TCP loss sensitivity analysis ADAM KRAJEWSKI, IT-CS-CE
|
|
- Byron Logan
- 8 years ago
- Views:
Transcription
1 TCP loss sensitivity analysis ADAM KRAJEWSKI, IT-CS-CE
2 Original problem IT-DB was backuping some data to Wigner CC. High transfer rate was required in order to avoid service degradation. 4G out of... 10G Meyrin But the transfer rate was: Initial: ~1G After some tweaking: ~4G Wigner The problem lies within TCP internals! ADAM KRAJEWSKI - TCP CONGESTION CONTROL 2 / 37
3 TCP introduction TCP (Transmission Control Protocol) is a protocol providing reliable, connection-oriented transport over network. It operates at Transport Layer (4th) of the OSI reference model. Defined in RFC 793 from [10 Mb/s at that time! ] Its reliability means that it guarantees no data will be lost during communication. It is connection-oriented because it creates and maintains a logical connection between sender and receiver. Application Presentation Session Transport Network Data Link Physical ADAM KRAJEWSKI - TCP CONGESTION CONTROL 3 / 37
4 TCP operation basics: connection init Connection initiation: 3-way handshake Sequence counters setup: Client sends random SEQ number (ISN Initial Sequence Number) Server confirms it (ACK=SEQ+1) and sends its own SEQ number Client confirms and syncs to server s SEQ number Client Server ADAM KRAJEWSKI - TCP CONGESTION CONTROL 4 / 37
5 TCP is reliable TCP uses SEQ and ACK numbers to monitor which segments have been successfully transmitted. Lost packets are easily detected and retransmitted. This provides reliability....but do we really need to wait for every ACK? Timeout Client Server ADAM KRAJEWSKI - TCP CONGESTION CONTROL 5 / 37
6 TCP window (1) Let us assume that we have a client and a server connected with a 1G Ethernet link with 1 ms delay... RTT = 2ms, B = 1 Gbps 2ms CLIENT DATA ACK SERVER If we send packets of 1460 bytes each and wait for acknowledgment, then the effective transfer rate is 1460B/2ms = 5.84 Mbps. So we end up using 0.5% of available bandwidth. ADAM KRAJEWSKI - TCP CONGESTION CONTROL 6 / 37
7 TCP window (2) In order to use the full bandwidth we need to send at least B RTT unacknowledged bytes. This way we make sure we will not just sleep and wait for ACKs to come, but keep sending traffic in the meantime. 2ms CLIENT ACK-1 ACK-2 ACK-3 ACK-4 ACK-5 SERVER The B RTT factor is referred to as Bandwidth-Delay product. ADAM KRAJEWSKI - TCP CONGESTION CONTROL 7 / 37
8 TCP window (3) Client sends a certain amount of segments one after another. As soon as first ACK is received it assumes transmission is fine and continues to send segments. Basically, at each time t 0 there are W unacknowledged bytes on the wire. W is referred to as TCP Window Size W!= const Client ACK=1461 Server 1 W SEQ ACK=2921 ADAM KRAJEWSKI - TCP CONGESTION CONTROL 8 / 37
9 Window growth It starts with a default value wnd W def W DROP Then, it grows by 1 every RTT: wnd wnd + 1 But if a packet loss is detected, the window is cut in half: wnd wnd/2 W W 1 W def α α This is an AIMD algorithm (Additive Increase Multiplicative Decrease). t ADAM KRAJEWSKI - TCP CONGESTION CONTROL 9 / 37
10 Congestion control Network congestion appears when there is more traffic that the switching devices can handle. TCP prevents congestion! It starts with a small window thus low transfer rate Then the window grows linearly thus increasing transfer rate TCP assumes that congestion is happening when there are packet losses. So in case of a packet loss it cuts the window size in half thus reducing transfer rate. B [Gbps] B c 0.5 B c B 0 α α t [s] ADAM KRAJEWSKI - TCP CONGESTION CONTROL 10 / 37
11 Long Fat Network problem Long Fat Networks (LFNs) high bandwidth-delay product (B RTT) Example: CERN link to Wigner. To get full bandwith on 10G link with 25ms RTT we need a window: W 25 = 10Gbps 25ms MB If drop occurs at peak throughput... W drop = MB T Wdrop W 25 = ms 108h ADAM KRAJEWSKI - TCP CONGESTION CONTROL 11 / 37
12 TCP algorithms (1) The default TCP algorithm (reno) behaves poorly. Other congestion control algorithms have been developed such as: BIC CUBIC Scalable Compund TCP Each of them behaves differently and we want to see how they perform in our case... ADAM KRAJEWSKI - TCP CONGESTION CONTROL 12 / 37
13 Testbed Two servers connected back-to-back. How the congestion control algorithm performance changes with packet loss and delay? Tested with iperf3. Packet loss and delay emulated using NetEm in Linux: tc qdisc add dev eth2 root netem loss 0.1 delay 12.5ms ADAM KRAJEWSKI - TCP CONGESTION CONTROL 13 / 37
14 Bandwidth [Gbps] 0 ms delay, default settings cubic reno bic scalable Packet loss rate [%] ADAM KRAJEWSKI - TCP CONGESTION CONTROL 14 / 37
15 Bandwidth [Gbps] 25ms delay, default settings PROBLEM cubic reno bic scalable Packet loss rate [%] ADAM KRAJEWSKI - TCP CONGESTION CONTROL 15 / 37
16 Growing the window (1) We need... W 25 = B RTT = 10Gbps 25ms MB Default settings: net.core.rmem_max = 124K net.core.wmem_max = 124K net.ipv4.tcp_rmem = 4K 87K 4M net.ipv4.tcp_wmem = 4K 16K 4M net.core.netdev_max_backlog = 1K B max = W max RTT = 4MB 25ms Window can t grow bigger than maximum TCP send and receive buffers! Gbps WARNING: The real OS numbers are in pure bytes count so less readable. ADAM KRAJEWSKI - TCP CONGESTION CONTROL 16 / 37
17 Growing the window (2) We tune TCP settings on both server and client. Tuned settings: net.core.rmem_max = 67M net.core.wmem_max = 67M net.ipv4.tcp_rmem = 4K 87K 67M net.ipv4.tcp_wmem = 4K 65K 67M net.core.netdev_max_backlog = 30K Now it s fine WARNING: TCP buffer size doesn t translate directly to window size because TCP uses some portion of its buffers to allocate operational data structures. So the effective window size will be smaller than maximum buffer size set. Helpful link: ADAM KRAJEWSKI - TCP CONGESTION CONTROL 17 / 37
18 Bandwidth [Gbps] 25 ms delay, tuned settings Packet loss rate [%] cubic reno scalable bic ADAM KRAJEWSKI - TCP CONGESTION CONTROL 18 / 37
19 Bandwidth [Gbps] 0 ms delay, tuned settings cubic 6 5 DEFAULT CUBIC scalable reno bic Packet loss rate [%] ADAM KRAJEWSKI - TCP CONGESTION CONTROL 19 / 37
20 Bandwith fairness Goal: Each TCP flow should get a fair share of available bandwidth B 10G 10G 5G 10G 5G 5G t ADAM KRAJEWSKI - TCP CONGESTION CONTROL 20 / 37
21 Bandwith competition How do congestion control algorithms compete? Tests were done for: Reno, BIC, CUBIC, Scalable 0ms and 25ms delay Two cases: 2 flows starting at the same time 1 flow delayed by 30s 10G 10G congestion 10G ADAM KRAJEWSKI - TCP CONGESTION CONTROL 21 / 37
22 cubic vs cubic + offset ADAM KRAJEWSKI - TCP CONGESTION CONTROL 23 / 37
23 Bandwidth [Gbps] cubic vs bic 10 Congestion control 0ms 8 6 cubic 4 bic Packet loss rate [%] ADAM KRAJEWSKI - TCP CONGESTION CONTROL 24 / 37
24 Bandwidth [Gbps] cubic vs scalable Congestion control 0ms Packet loss rate [%] cubic scalable ADAM KRAJEWSKI - TCP CONGESTION CONTROL 25 / 37
25 TCP (reno) friendliness ADAM KRAJEWSKI - TCP CONGESTION CONTROL 26 / 37
26 Bandwidth [Gbps] cubic vs reno Congestion control 25ms delay Packet loss rate [%] cubic reno ADAM KRAJEWSKI - TCP CONGESTION CONTROL 27 / 37
27 Why default cubic? (1) BIC was the default Linux TCP congestion algorithm until kernel version It was changed to CUBIC in kernel with commit message: Change default congestion control used from BIC to the newer CUBIC which it the successor to BIC but has better properties over long delay links. Why? ADAM KRAJEWSKI - TCP CONGESTION CONTROL 28 / 37
28 Why default cubic? (2) It is more friendly to other congestion algorithms to Reno... ADAM KRAJEWSKI - TCP CONGESTION CONTROL 29 / 37
29 Why default cubic? (2) It is more friendly to other congestion algorithms to CTCP (Windows default)... ADAM KRAJEWSKI - TCP CONGESTION CONTROL 30 / 37
30 Why default cubic? (3) It has better RTT fairness properties 0 ms RTT 25 ms RTT Meyrin Wigner ADAM KRAJEWSKI - TCP CONGESTION CONTROL 31 / 37
31 Why default cubic? (4) RTT fairness test: 0 ms RTT 0 ms RTT 25 ms RTT 25 ms RTT ADAM KRAJEWSKI - TCP CONGESTION CONTROL 32 / 37
32 The real problem Lots of networks paths! LAG Meyrin ToR 100G 100G LAG Packet losses on: Links (dirty fibers,...) NICs (hardware limitations, bugs,...) ToR Wigner Difficult to troubleshoot! ADAM KRAJEWSKI - TCP CONGESTION CONTROL 33 / 37
33 Conclusions To achieve high transfer rate to Wigner: User part Tune TCP settings! Follow Make sure you use at least CUBIC for Linux and CTCP for Windows Networking team part Minimizing packet loss throughout the network Fiber cleaning Avoid BIC: Better performance on lossy links, but unfair to other congestion algorithms unfair to itself (RTT fairness) Submit a ticket if you observe low network performance for your data transfer Collaboration is essential! ADAM KRAJEWSKI - TCP CONGESTION CONTROL 34 / 37
34 Setting TCP algorithms (1) OS-wide setting (sysctl...): net.ipv4.tcp_congestion_control = reno Add new: # modprobe tcp_bic net.ipv4.tcp_available_congestion_control = cubic reno bic Local setting: setsockopt(), TCP_CONGESTION optname net.ipv4.tcp_allowed_congestion_control = cubic reno ADAM KRAJEWSKI - TCP CONGESTION CONTROL 35 / 37
35 Setting TCP algorithms (2) OS-wide settings: C:\> netsh interface tcp show global Add-On Congestion Control Provider: ctcp Enabled by default in Windows Server 2008 and newer. Needs to be enabled manually on client systems: Windows 7: C:\>netsh interface tcp set global congestionprovider=ctcp Windows 8/8.1 [Powershell]: Set-NetTCPSetting CongestionProvider ctcp ADAM KRAJEWSKI - TCP CONGESTION CONTROL 36 / 37
36 References [1] [2] hepix-ferrari.pdf ADAM KRAJEWSKI - TCP CONGESTION CONTROL 37 / 37
37 TCP loss sensitivity analysis ADAM KRAJEWSKI, IT-CS-CE
High-Speed TCP Performance Characterization under Various Operating Systems
High-Speed TCP Performance Characterization under Various Operating Systems Y. Iwanaga, K. Kumazoe, D. Cavendish, M.Tsuru and Y. Oie Kyushu Institute of Technology 68-4, Kawazu, Iizuka-shi, Fukuoka, 82-852,
More informationALTHOUGH it is one of the first protocols
TCP Performance - CUBIC, Vegas & Reno Ing. Luis Marrone lmarrone@linti.unlp.edu.ar Lic. Andrés Barbieri barbieri@cespi.unlp.edu.ar Mg. Matías Robles mrobles@info.unlp.edu.ar LINTI - Facultad de Informática
More informationIperf Tutorial. Jon Dugan <jdugan@es.net> Summer JointTechs 2010, Columbus, OH
Iperf Tutorial Jon Dugan Summer JointTechs 2010, Columbus, OH Outline What are we measuring? TCP Measurements UDP Measurements Useful tricks Iperf Development What are we measuring? Throughput?
More informationEVALUATING NETWORK BUFFER SIZE REQUIREMENTS
EVALUATING NETWORK BUFFER SIZE REQUIREMENTS for Very Large Data Transfers Michael Smitasin Lawrence Berkeley National Laboratory (LBNL) Brian Tierney Energy Sciences Network (ESnet) [ 2 ] Example Workflow
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 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 informationTCP Tuning Techniques for High-Speed Wide-Area Networks. Wizard Gap
NFNN2, 20th-21st June 2005 National e-science Centre, Edinburgh TCP Tuning Techniques for High-Speed Wide-Area Networks Distributed Systems Department Lawrence Berkeley National Laboratory http://gridmon.dl.ac.uk/nfnn/
More informationI N T E R I M R E P O R T O N N E T W O R K P E R F O R M A N C E
I N T E R I M R E P O R T O N N E T W O R K P E R F O R M A N C E Document Filename: Activity: Partner(s): Lead Partner: Document classification: SA2 KTH, EENet, KBFI, VU, RTU, ITPA, NICH BNTU, UIIP NASB
More informationFrequently Asked Questions
Frequently Asked Questions 1. Q: What is the Network Data Tunnel? A: Network Data Tunnel (NDT) is a software-based solution that accelerates data transfer in point-to-point or point-to-multipoint network
More informationLinux NIC and iscsi Performance over 40GbE
Linux NIC and iscsi Performance over 4GbE Chelsio T8-CR vs. Intel Fortville XL71 Executive Summary This paper presents NIC and iscsi performance results comparing Chelsio s T8-CR and Intel s latest XL71
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 information4 High-speed Transmission and Interoperability
4 High-speed Transmission and Interoperability Technology 4-1 Transport Protocols for Fast Long-Distance Networks: Comparison of Their Performances in JGN KUMAZOE Kazumi, KOUYAMA Katsushi, HORI Yoshiaki,
More informationDDoS attacks on electronic payment systems. Sean Rijs and Joris Claassen Supervisor: Stefan Dusée
DDoS attacks on electronic payment systems Sean Rijs and Joris Claassen Supervisor: Stefan Dusée Scope High volume DDoS attacks Electronic payment systems Low bandwidth requirements: 5 from account X to
More informationNames & Addresses. Names & Addresses. Hop-by-Hop Packet Forwarding. Longest-Prefix-Match Forwarding. Longest-Prefix-Match Forwarding
Names & Addresses EE 122: IP Forwarding and Transport Protocols Scott Shenker http://inst.eecs.berkeley.edu/~ee122/ (Materials with thanks to Vern Paxson, Jennifer Rexford, and colleagues at UC Berkeley)
More informationMurari Sridharan Windows TCP/IP Networking, Microsoft Corp. (Collaborators: Kun Tan, Jingmin Song, MSRA & Qian Zhang, HKUST)
Murari Sridharan Windows TCP/IP Networking, Microsoft Corp. (Collaborators: Kun Tan, Jingmin Song, MSRA & Qian Zhang, HKUST) Design goals Efficiency Improve throughput by efficiently using the spare capacity
More informationTCP Behavior across Multihop Wireless Networks and the Wired Internet
TCP Behavior across Multihop Wireless Networks and the Wired Internet Kaixin Xu, Sang Bae, Mario Gerla, Sungwook Lee Computer Science Department University of California, Los Angeles, CA 90095 (xkx, sbae,
More informationWEB SERVER PERFORMANCE WITH CUBIC AND COMPOUND TCP
WEB SERVER PERFORMANCE WITH CUBIC AND COMPOUND TCP Alae Loukili, Alexander Wijesinha, Ramesh K. Karne, and Anthony K. Tsetse Towson University Department of Computer & Information Sciences Towson, MD 21252
More informationUsing Linux Traffic Control on Virtual Circuits J. Zurawski Internet2 zurawski@internet2.edu February 25 nd 2013
Using Linux Traffic Control on Virtual Circuits J. Zurawski Internet2 zurawski@internet2.edu February 25 nd 2013 1. Abstract Research and Education (R&E) networks have experimented with the concept of
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 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 informationNetwork Probe. Figure 1.1 Cacti Utilization Graph
Network Probe Description The MCNC Client Network Engineering group will install several open source network performance management tools on a computer provided by the LEA or charter school to build a
More informationOperating Systems and Networks Sample Solution 1
Spring Term 2014 Operating Systems and Networks Sample Solution 1 1 byte = 8 bits 1 kilobyte = 1024 bytes 10 3 bytes 1 Network Performance 1.1 Delays Given a 1Gbps point to point copper wire (propagation
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 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 informationRFC 6349 Testing with TrueSpeed from JDSU Experience Your Network as Your Customers Do
RFC 6349 Testing with TrueSpeed from JDSU Experience Your Network as Your Customers Do RFC 6349 is the new transmission control protocol (TCP) throughput test methodology that JDSU co-authored along with
More informationAchieving Reliable High Performance in LFNs
Achieving Reliable High Performance in LFNs ven Ubik, and Pavel Cimbal, CENET, Prague, Czech Republic Abstract The PC hardware architecture and commodity operating
More informationA Survey: High Speed TCP Variants in Wireless Networks
ISSN: 2321-7782 (Online) Volume 1, Issue 7, December 2013 International Journal of Advance Research in Computer Science and Management Studies Research Paper Available online at: www.ijarcsms.com A Survey:
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 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 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 informationApplications. Network Application Performance Analysis. Laboratory. Objective. Overview
Laboratory 12 Applications Network Application Performance Analysis Objective The objective of this lab is to analyze the performance of an Internet application protocol and its relation to the underlying
More informationQuantifying the Performance Degradation of IPv6 for TCP in Windows and Linux Networking
Quantifying the Performance Degradation of IPv6 for TCP in Windows and Linux Networking Burjiz Soorty School of Computing and Mathematical Sciences Auckland University of Technology Auckland, New Zealand
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 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 informationUsing TrueSpeed VNF to Test TCP Throughput in a Call Center Environment
Using TrueSpeed VNF to Test TCP Throughput in a Call Center Environment TrueSpeed VNF provides network operators and enterprise users with repeatable, standards-based testing to resolve complaints about
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 informationThe new frontier of the DATA acquisition using 1 and 10 Gb/s Ethernet links. Filippo Costa on behalf of the ALICE DAQ group
The new frontier of the DATA acquisition using 1 and 10 Gb/s Ethernet links Filippo Costa on behalf of the ALICE DAQ group DATE software 2 DATE (ALICE Data Acquisition and Test Environment) ALICE is a
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 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 informationApplication Note. Windows 2000/XP TCP Tuning for High Bandwidth Networks. mguard smart mguard PCI mguard blade
Application Note Windows 2000/XP TCP Tuning for High Bandwidth Networks mguard smart mguard PCI mguard blade mguard industrial mguard delta Innominate Security Technologies AG Albert-Einstein-Str. 14 12489
More informationThe Problem with TCP. Overcoming TCP s Drawbacks
White Paper on managed file transfers How to Optimize File Transfers Increase file transfer speeds in poor performing networks FileCatalyst Page 1 of 6 Introduction With the proliferation of the Internet,
More informationOptimizing Throughput on Guaranteed-Bandwidth WAN Networks for the Large Synoptic Survey Telescope (LSST)
Optimizing Throughput on Guaranteed-Bandwidth WAN Networks for the Large Synoptic Survey Telescope (LSST) D. Michael Freemon National Center for Supercomputing Applications University of Illinois Urbana,
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 informationSupermicro Ethernet Switch Performance Test Straightforward Public Domain Test Demonstrates 40Gbps Wire Speed Performance
Straightforward Public Domain Test Demonstrates 40Gbps Wire Speed Performance SSE-X3348S/SR Test report- 40G switch port performance on Supermicro SSE-X3348 ethernet switches. SSE-X3348T/TR 1. Summary
More informationEnd-to-End Network/Application Performance Troubleshooting Methodology
End-to-End Network/Application Performance Troubleshooting Methodology Wenji Wu, Andrey Bobyshev, Mark Bowden, Matt Crawford, Phil Demar, Vyto Grigaliunas, Maxim Grigoriev, Don Petravick Fermilab, P.O.
More informationHow do I get to www.randomsite.com?
Networking Primer* *caveat: this is just a brief and incomplete introduction to networking to help students without a networking background learn Network Security. How do I get to www.randomsite.com? Local
More informationImproving Effective WAN Throughput for Large Data Flows By Peter Sevcik and Rebecca Wetzel November 2008
Improving Effective WAN Throughput for Large Data Flows By Peter Sevcik and Rebecca Wetzel November 2008 When you buy a broadband Wide Area Network (WAN) you want to put the entire bandwidth capacity to
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 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 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 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 informationMaster s Thesis. Design, Implementation and Evaluation of
Master s Thesis Title Design, Implementation and Evaluation of Scalable Resource Management System for Internet Servers Supervisor Prof. Masayuki Murata Author Takuya Okamoto February, 2003 Department
More informationMike Canney Principal Network Analyst getpackets.com
Mike Canney Principal Network Analyst getpackets.com 1 My contact info contact Mike Canney, Principal Network Analyst, getpackets.com canney@getpackets.com 319.389.1137 2 Capture Strategies capture Capture
More informationNetwork Security TCP/IP Refresher
Network Security TCP/IP Refresher What you (at least) need to know about networking! Dr. David Barrera Network Security HS 2014 Outline Network Reference Models Local Area Networks Internet Protocol (IP)
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 informationQuestion: 3 When using Application Intelligence, Server Time may be defined as.
1 Network General - 1T6-521 Application Performance Analysis and Troubleshooting Question: 1 One component in an application turn is. A. Server response time B. Network process time C. Application response
More informationCOMP 361 Computer Communications Networks. Fall Semester 2003. Midterm Examination
COMP 361 Computer Communications Networks Fall Semester 2003 Midterm Examination Date: October 23, 2003, Time 18:30pm --19:50pm Name: Student ID: Email: Instructions: 1. This is a closed book exam 2. This
More informationLinux TCP Implementation Issues in High-Speed Networks
Linux TCP Implementation Issues in High-Speed Networks D.J.Leith Hamilton Institute, Ireland www.hamilton.ie 1. Implementation Issues 1.1. SACK algorithm inefficient Packets in flight and not yet acknowledged
More informationMeasure wireless network performance using testing tool iperf
Measure wireless network performance using testing tool iperf By Lisa Phifer, SearchNetworking.com Many companies are upgrading their wireless networks to 802.11n for better throughput, reach, and reliability,
More informationScience DMZs Understanding their role in high-performance data transfers
Science DMZs Understanding their role in high-performance data transfers Chris Tracy, Network Engineer Eli Dart, Network Engineer ESnet Engineering Group Overview Bulk Data Movement a common task Pieces
More informationCSE331: Introduction to Networks and Security. Lecture 9 Fall 2006
CSE33: Introduction to Networks and Security Lecture 9 Fall 2006 Announcements Project Due TODAY HW Due on Friday Midterm I will be held next Friday, Oct. 6th. Will cover all course material up to next
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 informationHomework 2 assignment for ECE374 Posted: 02/21/14 Due: 02/28/14
1 Homework 2 assignment for ECE374 Posted: 02/21/14 Due: 02/28/14 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
More informationTCP/IP Inside the Data Center and Beyond. Dr. Joseph L White, Juniper Networks
Dr. Joseph L White, Juniper Networks SNIA Legal Notice The material contained in this tutorial is copyrighted by the SNIA. Member companies and individual members may use this material in presentations
More informationA Passive Method for Estimating End-to-End TCP Packet Loss
A Passive Method for Estimating End-to-End TCP Packet Loss Peter Benko and Andras Veres Traffic Analysis and Network Performance Laboratory, Ericsson Research, Budapest, Hungary {Peter.Benko, Andras.Veres}@eth.ericsson.se
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 informationSockets vs. RDMA Interface over 10-Gigabit Networks: An In-depth Analysis of the Memory Traffic Bottleneck
Sockets vs. RDMA Interface over 1-Gigabit Networks: An In-depth Analysis of the Memory Traffic Bottleneck Pavan Balaji Hemal V. Shah D. K. Panda Network Based Computing Lab Computer Science and Engineering
More informationAnswer: that dprop equals dtrans. seconds. a) d prop. b) d trans
Chapter 1 1) p. 98: P-6 This elementary problem begins to explore propagation delay and transmission delay, two central concepts in data networking. Consider two hosts, A and B, connected by single link
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 informationTCP Offload Engines. As network interconnect speeds advance to Gigabit. Introduction to
Introduction to TCP Offload Engines By implementing a TCP Offload Engine (TOE) in high-speed computing environments, administrators can help relieve network bottlenecks and improve application performance.
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 informationUDT: UDP-based Data Transfer for High-Speed Wide Area Networks
UDT: UDP-based Data Transfer for High-Speed Wide Area Networks Yunhong Gu and Robert L. Grossman National Center for Data Mining, University of Illinois at Chicago 851 S Morgan St, M/C 249, Chicago, IL
More informationQuality of Service in the Internet. QoS Parameters. Keeping the QoS. Traffic Shaping: Leaky Bucket Algorithm
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 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 informationWhere IT perceptions are reality. Test Report. OCe14000 Performance. Featuring Emulex OCe14102 Network Adapters Emulex XE100 Offload Engine
Where IT perceptions are reality Test Report OCe14000 Performance Featuring Emulex OCe14102 Network Adapters Emulex XE100 Offload Engine Document # TEST2014001 v9, October 2014 Copyright 2014 IT Brand
More informationNetwork Friendliness of Mobility Management Protocols
Network Friendliness of Mobility Management Protocols Md Sazzadur Rahman, Mohammed Atiquzzaman Telecommunications and Networks Research Lab School of Computer Science, University of Oklahoma, Norman, OK
More informationTest Methodology White Paper. Author: SamKnows Limited
Test Methodology White Paper Author: SamKnows Limited Contents 1 INTRODUCTION 3 2 THE ARCHITECTURE 4 2.1 Whiteboxes 4 2.2 Firmware Integration 4 2.3 Deployment 4 2.4 Operation 5 2.5 Communications 5 2.6
More informationHow Router Technology Shapes Inter-Cloud Computing Service Architecture for The Future Internet
How Router Technology Shapes Inter-Cloud Computing Service Architecture for The Future Internet Professor Jiann-Liang Chen Friday, September 23, 2011 Wireless Networks and Evolutional Communications Laboratory
More informationGateway Strategies for VoIP Traffic over Wireless Multihop Networks
KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS VOL. 5, NO. 1, January 2011 24 Copyright c 2011 KSII Gateway Strategies for VoIP Traffic over Wireless Multihop Networks Kyungtae Kim 1, Dragoş Niculescu
More informationThe Fundamentals of Intrusion Prevention System Testing
The Fundamentals of Intrusion Prevention System Testing New network-based Intrusion Prevention Systems (IPS) complement traditional security products to provide enterprises with unparalleled protection
More informationDavor Guttierrez dguttierrez@me.com 3 Gen d.o.o. Optimizing Linux Servers
Davor Guttierrez dguttierrez@me.com 3 Gen d.o.o. Optimizing Linux Servers Davor Guttierrez 3 Gen d.o.o since 1996 located in Ljubljana; Slovenia 33 employees large IBM mainframe systems and UNIX-oriented
More informationBurst Testing. New mobility standards and cloud-computing network. This application note will describe how TCP creates bursty
Burst Testing Emerging high-speed protocols in mobility and access networks, combined with qualityof-service demands from business customers for services such as cloud computing, place increased performance
More informationFile Transfer Protocol Performance Study for EUMETSAT Meteorological Data Distribution
Scientific Papers, University of Latvia, 2011. Vol. 770 Computer Science and Information Technologies 56 67 P. File Transfer Protocol Performance Study for EUMETSAT Meteorological Data Distribution Leo
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 informationChallenges of Sending Large Files Over Public Internet
Challenges of Sending Large Files Over Public Internet CLICK TO EDIT MASTER TITLE STYLE JONATHAN SOLOMON SENIOR SALES & SYSTEM ENGINEER, ASPERA, INC. CLICK TO EDIT MASTER SUBTITLE STYLE OUTLINE Ø Setting
More informationPerformance Evaluation of Different TCP Congestion Control Schemes in 4G System
Li Jie Performance Evaluation of Different TCP Congestion Control Schemes in 4G System Information Technology 2013 VAASAN AMMATTIKORKEAKOULU UNIVERSITY OF APPLIED SCIENCES Information Technology ABSTRACT
More informationTCP Labs. WACREN Network Monitoring and Measurement Workshop Antoine Delvaux a.delvaux@man.poznan.pl perfsonar developer 30.09.
TCP Labs WACREN Network Monitoring and Measurement Workshop Antoine Delvaux a.delvaux@man.poznan.pl perfsonar developer 30.09.2015 Hands-on session We ll explore practical aspects of TCP Checking the effect
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 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 informationThe Data Replication Bottleneck: Overcoming Out of Order and Lost Packets across the WAN
The Data Replication Bottleneck: Overcoming Out of Order and Lost Packets across the WAN By Jim Metzler, Cofounder, Webtorials Editorial/Analyst Division Background and Goal Many papers have been written
More informationThroughput Issues for High-Speed Wide-Area Networks
Throughput Issues for High-Speed Wide-Area Networks Brian L. Tierney ESnet Lawrence Berkeley National Laboratory http://fasterdata.es.net/ (HEPIX Oct 30, 2009) Why does the Network seem so slow? TCP Performance
More informationArchitecture and Performance of the Internet
SC250 Computer Networking I Architecture and Performance of the Internet Prof. Matthias Grossglauser School of Computer and Communication Sciences EPFL http://lcawww.epfl.ch 1 Today's Objectives Understanding
More informationPSM-throttling: Minimizing Energy Consumption for Bulk Data Communications in WLANs
PSM-throttling: Minimizing Energy Consumption for Bulk Data Communications in WLANs Xiaodong Zhang Ohio State University in Collaborations with Enhua Tan, Ohio State Lei Guo, Yahoo! Songqing Chen, George
More informationNetest: A Tool to Measure the Maximum Burst Size, Available Bandwidth and Achievable Throughput
Netest: A Tool to Measure the Maximum Burst Size, Available Bandwidth and Achievable Throughput Guojun Jin Brian Tierney Distributed Systems Department Lawrence Berkeley National Laboratory 1 Cyclotron
More informationCampus Network Design Science DMZ
Campus Network Design Science DMZ Dale Smith Network Startup Resource Center dsmith@nsrc.org The information in this document comes largely from work done by ESnet, the USA Energy Sciences Network see
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 informationEffects of Filler Traffic In IP Networks. Adam Feldman April 5, 2001 Master s Project
Effects of Filler Traffic In IP Networks Adam Feldman April 5, 2001 Master s Project Abstract On the Internet, there is a well-documented requirement that much more bandwidth be available than is used
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 informationBased on Computer Networking, 4 th Edition by Kurose and Ross
Computer Networks Ethernet Hubs and Switches Based on Computer Networking, 4 th Edition by Kurose and Ross Ethernet dominant wired LAN technology: cheap $20 for NIC first widely used LAN technology Simpler,
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 information