Lecture 4b. Local Area Networks and Bridges Lecture 4b Local Area Networks and Bridges Ethernet Invented by Boggs and Metcalf in the 1970 s at Xerox Local area networks were needed to connect computers, share files, etc. Thick or Thin Ethernet Cable

More information

Data Link Layer, Part 3 Medium Access Control. Preface

Data Link Layer, Part 3 Medium Access Control. Preface Data Link Layer, Part 3 Medium Access Control These slides are created by Dr. Yih Huang of George Mason University. Students registered in Dr. Huang's courses at GMU can make a single machine-readable

More information

Contention Protocols and Networks

Contention Protocols and Networks 4/13/2005 314 Lecture Contention Protocols and Networks 1 Contention Protocols and Networks Contention Protocols CSMA/CD Network Topologies Ethernet 4/13/2005 314 Lecture Contention Protocols and Networks

More information

Media Access Control (MAC) Sub-layer and Ethernet

Media Access Control (MAC) Sub-layer and Ethernet Media Access Control (MAC) Sub-layer and Ethernet Dr. Sanjay P. Ahuja, Ph.D. Fidelity National Financial Distinguished Professor of CIS School of Computing, UNF MAC Sub-layer The MAC sub-layer is a sub-layer

More information

Introduction to LAN Topologies Cabling. 2000, Cisco Systems, Inc. 3-1

Introduction to LAN Topologies Cabling. 2000, Cisco Systems, Inc. 3-1 Introduction to LAN Topologies Cabling 2000, Cisco Systems, Inc. 3-1 Objectives Upon completion of this chapter, you will be able to perform the following tasks: Media / Cabling Local Area Network Cabling

More information

Medium Access Protocols

Medium Access Protocols Medium Access Protocols Summary of MAC protocols What do you do with a shared media? Channel Partitioning, by time, frequency or code Time Division,Code Division, Frequency Division Random partitioning

More information

Outline: Connecting Many Computers

Outline: Connecting Many Computers Outline: Connecting Many Computers Last lecture: sending data between two computers This lecture: link-level network protocols (from last lecture) sending data among many computers 1 Review: A simple point-to-point

More information

Principles behind data link layer services

Principles behind data link layer services Data link layer Goals: Principles behind data link layer services Error detection, correction Sharing a broadcast channel: Multiple access Link layer addressing Reliable data transfer, flow control: Done!

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

CS 123: Lecture 12, LANs, and Ethernet. George Varghese. October 24, 2006

CS 123: Lecture 12, LANs, and Ethernet. George Varghese. October 24, 2006 CS 123: Lecture 12, LANs, and Ethernet George Varghese October 24, 2006 Selective Reject Modulus failure Example w = 2, Max = 3 0 0 1 3 0 A(1) A(2) 1 0 retransmit A(1) A(2) buffer Case 1 Case 2 reject

More information

Chapter 6: DataLink Layer - Ethernet Olivier Bonaventure (2010)

Chapter 6: DataLink Layer - Ethernet Olivier Bonaventure (2010) Chapter 6: DataLink Layer - Ethernet Olivier Bonaventure (2010) 6.3.2. Ethernet Ethernet was designed in the 1970s at the Palo Alto Research Center [Metcalfe1976]. The first prototype [5] used a coaxial

More information

Computer Networks. Medium Access Sublayer (Part I)

Computer Networks. Medium Access Sublayer (Part I) Computer Networks Medium Access Sublayer (Part I) Topics Introduction Multiple Access Protocols Ethernet Wireless LAN Protocols Bridges Misc (brief) High-Speed LANs Satellite Networks Introduction Remember,

More information

Direct Link Networks (II)

Direct Link Networks (II) Direct Link Networks (II) Computer Networking Lecture 03 HKU SPACE Community College January 30, 2012 HKU SPACE CC CN Lecture 03 1/25 Outline Reliable Link Service Stop-and-Wait Sliding Window Media Access

More information

Computer and Network Security

Computer and Network Security CIS 551 / TCOM 401 Computer and Network Security Spring 2009 Lecture 6 Announcements First project: Due: 6 Feb. 2009 at 11:59 p.m. http://www.cis.upenn.edu/~cis551/project1.html Plan for Today: Networks:

More information

Redes de Computadores. Medium Access Control

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

More information

LAN Protocols. Required reading: Forouzan 13.1 to 13.5 Garcia 6.7, 6.8. CSE 3213, Fall 2015 Instructor: N. Vlajic

LAN Protocols. Required reading: Forouzan 13.1 to 13.5 Garcia 6.7, 6.8. CSE 3213, Fall 2015 Instructor: N. Vlajic 1 LAN Protocols Required reading: Forouzan 13.1 to 13.5 Garcia 6.7, 6.8 CSE 3213, Fall 2015 Instructor: N. Vlajic What is LAN? 2 Local Area Network (LAN) properties private ownership freedom to choose/change/upgrade

More information

CIS 551 / TCOM 401 Computer and Network Security. Spring 2007 Lecture 7

CIS 551 / TCOM 401 Computer and Network Security. Spring 2007 Lecture 7 CIS 551 / TCOM 401 Computer and Network Security Spring 2007 Lecture 7 Announcements Reminder: Project 1 is due on Thursday. 2/1/07 CIS/TCOM 551 2 Network Architecture General blueprints that guide the

More information

A LAN is a high-speed data network that covers a relatively small geographic area. It typically connects workstations, personal computers, printers,

A LAN is a high-speed data network that covers a relatively small geographic area. It typically connects workstations, personal computers, printers, CBCN4103 A LAN is a high-speed data network that covers a relatively small geographic area. It typically connects workstations, personal computers, printers, servers, and other devices. LANs offer computer

More information

CSE 461: Multiple Access. Homework: Chapter 2, problems 1, 8, 12, 18, 23, 24, 35, 43, 46, and 58

CSE 461: Multiple Access. Homework: Chapter 2, problems 1, 8, 12, 18, 23, 24, 35, 43, 46, and 58 CSE 461: Multiple Access Homework: Chapter 2, problems 1, 8, 12, 18, 23, 24, 35, 43, 46, and 58 Next Topic Key Focus: How do multiple parties share a wire? This is the Medium Access Control (MAC) portion

More information

Topics. Link Layer Services (more) Link Layer Services LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS. flow control: error detection:

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

More information

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

Ethernet Basics. based on Chapter 4 of CompTIA Network+ Exam Guide, 4 th ed., Mike Meyers Ethernet Basics based on Chapter 4 of CompTIA Network+ Exam Guide, 4 th ed., Mike Meyers Ethernet Basics History Ethernet Frames CSMA/CD Obsolete versions 10Mbps versions Segments Spanning Tree Protocol

More information

The Link Layer and LANs. Chapter 6: Link layer and LANs

The Link Layer and LANs. Chapter 6: Link layer and LANs The Link Layer and LANs EECS3214 2018-03-14 4-1 Chapter 6: Link layer and LANs our goals: understand principles behind link layer services: error detection, correction sharing a broadcast channel: multiple

More information

Lecture 5 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it

Lecture 5 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Lecture 5 The Data Link Layer Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Link Layer: setting the context two physically connected devices: host-router, router-router, host-host,

More information

Internet Architecture and Protocol

Internet Architecture and Protocol Internet Architecture and Protocol Set# 03 Local Area Networks Delivered By: Engr Tahir Niazi Layer Reference to Protocol Application Presentation Session Application FTP, Telnet, SMTP, HTTP, SNMP.. Transport

More information

Lecture 9: Bridging & Switching"

Lecture 9: Bridging & Switching Lecture 9: Bridging & Switching" CSE 123: Computer Networks Alex C. Snoeren HW 2 due Wednesday! Lecture 9 Overview" Finishing up media access Contention-free methods (rings) Moving beyond one wire Link

More information

Chapter 9 Ethernet Part 1

Chapter 9 Ethernet Part 1 Chapter 9 Ethernet Part 1 Introduction to Ethernet Ethernet Local Area Networks (LANs) LAN (Local Area Network) - A computer network connected through a wired or wireless medium by networking devices (s,

More information

Principles behind data link layer services:

Principles behind data link layer services: Data link layer Goals: Principles behind data link layer services: Error detection, correction Sharing a broadcast channel: Multiple access Link layer addressing Reliable data transfer, flow control Example

More information

Direct Link Communication II: Wired Media. Multi-Access Communication

Direct Link Communication II: Wired Media. Multi-Access Communication Direct Link Communication II: Wired Media Multi-Access Communication Two classes: contention-based e.g., CSMA/CD, CSMA/CA used in Ethernet, WLAN contention-free e.g., TDM, FDM, TDMA, CDMA, token ring one

More information

CSE 461 Multiple Access. David Wetherall

CSE 461 Multiple Access. David Wetherall CSE 461 Multiple Access David Wetherall djw@cs.washington.edu How to share a link Multiplexing = networking term for sharing a resource among multiple users (e.g., link, protocol instance) Topics: Multiplexing

More information

Chapter 5 Link Layer and LANs

Chapter 5 Link Layer and LANs Chapter 5 Link Layer and LANs A note on the use of these ppt slides: All material copyright 1996-2007 J.F Kurose and K.W. Ross, All Rights Reserved Computer Networking: A Top Down Approach 4 th edition.

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 5.4: Multiple Access Protocols Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527

More information

CCNA Exploration1 Chapter 7: OSI Data Link Layer

CCNA Exploration1 Chapter 7: OSI Data Link Layer CCNA Exploration1 Chapter 7: OSI Data Link Layer LOCAL CISCO ACADEMY ELSYS TU INSTRUCTOR: STELA STEFANOVA 1 Explain the role of Data Link layer protocols in data transmission; Objectives Describe how the

More information

Computer Networking Lecture 5 Data link Layer Access Control. Based on slides by Peter Steenkiste Copyright, Carnegie Mellon

Computer Networking Lecture 5 Data link Layer Access Control. Based on slides by Peter Steenkiste Copyright, Carnegie Mellon 15-441 Computer Networking Lecture 5 Data link Layer Access Control Based on slides by Peter Steenkiste Copyright, Carnegie Mellon 2007-12 1 Datalink Functions Framing: encapsulating a network layer datagram

More information

Lecture 05 Chapter 16 High Speed LANs

Lecture 05 Chapter 16 High Speed LANs NET 456 High Speed Networks Lecture 05 Chapter 16 High Speed LANs Dr. Anis Koubaa Reformatted slides from textbook Data and Computer Communications, Ninth Edition by William Stallings, 1 (c) Pearson Education

More information

College of Computer and Information Sciences Department of Computer Engineering CEN444 Computer Networks Midterm 2 Exam Second Semester 1434/1435

College of Computer and Information Sciences Department of Computer Engineering CEN444 Computer Networks Midterm 2 Exam Second Semester 1434/1435 College of Computer and Information Sciences Department of Computer Engineering CEN444 Computer Networks Midterm 2 Exam Second Semester 1434/1435 Student Name ID Time Allowed: 2.0 Hours. Closed Book, Closed

More information

Lecture 6 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it

Lecture 6 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Lecture 6 The Data Link Layer Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Link Layer: setting the context two physically connected devices: host-router, router-router, host-host,

More information

Networks 15.2 Multiplexing Technologies Access Networks 15.5 Common Peripheral Interfaces

Networks 15.2 Multiplexing Technologies Access Networks 15.5 Common Peripheral Interfaces Chapter 15 Computer and Multimedia Networks 15.11 Basics of Computer and Multimedia Networks 15.2 Multiplexing Technologies 15.3 LAN and WAN 15.4 Access Networks 15.5 Common Peripheral Interfaces 15.6

More information

Chapter 4: The Medium Access Layer

Chapter 4: The Medium Access Layer Chapter 4: The Medium Access Layer Computer Networks Maccabe Computer Science Department The University of New Mexico September 2002 Medium Access Layer Point-to-point versus broadcast networks Broadcast

More information

CCM 4300 Lecture 5 Computer Networks, Wireless and Mobile Communications. Dr Shahedur Rahman. Room: T115

CCM 4300 Lecture 5 Computer Networks, Wireless and Mobile Communications. Dr Shahedur Rahman. Room: T115 CCM 4300 Lecture 5 Computer Networks, Wireless and Mobile Communications Dr Shahedur Rahman s.rahman@mdx.ac.uk Room: T115 1 Recap of Last Session Described the physical layer Analogue and Digital signal

More information

2. LAN Topologies Gilbert Ndjatou Page 1

2. LAN Topologies Gilbert Ndjatou Page 1 2. LAN Topologies Two basic categories of network topologies exist, physical topologies and logical topologies. The physical topology of a network is the cabling layout used to link devices. This refers

More information

Chapter 5 Link Layer and LANs

Chapter 5 Link Layer and LANs Chapter 5 Link Layer and LANs Computer Networking: A Top Down Approach 4 th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007. All material copyright 1996-2007 J.F Kurose and K.W. Ross, All Rights

More information

Integrating Information Systems: Technology, Strategy, and Organizational Factors

Integrating Information Systems: Technology, Strategy, and Organizational Factors MASSACHUSETTS INSTITUTE OF TECHNOLOGY SLOAN SCHOOL OF MANAGEMENT 15.565 Integrating Information Systems: Technology, Strategy, and Organizational Factors 15.578 Global Information Systems: Communications

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

Data Link Layer -2- Network Access

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

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 The

More information

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols Link Layer: Introduction daptors ommunicating hosts and routers are nodes links connect nodes wired links wireless links layer-2 packet is a frame, encapsulates datagram datagram controller sending host

More information

Chapter 5 Link Layer and LANs

Chapter 5 Link Layer and LANs 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, readers). They re in PowerPoint form so you can add, modify, and

More information

ECEN 5032 Data Networks Medium Access Control Sublayer

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:

More information

Sharing Channels CS 118

Sharing Channels CS 118 Sharing Channels Computer Network Fundamentals Peter Reiher Page 1 Outline Carrier sense channel sharing Naming?? Page 2 Sending without a master 1. Message to send 2. Listen for quiet 3. Send message

More information

! High Data Rates (0.1 to 1000 Mbps)! Short Distances (0.1 to 25 km) ! Low Error Rate (10 to 10 ) Local Area Networks

! High Data Rates (0.1 to 1000 Mbps)! Short Distances (0.1 to 25 km) ! Low Error Rate (10 to 10 ) Local Area Networks Local Area Networks A Local Area Netw ork is a communications netw ork that provides interconnection of a variety of data communicating devices w ithin a small area. Typical Characteristics! High Data

More information

The Medium Access Sublayer

The Medium Access Sublayer The Medium Access Sublayer shivkuma@ecse.rpi.edu http://www.ecse.rpi.edu/homepages/shivkuma 1-1 Based in part upon the slides of Prof. Raj Jain (OSU), K. Vastola (RPI) Overview Multiple Access: Aloha,

More information

Lecture 6 Datalink Framing, Switching. From Signals to Packets

Lecture 6 Datalink Framing, Switching. From Signals to Packets Lecture 6 Datalink Framing, Switching David Andersen Department of Computer Science Carnegie Mellon University 15-441 Networking, Spring 2005 http://www.cs.cmu.edu/~srini/15-441/s05/ 1 From Signals to

More information

Ethernet. Introduction. CSE 3213 Fall 2011

Ethernet. Introduction. CSE 3213 Fall 2011 Ethernet CSE 3213 Fall 2011 19 October 2011 1 Introduction Rapid changes in technology designs Broader use of LANs New schemes for high-speed LANs High-speed LAN technologies: Fast and gigabit Ethernet

More information

Hubs, Bridges, and Switches (oh my) Hubs

Hubs, Bridges, and Switches (oh my) Hubs Hubs, Bridges, and Switches (oh my) Used for extending LANs in terms of geographical coverage, number of nodes, administration capabilities, etc. Differ in regards to: collision domain isolation layer

More information

Link Layer and LANs 안상현서울시립대학교컴퓨터 통계학과.

Link Layer and LANs 안상현서울시립대학교컴퓨터 통계학과. Link Layer and LANs 안상현서울시립대학교컴퓨터 통계학과 ahn@venus.uos.ac.kr Data Link Layer Goals: understand principles behind data link layer services: error detection, correction sharing a broadcast channel: multiple

More information

The Link Layer II: Ethernet

The Link Layer II: Ethernet Monday Recap The Link Layer II: Ethernet q Link layer services q Principles for multiple access protocols q Categories of multiple access protocols CSC 249 March 24, 2017 1 2 Recap: Random Access Protocols

More information

Chapter 6 Medium Access Control Protocols and Local Area Networks

Chapter 6 Medium Access Control Protocols and Local Area Networks Chapter 6 Medium Access Control Protocols and Local Area Networks Part I: Medium Access Control Part II: Local Area Networks CSE 3213, Winter 2010 Instructor: Foroohar Foroozan Chapter Overview Broadcast

More information

Internetworking is connecting two or more computer networks with some sort of routing device to exchange traffic back and forth, and guide traffic on

Internetworking is connecting two or more computer networks with some sort of routing device to exchange traffic back and forth, and guide traffic on CBCN4103 Internetworking is connecting two or more computer networks with some sort of routing device to exchange traffic back and forth, and guide traffic on the correct path across the complete network

More information

Chapter 5 Link Layer. Computer Networking: A Top Down Approach. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012

Chapter 5 Link Layer. Computer Networking: A Top Down Approach. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 Chapter 5 Link Layer A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint form so you see the animations; and can

More information

transferring datagram from one node data-link layer has responsibility of to adjacent node over a link 5-1 TDTS06 Computer networks

transferring datagram from one node data-link layer has responsibility of to adjacent node over a link 5-1 TDTS06 Computer networks TDTS06 Computer networks Lecture 7: The link layer I Link Layer: Introduction Some terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are

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

CSCI-1680 Link Layer Wrap-Up Rodrigo Fonseca

CSCI-1680 Link Layer Wrap-Up Rodrigo Fonseca CSCI-1680 Link Layer Wrap-Up Rodrigo Fonseca Based partly on lecture notes by David Mazières, Phil Levis, John Jannotti Administrivia Homework I out later today, due next Thursday Today: Link Layer (cont.)

More information

CSC 4900 Computer Networks: Link Layer (2)

CSC 4900 Computer Networks: Link Layer (2) CSC 4900 Computer Networks: Link Layer (2) Professor Henry Carter Fall 2017 Link Layer 6.1 Introduction and services 6.2 Error detection and correction 6.3 Multiple access protocols 6.4 LANs addressing,

More information

RMIT University. Data Communication and Net-Centric Computing COSC 1111/2061/1110. Lecture 8. Medium Access Control Methods & LAN

RMIT University. Data Communication and Net-Centric Computing COSC 1111/2061/1110. Lecture 8. Medium Access Control Methods & LAN RMIT University Data Communication and Net-Centric Computing COSC 1111/2061/1110 Medium Access Control Methods & LAN Technology Slide 1 Lecture Overview During this lecture, we will Look at several Multiple

More information

Jaringan Komputer. Broadcast Network. Outline. MAC (Medium Access Control) Channel Allocation Problem. Dynamic Channel Allocation

Jaringan Komputer. Broadcast Network. Outline. MAC (Medium Access Control) Channel Allocation Problem. Dynamic Channel Allocation Broadcast Network Jaringan Komputer Medium Access Control Sublayer 2 network categories: point-to-point connections broadcast channels Key issue in broadcast network: how to determine who gets to use the

More information

TCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS

TCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS TCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS Communication Networks Allow Exchange of Information between Users telephone network for voice communication interconnected computers and peripherals,

More information

Links. CS125 - mylinks 1 1/22/14

Links. CS125 - mylinks 1 1/22/14 Links 1 Goals of Today s Lecture Link-layer services Encoding, framing, and error detection Error correction and flow control Sharing a shared media Channel partitioning Taking turns Random access Shared

More information

LANs Local Area Networks LANs provide an efficient network solution : To support a large number of stations Over moderately high speed

LANs Local Area Networks LANs provide an efficient network solution : To support a large number of stations Over moderately high speed Local Area Networks LANs provide an efficient network solution : To support a large number of stations Over moderately high speed With relatively small bit errors Multiaccess Protocols Communication among

More information

Outline. Introduction to Networked Embedded Systems - Embedded systems Networked embedded systems Embedded Internet - Network properties

Outline. Introduction to Networked Embedded Systems - Embedded systems Networked embedded systems Embedded Internet - Network properties Outline Introduction to Networked Embedded Systems - Embedded systems Networked embedded systems Embedded Internet - Network properties Layered Network Architectures - OSI framework descriptions of layers

More information

Data always flows in one direction around ring Like Ethernet, all nodes see all frames, and protocol is necessary to decide when to send

Data always flows in one direction around ring Like Ethernet, all nodes see all frames, and protocol is necessary to decide when to send Token Ring Developed by IBM, adopted by IEEE as 802.5 standard Token rings latter extended to FDDI (Fiber Distributed Data Interface) and 802.17 (Resilient Packet Ring) standards Nodes connected in a ring

More information

COMP/ELEC 429/556 Introduction to Computer Networks

COMP/ELEC 429/556 Introduction to Computer Networks COMP/ELEC 429/556 Introduction to Computer Networks Broadcast network access control Some slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica, Hui Zhang T. S. Eugene Ng eugeneng

More information

Networks. Randal E. Bryant CS347 Lecture 24 April 16, 1997

Networks. Randal E. Bryant CS347 Lecture 24 April 16, 1997 Networks Randal E. Bryant CS347 Lecture 24 April 16, 1997 Topics Overview Telephone system Ethernet ATM Computer system Keyboard Mouse Modem Printer Processor and L1 cache Interrupt controller Keyboard

More information

CS 43: Computer Networks Switches and LANs. Kevin Webb Swarthmore College December 5, 2017

CS 43: Computer Networks Switches and LANs. Kevin Webb Swarthmore College December 5, 2017 CS 43: Computer Networks Switches and LANs Kevin Webb Swarthmore College December 5, 2017 Ethernet Metcalfe s Ethernet sketch Dominant wired LAN technology: cheap $20 for NIC first widely used LAN technology

More information

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 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

More information

Data Link Layer (Sicherungsschicht) Medium Access Control (Zugriffsverfahren)

Data Link Layer (Sicherungsschicht) Medium Access Control (Zugriffsverfahren) Data Link Layer (Sicherungsschicht) Medium Access Control (Zugriffsverfahren) f References: [Bossert99] [Wa0102] www.comnets.uni-bremen.de MAC - 1 LOGICAL LINK CONTROL MEDIUM ACCESS CONTROL PHYSICAL SIGNALING

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

Data Link Protocols. TCP/IP Suite and OSI Reference Model

Data Link Protocols. TCP/IP Suite and OSI Reference Model Data Link Protocols Relates to Lab. This module covers data link layer issues, such as local area networks (LANs) and point-to-point links, Ethernet, and the Point-to-Point Protocol (PPP). 1 TCP/IP Suite

More information

Physical and Link Layers. CS144 Review Session 6 November 6 th, 2008 Roger Liao Based on slides by Ben Nham

Physical and Link Layers. CS144 Review Session 6 November 6 th, 2008 Roger Liao Based on slides by Ben Nham Physical and Link Layers CS144 Review Session 6 November 6 th, 2008 Roger Liao Based on slides by Ben Nham Outline Physical layer Encoding of signals Chips vs. bits Link layer Communication through shared

More information

Multiple Access Protocols

Multiple Access Protocols Multiple Access Protocols Computer Networks Lecture 2 http://goo.gl/pze5o8 Multiple Access to a Shared Channel The medium (or its sub-channel) may be shared by multiple stations (dynamic allocation) just

More information

Medium Access Control Sublayer

Medium Access Control Sublayer Wireless (WLAN) Medium Access Control Sublayer Mahalingam Mississippi State University, MS October 20, 2014 Outline Medium Access Protocols Wireless (WLAN) 1 Medium Access Protocols ALOHA Slotted ALOHA

More information

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 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,

More information

1. Data Link Layer Protocols

1. Data Link Layer Protocols 1. Data Link Layer Protocols Purpose of the Data Link Layer The Data Link Layer Purpose of the Data Link Layer Data Link Sublayers Network LLC Sublayer Data Link Physical MAC Sublayer 802.3 Ethernet 802.11

More information

CSC 4900 Computer Networks: The Link Layer

CSC 4900 Computer Networks: The Link Layer CSC 4900 Computer Networks: The Link Layer Professor Henry Carter Fall 2017 Last Time We talked about intra-as routing protocols: Which routing algorithm is used in RIP? OSPF? What techniques allow OSPF

More information

Networks Homework # 2

Networks Homework # 2 ISLAMIC UNIVERSITY OF GAZA COMPUTER ENGINEERING DEPARTMENT Networks Homework # 2 INSTRUCTIONS: 1. Show your work (i.e., how you derived your answer or the reason behind your thinking) in addition to your

More information

Medium Access Control

Medium Access Control Medium Access Control Mark Handley UCL Computer Science CS 3035/GZ01 Context: OSI Layer 2, S&K Link Layer email WWW phone...! SMTP HTTP RTP...! TCP UDP!! IP!! ethernet PPP! CSMA async sonet...! copper

More information

Guide to Networking Essentials Fifth Edition. Chapter 7 Network Architectures

Guide to Networking Essentials Fifth Edition. Chapter 7 Network Architectures Guide to Networking Essentials Fifth Edition Chapter 7 Network Architectures Objectives Compare and contrast media access methods used in network architectures Describe the operation of Ethernet Differentiate

More information

The following pages contain a guide for the installation

The following pages contain a guide for the installation INDEX The goal of this section is to illustrate how Siemon Company products can be used to support some of the most popular and emerging networks on the market. Section Contents 100Base-T....................................

More information

Growth. Individual departments in a university buy LANs for their own machines and eventually want to interconnect with other campus LANs.

Growth. Individual departments in a university buy LANs for their own machines and eventually want to interconnect with other campus LANs. Internetworking Multiple networks are a fact of life: Growth. Individual departments in a university buy LANs for their own machines and eventually want to interconnect with other campus LANs. Fault isolation,

More information

Master Course Computer Networks IN2097

Master Course Computer Networks IN2097 Chair for Network Architectures and Services Prof. Carle Department for Computer Science TU München Master Course Computer Networks IN2097 Prof. Dr.-Ing. Georg Carle Christian Grothoff, Ph.D. Chair for

More information

Data Link Networks. Hardware Building Blocks. Nodes & Links. CS565 Data Link Networks 1

Data Link Networks. Hardware Building Blocks. Nodes & Links. CS565 Data Link Networks 1 Data Link Networks Hardware Building Blocks Nodes & Links CS565 Data Link Networks 1 PROBLEM: Physically connecting Hosts 5 Issues 4 Technologies Encoding - encoding for physical medium Framing - delineation

More information

More on LANS. LAN Wiring, Interface

More on LANS. LAN Wiring, Interface More on LANS Chapters 10-11 LAN Wiring, Interface Mostly covered this material already NIC = Network Interface Card Separate processor, buffers incoming/outgoing data CPU might not be able to keep up network

More information

Underlying Technologies -Continued-

Underlying Technologies -Continued- S465 omputer Networks Spring 2004 hapter 3 (Part B) Underlying Technologies -ontinued- Dr. J. Harrison These slides were produced from material by Behrouz Forouzan for the text TP/IP Protocol Suite (2

More information

Network Topology. By Dr. Piya Techateerawat. Bus Topology Ring Topology Star Topology Fully Connected Topology. Combined Topology

Network Topology. By Dr. Piya Techateerawat. Bus Topology Ring Topology Star Topology Fully Connected Topology. Combined Topology By Dr. Piya Techateerawat Network Topology Bus Topology Ring Topology Star Topology Fully Connected Topology (Please refer to the 1 st lecture) Combined Topology Local Area Network IEEE 802.3:- Ethernet

More information

CCM 4300 Lecture 6 Computer Networks, Wireless and Mobile Communications. Dr Shahedur Rahman. Room: T115

CCM 4300 Lecture 6 Computer Networks, Wireless and Mobile Communications. Dr Shahedur Rahman. Room: T115 CCM 4300 Lecture 6 Computer Networks, Wireless and Mobile Communications Dr Shahedur Rahman s.rahman@mdx.ac.uk Room: T115 1 Recap of Last Session Access Control ALOHA FDMA, TDMA, CDMA OSI Model Internetworking

More information

Local Area Networks CONSYL Introduction to Computer Communications and Networks

Local Area Networks CONSYL Introduction to Computer Communications and Networks Local rea Networks 4/11/40 page 1 Faculty of Engineering, Kasetsart University Local rea Networks 1-1 LN characteristics confined within geographical area relatively high data rate under single management

More information

Topics Today. Lecture 8: Physical and Link Layers. Protocol Layering. Physical layer: chips versus bits. Physical Layer (Layer 1) Protocol Layering

Topics Today. Lecture 8: Physical and Link Layers. Protocol Layering. Physical layer: chips versus bits. Physical Layer (Layer 1) Protocol Layering Topics Today Physical layer: chips versus bits Lecture 8: Physical and Link Layers Link layer and media access control (MAC) Ethernet Hubs and Switches MPLS Protocol Layering Physical layer: chips versus

More information

Chapter V: Link Layer

Chapter V: Link Layer Chapter V: Link Layer UG3 Computer Communications & Networks (COMN) Myungjin Lee myungjin.lee@ed.ac.uk Slides copyright of Kurose and Ross Link layer services framing, link access: encapsulate datagram

More information

CSCI 466 Midterm Networks Fall 2011

CSCI 466 Midterm Networks Fall 2011 CSCI 466 Midterm Networks Fall 2011 Name: This exam consists of 7 problems on the following 9 pages. You may use your single- sided hand- written 8 ½ x 11 note sheet and a calculator during the exam. No

More information

ICE 1332/0715 Mobile Computing (Summer, 2008)

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

More information

Packet Switching. Hongwei Zhang Nature seems to reach her ends by long circuitous routes.

Packet Switching. Hongwei Zhang  Nature seems to reach her ends by long circuitous routes. Problem: not all networks are directly connected Limitations of directly connected networks: limit on the number of hosts supportable limit on the geographic span of the network Packet Switching Hongwei

More information