Wireless TCP Performance Issues
|
|
- Mervyn Warren
- 6 years ago
- Views:
Transcription
1 Wireless TCP Performance Issues
2 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 rest of these slides
3 Tutorial: TCP 101 The Transmission Control Protocol (TCP) is the protocol that sends your data reliably Used for , Web, ftp, telnet, p2p, Makes sure that data is received correctly: right data, right order, exactly once Detects and recovers from any problems that occur at the IP network layer Mechanisms for reliable data transfer: sequence numbers, acknowledgements, timers, retransmissions, flow control...
4 TCP 101 (Cont d) TCP is a connection-oriented protocol SYN SYN/ACK GET URL ACK Web Client YOUR DATA HERE Web Server FIN ACK FIN/ACK
5 TCP 101 (Cont d) TCP slow-start and congestion avoidance ACK
6 TCP 101 (Cont d) TCP slow-start and congestion avoidance ACK
7 TCP 101 (Cont d) TCP slow-start and congestion avoidance ACK
8 TCP 101 (Cont d) This (exponential growth) slow start process continues until either: packet loss: after a brief recovery phase, you enter a (linear growth) congestion avoidance phase based on slow-start threshold found limit reached: slow-start threshold, or maximum advertised receive window size all done: terminate connection and go home
9 CA: Additive Increase, Multiplicative Decrease We have additive increase in the absence of loss events After loss event, decrease congestion window by half multiplicative decrease ssthresh = W/2 9
10 TCP Reno Window Note how there is Fast Recovery after cutting Window in half Reached initial ssthresh value; switch to CA mode Slow Start Time 10
11 Detecting Packet Loss Assumption: loss indicates congestion Option 1: time-out Waiting for a time-out can be long! Option 2: duplicate ACKs How many? At least Sender Receiver 11
12 TCP Reno Window Note how there is Fast Recovery after cutting Window in half Reached initial ssthresh value; switch to CA mode Slow Start Time 12
13 How do losses occur? Congestion control assumes: due to congestion packets queue in router buffers if queue is full, arriving packets dropped (Drop-Tail) packet being transmitted (delay) A B packets queueing (delay) free (available) buffers: arriving packets dropped (loss) if no free buffers
14 How do losses occur? In wireless (and mobile) environment... We find many other reasons A Packet losses due to - wireless characteristics (e.g., interference, bit errors, etc.) - mobility (including handover issues)
15 Wireless, mobility: impact on higher layer protocols logically, impact should be minimal best effort service model remains unchanged TCP and UDP can (and do) run over wireless, mobile but performance-wise: packet loss/delay due to bit-errors (discarded packets, delays for link-layer retransmissions), and handoff TCP interprets loss as congestion, will decrease congestion window un-necessarily delay impairments for real-time traffic limited bandwidth of wireless links
16
17 Also, not all packet losses the same What happens when a packet loss occurs? Quiz Time... Consider a 14-packet Web document For simplicity, consider only a single packet loss 17
18 SeqNum Key: Data Packet Ack Packet Time 18
19 SeqNum Key: Data Packet Ack Packet? Time 19
20 SeqNum Key: Data Packet Ack Packet Time 20
21 SeqNum Key: Data Packet Ack Packet Time 21
22 SeqNum Key: Data Packet Ack Packet? Time 22
23 SeqNum Key: Data Packet Ack Packet Time 23
24 SeqNum Key: Data Packet Ack Packet Time 24
25 SeqNum Key: Data Packet Ack Packet? Time 25
26 SeqNum Key: Data Packet Ack Packet Time 26
27 SeqNum Key: Data Packet Ack Packet Time 27
28 SeqNum Key: Data Packet Ack Packet? Time 28
29 SeqNum Key: Data Packet Ack Packet Time 29
30 TCP 301 (Cont d) Main observation: Not all packet losses are created equal Losses early in the transfer have a huge adverse impact on the transfer latency Losses near the end of the transfer always cost at least a retransmit timeout Losses in the middle may or may not hurt, depending on congestion window size at the time of the loss 30
31
32 TCP Reno Window Note how there is Fast Recovery after cutting Window in half Reached initial ssthresh value; switch to CA mode Slow Start Time 32
33 Let s reason about TCP throughput Wired: What s the average throughout of TCP as a function of window size and RTT? Ignore slow start Let W be the window size when loss occurs. When window is W, throughput is W/RTT Just after loss, window drops to W/2, throughput to W/2RTT. Average throughout:.75 W/RTT Loss rate proportional to 1/W 2 33
34 TCP under lots of losses Throughput in terms of loss rate: 1.22 MSS RTT Wireless TCP versions or handling losses where they occur L 34
35 Example #1 Wireless TCP Performance Problems Low capacity, high error rate Wireless Access Wired Internet Hard to distinguish losses here from losses here High capacity, low error rate
36 Example #1 (Cont d) Solution: wireless-aware TCP (I-TCP, ProxyTCP, Snoop-TCP, split connections...)
37 Example trends and issues... Middle boxes [e2e arguments, equation] Customized wireless TCP solutions Multi-path TCP 37
38 Example #2 Wireless TCP Fairness Problems D DATA Wireless Bottleneck U ACK AP DATA ACK Wired Internet Loss of ACK = Loss of DATA
39 Example #3 Multi-hop ad hoc networking Kelly Carey
40 Example #3 (Cont d) Multi-hop ad hoc networking Kelly Carey
41 Example #3 (Cont d) Multi-hop ad hoc networking Kelly Carey
42 Example #3 (Cont d) Multi-hop ad hoc networking Kelly Carey
43 Example #3 (Cont d) Multi-hop ad hoc networking Kelly Carey
44 Example #3 (Cont d) Multi-hop ad hoc networking Kelly Carey
45 Example #3 (Cont d) Multi-hop ad hoc networking Kelly Carey
46 Example #3 (Cont d) Multi-hop ad hoc networking (e.g., TCP-F, TCP-ELFN, etc.) Kelly Carey
47 Example #3 (Cont d) Multi-hop ad hoc networking (e.g., TCP-F, TCP-ELFN, etc.) Kelly Carey
48 Example #3 (Cont d) Multi-hop ad hoc networking (e.g., TCP-F, TCP-ELFN, etc.) Kelly Carey
49 Example #3 (Cont d) Multi-hop ad hoc networking (e.g., TCP-F, TCP-ELFN, etc.) Kelly Carey
50 Example #3 (Cont d) Multi-hop ad hoc networking (e.g., TCP-F, TCP-ELFN, etc.) Kelly Carey
51 TCP performance issues in adhoc networks Route failure TCP may lose a congestion window of packets Large RTT variation Degrades TCP throughput Route re-computations Incur extra delay Inflated re-transmission time-out
52 TCP performance issues in adhoc networks (cont d) Network partition TCP may reset the connection if the partition lasts for more than 100 sec. TCP enters slow-start phase after cutting down its window size to 1 Degrades TCP throughput
53 Summary of Wireless TCP TCP is the four wheel drive of TP s Wireless is a newly emerging technology with rapidly growing deployment popularity TCP and Wireless don t fit together all that well Making TCP smarter about wireless helps!
54
55 More slides
56 TCP performance issues in Ad-hoc networks Misinterpretation of packet loss E.g., packet loss/delay due to bit-errors (discarded packets, delays for link-layer retransmissions), and handoff Frequent path breaks Network partitioning and remerging Path length effects Misinterpretation of congestion window Asymmetric link behavior Uni-directional paths Multi-path routing The use of sliding window
57 More interesting problems Two interesting subproblems: Dynamic ad hoc routing: node movement can disrupt the IP routing path at any time, disrupting TCP connection; yet another way to lose packets!!!; possible solution: Explicit Loss Notification (ELN)? Handoff? Route prediction? TCP flow control: the bursty nature of TCP packet transmissions can create contention for the shared wireless channel among forwarding nodes; collisions between DATA and ACKs possible solution: rate-based flow control? Burst mode? Spatial reuse of channels?
58
Transmission Control Protocol. ITS 413 Internet Technologies and Applications
Transmission Control Protocol ITS 413 Internet Technologies and Applications Contents Overview of TCP (Review) TCP and Congestion Control The Causes of Congestion Approaches to Congestion Control TCP Congestion
More informationOutline Computer Networking. TCP slow start. TCP modeling. TCP details AIMD. Congestion Avoidance. Lecture 18 TCP Performance Peter Steenkiste
Outline 15-441 Computer Networking Lecture 18 TCP Performance Peter Steenkiste Fall 2010 www.cs.cmu.edu/~prs/15-441-f10 TCP congestion avoidance TCP slow start TCP modeling TCP details 2 AIMD Distributed,
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 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 informationTransport Layer PREPARED BY AHMED ABDEL-RAOUF
Transport Layer PREPARED BY AHMED ABDEL-RAOUF TCP Flow Control TCP Flow Control 32 bits source port # dest port # head len sequence number acknowledgement number not used U A P R S F checksum Receive window
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 informationCongestions and Control Mechanisms in Wired and Wireless Networks
Research Inventy: International Journal of Engineering And Science Vol.4, Issue 6 (June 2014), PP -57-62 Issn (e): 2278-4721, Issn (p):2319-6483, www.researchinventy.com Congestions and Control Mechanisms
More informationPage 1. Review: Internet Protocol Stack. Transport Layer Services. Design Issue EEC173B/ECS152C. Review: TCP
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 Transport Layer Services Design Issue Underlying
More informationTCP so far Computer Networking Outline. How Was TCP Able to Evolve
TCP so far 15-441 15-441 Computer Networking 15-641 Lecture 14: TCP Performance & Future Peter Steenkiste Fall 2016 www.cs.cmu.edu/~prs/15-441-f16 Reliable byte stream protocol Connection establishments
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 informationChapter 3 outline. 3.5 Connection-oriented transport: TCP. 3.6 Principles of congestion control 3.7 TCP congestion control
Chapter 3 outline 3.1 Transport-layer services 3.2 Multiplexing and demultiplexing 3.3 Connectionless transport: UDP 3.4 Principles of reliable data transfer 3.5 Connection-oriented transport: TCP segment
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 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 informationCSCI Topics: Internet Programming Fall 2008
CSCI 491-01 Topics: Internet Programming Fall 2008 Transport Layer Derek Leonard Hendrix College October 22, 2008 Original slides copyright 1996-2007 J.F Kurose and K.W. Ross 1 Chapter 3: Roadmap 3.1 Transport-layer
More informationCSCI Topics: Internet Programming Fall 2008
CSCI 491-01 Topics: Internet Programming Fall 2008 Transport Layer Derek Leonard Hendrix College October 20, 2008 Original slides copyright 1996-2007 J.F Kurose and K.W. Ross 1 Chapter 3: Roadmap 3.1 Transport-layer
More informationTCP Congestion Control
TCP Congestion Control What is Congestion The number of packets transmitted on the network is greater than the capacity of the network Causes router buffers (finite size) to fill up packets start getting
More informationTCP Congestion Control
What is Congestion TCP Congestion Control The number of packets transmitted on the network is greater than the capacity of the network Causes router buffers (finite size) to fill up packets start getting
More informationCS321: Computer Networks Congestion Control in TCP
CS321: Computer Networks Congestion Control in TCP Dr. Manas Khatua Assistant Professor Dept. of CSE IIT Jodhpur E-mail: manaskhatua@iitj.ac.in Causes and Cost of Congestion Scenario-1: Two Senders, a
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 informationCS519: Computer Networks. Lecture 5, Part 4: Mar 29, 2004 Transport: TCP congestion control
: Computer Networks Lecture 5, Part 4: Mar 29, 2004 Transport: TCP congestion control TCP performance We ve seen how TCP the protocol works Sequencing, receive window, connection setup and teardown And
More informationCongestion Control End Hosts. CSE 561 Lecture 7, Spring David Wetherall. How fast should the sender transmit data?
Congestion Control End Hosts CSE 51 Lecture 7, Spring. David Wetherall Today s question How fast should the sender transmit data? Not tooslow Not toofast Just right Should not be faster than the receiver
More informationPerformance Analysis of TCP Variants
102 Performance Analysis of TCP Variants Abhishek Sawarkar Northeastern University, MA 02115 Himanshu Saraswat PES MCOE,Pune-411005 Abstract The widely used TCP protocol was developed to provide reliable
More informationCOMP/ELEC 429/556 Introduction to Computer Networks
COMP/ELEC 429/556 Introduction to Computer Networks The TCP Protocol Some slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica, Hui Zhang T. S. Eugene Ng eugeneng at cs.rice.edu
More informationCS4700/CS5700 Fundamentals of Computer Networks
CS4700/CS5700 Fundamentals of Computer Networks Lecture 15: Congestion Control Slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica, Hui Zhang Alan Mislove amislove at ccs.neu.edu
More informationOverview. TCP & router queuing Computer Networking. TCP details. Workloads. TCP Performance. TCP Performance. Lecture 10 TCP & Routers
Overview 15-441 Computer Networking TCP & router queuing Lecture 10 TCP & Routers TCP details Workloads Lecture 10: 09-30-2002 2 TCP Performance TCP Performance Can TCP saturate a link? Congestion control
More informationCS3600 SYSTEMS AND NETWORKS
CS3600 SYSTEMS AND NETWORKS NORTHEASTERN UNIVERSITY Lecture 24: Congestion Control Prof. Alan Mislove (amislove@ccs.neu.edu) Slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica,
More informationChapter III: Transport Layer
Chapter III: Transport Layer UG3 Computer Communications & Networks (COMN) Mahesh Marina mahesh@ed.ac.uk Slides thanks to Myungjin Lee and copyright of Kurose and Ross Principles of congestion control
More informationCS 5520/ECE 5590NA: Network Architecture I Spring Lecture 13: UDP and TCP
CS 5520/ECE 5590NA: Network Architecture I Spring 2008 Lecture 13: UDP and TCP Most recent lectures discussed mechanisms to make better use of the IP address space, Internet control messages, and layering
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 informationTCP congestion control:
TCP congestion control: Probing for usable bandwidth: Ideally: transmit as fast as possible (cwnd as large as possible) without loss Increase cwnd until loss (congestion) Loss: decrease cwnd, then begin
More informationChapter III. congestion situation in Highspeed Networks
Chapter III Proposed model for improving the congestion situation in Highspeed Networks TCP has been the most used transport protocol for the Internet for over two decades. The scale of the Internet and
More informationChapter 3 Transport Layer
Chapter 3 Transport Layer 1 Chapter 3 outline 3.1 Transport-layer services 3.2 Multiplexing and demultiplexing 3.3 Connectionless transport: UDP 3.4 Principles of reliable data transfer 3.5 Connection-oriented
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 informationWireless Challenges : Computer Networking. Overview. Routing to Mobile Nodes. Lecture 25: Wireless Networking
Wireless Challenges 15-441: Computer Networking Lecture 25: Wireless Networking Force us to rethink many assumptions Need to share airwaves rather than wire Don t know what hosts are involved Host may
More informationTCP based Receiver Assistant Congestion Control
International Conference on Multidisciplinary Research & Practice P a g e 219 TCP based Receiver Assistant Congestion Control Hardik K. Molia Master of Computer Engineering, Department of Computer Engineering
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 informationDepartment of Computer and IT Engineering University of Kurdistan. Transport Layer. By: Dr. Alireza Abdollahpouri
Department of Computer and IT Engineering University of Kurdistan Transport Layer By: Dr. Alireza Abdollahpouri TCP/IP protocol suite 2 Transport Layer The transport layer is responsible for process-to-process
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 informationOutline. TCP: Overview RFCs: 793, 1122, 1323, 2018, Development of reliable protocol Sliding window protocols
Outline Development of reliable protocol Sliding window protocols Go-Back-N, Selective Repeat Protocol performance Sockets, UDP, TCP, and IP UDP operation TCP operation connection management flow control
More informationOverview. TCP congestion control Computer Networking. TCP modern loss recovery. TCP modeling. TCP Congestion Control AIMD
Overview 15-441 Computer Networking Lecture 9 More TCP & Congestion Control TCP congestion control TCP modern loss recovery TCP modeling Lecture 9: 09-25-2002 2 TCP Congestion Control Changes to TCP motivated
More informationInternet Networking recitation #10 TCP New Reno Vs. Reno
recitation #0 TCP New Reno Vs. Reno Spring Semester 200, Dept. of Computer Science, Technion 2 Introduction Packet Loss Management TCP Reno (RFC 258) can manage a loss of at most one packet from a single
More informationChapter 3 outline. 3.5 Connection-oriented transport: TCP. 3.6 Principles of congestion control 3.7 TCP congestion control
Chapter 3 outline 3.1 Transport-layer services 3.2 Multiplexing and demultiplexing 3.3 Connectionless transport: UDP 3.4 Principles of reliable data transfer 3.5 Connection-oriented transport: TCP segment
More informationAdvanced Computer Networks
Advanced Computer Networks Congestion control in TCP Contents Principles TCP congestion control states Congestion Fast Recovery TCP friendly applications Prof. Andrzej Duda duda@imag.fr http://duda.imag.fr
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 Networking Introduction
Computer Networking Introduction Halgurd S. Maghdid Software Engineering Department Koya University-Koya, Kurdistan-Iraq Lecture No.11 Chapter 3 outline 3.1 transport-layer services 3.2 multiplexing and
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 informationTCP over Wireless. Protocols and Networks Hadassah College Spring 2018 Wireless Dr. Martin Land 1
TCP over Wireless Protocols and Networks Hadassah College Spring 218 Wireless Dr. Martin Land 1 Classic TCP-Reno Ideal operation in-flight segments = cwnd (send cwnd without stopping) Cumulative ACK for
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 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 informationLecture 11. Transport Layer (cont d) Transport Layer 1
Lecture 11 Transport Layer (cont d) Transport Layer 1 Agenda The Transport Layer (continue) Connection-oriented Transport (TCP) Flow Control Connection Management Congestion Control Introduction to the
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 informationTCP Congestion Control
6.033, Spring 2014 TCP Congestion Control Dina Katabi & Sam Madden nms.csail.mit.edu/~dina Sharing the Internet How do you manage resources in a huge system like the Internet, where users with different
More informationimage 3.8 KB Figure 1.6: Example Web Page
image. KB image 1 KB Figure 1.: Example Web Page and is buffered at a router, it must wait for all previously queued packets to be transmitted first. The longer the queue (i.e., the more packets in the
More informationECE 333: Introduction to Communication Networks Fall 2001
ECE 333: Introduction to Communication Networks Fall 2001 Lecture 28: Transport Layer III Congestion control (TCP) 1 In the last lecture we introduced the topics of flow control and congestion control.
More informationRecap. More TCP. Congestion avoidance. TCP timers. TCP lifeline. Application Presentation Session Transport Network Data Link Physical
Recap ½ congestion window ½ congestion window More TCP Congestion avoidance TCP timers TCP lifeline Application Presentation Session Transport Network Data Link Physical 1 Congestion Control vs Avoidance
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 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 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 informationFast Retransmit. Problem: coarsegrain. timeouts lead to idle periods Fast retransmit: use duplicate ACKs to trigger retransmission
Fast Retransmit Problem: coarsegrain TCP timeouts lead to idle periods Fast retransmit: use duplicate ACKs to trigger retransmission Packet 1 Packet 2 Packet 3 Packet 4 Packet 5 Packet 6 Sender Receiver
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 informationLecture 4: Congestion Control
Lecture 4: Congestion Control Overview Internet is a network of networks Narrow waist of IP: unreliable, best-effort datagram delivery Packet forwarding: input port to output port Routing protocols: computing
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 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 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 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 informationChapter 09 Network Protocols
Chapter 09 Network Protocols Copyright 2011, Dr. Dharma P. Agrawal and Dr. Qing-An Zeng. All rights reserved. 1 Outline Protocol: Set of defined rules to allow communication between entities Open Systems
More informationCMPE 150/L : Introduction to Computer Networks. Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 10
CMPE 150/L : Introduction to Computer Networks Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 10 1 Midterm exam Midterm next Thursday Close book but one-side 8.5"x11" note is allowed (must
More informationWireless Challenges : Computer Networking. Overview. Routing to Mobile Nodes. Lecture 24: Mobile and Wireless
Wireless Challenges 15-441: Computer Networking Lecture 24: Mobile and Wireless Peter Steenkiste Fall 2010 www.cs.cmu.edu/~prs/15-441-f10 Force us to rethink many assumptions Need to share airwaves rather
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 informationCS 43: Computer Networks. 19: TCP Flow and Congestion Control October 31, Nov 2, 2018
CS 43: Computer Networks 19: TCP Flow and Congestion Control October 31, Nov 2, 2018 Five-layer Internet Model Application: the application (e.g., the Web, Email) Transport: end-to-end connections, reliability
More information05 Transmission Control Protocol (TCP)
SE 4C03 Winter 2003 05 Transmission Control Protocol (TCP) Instructor: W. M. Farmer Revised: 06 February 2003 1 Interprocess Communication Problem: How can a process on one host access a service provided
More informationCongestion Control In The Internet Part 2: How it is implemented in TCP. JY Le Boudec 2014
1 Congestion Control In The Internet Part 2: How it is implemented in TCP JY Le Boudec 2014 Contents 1. Congestion control in TCP 2. The fairness of TCP 3. The loss throughput formula 4. Explicit Congestion
More informationII. Principles of Computer Communications Network and Transport Layer
II. Principles of Computer Communications Network and Transport Layer A. Internet Protocol (IP) IPv4 Header An IP datagram consists of a header part and a text part. The header has a 20-byte fixed part
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 informationTransport Layer Marcos Vieira
Transport Layer 2014 Marcos Vieira Transport Layer Transport protocols sit on top of network layer and provide Application-level multiplexing ( ports ) Error detection, reliability, etc. UDP User Datagram
More informationCongestion Control In The Internet Part 2: How it is implemented in TCP. JY Le Boudec 2014
1 Congestion Control In The Internet Part 2: How it is implemented in TCP JY Le Boudec 2014 Contents 1. Congestion control in TCP 2. The fairness of TCP 3. The loss throughput formula 4. Explicit Congestion
More informationECE 610: Homework 4 Problems are taken from Kurose and Ross.
ECE 610: Homework 4 Problems are taken from Kurose and Ross. Problem 1: Host A and B are communicating over a TCP connection, and Host B has already received from A all bytes up through byte 248. Suppose
More informationTopics. TCP sliding window protocol TCP PUSH flag TCP slow start Bulk data throughput
Topics TCP sliding window protocol TCP PUSH flag TCP slow start Bulk data throughput 2 Introduction In this chapter we will discuss TCP s form of flow control called a sliding window protocol It allows
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 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 informationSupporting mobility only on lower layers up to the network layer is not
Mobile transport layer Supporting mobility only on lower layers up to the network layer is not enough to provide mobility support for applications. Most applications rely on a transport layer, such as
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 informationAdvanced Computer Networks
Advanced Computer Networks Congestion control in TCP Prof. Andrzej Duda duda@imag.fr http://duda.imag.fr 1 Contents Principles TCP congestion control states Slow Start Congestion Avoidance Fast Recovery
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 Layer Congestion Control
Transport Layer Congestion Control Tom Kelliher, CS 325 Apr. 7, 2008 1 Administrivia Announcements Assignment Read 4.1 4.3. From Last Time TCP Reliability. Outline 1. Congestion control principles. 2.
More informationTransport Layer Protocols TCP
Transport Layer Protocols TCP Gail Hopkins Introduction Features of TCP Packet loss and retransmission Adaptive retransmission Flow control Three way handshake Congestion control 1 Common Networking Issues
More informationChapter 3 Transport Layer
Chapter 3 Transport Layer A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint form so you can add, modify, and delete
More information15-744: Computer Networking TCP
15-744: Computer Networking TCP Congestion Control Congestion Control Assigned Reading [Jacobson and Karels] Congestion Avoidance and Control [TFRC] Equation-Based Congestion Control for Unicast Applications
More informationCongestion / Flow Control in TCP
Congestion and Flow Control in 1 Flow Control and Congestion Control Flow control Sender avoids overflow of receiver buffer Congestion control All senders avoid overflow of intermediate network buffers
More informationUDP, TCP, IP multicast
UDP, TCP, IP multicast Dan Williams In this lecture UDP (user datagram protocol) Unreliable, packet-based TCP (transmission control protocol) Reliable, connection oriented, stream-based IP multicast Process-to-Process
More informationOutline. TCP: Overview RFCs: 793, 1122, 1323, 2018, steam: r Development of reliable protocol r Sliding window protocols
Outline r Development of reliable protocol r Sliding window protocols m Go-Back-N, Selective Repeat r Protocol performance r Sockets, UDP, TCP, and IP r UDP operation r TCP operation m connection management
More informationTransport Layer. Application / Transport Interface. Transport Layer Services. Transport Layer Connections
Application / Transport Interface Application requests service from transport layer Transport Layer Application Layer Prepare Transport service requirements Data for transport Local endpoint node address
More informationBandwidth Allocation & TCP
Bandwidth Allocation & TCP The Transport Layer Focus Application Presentation How do we share bandwidth? Session Topics Transport Network Congestion control & fairness Data Link TCP Additive Increase/Multiplicative
More informationTCP Review. Carey Williamson Department of Computer Science University of Calgary Winter 2018
TCP Review Carey Williamson Department of Computer Science University of Calgary Winter 2018 Credit: Much of this content came courtesy of Erich Nahum (IBM Research) The TCP Protocol Connection-oriented,
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 informationcs/ee 143 Communication Networks
cs/ee 143 Communication Networks Chapter 4 Transport Text: Walrand & Parakh, 2010 Steven Low CMS, EE, Caltech Recap: Internet overview Some basic mechanisms n Packet switching n Addressing n Routing o
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 informationCongestion Control. Principles of Congestion Control. Network-assisted Congestion Control: ATM. Congestion Control. Computer Networks 10/21/2009
Congestion Control Kai Shen Principles of Congestion Control Congestion: informally: too many sources sending too much data too fast for the network to handle results of congestion: long delays (e.g. queueing
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 informationSIMPLE MODEL FOR TRANSMISSION CONTROL PROTOCOL (TCP) Irma Aslanishvili, Tariel Khvedelidze
80 SIMPLE MODEL FOR TRANSMISSION CONTROL PROTOCOL (TCP) Irma Aslanishvili, Tariel Khvedelidze Abstract: Ad hoc Networks are complex distributed systems that consist of wireless mobile or static nodes that
More information