Presentation is loading. Please wait.

Presentation is loading. Please wait.

ICOM 6115©Manuel Rodriguez-Martinez ICOM 6115 – Computer Networks and the WWW Manuel Rodriguez-Martinez, Ph.D. Lecture 3.

Published byDerek Benson Modified over 9 years ago

Similar presentations

Presentation on theme: "ICOM 6115©Manuel Rodriguez-Martinez ICOM 6115 – Computer Networks and the WWW Manuel Rodriguez-Martinez, Ph.D. Lecture 3."— Presentation transcript:

1 ICOM 6115©Manuel Rodriguez-Martinez ICOM 6115 – Computer Networks and the WWW Manuel Rodriguez-Martinez, Ph.D. Lecture 3

2 ICOM 6115©Manuel Rodriguez-Martinez Lecture Objectives Close some gaps from Hardware Lecture Understand the Architecture of Networking Software Client – Server model for communications Design Principles –Layering –Vertical and Horizontal Communication –Finite State Machines

3 ICOM 6115©Manuel Rodriguez-Martinez Wireless Networks Fundamental idea: Network without wires –Cheaper to deploy –Less of a hassle to people Most successful ones: based on radio –each host has Radio modem + antenna –Access point are used to connect wired and wireless parts

4 ICOM 6115©Manuel Rodriguez-Martinez Examples Configurations Access Point Fully WirelessWireless + Wires

5 ICOM 6115©Manuel Rodriguez-Martinez Existing technologies Bluetooth –Localized connectivity (few meters) –Bandwidth – 2Mbps IEEE 802.11 –LAN connectivity –Bandwidth – 802.11b – 11Mbps 802.11a – 54Mbps 3G (Cellular) –WAN –Bandwidth – less than 1Mbps Centennial Flex – 144Kpbs

6 ICOM 6115©Manuel Rodriguez-Martinez Metropolitan Area Networks (MAN) Networks that are –bigger than LANs –Not as big as WANs –Mostly dead until Cable TV became ISP Used to provide connectivity for cities –Broadband Systems Cable and DSL are current players Next Big Player? : IEEE 802.16 –Wireless Local Loop (Wireless Broadband)

7 ICOM 6115©Manuel Rodriguez-Martinez Cable TV MAN (Cable Modem) Typical Bandwidth: 128Kbps – 1Mbps

8 ICOM 6115©Manuel Rodriguez-Martinez Wireless Local Loop (IEEE 802.16) Bandwidth: 150Mbps, 100Mbps, or 50Mbps

9 ICOM 6115©Manuel Rodriguez-Martinez Future Trends: Home Area Networks

10 ICOM 6115©Manuel Rodriguez-Martinez Design Issues for Networking Software What are the programming models? What are communications protocols? What are the principles that guide protocols design? What is the impact of hardware characteristics on networking software What are the performance trade-offs? What is the operating systems support for networking?

11 ICOM 6115©Manuel Rodriguez-Martinez Client-Server Model Dominant paradigm for programming networked application Client application –Used by the user to obtain a given service from the network Web browser, E-mail, News, SSH client (Open SSH) Server Application –Provides a well-defined service Data or computation service Web Server, Time server, Parallel Machine, SSH Server

12 ICOM 6115©Manuel Rodriguez-Martinez Client-Server Interaction Web Surfers Web Server Req Reply

13 ICOM 6115©Manuel Rodriguez-Martinez Request-Reply Interaction Client requests a given data or service Server replies with either –Requested data or service –Error indication

14 ICOM 6115©Manuel Rodriguez-Martinez Peer-to-Peer Model Old and New model –Existed since the early 70’s Distributed Databases –Rediscovered in the 90’s Napster Applications can act as both client and server –Get data from some site –Serve data to others

15 ICOM 6115©Manuel Rodriguez-Martinez Peer-to-Peer Interaction Anyone can be a server and a client (dual role)

16 ICOM 6115©Manuel Rodriguez-Martinez Peer-to-Peer Exchange

17 ICOM 6115©Manuel Rodriguez-Martinez Peer-to-Peer tend branch out

18 ICOM 6115©Manuel Rodriguez-Martinez Client-Server vs. P2P Client-Server –simpler –highly scalable –Fast –But covers little of the network P2P –Can access more sites –More complex to program –Can be very slow (too much branching out) Scalability problems

19 ICOM 6115©Manuel Rodriguez-Martinez Networking Protocols Networking protocol –a set of rules, data formats and algorithms that govern a given communications process Ex.: Generic Request-Reply protocol scheme

20 ICOM 6115©Manuel Rodriguez-Martinez Protocol Design Principles Use Layering to simplify design and implementation Understand the type of Service –Connection vs. connectionless –Best-effort vs. Guaranteed services QoS and Differentiated Services Understand the performance characteristics of network –Bandwidth, throughput, delay, delay x bandwidth Develop a sound Mathematical model –Finite State Machines, Graph and Queuing Theory

21 ICOM 6115©Manuel Rodriguez-Martinez Protocol Layering Divide the problem into well-defined sub- problems and solve each one –Divide and Conquer Organize solutions into layers of services –Protocol Stack Each layer must solve a well-defined issue –Data Link – deals with moving packets between network cards. –Network Layer – deals with moving packets between hosts (possibly on different LANs)

22 ICOM 6115©Manuel Rodriguez-Martinez Example: TCP/IP Protocol Stack FTP SSH HTTP TCP UDP IP Ethernet PPP Fiber Cooper Air Physical Layer Data Link Layer Network Layer Transport Layer Application Layer

23 ICOM 6115©Manuel Rodriguez-Martinez Service Primitives Primitives are the set of operations provided by a given layer –Similar to methods in a class –Abstract the what from the how? –Modular Design Can change implementation of primitives Primitives form the interface for interaction between layers Principle of Vertical Communication

24 ICOM 6115©Manuel Rodriguez-Martinez Vertical Communication

25 ICOM 6115©Manuel Rodriguez-Martinez Data Encapsulation Packets have –Header – control information Source, destination, flags –Trailer (optional) – more control information –Payload – space where the data transmitted by the packet is held HeaderPayloadTrailer Packet Organization

26 ICOM 6115©Manuel Rodriguez-Martinez Data Encapsulation The packet for one layer becomes the payload in the packet of the lower layer. –Sometimes more than packet might be needed at lower layer –Lower layers should not care about structure of payload –Not 100% true Some routers inspect payload –Security –Differentiated services

27 ICOM 6115©Manuel Rodriguez-Martinez Encapsulation and De-capsulation IP TCP SSH 802.11 Bit Pipe Sender Receiver

28 ICOM 6115©Manuel Rodriguez-Martinez More on Encapsulation Sometimes a packet at layer N won’t fit on one packet at the lower layer –Must be broken and re-assembled at the destination Horizontal Communication –The packet sent by a given layer X should be understood only by the layer X at the receiver

29 ICOM 6115©Manuel Rodriguez-Martinez More on Encapsulation

Download ppt "ICOM 6115©Manuel Rodriguez-Martinez ICOM 6115 – Computer Networks and the WWW Manuel Rodriguez-Martinez, Ph.D. Lecture 3."

Similar presentations

INTRODUCTION TO COMPUTER NETWORKS Zeeshan Abbas. Introduction to Computer Networks INTRODUCTION TO COMPUTER NETWORKS.

INTRODUCTION TO COMPUTER NETWORKS Zeeshan Abbas. Introduction to Computer Networks INTRODUCTION TO COMPUTER NETWORKS.
Network Services Networking for Home & Small Business.

Network Services Networking for Home & Small Business.
Introduction to Networking V.T. Raja, PhD James R. Coakley, PhD BA 572 – Advanced Information Systems.

Introduction to Networking V.T. Raja, PhD James R. Coakley, PhD BA 572 – Advanced Information Systems.
ISOC-Chicago 2001John Kristoff - DePaul University1 Journey to the Center of the Internet John Kristoff +1 312 362-5878 DePaul University.

ISOC-Chicago 2001John Kristoff - DePaul University1 Journey to the Center of the Internet John Kristoff DePaul University.
Lecture 1 Internet Overview: roadmap 1.1 What is the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  network structure,

Lecture 1 Internet Overview: roadmap 1.1 What is the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  network structure,
Understanding Networks. Objectives Compare client and network operating systems Learn about local area network technologies, including Ethernet, Token.

Understanding Networks. Objectives Compare client and network operating systems Learn about local area network technologies, including Ethernet, Token.
Lecture 1 1-1 Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  network structure,

Lecture Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  network structure,
Introduction To Networking

Introduction To Networking
04/26/2004CSCI 315 Operating Systems Design1 Computer Networks.

04/26/2004CSCI 315 Operating Systems Design1 Computer Networks.
Understanding Networks. Objectives Compare client and network operating systems Learn about local area network technologies, including Ethernet, Token.

Understanding Networks. Objectives Compare client and network operating systems Learn about local area network technologies, including Ethernet, Token.
11 Networks The Great Information Exchange. 2 Networking Fundamentals Computer network: Two or more computers connected together Each is a Node Benefits.

11 Networks The Great Information Exchange. 2 Networking Fundamentals Computer network: Two or more computers connected together Each is a Node Benefits.
Lecture 1 Overview: roadmap 1.1 What is computer network? the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  network.

Lecture 1 Overview: roadmap 1.1 What is computer network? the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  network.
Chapter 15 Networks.

Chapter 15 Networks.
Introduction Chapter 1 1.1 - 1.3 Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011.

Introduction Chapter Computer Networks, Fifth Edition by Andrew Tanenbaum and David Wetherall, © Pearson Education-Prentice Hall, 2011.
1 Networking A computer network is a collection of computing devices that are connected in various ways in order to communicate and share resources. The.

1 Networking A computer network is a collection of computing devices that are connected in various ways in order to communicate and share resources. The.
15-1 Networking Computer network A collection of computing devices that are connected in various ways in order to communicate and share resources Usually,

15-1 Networking Computer network A collection of computing devices that are connected in various ways in order to communicate and share resources Usually,
INTRODUCTION TO COMPUTER NETWORKS INTRODUCTION Lecture # 1 (

INTRODUCTION TO COMPUTER NETWORKS INTRODUCTION Lecture # 1 (
Lead Black Slide Powered by DeSiaMore1. 2 Chapter 6 Information System Networks and the Internet.

Lead Black Slide Powered by DeSiaMore1. 2 Chapter 6 Information System Networks and the Internet.
CP476 Internet ComputingCh.1 # 1 Lecture 2. A Brief Introduction to the Internet The objective is to understand The history of Internet What the Internet.

CP476 Internet ComputingCh.1 # 1 Lecture 2. A Brief Introduction to the Internet The objective is to understand The history of Internet What the Internet.
Chapter 2 The Infrastructure. Copyright © 2003, Addison Wesley Understand the structure & elements As a business student, it is important that you understand.

Chapter 2 The Infrastructure. Copyright © 2003, Addison Wesley Understand the structure & elements As a business student, it is important that you understand.

Similar presentations

Ads by Google