Today s Outline Overview EECS 122 Lecture 1 Course Information and Goals Overview Department of Electrical Engineering and Computer Sciences University of California Berkeley Applications Protocols and Components The Network Edge and Core Divsion Packet and Circuit Switching Examples of Networks What is the Internet Great way to familiarize you with some terms and concepts The rest of course will delve deeper into what you hear about today January 17 2006 Administrivia Marghoob Mohiyuddin marghoob eecs Office hours TBA Nikhil Shetty nikhils eecs Office Hours TBA Recitations Tues Thursday 2 3pm in the Qualcomm Room 200 Cory Class Web page Tues Thursday 12 30 2pm Office hour W F Lecture time Abhay Parekh parekh eecs berkeley edu 223 Cory David Tse dtse eecs berkeley edu 224 Cory TAs http inst eecs berkeley edu ee122 not up yet Text Computer Networking A Top Down Approach Featuring the Internet 3rd Edition by Kurose and Ross January 17 2006 2 Course Structure Instructors EECS122 Lecture 1 AKP EECS122 Lecture 1 AKP 3 Prerequisites C and Java you don t have to be a great programmer but comfortable with the syntax Algorithms and their analysis no difficult math but you have to be comfortable looking at problems analytically Grading Homework Assignments 15 Projects 30 Midterm 20 Final 35 Homework Paper pencil problems and Ethereal Lab problems Projects Network Simulator NS2 based project Several shorter programming projects based on C and Java January 17 2006 EECS122 Lecture 1 AKP 4 1 Course Structure http Attend Lecture Be on Time Ask Questions Utilize the course resources Lectures Recitations Labs Office Hours Companion Website for the book TCP IP 802 11 Voice Data P2P Networking is a very complex subject WWW Routers This is a big class so please What is networking try to focus on concepts not just details Free Stuff Late Hand ins 25 off for the first late day Nothing accepted that is more late than one day January 17 2006 Cable Modem 5 EECS122 Lecture 1 AKP Applications January 17 2006 IM 6 EECS122 Lecture 1 AKP Components WWW Routers WWW Routers http http TCP IP TCP IP 802 11 802 11 P2P P2P Free Stuff Free Stuff Optical Fiber January 17 2006 Optical Fiber IM EECS122 Lecture 1 AKP Cable Modem Optical Fiber 7 January 17 2006 IM EECS122 Lecture 1 AKP Cable Modem 8 2 Protocols What s a protocol WWW Routers human protocols Meal time I have a question introductions http TCP IP 802 11 specific msgs sent specific actions taken when msgs received or other events P2P Free Stuff Optical Fiber January 17 2006 Cable Modem IM 9 EECS122 Lecture 1 AKP January 17 2006 a human protocol and a computer network protocol TCP connection request TCP connection response Let s hang up Over 10 What is its structure How does it scale Who owns it How can we make it better Get http www berkeley edu Sure Over and out file time January 17 2006 EECS122 Lecture 1 AKP Our Focus will be on the internet Hello Over protocols define format order of msgs sent and received among network entities and actions taken on msg transmission receipt Applications Protocols Components How do they all come together What s a protocol Hi Over network protocols machines rather than humans all communication activity in Internet governed by protocols EECS122 Lecture 1 AKP 11 How does one write a new network application How does one insert a new component a faster router for example This will help us understand other kinds of networks e g the voice network as well January 17 2006 EECS122 Lecture 1 AKP 12 3 Course Goals To gain a fundamental understanding of what the internet is and how it works today The Simplest Network Hosts This is a first course so we may be more wide than deep A To understand how the internet may evolve in the future January 17 2006 EECS122 Lecture 1 AKP 13 Networks are created from a need to communicate B Link January 17 2006 14 EECS122 Lecture 1 AKP Inevitably Networks Grow C Hundreds of Millions of End Nodes or Hosts B A D Web Servers E Directly connecting n hosts takes O n2 links Complications Hosts 1 must forward 2 choose among multiple paths 1 The forwarding function becomes a performance bottleneck 2 There too many alternative paths the overhead to select among them becomes prohibitive Skype Phones January 17 2006 EECS122 Lecture 1 AKP 15 January 17 2006 EECS122 Lecture 1 AKP 16 4 Enter Routers Enter Routers C E C B A D Hosts connect to specialized devices called Routers Routers are built HW and Software to discover the topology select good paths and forward messages quickly They respond to changing network conditions January 17 2006 17 EECS122 Lecture 1 AKP Enter More Network Infrastructure C Hosts connect to specialized devices called Routers Routers are built HW and Software to discover the topology select good paths and forward messages quickly They respond to changing network conditions January 17 2006 18 EECS122 Lecture 1 AKP Host Core Division The Core provides a network service to the hosts E B A B A D E C B A D E D A directory server that helps an application node figure out which network address es it should send its messages to In the internet this is DNS The devices inside the network cloud are what make the internet tick The applications in end hosts make the internet useful and powerful The end hosts form the Network Edge January 17 2006 EECS122 Lecture 1 AKP 19 January 17 2006 EECS122 Lecture 1 AKP 20 5 Special Case Broadcast C E The network edge client server model Directly connecting n hosts takes O n2 links B A D The core is very simple for broadcast networks although other problems to be studied later arise client host requests receives service from always on server e g Web browser server email client server peer peer model minimal or no use of dedicated servers e g Gnutella KaZaA Skype Every transmission is received by all the other hosts Examples 1 Satellite Transmission 2 Local Area Networks January 17 2006 EECS122 Lecture 1 AKP 21 Many interconnected subnetworks Many different architectures Advertises a service to the end devices Example The Internet Virtual Circuit All the packets from a given stream take the same path through the network 23 Once a call goes through subsequent calls cannot degrade call quality Packet Switched Information is exchanged in units of packets Typically no resources are reserved Datagram Each packet is forwarded independently EECS122 Lecture 1 AKP 22 Circuit Switched Information is exchanged in units of calls Network resources are reserved for the duration of
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