CS551: Computer Communications Fall 2002 Christos Papadopoulos (http://netweb.usc.edu/cs551/)http://netweb.usc.edu/cs551/)

Slides:



Advertisements
Similar presentations
Fred P. Baker CCIE, CCIP(security), CCSA, MCSE+I, MCSE(2000)
Advertisements

Introduction 2 1: Introduction.
CPSC Network Layer4-1 IP addresses: how to get one? Q: How does a host get IP address? r hard-coded by system admin in a file m Windows: control-panel->network->configuration-
© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Introduction to IPv4 Introduction to Networks.
IP datagrams Service paradigm, IP datagrams, routing, encapsulation, fragmentation and reassembly.
CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 25 Introduction to Computer Networks.
1 o Two issues in practice – Scale – Administrative autonomy o Autonomous system (AS) or region o Intra autonomous system routing protocol o Gateway routers.
Cs/ee 143 Communication Networks Chapter 6 Internetworking Text: Walrand & Parekh, 2010 Steven Low CMS, EE, Caltech.
Packet Switching COM1337/3501 Textbook: Computer Networks: A Systems Approach, L. Peterson, B. Davie, Morgan Kaufmann Chapter 3.
Spring 2000CS 4611 Introduction Outline Statistical Multiplexing Inter-Process Communication Network Architecture Performance Metrics.
UNIT-IV Computer Network Network Layer. Network Layer Prepared by - ROHIT KOSHTA In the seven-layer OSI model of computer networking, the network layer.
Internet -- network of networks –network delivers packets (& locates nodes) –router (gateway) moves packets between networks –IP interoperability on top.
Networking Theory (Part 1). Introduction Overview of the basic concepts of networking Also discusses essential topics of networking theory.
CS335 Networking & Network Administration Tuesday, May 18, 2010.
Data Communications I & II Project Sequence Tom Costello.
1 Last Class! Today: r what have we learned? r where is the networking world going? r question and answers r evaluation.
CS 4119: Computer Networks Henning Schulzrinne Dept. of Computer Science Columbia University
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.
15-744: Computer Networking L-1 Intro to Computer Networks.
Networking Components Chad Benedict – LTEC
Lecture 1, 1Spring 2003, COM1337/3501Computer Communication Networks Rajmohan Rajaraman COM1337/3501 Textbook: Computer Networks: A Systems Approach, L.
TCP/IP Web Design & Layout January 23, TCP/IP For Dummies  The guts and the rules of the Internet and World Wide Web. A set of protocols, services,
Overview, Circuit & Packet Switching, Addressing
Presentation Title Subtitle Author Copyright © 2002 OPNET Technologies, Inc. TM Introduction to IP and Routing.
S305 – Network Infrastructure Chapter 5 Network and Transport Layers.
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.
Communications Recap Duncan Smeed. Introduction 1-2 Chapter 1: Introduction Our goal: get “feel” and terminology more depth, detail later in course.
S305 – Network Infrastructure Chapter 5 Network and Transport Layers.
CS448 Computer Networking Chapter 1 Introduction to Computer Networks Instructor: Li Ma Office: NBC 126 Phone: (713)
Chapter 4. After completion of this chapter, you should be able to: Explain “what is the Internet? And how we connect to the Internet using an ISP. Explain.
Lecture 8 Page 1 Advanced Network Security Review of Networking Basics: Internet Architecture, Routing, and Naming Advanced Network Security Peter Reiher.
Cisco 1 - Networking Basics Perrine. J Page 19/17/2015 Chapter 9 What transport layer protocol does TFTP use? 1.TCP 2.IP 3.UDP 4.CFTP.
Common Devices Used In Computer Networks
© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ITE PC v4.0 Chapter 1 1 Connecting to the Network Networking for Home and Small Businesses.
1 Introduction to Networking Dr. Mahdi Nasereddin PPU.
1.1 What is the Internet What is the Internet? The Internet is a shared media (coaxial cable, copper wire, fiber optics, and radio spectrum) communication.
Operating Systems Lesson 10. Networking Communications protocol is the set of standard rules for ◦ Data representation ◦ Signaling ◦ Authentication ◦
CS 381 Final Exam Study Guide Final Exam Date: Tuesday, May 12 th Time: 10:30am -12:30pm Room: SB 105 Exam aid: 8 ½ x 11 page of notes front and back.
Chi-Cheng Lin, Winona State University CS 313 Introduction to Computer Networking & Telecommunication Introduction – Part II.
Objectives: Chapter 5: Network/Internet Layer  How Networks are connected Network/Internet Layer Routed Protocols Routing Protocols Autonomous Systems.
1 ECE 156 Computer Network Architecture Professor Krish Chakrabarty Department of Electrical and Computer Engineering Fall 2006.
15-1 Networking Computer network A collection of computing devices that are connected in various ways in order to communicate and share resources.
Communication Networks Fourth Meeting. Types of Networks  What is a circuit network?  Two people are connected and allocated them their own physical.
Network Protocols: Design and Analysis Polly Huang EE NTU
Computer Networking. 2 Outline 3 Objectives Understand the state-of-the-art in network protocols, architectures and applications Understand how networking.
Networks CS105. What is a computer network? A computer network is a collection of computing devices that are connected in various ways so that they can.
S305 – Network Infrastructure Chapter 5 Network and Transport Layers.
Ch 1. Computer Networks and the Internet Myungchul Kim
Univ. of TehranComputer Network1 Computer Networks Computer Networks (Graduate level) University of Tehran Dept. of EE and Computer Engineering By: Dr.
Networking Fundamentals. Basics Network – collection of nodes and links that cooperate for communication Nodes – computer systems –Internal (routers,
1 Pre-Introduction What is computer network?. 2 Pre-Introduction Suppose you want to build a computer network The question is: –What available technologies.
1 ECE453 - Introduction to Computer Networks Lecture 1: Introduction.
Introduction to Data Communication
© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 Connecting to the Network Introduction to Networking Concepts.
Internet Protocols. ICMP ICMP – Internet Control Message Protocol Each ICMP message is encapsulated in an IP packet – Treated like any other datagram,
Cisco Confidential © 2013 Cisco and/or its affiliates. All rights reserved. 1 Cisco Networking Training (CCENT/CCT/CCNA R&S) Rick Rowe Ron Giannetti.
science/internet-intro
Networking Components William Isakson LTEC 4550 October 7, 2012 Module 3.
Introduction Computer networks: – definition – computer networks from the perspectives of users and designers – Evaluation criteria – Some concepts: –
S305 – Network Infrastructure Chapter 5 Network and Transport Layers.
Network Layer IP Address.
Network Processing Systems Design
1 Computer Networks Chapter 5. Network layer The network layer is concerned with getting packets from the source all the way to the destination. Getting.
Vocabulary Prototype: A preliminary sketch of an idea or model for something new. It’s the original drawing from which something real might be built or.
CS 268: Computer Networking
Vocabulary Prototype: A preliminary sketch of an idea or model for something new. It’s the original drawing from which something real might be built or.
Chapter 5 Network and Transport Layers
Computer Science 457 Networking and the Internet
CS Lecture 2 Network Performance
Presentation transcript:

CS551: Computer Communications Fall 2002 Christos Papadopoulos (

Admin Stuff Class web page will be complete soon – No class Monday (labor day) Ns and nam tutorial on Wed –Padma Haldar from ISI –Will host students from Tue section Watch out for easy first homework and possible warm-up socket programming assignment

Course Topics (Tentative) Introduction Design principles Unicast routing TCP and congestion Wireless systems Web issues Integrated and differentiated services Multicast routing Multicast applications Current Topics

Focus of the Class Protocols and mechanisms –We will not deal with how bits move in physical media - you did this in your undergrad class We will deal with: –Protocol rules and algorithms –Investigate mechanism tradeoffs –Why this way and not another?

The Internet, Circa 1969

A Recent Internet ISP Map

The Internet, on a Poster, Circa 2000 [data courtesy of UCSD’s caida]

Internet Development Mantra Quote from a t-shirt commonly worn at IETF meetings: “We reject kings, presidents and voting. We believe in rough consensus and running code.” (Dave Clark)

Glimpses of the Future? (an 8-bit web server with Ethernet) UCB mote: an 8-bit sensor node with non-IP based networking a sensor network (tracking the truck)

Some Definitions Host: computer, PDA, light switch,... Link: path followed by bits. –Wire or wireless. –Broadcast or switched (or both). Switch: moves bits between links. –Packet switching: stateless, store&forward. –Circuit switching: stateful, cut through.

Networks … Point-to-Point Multiple Access … Wireless

Switched Networks –Two or more nodes connected by a link, or –two or more networks connected by two or more nodes A network can be defined recursively as...

What Is the Problem?

But What to Scale? Always define what kind of“scale” you mean –Number of hosts, globally routable –Network should support many link layers –Geographic distance –Many versions of software, hardware technologies –Range of bandwidths –Different application needs (QoS, etc) –Levels of trust / administrative boundaries –Range of price points for hardware Lots of dimensions of “scaling” to consider

Applications Rule! Sometimes easy to forget in this course Aside: What are the implications of global connectivity? –Technological issues –Societal issues –Economic issues –Security issues –etc

Application Considerations Application input to network –Traffic data rate –Traffic pattern (bursty or constant bit rate) –Traffic target (multipoint or single destination, mobile or fixed) Network service delivered to application –Delay sensitivity –Loss sensitivity

Reliable File Transfer Loss sensitive Not delay sensitive relative to round trip times Point-to-point or multipoint Bursty

Remote Login Loss sensitive Delay sensitive –Subject to interactive constraints –Can tolerate up to several hundreds of milliseconds Bursty Point to point

Network Audio Relatively low bandwidth –Digitized samples, packetized Delay variance sensitive Loss tolerant Possibly multipoint, long duration sessions –Natural limit to number of simultaneous senders

Network Video High bandwidth Compressed video, bursty Loss tolerance function of compression Delay tolerance a function of interactivity Possibly multipoint Larger number of simultaneous sources

Web Transactional traffic –Short requests, possibly large responses Loss (bug?) tolerant Delay sensitive –Human interactivity Point-to-point (multipoint is asynchronous)

Disruptive Applications Applications that “disrupt” business as usual Not easy to predict: multicast case in point Web was arguably the first, and not many saw that coming Napster is the poster child Gnutella, Kazaa, Morpheus (?) Others? What’s next?

The Global Network

Getting Started Host configuration Network configuration ISP Computers meeting computers Computers exchanging data

Host Configuration Host configuration needs: –a physical network cable (Ethernet, etc.) –an IP address –a network mask –a gateway –a DNS server (and other servers) Automated with DHCP

A Network Network configuration needs: –wires (from the phone or cable company) –Router(s) –a firewall? –an ISP to connect to the Internet –network addresses (e.g., xxx) –servers

An ISP ISP needs: –a (big?) block of addresses –connections to one or more other ISPs, peerings –multiple routers, probably at exchange points –servers for your users: mail, web, etc –servers for you: monitoring, etc –competent network admins (recommended) –an AUP (Acceptable Use Policy) –a lawyer

What Is…. Structure Metrics Failure modes Functions

Idealized Network Structure Backbones Regionals Campus LANs

How Do Computers Find Each Other? Internet Computer1Computer 2

What Are the Different Kinds of Addresses? Have domain name (e.g., –Global, human readable name DNS translates name to IP address (e.g ) –Global, understood by all networks Finally, we need local net address –e.g., Ethernet ( c-19-dc-45) –Local, works only on a particular network

Domain Naming System (DNS) Local DNS server What’s the IP address for Computer 1 It is DNS address manually configured into OS

Finding Ether Address: Address Resolution (ARP) Ethernet Broadcast: who knows the Ethernet address for ? Ethernet Broadcast: I do, it is c-19-dc-45

Sending a Packet Through the Internet R R R R R HH H H H R R H R Routers send packet to next closest point H: Hosts R: Routers

How Do the Routers Know Where to Send Data? Forwarding tables at each router populated by routing protocols. Original internet: manually updated. Routing protocols update tables based on “cost.” –Exchange tables with neighbors or everyone. –Use neighbor leading to shortest path.

Network Metrics Bandwidth –Transmission capacity (a.k.a. How many bits can fit in a section of a link?) Delay –queueing delay –Propagation delay (limited by c) Delay-bandwidth product –Important for control algorithms

Network Failures Packet loss –Queue overflows –Line noise Node or link failures Routing transients or failures

Engineering Trade-offs Network can be engineered to provide: Reliability Low delay Cost Pick any two