CMPE 150 Winter 2009
|
|
- Bennett Leonard
- 6 years ago
- Views:
Transcription
1 CMPE 150 Winter 2009 Lecture 17 March 5, 2009 P.E. Mantey
2 CMPE Introduction to Computer Networks Instructor: Patrick Mantey / t / Office: Engr. 2 Room 595J Office hours: Tues 3-5 PM, Mon 5-6 PM* TA: Anselm Kia akia@soe.ucsc.edu Web site: Text: Tannenbaum: Computer Networks (4 th edition available in bookstore, etc. )
3 Syllabus
4 Text Readings Today: Chapter 6, Section (TCP Performance) Tuesday March 10 Chapter 7.1 (DNS), Chapter 7.4 (Multimedia)
5 Internet Layering Level 5 -- Application Layer (rlogin, ftp, SMTP, POP3, IMAP, HTTP..) Level 4 -- Transport Layer(a.k.a a Host-to-Host) to Host) (TCP, UDP) Level 3 -- Network Layer (a.k.a. Internet) (IP, ICMP, ARP) Level 2 -- (Data) Link Layer / MAC sub-layer (a.k.a. Network Interface or Network Access Layer) Level 1 -- Physical Layer
6 Transport Layer Connection Oriented Service Addressing / Access Points Connection Request / Establishment Delayed Duplicate Packet Problem Timer management Connection points Connection Release
7 Today s Agenda Transport Layer TCP: Timers / RTT estimates Exponential backoff Wireless vs. wired Transactional TCP Performance
8
9 Port Detective
10
11
12 3389 Remote desktop (Windows XP) Reference: p g p p_ p ========================================================== See also:
13 TCP Congestion Control (a) A fast network feeding a low capacity receiver.
14 Jacobson s Algorithm 1 Determining the round-trip time: TCP keeps RTT variable. When segment sent, TCP measures how long it takes to get ACK back (M). RTT = alpha*rtt + (1-alpha)M. alpha: smoothing factor; determines weight given to previous estimate. Typically, alpha=7/8.
15 Jacobson s Algorithm 2 Determining timeout value: Measure RTT variation, or RTT-M. Keeps smoothed value of cumulative variation D=alpha*D+(1-alpha) RTT-M. Alpha may or may not be the same as value used to smooth RTT. Timeout = RTT+4*D.
16 Karn s Algorithm How to account for ACKs of retransmitted segments? Count it for first or second transmission? Karn proposed not to update RTT on any retransmitted segment. Instead RTT is doubled on each failure until segments get through.
17 TCP Congestion Control: Example cwin timeout threshold threshold time
18 Persistence Timer Prevents deadlock if an window update packet is lost and advertised window = 0. When persistence timer goes off, sender probes receiver; receiver replies with its current advertised window. If = 0, persistence timer is set again.
19 Keepalive Timer Goes off when a connection is idle for a long time. Causes one side to check whether the other side is still alive. If no answer, connection terminated.
20 TCP Timer Management (a) Probability density of ACK arrival times in the data link layer. (b) Probability density of ACK arrival times for TCP.
21 TCP Retransmission Timer When segment sent, retransmission timer starts. If segment ACKed, timer stops. If time out, segment retransmitted and timer starts eou,seg e e s ed d e s s again.
22 How to set timer? Based on round-trip time: time between a segment is sent and ACK comes back. If timer is too short, unnecessary retransmissions. If timer is too long, long retransmission delay.
23 Jacobson s Algorithm 1 Determining the round-trip time: TCP keeps RTT variable. When segment sent, TCP measures how long it takes to get ACK back (M). RTT = alpha*rtt + (1-alpha)M. alpha: smoothing factor; determines weight given to previous estimate. Typically, alpha=7/8.
24 Jacobson s Algorithm 2 Determining timeout value: Measure RTT variation, or RTT-M. Keeps smoothed value of cumulative variation D=alpha*D+(1-alpha) RTT-M. Alpha may or may not be the same as value used to smooth RTT. Timeout = RTT+4*D.
25 Karn s Algorithm How to account for ACKs of retransmitted segments? Count it for first or second transmission? Karn proposed not to update RTT on any retransmitted segment. Instead RTT is doubled on each failure until segments get through.
26 Persistence Timer Prevents deadlock if an window update packet is lost and advertised window = 0. When persistence timer goes off, sender probes receiver; receiver replies with its current advertised window. If = 0, persistence timer is set again.
27 Keepalive Timer Goes off when a connection is idle for a long time. Causes one side to check whether the other side is still alive. If no answer, connection terminated.
28 Performance Issues Performance Problems in Computer Networks Network Performance Measurement System Design for Better Performance Fast TPDU Processing Protocols for Gigabit Networks
29
30
31
32 System Design for Better Performance Rules: CPU speed is more important than network speed. Reduce packet count to reduce software overhead. Minimize context switches. Minimize copying. You can buy more bandwidth but not lower delay. Avoiding congestion is better than recovering from it. Avoid timeouts.
33 Wireless TCP and UDP Splitting a TCP connection into two connections.
34 Wireless TCP 1 According to layered system design principles, transport protocol should be independent of underlying technology. However, wireless networks invalidate this principle. Ignoring properties of wireless medium can lead to poor TCP performance. Problem: TCP s congestion control.
35 Wireless TCP 2 Problem: packet loss as congestion indicator. When retransmission timer times out, sender slows down. Wireless links are lossy! Dealing with losses in this case should be re-sending lost segments asap.
36 Indirect TCP (I-TCP) [Bakne and Badrinath, 1995]. Split TCP connection in 2: one from sender to base station and the other from base station to receiver. Base station serves as repeater : copies segments between connections in both directions. Connections are homogeneous; timeouts on 1st. connection, slow down sender. Problem: violates TCP s e2e ness. Example: ACKs to sender mean base station received segments, not necessarily receiver.
37 Snoop TCP [Balakrishnan et al., 1995]. Does not break connection. Modifications to base station s network layer code. Snooping agent on base station observes and caches TCP segments sent to mobile host and ACKs coming back. If it doesn t see an ACK for a segment or sees duplicate ACKs, it times out and retransmits. But source may time out anyway.
CMPE 150 Winter 2009
CMPE 150 Winter 2009 Lecture 16 March 3, 2009 P.E. Mantey CMPE 150 -- Introduction to Computer Networks Instructor: Patrick Mantey mantey@soe.ucsc.edu http://www.soe.ucsc.edu/~mantey/ / t / Office: Engr.
More informationCMPE 150 Winter 2009
CMPE 150 Winter 2009 Lecture 9 February 3, 2009 P.E. Mantey CMPE 150 -- Introduction to Computer Networks Instructor: Patrick Mantey mantey@soe.ucsc.edu http://www.soe.ucsc.edu/~mantey/ / t / Office: Engr.
More information8. TCP Congestion Control
8. TCP Congestion Control 1 TCP Congestion Control Slow-start increase Multiplicative decrease Congestion avoidance Measurement of variation Exponential timer backoff 2002 Yanghee Choi 2 Congestion Control
More informationTCP over Wireless PROF. MICHAEL TSAI 2016/6/3
TCP over Wireless PROF. MICHAEL TSAI 2016/6/3 2 TCP Congestion Control (TCP Tahoe) Only ACK correctly received packets Congestion Window Size: Maximum number of bytes that can be sent without receiving
More informationComputer Networks and Data Systems
Computer Networks and Data Systems Transport Layer TDC463 Winter 2011/12 John Kristoff - DePaul University 1 Why a transport layer? IP gives us end-to-end connectivity doesn't it? Why, or why not, more
More informationCMPE 257: Wireless and Mobile Networking
CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 10 CMPE 257 Spring'15 1 Student Presentations Schedule May 21: Sam and Anuj May 26: Larissa
More informationECS-087: Mobile Computing
ECS-087: Mobile Computing TCP over wireless TCP and mobility Most of the Slides borrowed from Prof. Sridhar Iyer s lecture IIT Bombay Diwakar Yagyasen 1 Effect of Mobility on Protocol Stack Application:
More informationECE 435 Network Engineering Lecture 10
ECE 435 Network Engineering Lecture 10 Vince Weaver http://web.eece.maine.edu/~vweaver vincent.weaver@maine.edu 28 September 2017 Announcements HW#4 was due HW#5 will be posted. midterm/fall break You
More informationThe Transmission Control Protocol (TCP)
The Transmission Control Protocol (TCP) Application Services (Telnet, FTP, e-mail, WWW) Reliable Stream Transport (TCP) Unreliable Transport Service (UDP) Connectionless Packet Delivery Service (IP) Goals
More informationWireless TCP. TCP mechanism. Wireless Internet: TCP in Wireless. Wireless TCP: transport layer
Wireless TCP W.int.2-2 Wireless Internet: TCP in Wireless Module W.int.2 Mobile IP: layer, module W.int.1 Wireless TCP: layer Dr.M.Y.Wu@CSE Shanghai Jiaotong University Shanghai, China Dr.W.Shu@ECE University
More informationInternet Applications and the Application Layer Material from Kurose and Ross, Chapter 2: The Application Layer
Midterm Study Sheet Below is a list of topics that will be covered on the midterm exam. Some topics may have summaries to clarify the coverage of the topic during the lecture. Disclaimer: the list may
More informationTCP: Flow and Error Control
1 TCP: Flow and Error Control Required reading: Kurose 3.5.3, 3.5.4, 3.5.5 CSE 4213, Fall 2006 Instructor: N. Vlajic TCP Stream Delivery 2 TCP Stream Delivery unlike UDP, TCP is a stream-oriented protocol
More informationAnnouncements. IP Forwarding & Transport Protocols. Goals of Today s Lecture. Are 32-bit Addresses Enough? Summary of IP Addressing.
IP Forwarding & Transport Protocols EE 122: Intro to Communication Networks Fall 2007 (WF 4-5:30 in Cory 277) Vern Paxson TAs: Lisa Fowler, Daniel Killebrew & Jorge Ortiz http://inst.eecs.berkeley.edu/~ee122/
More informationTCP and Congestion Control (Day 1) Yoshifumi Nishida Sony Computer Science Labs, Inc. Today's Lecture
TCP and Congestion Control (Day 1) Yoshifumi Nishida nishida@csl.sony.co.jp Sony Computer Science Labs, Inc 1 Today's Lecture Part1: TCP concept Part2: TCP detailed mechanisms Part3: Tools for TCP 2 1
More informationChapter 6. The Transport Layer. The Transport Service. Services Provided to the Upper Layers. Transport Service Primitives (3) 10/7/2010
The Transport Service Chapter 6 The Transport Layer Services Provided to the Upper Layers Transport Service Primitives Berkeley Sockets An Example of Socket Programming: An Internet File Server Services
More informationCMSC 417. Computer Networks Prof. Ashok K Agrawala Ashok Agrawala. October 25, 2018
CMSC 417 Computer Networks Prof. Ashok K Agrawala 2018 Ashok Agrawala Message, Segment, Packet, and Frame host host HTTP HTTP message HTTP TCP TCP segment TCP router router IP IP packet IP IP packet IP
More informationIntro to LAN/WAN. Transport Layer
Intro to LAN/WAN Transport Layer Transport Layer Topics Introduction (6.1) Elements of Transport Protocols (6.2) Internet Transport Protocols: TDP (6.5) Internet Transport Protocols: UDP (6.4) socket interface
More informationChapter 13 TRANSPORT. Mobile Computing Winter 2005 / Overview. TCP Overview. TCP slow-start. Motivation Simple analysis Various TCP mechanisms
Overview Chapter 13 TRANSPORT Motivation Simple analysis Various TCP mechanisms Distributed Computing Group Mobile Computing Winter 2005 / 2006 Distributed Computing Group MOBILE COMPUTING R. Wattenhofer
More informationImproving Reliable Transport and Handoff Performance in Cellular Wireless Networks
Improving Reliable Transport and Handoff Performance in Cellular Wireless Networks H. Balakrishnan, S. Seshan, and R. H. Katz ACM Wireless Networks Vol. 1, No. 4, pp. 469-482 Dec. 1995 P. 1 Introduction
More informationNetwork Protocols. Transmission Control Protocol (TCP) TDC375 Autumn 2009/10 John Kristoff DePaul University 1
Network Protocols Transmission Control Protocol (TCP) TDC375 Autumn 2009/10 John Kristoff DePaul University 1 IP review IP provides just enough connected ness Global addressing Hop by hop routing IP over
More informationCMSC 417. Computer Networks Prof. Ashok K Agrawala Ashok Agrawala. October 30, 2018
CMSC 417 Computer Networks Prof. Ashok K Agrawala 2018 Ashok Agrawala October 30, 2018 Message, Segment, Packet, and Frame host host HTTP HTTP message HTTP TCP TCP segment TCP router router IP IP packet
More informationChapter 6. (Week 12) The Transport Layer (CONTINUATION) ANDREW S. TANENBAUM COMPUTER NETWORKS FOURTH EDITION PP
Chapter 6 (Week 12) The Transport Layer (CONTINUATION) ANDREW S. TANENBAUM COMPUTER NETWORKS FOURTH EDITION PP. 524-574 1 THE TRANSPORT LAYER S TASK IS TO PROVIDE RELIABLE, COST- EFFECTIVE DATA TRANSPORT
More informationTCP over wireless links
CSc 450/550 Computer Communications & Networks TCP over wireless links Jianping Pan (stand-in for Dr. Wu) 1/31/06 CSc 450/550 1 TCP over wireless links TCP a quick review on how TCP works Wireless links
More informationUNIT IV -- TRANSPORT LAYER
UNIT IV -- TRANSPORT LAYER TABLE OF CONTENTS 4.1. Transport layer. 02 4.2. Reliable delivery service. 03 4.3. Congestion control. 05 4.4. Connection establishment.. 07 4.5. Flow control 09 4.6. Transmission
More informationLecture 20 Overview. Last Lecture. This Lecture. Next Lecture. Transport Control Protocol (1) Transport Control Protocol (2) Source: chapters 23, 24
Lecture 20 Overview Last Lecture Transport Control Protocol (1) This Lecture Transport Control Protocol (2) Source: chapters 23, 24 Next Lecture Internet Applications Source: chapter 26 COSC244 & TELE202
More informationOutline. CS5984 Mobile Computing
CS5984 Mobile Computing Dr. Ayman Abdel-Hamid Computer Science Department Virginia Tech Outline Review Transmission Control Protocol (TCP) Based on Behrouz Forouzan, Data Communications and Networking,
More informationLecture 15: TCP over wireless networks. Mythili Vutukuru CS 653 Spring 2014 March 13, Thursday
Lecture 15: TCP over wireless networks Mythili Vutukuru CS 653 Spring 2014 March 13, Thursday TCP - recap Transport layer TCP is the dominant protocol TCP provides in-order reliable byte stream abstraction
More informationInternet and Intranet Protocols and Applications
Internet and Intranet Protocols and Applications Lecture 1b: The Transport Layer in the Internet January 17, 2006 Arthur Goldberg Computer Science Department New York University artg@cs.nyu.edu 01/17/06
More informationOutline 9.2. TCP for 2.5G/3G wireless
Transport layer 9.1 Outline Motivation, TCP-mechanisms Classical approaches (Indirect TCP, Snooping TCP, Mobile TCP) PEPs in general Additional optimizations (Fast retransmit/recovery, Transmission freezing,
More informationChapter 24. Transport-Layer Protocols
Chapter 24. Transport-Layer Protocols 23.1 Introduction 23.2 User Datagram Protocol 23.3 Transmission Control Protocol 23.4 SCTP Computer Networks 24-1 Position of Transport-Layer Protocols UDP is an unreliable
More informationTCP/IP Networking. Part 4: Network and Transport Layer Protocols
TCP/IP Networking Part 4: Network and Transport Layer Protocols Orientation Application Application protocol Application TCP TCP protocol TCP IP IP protocol IP IP protocol IP IP protocol IP Network Access
More informationWireless TCP Performance Issues
Wireless TCP Performance Issues Issues, transport layer protocols Set up and maintain end-to-end connections Reliable end-to-end delivery of data Flow control Congestion control Udp? Assume TCP for the
More informationCSE 4215/5431: Mobile Communications Winter Suprakash Datta
CSE 4215/5431: Mobile Communications Winter 2013 Suprakash Datta datta@cse.yorku.ca Office: CSEB 3043 Phone: 416-736-2100 ext 77875 Course page: http://www.cse.yorku.ca/course/4215 Some slides are adapted
More informationTransport layer issues
Transport layer issues Dmitrij Lagutin, dlagutin@cc.hut.fi T-79.5401 Special Course in Mobility Management: Ad hoc networks, 28.3.2007 Contents Issues in designing a transport layer protocol for ad hoc
More informationLecture 3: The Transport Layer: UDP and TCP
Lecture 3: The Transport Layer: UDP and TCP Prof. Shervin Shirmohammadi SITE, University of Ottawa Prof. Shervin Shirmohammadi CEG 4395 3-1 The Transport Layer Provides efficient and robust end-to-end
More informationLecture 5: Flow Control. CSE 123: Computer Networks Alex C. Snoeren
Lecture 5: Flow Control CSE 123: Computer Networks Alex C. Snoeren Pipelined Transmission Sender Receiver Sender Receiver Ignored! Keep multiple packets in flight Allows sender to make efficient use of
More informationTransport Protocols and TCP: Review
Transport Protocols and TCP: Review CSE 6590 Fall 2010 Department of Computer Science & Engineering York University 1 19 September 2010 1 Connection Establishment and Termination 2 2 1 Connection Establishment
More informationfile:///c:/users/hpguo/dropbox/website/teaching/fall 2017/CS4470/H...
1 of 9 11/26/2017, 11:28 AM Homework 3 solutions 1. A window holds bytes 2001 to 5000. The next byte to be sent is 3001. Draw a figure to show the situation of the window after the following two events:
More informationTSIN02 - Internetworking
Lecture 4: Transport Layer Literature: Forouzan: ch 11-12 2004 Image Coding Group, Linköpings Universitet Lecture 4: Outline Transport layer responsibilities UDP TCP 2 Transport layer in OSI model Figure
More informationCIS 632 / EEC 687 Mobile Computing
CIS 632 / EEC 687 Mobile Computing TCP in Mobile Networks Prof. Chansu Yu Contents Physical layer issues Communication frequency Signal propagation Modulation and Demodulation Channel access issues Multiple
More informationTransport Over IP. CSCI 690 Michael Hutt New York Institute of Technology
Transport Over IP CSCI 690 Michael Hutt New York Institute of Technology Transport Over IP What is a transport protocol? Choosing to use a transport protocol Ports and Addresses Datagrams UDP What is a
More informationComputer Communication Networks Midterm Review
Computer Communication Networks Midterm Review ICEN/ICSI 416 Fall 2018 Prof. Aveek Dutta 1 Instructions The exam is closed book, notes, computers, phones. You can use calculator, but not one from your
More informationLecture 7: Flow Control"
Lecture 7: Flow Control" CSE 123: Computer Networks Alex C. Snoeren No class Monday! Lecture 7 Overview" Flow control Go-back-N Sliding window 2 Stop-and-Wait Performance" Lousy performance if xmit 1 pkt
More informationTCP OVER AD HOC NETWORK
TCP OVER AD HOC NETWORK Special course on data communications and networks Zahed Iqbal (ziqbal@cc.hut.fi) Agenda Introduction Versions of TCP TCP in wireless network TCP in Ad Hoc network Conclusion References
More informationMobile Transport Layer
Mobile Transport Layer 1 Transport Layer HTTP (used by web services) typically uses TCP Reliable transport between TCP client and server required - Stream oriented, not transaction oriented - Network friendly:
More informationMobile Transport Layer Lesson 10 Timeout Freezing, Selective Retransmission, Transaction Oriented TCP and Explicit Notification Methods
Mobile Transport Layer Lesson 10 Timeout Freezing, Selective Retransmission, Transaction Oriented TCP and Explicit Notification Methods 1 Timeout freezing of transmission (TFT) Used in situations where
More informationAdvanced Network Design
Advanced Network Design Organization Whoami, Book, Wikipedia www.cs.uchicago.edu/~nugent/cspp54015 Grading Homework/project: 60% Midterm: 15% Final: 20% Class participation: 5% Interdisciplinary Course
More informationEE 122: IP Forwarding and Transport Protocols
EE 1: IP Forwarding and Transport Protocols Ion Stoica (and Brighten Godfrey) TAs: Lucian Popa, David Zats and Ganesh Ananthanarayanan http://inst.eecs.berkeley.edu/~ee1/ (Materials with thanks to Vern
More informationImpact of transmission errors on TCP performance. Outline. Random Errors
Impact of transmission errors on TCP performance 1 Outline Impact of transmission errors on TCP performance Approaches to improve TCP performance Classification Discussion of selected approaches 2 Random
More informationTransport Protocols & TCP TCP
Transport Protocols & TCP CSE 3213 Fall 2007 13 November 2007 1 TCP Services Flow control Connection establishment and termination Congestion control 2 1 TCP Services Transmission Control Protocol (RFC
More informationTRANSMISSION CONTROL PROTOCOL
COMP 635: WIRELESS NETWORKS TRANSMISSION CONTROL PROTOCOL Jasleen Kaur Fall 2015 1 Impact of Wireless on Protocol Layers Application layer Transport layer Network layer Data layer Physical layer service
More informationECE697AA Lecture 3. Today s lecture
ECE697AA Lecture 3 Transport Layer: TCP and UDP Tilman Wolf Department of Electrical and Computer Engineering 09/09/08 Today s lecture Transport layer User datagram protocol (UDP) Reliable data transfer
More informationSirindhorn International Institute of Technology Thammasat University
Name.............................. ID............... Section...... Seat No...... Thammasat University Final Exam: Semester, 205 Course Title: Introduction to Data Communications Instructor: Steven Gordon
More informationTransport layer. UDP: User Datagram Protocol [RFC 768] Review principles: Instantiation in the Internet UDP TCP
Transport layer Review principles: Reliable data transfer Flow control Congestion control Instantiation in the Internet UDP TCP 1 UDP: User Datagram Protocol [RFC 768] No frills, bare bones Internet transport
More informationIntroduction to Networks and the Internet
Introduction to Networks and the Internet CMPE 80N Announcements Project 2. Reference page. Library presentation. Internet History video. Spring 2003 Week 7 1 2 Today Internetworking (cont d). Fragmentation.
More informationTransport layer. Review principles: Instantiation in the Internet UDP TCP. Reliable data transfer Flow control Congestion control
Transport layer Review principles: Reliable data transfer Flow control Congestion control Instantiation in the Internet UDP TCP 1 UDP: User Datagram Protocol [RFC 768] No frills, bare bones Internet transport
More informationCS519: Computer Networks. Lecture 5, Part 1: Mar 3, 2004 Transport: UDP/TCP demux and flow control / sequencing
: Computer Networks Lecture 5, Part 1: Mar 3, 2004 Transport: UDP/TCP demux and flow control / sequencing Recall our protocol layers... ... and our protocol graph IP gets the packet to the host Really
More informationMidterm Review. EECS 489 Computer Networks Z. Morley Mao Monday Feb 19, 2007
Midterm Review EECS 489 Computer Networks http://www.eecs.umich.edu/courses/eecs489/w07 Z. Morley Mao Monday Feb 19, 2007 Acknowledgement: Some slides taken from Kurose&Ross and Katz&Stoica 1 Adminstrivia
More informationTransport Protocols and TCP
Transport Protocols and TCP Functions Connection establishment and termination Breaking message into packets Error recovery ARQ Flow control Multiplexing, de-multiplexing Transport service is end to end
More informationApplied Networks & Security
Applied Networks & Security TCP/IP Protocol Suite http://condor.depaul.edu/~jkristof/it263/ John Kristoff jtk@depaul.edu IT 263 Spring 2006/2007 John Kristoff - DePaul University 1 ARP overview datalink
More informationPage 1. Review: Internet Protocol Stack. Transport Layer Services EEC173B/ECS152C. Review: TCP. Transport Layer: Connectionless Service
EEC7B/ECS5C Review: Internet Protocol Stack Review: TCP Application Telnet FTP HTTP Transport Network Link Physical bits on wire TCP LAN IP UDP Packet radio Do you remember the various mechanisms we have
More informationCMPE150 Midterm Solutions
CMPE150 Midterm Solutions Question 1 Packet switching and circuit switching: (a) Is the Internet a packet switching or circuit switching network? Justify your answer. The Internet is a packet switching
More informationNWEN 243. Networked Applications. Transport layer and application layer
NWEN 243 Networked Applications Transport layer and application layer 1 Topic TCP flow control TCP congestion control The Application Layer 2 Fast Retransmit Time-out period often relatively long: long
More informationPerformance Evaluation of TCP over WLAN with the Snoop Performance Enhancing Proxy
Performance Evaluation of TCP over WLAN 802.11 with the Snoop Performance Enhancing Proxy Case study Chi-ho Ng, Jack Chow, and Ljiljana Trajković Simon Fraser University 1 Roadmap Introducing the problem
More informationChapter 7. The Transport Layer
Chapter 7 The Transport Layer 1 2 3 4 5 6 7 8 9 10 11 Addressing TSAPs, NSAPs and transport connections. 12 For rarely used processes, the initial connection protocol is used. A special process server,
More informationIntroduction to Protocols
Chapter 6 Introduction to Protocols 1 Chapter 6 Introduction to Protocols What is a Network Protocol? A protocol is a set of rules that governs the communications between computers on a network. These
More informationContents. CIS 632 / EEC 687 Mobile Computing. TCP in Fixed Networks. Prof. Chansu Yu
CIS 632 / EEC 687 Mobile Computing TCP in Fixed Networks Prof. Chansu Yu Contents Physical layer issues Communication frequency Signal propagation Modulation and Demodulation Channel access issues Multiple
More informationDifferent Layers Lecture 21
Different Layers Lecture 21 10/17/2003 Jian Ren 1 The Transport Layer 10/17/2003 Jian Ren 2 Transport Services and Protocols Provide logical communication between app processes running on different hosts
More informationGuide To TCP/IP, Second Edition UDP Header Source Port Number (16 bits) IP HEADER Protocol Field = 17 Destination Port Number (16 bit) 15 16
Guide To TCP/IP, Second Edition Chapter 5 Transport Layer TCP/IP Protocols Objectives Understand the key features and functions of the User Datagram Protocol (UDP) Explain the mechanisms that drive segmentation,
More informationCSE 123: Computer Networks Alex C. Snoeren. HW 1 due NOW!
CSE 123: Computer Networks Alex C. Snoeren HW 1 due NOW! Automatic Repeat Request (ARQ) Acknowledgements (ACKs) and timeouts Stop-and-Wait Sliding Window Forward Error Correction 2 Link layer is lossy
More informationWhat is TCP? Transport Layer Protocol
UNIT IV TRANSPORT LAYER Duties of transport layer Multiplexing Demultiplexing Sockets User Datagram Protocol (UDP) Transmission Control Protocol (TCP) Congestion Control Quality of services (QOS) Integrated
More informationCommunications Software. CSE 123b. CSE 123b. Spring Lecture 3: Reliable Communications. Stefan Savage. Some slides couresty David Wetherall
CSE 123b CSE 123b Communications Software Spring 2002 Lecture 3: Reliable Communications Stefan Savage Some slides couresty David Wetherall Administrativa Home page is up and working http://www-cse.ucsd.edu/classes/sp02/cse123b/
More informationQuestion 1 (6 points) Compare circuit-switching and packet-switching networks based on the following criteria:
Question 1 (6 points) Compare circuit-switching and packet-switching networks based on the following criteria: (a) Reserving network resources ahead of data being sent: (2pts) In circuit-switching networks,
More informationTRANSMISSION CONTROL PROTOCOL
COMP 635: WIRELESS & MOBILE COMMUNICATIONS TRANSMISSION CONTROL PROTOCOL Jasleen Kaur Fall 2017 1 Impact of Wireless on Protocol Layers Application layer Transport layer Network layer Data link layer Physical
More informationSuprakash Datta. Office: CSEB 3043 Phone: ext Course page:
CSE 3214: Computer Networks Protocols and Applications Suprakash Datta datta@cse.yorku.ca Office: CSEB 3043 Phone: 416-736-2100 ext 77875 Course page: http://www.cse.yorku.ca/course/3214 These slides are
More informationMobile Communications Chapter 9: Mobile Transport Layer
Prof. Dr.-Ing Jochen H. Schiller Inst. of Computer Science Freie Universität Berlin Germany Mobile Communications Chapter 9: Mobile Transport Layer Motivation, TCP-mechanisms Classical approaches (Indirect
More informationL12: end to end layer
L12: end to end layer Dina Katabi 6.033 Spring 2007 http://web.mit.edu/6.033 Some slides are from lectures by Nick Mckeown, Ion Stoica, Frans Kaashoek, Hari Balakrishnan, Sam Madden, and Robert Morris
More information6.1 Internet Transport Layer Architecture 6.2 UDP (User Datagram Protocol) 6.3 TCP (Transmission Control Protocol) 6. Transport Layer 6-1
6. Transport Layer 6.1 Internet Transport Layer Architecture 6.2 UDP (User Datagram Protocol) 6.3 TCP (Transmission Control Protocol) 6. Transport Layer 6-1 6.1 Internet Transport Layer Architecture The
More informationConnection-oriented (virtual circuit) Reliable Transfer Buffered Transfer Unstructured Stream Full Duplex Point-to-point Connection End-to-end service
최양희서울대학교컴퓨터공학부 Connection-oriented (virtual circuit) Reliable Transfer Buffered Transfer Unstructured Stream Full Duplex Point-to-point Connection End-to-end service 1 2004 Yanghee Choi 2 Addressing: application
More informationData Communication & Networks Final Exam (Fall 2008) Page 1 / 13. Course Instructors: Engr. Waleed Ejaz. Marks Obtained Marks
Data Communication & Networks Final Exam (Fall 2008) Page 1 / 13 Data Communication & Networks Fall 2008 Semester FINAL Thursday, 4 th December 2008 Total Time: 180 Minutes Total Marks: 100 Roll Number
More informationCSE 123A Computer Networks
CSE 123A Computer Networks Winter 2005 Lecture 14 Congestion Control Some images courtesy David Wetherall Animations by Nick McKeown and Guido Appenzeller The bad news and the good news The bad news: new
More information7. TCP 최양희서울대학교컴퓨터공학부
7. TCP 최양희서울대학교컴퓨터공학부 1 TCP Basics Connection-oriented (virtual circuit) Reliable Transfer Buffered Transfer Unstructured Stream Full Duplex Point-to-point Connection End-to-end service 2009 Yanghee Choi
More informationCSCD 330 Network Programming
CSCD 330 Network Programming Lecture 10 Transport Layer Continued Spring 2018 Reading: Chapter 3 Some Material in these slides from J.F Kurose and K.W. Ross All material copyright 1996-2007 1 Last Time.
More informationPaper solution Subject: Computer Networks (TE Computer pattern) Marks : 30 Date: 5/2/2015
Paper solution Subject: Computer Networks (TE Computer- 2012 pattern) Marks : 30 Date: 5/2/2015 Q1 a) What is difference between persistent and non persistent HTTP? Also Explain HTTP message format. [6]
More informationTCP over Wireless Networks Using Multiple. Saad Biaz Miten Mehta Steve West Nitin H. Vaidya. Texas A&M University. College Station, TX , USA
TCP over Wireless Networks Using Multiple Acknowledgements (Preliminary Version) Saad Biaz Miten Mehta Steve West Nitin H. Vaidya Department of Computer Science Texas A&M University College Station, TX
More informationc) With the selective repeat protocol, it is possible for the sender to receive an ACK for a packet that falls outside of its current window.
Part 1 Question 1 [0.5 Marks] Suppose an application generates chunks of 40 bytes of data every 20 msec, and each chunk gets encapsulated by a TCP segment and then an IP datagram. What percentage of each
More informationCS419: Computer Networks. Lecture 10, Part 3: Apr 13, 2005 Transport: TCP performance
: Computer Networks Lecture 10, Part 3: Apr 13, 2005 Transport: TCP performance TCP performance We ve seen how TCP the protocol works But there are a lot of tricks required to make it work well Indeed,
More informationPLEASE READ CAREFULLY BEFORE YOU START
Page 1 of 20 MIDTERM EXAMINATION #1 - B COMPUTER NETWORKS : 03-60-367-01 U N I V E R S I T Y O F W I N D S O R S C H O O L O F C O M P U T E R S C I E N C E Fall 2008-75 minutes This examination document
More informationPLEASE READ CAREFULLY BEFORE YOU START
Page 1 of 20 MIDTERM EXAMINATION #1 - A COMPUTER NETWORKS : 03-60-367-01 U N I V E R S I T Y O F W I N D S O R S C H O O L O F C O M P U T E R S C I E N C E Fall 2008-75 minutes This examination document
More informationTCP Strategies. Keepalive Timer. implementations do not have it as it is occasionally regarded as controversial. between source and destination
Keepalive Timer! Yet another timer in TCP is the keepalive! This one is not required, and some implementations do not have it as it is occasionally regarded as controversial! When a TCP connection is idle
More informationCSE 461. TCP and network congestion
CSE 461 TCP and network congestion This Lecture Focus How should senders pace themselves to avoid stressing the network? Topics Application Presentation Session Transport Network congestion collapse Data
More informationChapter 6. What happens at the Transport Layer? Services provided Transport protocols UDP TCP Flow control Congestion control
Chapter 6 What happens at the Transport Layer? Services provided Transport protocols UDP TCP Flow control Congestion control OSI Model Hybrid Model Software outside the operating system Software inside
More informationName Student ID Department/Year. Midterm Examination. Introduction to Computer Networks Class#: 901 E31110 Fall 2007
Name Student ID Department/Year Midterm Examination Introduction to Computer Networks Class#: 901 E31110 Fall 2007 9:30-11:10 Tuesday November 27, 2007 Prohibited 1. You are not allowed to write down the
More informationTCP Congestion Control 65KB W
TCP Congestion Control 65KB W TO 3DA 3DA TO 0.5 0.5 0.5 0.5 3 3 1 SS SS CA SS CA TCP s Congestion Window Maintenance TCP maintains a congestion window (cwnd), based on packets Sender s window is limited
More informationChapter 12 Network Protocols
Chapter 12 Network Protocols 1 Outline Protocol: Set of defined rules to allow communication between entities Open Systems Interconnection (OSI) Transmission Control Protocol/Internetworking Protocol (TCP/IP)
More informationTCP/IP Performance ITL
TCP/IP Performance ITL Protocol Overview E-Mail HTTP (WWW) Remote Login File Transfer TCP UDP IP ICMP ARP RARP (Auxiliary Services) Ethernet, X.25, HDLC etc. ATM 4/30/2002 Hans Kruse & Shawn Ostermann,
More informationFall 2012: FCM 708 Bridge Foundation I
Fall 2012: FCM 708 Bridge Foundation I Prof. Shamik Sengupta Instructor s Website: http://jjcweb.jjay.cuny.edu/ssengupta/ Blackboard Website: https://bbhosted.cuny.edu/ Intro to Computer Networking Transport
More informationCS 268: Wireless Transport Protocols. Kevin Lai Feb 13, 2002
CS 268: Wireless Transport Protocols Kevin Lai Feb 13, 2002 Motivation! Wireless connectivity proliferating - Satellite, line-of-sight microwave, line-of-sight laser, cellular data (CDMA, GPRS, 3G), wireless
More informationLecture 7: Sliding Windows. CSE 123: Computer Networks Geoff Voelker (guest lecture)
Lecture 7: Sliding Windows CSE 123: Computer Networks Geoff Voelker (guest lecture) Please turn in HW #1 Thank you From last class: Sequence Numbers Sender Receiver Sender Receiver Timeout Timeout Timeout
More informationNetwork Technology 1 5th - Transport Protocol. Mario Lombardo -
Network Technology 1 5th - Transport Protocol Mario Lombardo - lombardo@informatik.dhbw-stuttgart.de 1 overview Transport Protocol Layer realizes process to process communication data unit is called a
More information