CS/ECE 438, CSE 425 Communication Networks Nikita Borisov ECE Department, UIUC
Course Information Instructor Prof. Nikita Borisov Office Hours: 460 CSL, 244-5385 10-12 Tuesdays nikita@uiuc.edu or by appointment TA Monika Battala, battala2@uiuc.edu Office hours TBA Webpage http://www.cs.uiuc.edu/class/fa06/cs438 Newsgroup class.cs438 on news.cs.uiuc.edu 8/25/06 UIUC - CS/ECE 438, Fall 2006 2
Acknowledgments Slides are adapted from Prof. Kravets Some material contributed by Profs. Luo, Lumetta, Hajek, Vaidya Some material from Larry Peterson & James Kurose & Keith Ross 8/25/06 UIUC - CS/ECE 438, Fall 2006 3
Prerequisites C Programming (CS241) Pre-req for ECE students is ECE290, but ECE391/398SSL or C experience highly recommended Probability and Statistics (MATH 461,463 or ECE 413) 8/25/06 UIUC - CS/ECE 438, Fall 2006 4
Textbook Computer Networks: A Top-Down Approach Featuring the Internet , by Kurose & Ross, 3rd Edition We will be covering this text out of order Ch 1 Ch 5 + some of 6 Ch 4 Ch 3 Some of Ch 2 8/25/06 UIUC - CS/ECE 438, Fall 2006 5
Recommended Text UNIX Network Programming, Volume 1 , by Stevens There are 3 editions Second & third edition more up-to-date First edition (1990) contains more background on general UNIX programming 8/25/06 UIUC - CS/ECE 438, Fall 2006 6
Grading Policy Homework 15% 7 homework assignments Mid-term Exam 20% Oct 12 Programming Projects 35% 4 Programming projects 2% off per hour late Final Exam 30% 8/25/06 UIUC - CS/ECE 438, Fall 2006 7
Homework and Projects Homeworks: Due Wednesdays at 2:00 in class. General extension to Thursdays at 2:00pm (hard deadline). No questions to TA or on newsgroup after class on Tuesday. Projects: Project 1: 5%, Projects 2- 4: 10% Due Fridays at 9:00pm. 8/25/06 UIUC - CS/ECE 438, Fall 2006 8
Academic Honesty Your work in this class must be your own. Penalties for excessive collaboration and cheating are severe Sharing strategies and small code fragments (5-10 lines) OK Sharing homework answers and large sections of code forbidden Don’t post these to newsgroup! If in doubt, ask the professor 8/25/06 UIUC - CS/ECE 438, Fall 2006 9
One Unit Students Graduate students MAY take an extra unit project in conjunction with this class Graduate students Register for 4 credits Write a survey paper in a networking research area of your choice. Project proposal with list of 10+ academic references (no URL’s) due September 22 Paper due last day of class Undergraduates may not take this project course 8/25/06 UIUC - CS/ECE 438, Fall 2006 10
Course Objectives At the end of the semester, you should be able to: Identify the problems that arise in networked communication Explain the advantages and disadvantages of existing solutions to these problems in the context of different networking regimes Understand the implications of a given solution for performance in various networking regimes Evaluate novel approaches to these problems 8/25/06 UIUC - CS/ECE 438, Fall 2006 11
Programming Objectives At the end of the semester, you should be able to Identify and describe the purpose of each component of the TCP/IP protocol suite Develop solid client-server applications using TCP/IP Understand the impact of trends in network hardware on network software issues 8/25/06 UIUC - CS/ECE 438, Fall 2006 12
Course Contents Overview UNIX Network Programming Direct Link Networks Multiple Access Packet Switched Networks Internetworking Reliable Transport Congestion Control, QoS & Fair Sharing Performance Analysis and Queueing Theory 8/25/06 UIUC - CS/ECE 438, Fall 2006 13
Connectivity Building Block Links: coax cable, optical fiber, … Nodes: workstations, routers, … Links: Point-to-point … Multiple access 8/25/06 UIUC - CS/ECE 438, Fall 2006 14
Indirect Connectivity Switched Networks Internetworks Recursive definition of a network Two or more nodes connected by a physical link Two or more networks connected by one or more nodes 8/25/06 UIUC - CS/ECE 438, Fall 2006 15
Indirect Connectivity Switched Networks Internetworks Recursive definition of a network Two or more nodes connected by a physical link Two or more networks connected by one or more nodes 8/25/06 UIUC - CS/ECE 438, Fall 2006 15
Indirect Connectivity Switched Networks Internetworks Recursive definition of a network Two or more nodes connected by a physical link Two or more networks connected by one or more nodes 8/25/06 UIUC - CS/ECE 438, Fall 2006 15
Network Problems 8/25/06 UIUC - CS/ECE 438, Fall 2006 16
Network Problems What must a network provide? Connectivity Cost-effective Resource Sharing Functionality Performance 8/25/06 UIUC - CS/ECE 438, Fall 2006 16
Addressing Addressing Unique byte-string used to indicate which node is the target of communication Routing The process of determining how to forward messages toward the destination node based on its address Types of Addresses Unicast: node-specific Broadcast: all nodes on the network Multicast: subset of nodes on the network 8/25/06 UIUC - CS/ECE 438, Fall 2006 17
Effects of Indirect Connectivity Nodes receive data on one link and forward it onto the next -> switching network Circuit Switching Telephone Stream-based (dedicated circuit) Links reserved for use by communication channel Send/receive bit stream at constant rate Packet Switching Internet Message-based (store-and-forward) Links used dynamically Admission policies and other traffic determine bandwidth 8/25/06 UIUC - CS/ECE 438, Fall 2006 18
Cost-Effective Sharing of Resources Physical links and switches must be shared among many users Common multiplexing strategies (Synchronous) time-division multiplexing (TDM) Frequency-division multiplexing (FDM) 8/25/06 UIUC - CS/ECE 438, Fall 2006 19
Circuit Switching: FDM and TDM 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM FDM frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency TDM time frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency TDM time frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency TDM time frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency TDM time frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Circuit Switching: FDM and TDM Example: FDM 4 users frequency TDM time frequency time 8/25/06 UIUC - CS/ECE 438, Fall 2006 20
Statistical Multiplexing Statistical Multiplexing (SM) On-demand time-division multiplexing Scheduled on a per-packet basis Packets from different sources are interleaved Uses upper bounds to limit transmission Queue size determines capacity per source 8/25/06 UIUC - CS/ECE 438, Fall 2006 21
Statistical Multiplexing in a Switch Packets buffered in switch until forwarded Selection of next packet depends on policy How do we make these decisions in a fair manner? Round Robin? FIFO? How should the switch handle congestion? … 8/25/06 UIUC - CS/ECE 438, Fall 2006 22
Functionality Support For Common Services Goal Meaningful communication between hosts on a network Idea Common services simplify the role of applications Hide the complexity of the network without overly constraining the application designer Semantics and interface depend on applications Request/reply: FTP, HTTP, DNS Message stream: video-on-demand, video conferencing 8/25/06 UIUC - CS/ECE 438, Fall 2006 23
Channels Channel The abstraction for application-level communication Idea Turn host-to-host connectivity into process-to-process communication 8/25/06 UIUC - CS/ECE 438, Fall 2006 24
Channels Channel The abstraction for application-level communication Idea Turn host-to-host connectivity into process-to-process communication Host Host Host Channel Channel Host Host 8/25/06 UIUC - CS/ECE 438, Fall 2006 24
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