Chapter 6 Congestion Control and Resource Allocation
|
|
- Linette Singleton
- 7 years ago
- Views:
Transcription
1 Chapter 6 Congestion Control and Resource Allocation 6.3 TCP Congestion Control Additive Increase/Multiplicative Decrease (AIMD) o Basic idea: repeatedly increase transmission rate until congestion occurs; reduce transmission rate when congestion occurs. o New state variable per connection: CongestionWindow CongestionWindow limits how much data source is allowed to have in transit in order to not cause congestion. MaxWindow = MIN(CongestionWindow, AdvertisedWindow) is the maximum number of unacked bytes allowed. EffeciveWindow = MaxWindow (LastByteSent LastByteAcked) o The AIMD algorithm Increase CongestionWindow by one MSS per RTT when all packets sent during the last RTT have been ACKed (additive increase) Divide CongestionWindow by two when a timeout occurs (multiplicative decrease) Source interprets timeouts as a sign of congestion CongestionWindow not allowed to fall below MSS In practice, CongestionWindow is incremented by a fraction of MSS when an ACK is received. Increment = MSS x (MSS/CongestionWindow) Slow Start o Slow start is used at the beginning of a connection to increase the congestion window rapidly. o The slow start algorithm: Begin with CongestionWindow = 1 MSS Double CongestionWindow each RTT Increment CongestionWindow by 1 MSS for each ACK
2 o Slow start is also used after a timeout occurs. Upon timeout: Threshold is set to 1/2 of CongestionWindow just before timeout. CongestionWindow set to 1 MSS. CongestionWindow grows exponentially to Threshold (slow start), then grows linearly (additive increase). Fast Retransmit and Fast Recovery o Fast retransmit Goal: trigger retransmission of a dropped packet sooner than the regular timeout mechanism. Trigger of retransmission: three duplicate ACKs Timeouts cannot be eliminated because There may not be enough packets in transit to cause 3 duplicate ACKs when the window size is small. A large number of packets may be lost. o Fast recovery: skip the slow start phase when fast retransmit detects a lost packet Threshold set to CongestionWindow/2. CongestionWindow set to Threshold, window grows linearly. Summary of TCP congestion control o When CongestionWindow is below Threshold, window grows exponentially. o When CongestionWindow is above Threshold, window grows linearly. o When timeout occurs, Threshold is set to CongestionWindow/2 and CongestionWindow is set to 1 MSS. o When a triple duplicate ACK occurs, Threshold is set to CongestionWindow/2 and CongestionWindow is set to Threshold. 6.4 Congestion-Avoidance Mechanisms Congestion avoidance o Predict when congestion is about to happen. o Reduce sending rate of source host before packets start being discarded.
3 Two congestion avoidance approaches o With router assistance: DECbit and RED. o Without router assistance: TCP Vegas. DECbit o Add a congestion bit to packet header. o Router actions Monitor average queue length over last busy + idle cycle, plus the current busy cycle. Set congestion bit if average queue length 1 when the packet arrives. A queue length of 1 maximizes throughput/delay. o End host actions Destination host echoes congestion bit back to source host. Source records the fraction of the last window s worth of packets that resulted in the congestion bit being set. If fraction < 50%, increase congestion window by 1 packet. If fraction 50%, decrease congestion window to times previous value. A threshold of 50% maximizes throughput/delay. Random Early Detection (RED) o Implicit notification: router drops packets when congestion is imminent. Designed to be used in conjunction with TCP. o Early random drop: router drops each arriving packet with some drop probability whenever the queue length exceeds a threshold. o RED details Average queue length computation AvgLen = (1 - Weight) x AvgLen + Weight x SampleLen, 0<Weight<1. Queue length measured every time a packet arrives.
4 Two queue length thresholds If AvgLen MinThreshold, queue the packet. If MinThreshold < AvgLen < MaxThreshold, calculate probability P and drop the arriving packet with probability P. If MaxThreshold Computing probability P AvgLen, drop the arriving packet. TempP = MaxP x (AvgLen MinThreshold) /(MaxThreshold - MinThreshold). P = TempP/(1 count x Temp), count = number of newly arriving packets that have been queued since the last drop. o Using count in the calculation ensures a roughly even distribution of drops over time. RED provides fair resource allocation because the probability of dropping a particular flow s packets is roughly proportional to the share of the bandwidth the flow is currently getting at the router. TCP Vegas o Goal: maintain the right amount of extra data in the network. Extra data data that the source would not have transmitted had it been trying to match exactly the available bandwidth of the network. Too much extra data: long delays and congestion. Too little extra data: cannot respond rapidly enough to transient increases in the available network bandwidth. o The algorithm Define BaseRTT to be the RTT of a packet when the flow is not congested. BaseRTT is set to the minimum of all measured RTTs. Calculate expected throughput ExpectedRate = CongestionWindow/BaseRTT
5 6.2 Queuing Disciplines Calculates current sending rate, ActualRate, once per RTT. ActualRate = K/(t1-t2), where t1 is the time a packet is sent, t2 is the time the ACK is received, K is the number of bytes transmitted between t1 and t2. Set congestion window based on ActualRate and ExpectedRate. Diff = ExpectedRate ActualRate (Diff 0) If Diff < α, increase CongestionWindow linearly during next RTT. If Diff > β, decrease CongestionWindow linearly during next RTT. If α < Diff < β, leave CongestionWindow unchanged. Use multiplicative decrease when a timeout occurs. Router implements queuing discipline that consists of o Scheduling discipline: determine the order in which packets are transmitted. (allocate link bandwidth) o Drop policy: determine which packets get discarded. (allocate buffer space) FIFO Queuing o The packets are transmitted in the order they arrive. o Tail drop. Priority Queuing - a variation of FIFO Queuing o Each packet is marked with a priority. o Routers implement one FIFO queue for each priority class. o Queues are serviced in strict order of queue priority. o Starvation problem. Fair Queuing (FQ) o Maintain a separate queue for each flow, queues serviced in roundrobin. Segregate traffic so that an ill-behaved source does not interfere with well-behaved sources.
6 o Approximate bit-by-bit round robin to fairly allocate link bandwidth. Imagine a clock that ticks once each time a bit is transmitted from all of the active flows. For a single flow Let P i denote the length of packet i. Let S i denote the time when the router starts to transmit packet i. Let F i denote the time when the router finishes transmitting packet i. Let A i denote the time when packet i arrives at the router. F i = S i +P i and S i = MAX (F i-1, A i ), so F i = MAX (F i-1, A i ) + P i. For multiple flows For each flow, calculate F i for each packet. Treat all F i s as timestamps, next packet to transmit is one with lowest timestamp. Not perfect: can t preempt a packet that is currently being transmitted. o Properties of FQ Work-conserving: the link is never left idle as long as there is at least one packet in the queue. Fair bandwidth allocation: when there are n flows, each flow gets 1/n th of the link bandwidth. Weighted Fair Queuing (WFQ) - a variation of FQ o A weight is assigned to each flow (queue) Weight specifies how many bits to transmit each time the router services that queue o Bandwidth received by a flow depends on its weight and the number of flows that are sharing the link. o If packet i belongs to a flow with weight w, then F i = MAX (F i-1, A i ) + P i /w
CSE 123: Computer Networks
CSE 123: Computer Networks Homework 4 Solutions Out: 12/03 Due: 12/10 1. Routers and QoS Packet # Size Flow 1 100 1 2 110 1 3 50 1 4 160 2 5 80 2 6 240 2 7 90 3 8 180 3 Suppose a router has three input
More informationQuality of Service versus Fairness. Inelastic Applications. QoS Analogy: Surface Mail. How to Provide QoS?
18-345: Introduction to Telecommunication Networks Lectures 20: Quality of Service Peter Steenkiste Spring 2015 www.cs.cmu.edu/~prs/nets-ece Overview What is QoS? Queuing discipline and scheduling Traffic
More informationCongestion Control Review. 15-441 Computer Networking. Resource Management Approaches. Traffic and Resource Management. What is congestion control?
Congestion Control Review What is congestion control? 15-441 Computer Networking What is the principle of TCP? Lecture 22 Queue Management and QoS 2 Traffic and Resource Management Resource Management
More informationData Networks Summer 2007 Homework #3
Data Networks Summer Homework # Assigned June 8, Due June in class Name: Email: Student ID: Problem Total Points Problem ( points) Host A is transferring a file of size L to host B using a TCP connection.
More informationLecture 15: Congestion Control. CSE 123: Computer Networks Stefan Savage
Lecture 15: Congestion Control CSE 123: Computer Networks Stefan Savage Overview Yesterday: TCP & UDP overview Connection setup Flow control: resource exhaustion at end node Today: Congestion control Resource
More informationOutline. TCP connection setup/data transfer. 15-441 Computer Networking. TCP Reliability. Congestion sources and collapse. Congestion control basics
Outline 15-441 Computer Networking Lecture 8 TCP & Congestion Control TCP connection setup/data transfer TCP Reliability Congestion sources and collapse Congestion control basics Lecture 8: 09-23-2002
More informationTCP in Wireless Mobile Networks
TCP in Wireless Mobile Networks 1 Outline Introduction to transport layer Introduction to TCP (Internet) congestion control Congestion control in wireless networks 2 Transport Layer v.s. Network Layer
More informationTCP over Multi-hop Wireless Networks * Overview of Transmission Control Protocol / Internet Protocol (TCP/IP) Internet Protocol (IP)
TCP over Multi-hop Wireless Networks * Overview of Transmission Control Protocol / Internet Protocol (TCP/IP) *Slides adapted from a talk given by Nitin Vaidya. Wireless Computing and Network Systems Page
More informationA Survey on Congestion Control Mechanisms for Performance Improvement of TCP
A Survey on Congestion Control Mechanisms for Performance Improvement of TCP Shital N. Karande Department of Computer Science Engineering, VIT, Pune, Maharashtra, India Sanjesh S. Pawale Department of
More informationThe network we see so far. Internet Best Effort Service. Is best-effort good enough? An Audio Example. Network Support for Playback
The network we see so far CSE56 - Lecture 08 QoS Network Xiaowei Yang TCP saw-tooth FIFO w/ droptail or red Best-effort service Web-surfing, email, ftp, file-sharing Internet Best Effort Service Our network
More informationLecture Objectives. Lecture 07 Mobile Networks: TCP in Wireless Networks. Agenda. TCP Flow Control. Flow Control Can Limit Throughput (1)
Lecture Objectives Wireless and Mobile Systems Design Lecture 07 Mobile Networks: TCP in Wireless Networks Describe TCP s flow control mechanism Describe operation of TCP Reno and TCP Vegas, including
More informationOptimization of Communication Systems Lecture 6: Internet TCP Congestion Control
Optimization of Communication Systems Lecture 6: Internet TCP Congestion Control Professor M. Chiang Electrical Engineering Department, Princeton University ELE539A February 21, 2007 Lecture Outline TCP
More informationTCP over Wireless Networks
TCP over Wireless Networks Raj Jain Professor of Computer Science and Engineering Washington University in Saint Louis Saint Louis, MO 63130 Audio/Video recordings of this lecture are available at: http://www.cse.wustl.edu/~jain/cse574-10/
More informationSJBIT, Bangalore, KARNATAKA
A Comparison of the TCP Variants Performance over different Routing Protocols on Mobile Ad Hoc Networks S. R. Biradar 1, Subir Kumar Sarkar 2, Puttamadappa C 3 1 Sikkim Manipal Institute of Technology,
More information1. The subnet must prevent additional packets from entering the congested region until those already present can be processed.
Congestion Control When one part of the subnet (e.g. one or more routers in an area) becomes overloaded, congestion results. Because routers are receiving packets faster than they can forward them, one
More informationActive Queue Management (AQM) based Internet Congestion Control
Active Queue Management (AQM) based Internet Congestion Control October 1 2002 Seungwan Ryu (sryu@eng.buffalo.edu) PhD Student of IE Department University at Buffalo Contents Internet Congestion Control
More informationTransport Layer Protocols
Transport Layer Protocols Version. Transport layer performs two main tasks for the application layer by using the network layer. It provides end to end communication between two applications, and implements
More informationRandom Early Detection Gateways for Congestion Avoidance
Random Early Detection Gateways for Congestion Avoidance Sally Floyd and Van Jacobson Lawrence Berkeley Laboratory University of California floyd@eelblgov van@eelblgov To appear in the August 1993 IEEE/ACM
More information17: Queue Management. Queuing. Mark Handley
17: Queue Management Mark Handley Queuing The primary purpose of a queue in an IP router is to smooth out bursty arrivals, so that the network utilization can be high. But queues add delay and cause jitter.
More information2 TCP-like Design. Answer
Homework 3 1 DNS Suppose you have a Host C, a local name server L, and authoritative name servers A root, A com, and A google.com, where the naming convention A x means that the name server knows about
More informationScheduling for QoS Management
Scheduling for QoS Management Domenico Massimo Parrucci Condello isti information science Facoltà and di Scienze technology e Tecnologie institute 1/number 1 Outline What is Queue Management and Scheduling?
More informationWhy Congestion Control. Congestion Control and Active Queue Management. Max-Min Fairness. Fairness
Congestion Control and Active Queue Management Congestion Control, Efficiency and Fairness Analysis of TCP Congestion Control A simple TCP throughput formula RED and Active Queue Management How RED wors
More informationApplication Level Congestion Control Enhancements in High BDP Networks. Anupama Sundaresan
Application Level Congestion Control Enhancements in High BDP Networks Anupama Sundaresan Organization Introduction Motivation Implementation Experiments and Results Conclusions 2 Developing a Grid service
More informationFEW would argue that one of TCP s strengths lies in its
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 13, NO. 8, OCTOBER 1995 1465 TCP Vegas: End to End Congestion Avoidance on a Global Internet Lawrence S. Brakmo, Student Member, IEEE, and Larry L.
More informationInternational Journal of Scientific & Engineering Research, Volume 6, Issue 7, July-2015 1169 ISSN 2229-5518
International Journal of Scientific & Engineering Research, Volume 6, Issue 7, July-2015 1169 Comparison of TCP I-Vegas with TCP Vegas in Wired-cum-Wireless Network Nitin Jain & Dr. Neelam Srivastava Abstract
More information6.6 Scheduling and Policing Mechanisms
02-068 C06 pp4 6/14/02 3:11 PM Page 572 572 CHAPTER 6 Multimedia Networking 6.6 Scheduling and Policing Mechanisms In the previous section, we identified the important underlying principles in providing
More informationCongestions and Control Mechanisms n Wired and Wireless Networks
International OPEN ACCESS Journal ISSN: 2249-6645 Of Modern Engineering Research (IJMER) Congestions and Control Mechanisms n Wired and Wireless Networks MD Gulzar 1, B Mahender 2, Mr.B.Buchibabu 3 1 (Asst
More informationTCP Westwood for Wireless
TCP Westwood for Wireless מבוא רקע טכני בקרת עומס ב- TCP TCP על קשר אלחוטי שיפור תפוקה עם פרוטוקול TCP Westwood סיכום.1.2.3.4.5 Seminar in Computer Networks and Distributed Systems Hadassah College Spring
More informationImproving the Performance of TCP Using Window Adjustment Procedure and Bandwidth Estimation
Improving the Performance of TCP Using Window Adjustment Procedure and Bandwidth Estimation R.Navaneethakrishnan Assistant Professor (SG) Bharathiyar College of Engineering and Technology, Karaikal, India.
More informationFirst Midterm for ECE374 03/24/11 Solution!!
1 First Midterm for ECE374 03/24/11 Solution!! Note: In all written assignments, please show as much of your work as you can. Even if you get a wrong answer, you can get partial credit if you show your
More informationTCP and Wireless Networks Classical Approaches Optimizations TCP for 2.5G/3G Systems. Lehrstuhl für Informatik 4 Kommunikation und verteilte Systeme
Chapter 2 Technical Basics: Layer 1 Methods for Medium Access: Layer 2 Chapter 3 Wireless Networks: Bluetooth, WLAN, WirelessMAN, WirelessWAN Mobile Networks: GSM, GPRS, UMTS Chapter 4 Mobility on the
More informationLecture 16: Quality of Service. CSE 123: Computer Networks Stefan Savage
Lecture 16: Quality of Service CSE 123: Computer Networks Stefan Savage Final Next week (trust Blink wrt time/location) Will cover entire class Style similar to midterm I ll post a sample (i.e. old) final
More informationReal-time apps and Quality of Service
Real-time apps and Quality of Service Focus What transports do applications need? What network mechanisms provide which kinds of quality assurances? Topics Real-time versus Elastic applications Adapting
More informationMobile Communications Chapter 9: Mobile Transport Layer
Mobile Communications Chapter 9: Mobile Transport Layer Motivation TCP-mechanisms Classical approaches Indirect TCP Snooping TCP Mobile TCP PEPs in general Additional optimizations Fast retransmit/recovery
More informationCongestion control in Mobile Ad-Hoc Networks (MANETs)
Congestion control in Mobile Ad-Hoc Networks (MANETs) A REPORT SUBMITTED TO SADIA HAMID KAZI OF COMPUTER SCIENCE AND ENGINEERING DEPARTMENT OF BRAC UNIVERSITY IN FULFILLMENT OF THE REQUIREMENTS FOR THESIS
More informationProtagonist International Journal of Management And Technology (PIJMT) Online ISSN- 2394-3742. Vol 2 No 3 (May-2015) Active Queue Management
Protagonist International Journal of Management And Technology (PIJMT) Online ISSN- 2394-3742 Vol 2 No 3 (May-2015) Active Queue Management For Transmission Congestion control Manu Yadav M.Tech Student
More informationA Study on TCP Performance over Mobile Ad Hoc Networks
215 A Study on TCP Performance over Mobile Ad Hoc Networks Shweta Sharma 1, Anshika Garg 2 1 School of Computing Science and Engineering, Galgotias University, Greater Noida 2 School of Computing Science
More informationCS268 Exam Solutions. 1) End-to-End (20 pts)
CS268 Exam Solutions General comments: ) If you would like a re-grade, submit in email a complete explanation of why your solution should be re-graded. Quote parts of your solution if necessary. In person
More informationPer-Flow Queuing Allot's Approach to Bandwidth Management
White Paper Per-Flow Queuing Allot's Approach to Bandwidth Management Allot Communications, July 2006. All Rights Reserved. Table of Contents Executive Overview... 3 Understanding TCP/IP... 4 What is Bandwidth
More information15-441: Computer Networks Homework 2 Solution
5-44: omputer Networks Homework 2 Solution Assigned: September 25, 2002. Due: October 7, 2002 in class. In this homework you will test your understanding of the TP concepts taught in class including flow
More informationTCP, Active Queue Management and QoS
TCP, Active Queue Management and QoS Don Towsley UMass Amherst towsley@cs.umass.edu Collaborators: W. Gong, C. Hollot, V. Misra Outline motivation TCP friendliness/fairness bottleneck invariant principle
More informationSimulation-Based Comparisons of Solutions for TCP Packet Reordering in Wireless Network
Simulation-Based Comparisons of Solutions for TCP Packet Reordering in Wireless Network 作 者 :Daiqin Yang, Ka-Cheong Leung, and Victor O. K. Li 出 處 :Wireless Communications and Networking Conference, 2007.WCNC
More informationCOMPARATIVE ANALYSIS OF DIFFERENT QUEUING MECHANISMS IN HETROGENEOUS NETWORKS
COMPARATIVE ANALYSIS OF DIFFERENT QUEUING MECHANISMS IN HETROGENEOUS NETWORKS Shubhangi Rastogi 1, Samir Srivastava 2 M.Tech Student, Computer Science and Engineering, KNIT, Sultanpur, India 1 Associate
More informationTCP Flow Control. TCP Receiver Window. Sliding Window. Computer Networks. Lecture 30: Flow Control, Reliable Delivery
TCP Flow Control Computer Networks The receiver side of a TCP connection maintains a receiver buffer: Lecture : Flow Control, eliable elivery application process may be slow at reading from the buffer
More informationFinal for ECE374 05/06/13 Solution!!
1 Final for ECE374 05/06/13 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam taker -
More informationTCP in Wireless Networks
Outline Lecture 10 TCP Performance and QoS in Wireless s TCP Performance in wireless networks TCP performance in asymmetric networks WAP Kurose-Ross: Chapter 3, 6.8 On-line: TCP over Wireless Systems Problems
More informationActive Queue Management
Course of Multimedia Internet (Sub-course Reti Internet Multimediali ), AA 2010-2011 Prof. 6. Active queue management Pag. 1 Active Queue Management Active Queue Management (AQM) is a feature that can
More informationPrefix AggregaNon. Company X and Company Y connect to the same ISP, and they are assigned the prefixes:
Data Transfer Consider transferring an enormous file of L bytes from Host A to B using a MSS of 1460 bytes and a 66 byte header. What is the maximum value of L such that TCP sequence numbers are not exhausted?
More informationRouting in packet-switching networks
Routing in packet-switching networks Circuit switching vs. Packet switching Most of WANs based on circuit or packet switching Circuit switching designed for voice Resources dedicated to a particular call
More informationAnalysis of Internet Transport Service Performance with Active Queue Management in a QoS-enabled Network
University of Helsinki - Department of Computer Science Analysis of Internet Transport Service Performance with Active Queue Management in a QoS-enabled Network Oriana Riva oriana.riva@cs.helsinki.fi Contents
More informationAN IMPROVED SNOOP FOR TCP RENO AND TCP SACK IN WIRED-CUM- WIRELESS NETWORKS
AN IMPROVED SNOOP FOR TCP RENO AND TCP SACK IN WIRED-CUM- WIRELESS NETWORKS Srikanth Tiyyagura Department of Computer Science and Engineering JNTUA College of Engg., pulivendula, Andhra Pradesh, India.
More informationPerformance improvement of active queue management with per-flow scheduling
Performance improvement of active queue management with per-flow scheduling Masayoshi Nabeshima, Kouji Yata NTT Cyber Solutions Laboratories, NTT Corporation 1-1 Hikari-no-oka Yokosuka-shi Kanagawa 239
More informationQuality of Service. Traditional Nonconverged Network. Traditional data traffic characteristics:
Quality of Service 1 Traditional Nonconverged Network Traditional data traffic characteristics: Bursty data flow FIFO access Not overly time-sensitive; delays OK Brief outages are survivable 2 1 Converged
More informationFirst Midterm for ECE374 03/09/12 Solution!!
1 First Midterm for ECE374 03/09/12 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam
More informationQuality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic.
Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic. A Network and Data Link Layer infrastructure Design to Improve QoS in Voice and video Traffic Jesús Arturo Pérez,
More informationQoS scheduling. Scheduling algorithms
QoS scheduling Andrea Bianco Telecommunication Network Group firstname.lastname@polito.it http://www.telematica.polito.it/ QoS Issues in Telecommunication Networks - 1 Scheduling algorithms Scheduling:
More informationNetwork management and QoS provisioning - QoS in the Internet
QoS in the Internet Inernet approach is based on datagram service (best effort), so provide QoS was not a purpose for developers. Mainly problems are:. recognizing flows;. manage the issue that packets
More informationComputer Networks - CS132/EECS148 - Spring 2013 ------------------------------------------------------------------------------
Computer Networks - CS132/EECS148 - Spring 2013 Instructor: Karim El Defrawy Assignment 3 - Solutions Deadline : May 9 th 9:30pm (hard and soft copies required) ------------------------------------------------------------------------------
More informationSources: Chapter 6 from. Computer Networking: A Top-Down Approach Featuring the Internet, by Kurose and Ross
M ultimedia Communication Multimedia Systems(Module 5 Lesson 3) Summary: Beyond Best-Effort Motivating QoS Q uality of Service (QoS) Scheduling and Policing Sources: Chapter 6 from Computer Networking:
More informationModeling Active Queue Management algorithms using Stochastic Petri Nets
Modeling Active Queue Management algorithms using Stochastic Petri Nets Master Thesis Author: S. Dijkstra Supervising committee: prof. dr. ir. B.R.H.M. Haverkort dr. ir. P.T. de Boer ir. N.D. van Foreest
More informationTCP for Wireless Networks
TCP for Wireless Networks Outline Motivation TCP mechanisms Indirect TCP Snooping TCP Mobile TCP Fast retransmit/recovery Transmission freezing Selective retransmission Transaction oriented TCP Adapted
More informationNetwork Protocol Design and Evaluation
Network Protocol Design and Evaluation 08 - Analytical Evaluation Stefan Rührup Summer 2009 Overview In the last chapter: Simulation In this part: Analytical Evaluation: case studies 2 Analytical Evaluation
More informationLa couche transport dans l'internet (la suite TCP/IP)
La couche transport dans l'internet (la suite TCP/IP) C. Pham Université de Pau et des Pays de l Adour Département Informatique http://www.univ-pau.fr/~cpham Congduc.Pham@univ-pau.fr Cours de C. Pham,
More informationNetwork Management Quality of Service I
Network Management Quality of Service I Patrick J. Stockreisser p.j.stockreisser@cs.cardiff.ac.uk Lecture Outline Basic Network Management (Recap) Introduction to QoS Packet Switched Networks (Recap) Common
More informationTCP/IP Over Lossy Links - TCP SACK without Congestion Control
Wireless Random Packet Networking, Part II: TCP/IP Over Lossy Links - TCP SACK without Congestion Control Roland Kempter The University of Alberta, June 17 th, 2004 Department of Electrical And Computer
More informationActive Queue Management
Active Queue Management TELCOM2321 CS2520 Wide Area Networks Dr. Walter Cerroni University of Bologna Italy Visiting Assistant Professor at SIS, Telecom Program Slides partly based on Dr. Znati s material
More informationB-2 Analyzing TCP/IP Networks with Wireshark. Ray Tompkins Founder of Gearbit www.gearbit.com
B-2 Analyzing TCP/IP Networks with Wireshark June 15, 2010 Ray Tompkins Founder of Gearbit www.gearbit.com SHARKFEST 10 Stanford University June 14-17, 2010 TCP In this session we will examine the details
More informationMaster s Thesis. A Study on Active Queue Management Mechanisms for. Internet Routers: Design, Performance Analysis, and.
Master s Thesis Title A Study on Active Queue Management Mechanisms for Internet Routers: Design, Performance Analysis, and Parameter Tuning Supervisor Prof. Masayuki Murata Author Tomoya Eguchi February
More informationComparative Analysis of Congestion Control Algorithms Using ns-2
www.ijcsi.org 89 Comparative Analysis of Congestion Control Algorithms Using ns-2 Sanjeev Patel 1, P. K. Gupta 2, Arjun Garg 3, Prateek Mehrotra 4 and Manish Chhabra 5 1 Deptt. of Computer Sc. & Engg,
More informationChaoyang University of Technology, Taiwan, ROC. {changb,s9227623}@mail.cyut.edu.tw 2 Department of Computer Science and Information Engineering
TCP-Taichung: A RTT-based Predictive Bandwidth Based with Optimal Shrink Factor for TCP Congestion Control in Heterogeneous Wired and Wireless Networks Ben-Jye Chang 1, Shu-Yu Lin 1, and Ying-Hsin Liang
More informationQoS Parameters. Quality of Service in the Internet. Traffic Shaping: Congestion Control. Keeping the QoS
Quality of Service in the Internet Problem today: IP is packet switched, therefore no guarantees on a transmission is given (throughput, transmission delay, ): the Internet transmits data Best Effort But:
More informationParallel TCP Data Transfers: A Practical Model and its Application
D r a g a n a D a m j a n o v i ć Parallel TCP Data Transfers: A Practical Model and its Application s u b m i t t e d t o the Faculty of Mathematics, Computer Science and Physics, the University of Innsbruck
More informationOptimizing Converged Cisco Networks (ONT)
Optimizing Converged Cisco Networks (ONT) Module 3: Introduction to IP QoS Introducing QoS Objectives Explain why converged networks require QoS. Identify the major quality issues with converged networks.
More informationTransport layer issues in ad hoc wireless networks Dmitrij Lagutin, dlagutin@cc.hut.fi
Transport layer issues in ad hoc wireless networks Dmitrij Lagutin, dlagutin@cc.hut.fi 1. Introduction Ad hoc wireless networks pose a big challenge for transport layer protocol and transport layer protocols
More informationCSE 473 Introduction to Computer Networks. Exam 2 Solutions. Your name: 10/31/2013
CSE 473 Introduction to Computer Networks Jon Turner Exam Solutions Your name: 0/3/03. (0 points). Consider a circular DHT with 7 nodes numbered 0,,...,6, where the nodes cache key-values pairs for 60
More informationTCP/IP Optimization for Wide Area Storage Networks. Dr. Joseph L White Juniper Networks
TCP/IP Optimization for Wide Area Storage Networks Dr. Joseph L White Juniper Networks SNIA Legal Notice The material contained in this tutorial is copyrighted by the SNIA. Member companies and individuals
More informationDenial-of-Service Shrew Attacks
Denial-of-Service Shrew Attacks Bhuvana Mahalingam mbhuvana@cs.bu.edu 1. Introduction A Denial of Service Attack is defined as An incident in which a user or organization is deprived of the services of
More informationLow-rate TCP-targeted Denial of Service Attack Defense
Low-rate TCP-targeted Denial of Service Attack Defense Johnny Tsao Petros Efstathopoulos University of California, Los Angeles, Computer Science Department Los Angeles, CA E-mail: {johnny5t, pefstath}@cs.ucla.edu
More informationScheduling. An Engineering Approach to Computer Networking
Scheduling An Engineering Approach to Computer Networking Outline What is scheduling Why we need it Requirements of a scheduling discipline Fundamental choices Scheduling best effort connections Scheduling
More informationSeamless Congestion Control over Wired and Wireless IEEE 802.11 Networks
Seamless Congestion Control over Wired and Wireless IEEE 802.11 Networks Vasilios A. Siris and Despina Triantafyllidou Institute of Computer Science (ICS) Foundation for Research and Technology - Hellas
More informationResearch of TCP ssthresh Dynamical Adjustment Algorithm Based on Available Bandwidth in Mixed Networks
Research of TCP ssthresh Dynamical Adjustment Algorithm Based on Available Bandwidth in Mixed Networks 1 Wang Zhanjie, 2 Zhang Yunyang 1, First Author Department of Computer Science,Dalian University of
More informationSELECTIVE-TCP FOR WIRED/WIRELESS NETWORKS
SELECTIVE-TCP FOR WIRED/WIRELESS NETWORKS by Rajashree Paul Bachelor of Technology, University of Kalyani, 2002 PROJECT SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF
More informationTCP/IP Performance with Random Loss and Bidirectional Congestion
IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 8, NO. 5, OCTOBER 2000 541 TCP/IP Performance with Random Loss and Bidirectional Congestion T. V. Lakshman, Senior Member, IEEE, Upamanyu Madhow, Senior Member,
More informationBasic Multiplexing models. Computer Networks - Vassilis Tsaoussidis
Basic Multiplexing models? Supermarket?? Computer Networks - Vassilis Tsaoussidis Schedule Where does statistical multiplexing differ from TDM and FDM Why are buffers necessary - what is their tradeoff,
More informationVisualizations and Correlations in Troubleshooting
Visualizations and Correlations in Troubleshooting Kevin Burns Comcast kevin_burns@cable.comcast.com 1 Comcast Technology Groups Cable CMTS, Modem, Edge Services Backbone Transport, Routing Converged Regional
More informationCS551 End-to-End Internet Packet Dynamics [Paxson99b]
CS551 End-to-End Internet Packet Dynamics [Paxson99b] Bill Cheng http://merlot.usc.edu/cs551-f12 1 End-to-end Packet Dynamics How do you measure Internet performance? Why do people want to know? Are ISPs
More informationAnnouncements. Midterms. Mt #1 Tuesday March 6 Mt #2 Tuesday April 15 Final project design due April 11. Chapters 1 & 2 Chapter 5 (to 5.
Announcements Midterms Mt #1 Tuesday March 6 Mt #2 Tuesday April 15 Final project design due April 11 Midterm #1 Chapters 1 & 2 Chapter 5 (to 5.2) 1 Congestion Too much traffic can destroy performance
More informationEECS 122: Introduction to Computer Networks Multiaccess Protocols. ISO OSI Reference Model for Layers
EECS 122: Introduction to Computer Networks Multiaccess Protocols Computer Science Division Department of Electrical Engineering and Computer Sciences University of California, Berkeley Berkeley, CA 94720-1776
More informationRobust Router Congestion Control Using Acceptance and Departure Rate Measures
Robust Router Congestion Control Using Acceptance and Departure Rate Measures Ganesh Gopalakrishnan a, Sneha Kasera b, Catherine Loader c, and Xin Wang b a {ganeshg@microsoft.com}, Microsoft Corporation,
More informationAPPENDIX 1 USER LEVEL IMPLEMENTATION OF PPATPAN IN LINUX SYSTEM
152 APPENDIX 1 USER LEVEL IMPLEMENTATION OF PPATPAN IN LINUX SYSTEM A1.1 INTRODUCTION PPATPAN is implemented in a test bed with five Linux system arranged in a multihop topology. The system is implemented
More informationMultimedia Requirements. Multimedia and Networks. Quality of Service
Multimedia Requirements Chapter 2: Representation of Multimedia Data Chapter 3: Multimedia Systems Communication Aspects and Services Multimedia Applications and Transfer/Control Protocols Quality of Service
More informationAdaptive or Active Queue Management
Adaptive or Active Queue Management Prof. C. Tschudin, M. Sifalakis, T. Meyer, & M. Monti University of Basel Cs321 - HS 2013 Overview Queue management inside Internet s routers Issues arising with queue
More informationModeling and Simulation of Queuing Scheduling Disciplines on Packet Delivery for Next Generation Internet Streaming Applications
Modeling and Simulation of Queuing Scheduling Disciplines on Packet Delivery for Next Generation Internet Streaming Applications Sarhan M. Musa Mahamadou Tembely Matthew N. O. Sadiku Pamela H. Obiomon
More informationECSE-6600: Internet Protocols Exam 2
ECSE-6600: Internet Protocols Exam 2 Time: 75 min (strictly enforced) Points: 50 YOUR NAME: Be brief, but DO NOT omit necessary detail {Note: Simply copying text directly from the slides or notes will
More informationAnalysis and Detection of a Denial-of-Service Attack Scenario generated by TCP Receivers to Edge Network
Analysis and Detection of a Denial-of-Service Attack Scenario generated by TCP Receivers to Edge Network V. Anil Kumar 1 and Dorgham Sisalem 2 (anil@cmmacs.ernet.in, sisalem@fokus.fhg.de) 1 CSIR Centre
More informationUsing median filtering in active queue management for telecommunication networks
Using median filtering in active queue management for telecommunication networks Sorin ZOICAN *, Ph.D. Cuvinte cheie. Managementul cozilor de aşteptare, filtru median, probabilitate de rejectare, întârziere.
More informationReferring to the above question, the end-to-end delay (transmission delay plus propagation delay) is
CS326e Quiz 3 The first correct 10 answers will be worth 1 point each. Each subsequent correct answer will be worth 0.2 points. Circle the correct answer. UTEID In the following 7 problems, we are sending
More informationRequirements of Voice in an IP Internetwork
Requirements of Voice in an IP Internetwork Real-Time Voice in a Best-Effort IP Internetwork This topic lists problems associated with implementation of real-time voice traffic in a best-effort IP internetwork.
More informationOn the Efficiency and Fairness of TCP over Wired/Wireless Networks. Dimitrios Vardalis. Master of Science in Computer Science
On the Efficiency and Fairness of TCP over Wired/Wireless Networks by Dimitrios Vardalis Master of Science in Computer Science State University of New York at Stony Brook 2001 The continuous growth in
More informationPacket Queueing Delay
Some Active Queue Management Methods for Controlling Packet Queueing Delay Mahmud H. Etbega Mohamed, MSc PhD 2009 Design and Performance Evaluation of Some New Versions of Active Queue Management Schemes
More information