Data Link Layer. Flow Control. Flow Control

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Data Link Layer. Flow Control. Flow Control"

Transcription

1 Data Link Layer Flow Control 1 Flow Control Flow Control is a technique for speed-matching of transmitter and receiver. Flow control ensures that a transmitting station does not overflow a receiving station with data We will discuss two protocols for flow control: Stop-and-Wait Sliding Window For the time being, we assume that we have a perfect channel (no errors) 2 1

2 Stop-and-Wait Flow Control Simplest form of flow control In Stop-and-Wait flow control, the receiver indicates its readiness to receive data for each frame Operations: 1. Sender: Transmit a single frame 2. Receiver: Transmit acknowledgment (CK). Goto 1. nalysis of Stop-and-Wait propagation delay Last bit received Frame CK End of Transmit of CK Receiver Efficiency =? Frame transmission delay CK Sender Start Transmit End Transmit Last bit of CK received 4 2

3 Sliding Window Flow Control Major Drawback of Stop-and-Wait Flow Control: Only one frame can be in transmission at a time This leads to inefficiency if propagation delay is much longer than the transmission delay Sliding Window Flow Control llows transmission of multiple frames ssigns each frame a k-bit sequence number Range of sequence number is [0..2 k -1], i.e., frames are counted modulo 2 k 5 Operation of Sliding Window Sending Window: t any instant, the sender is permitted to send frames with sequence numbers in a certain range (the sending window) Frames already transmitted Window of frames that may be transmitted Frame sequence number Last frame transmitted Window shrinks as frames are sent Window expands as acknowledgements are received 6

4 Operation of Sliding Window Receiving Window: The receiver maintains a receiving window corresponding to the sequence numbers of frames that are accepted Frames already received Window of frames that are accepted by receiver Last frame acknowledged Window shrinks as frames are received Window expands as acknowledgements are sent 7 Operation of Sliding Window How is flow control achieved? Receiver can control the size of the sending window y limiting the size of the sending window data flow from sender to receiver can be limited Interpretation of CK N message: Receiver acknowledges all packets until (but not including) sequence number N 8 4

5 Example Transmitter Receiver F0 F1 F2 CK4 9 Example Continued Transmitter F F4 F5 F6 Receiver CK

6 nalysis of Sliding Windows 0 a 1st frame received a+1 Wth frame received a+w Receiver W W 2a+1 1st CK received Sender 11 nalysis of Sliding Windows If the window size is sufficiently large the sender can continuously transmit packets: W 2a+1: Sender can transmit continuously normalized efficiency = 1 W < 2a+1: Sender can transmit W frames every 2a+1 time units W normalized efficiency = 1 + 2a 12 6

7 RQ Error Control Types of errors: Lost frames, damaged frames Most Error Control techniques are based on (1) Error Detection Scheme (e.g., Parity checks, CRC), and (2) Retransmission Scheme Error control schemes that involve error detection and retransmission of lost or corrupted frames are referred to as utomatic Repeat Request (RQ) error control 1 RQ Schemes The most common RQ retransmission schemes: Stop-and-Wait RQ Go-ack-N RQ Selective Repeat RQ The protocol for sending CKs in all RQ protocols are based on the sliding window flow control scheme 14 7

8 Stop-and-Wait RQ Stop-and-Wait RQ is an addition to the Stop-and- Wait flow control protocol: Frames have 1-bit sequence numbers (SN = 0 or 1) Receiver sends an CK (1-SN) if frame SN is correctly received Sender waits for an CK (1-SN) before transmitting the next frame with sequence number 1-SN If sender does not receive anything before a timeout value expires, it retransmits frame SN 15 Stop-and-Wait RQ Lost Frame Timeout CK 0 CK 1 CK

9 Stop-and-Wait RQ Lost CK Timeout CK 0 CK 1 CK 1 17 Go-ack-N RQ Go-ack-N uses the sliding window flow control protocol. If no errors occur the operations are identical to Sliding Window 18 9

10 Go-ack-N RQ Operations: station may send multiple frames as allowed by the window size Receiver sends a NK i if frame i is in error. fter that, the receiver discards all incoming frames until the frame in error was correctly retransmitted If sender receives a NK i it will retransmit frame i and all packets i+1, i+2,... which have been sent, but not been acknowledged 19 Go-ack-N RQ Lost Frame Frames 4,5,6 are retransmitted Frame 5 Frame 4 Frame 6 Frame 5 Frame 4 Frame Frame 2 Frame 6 CK NK 4 CK 6 Frames 5 and 6 are discarded 20 10

11 Go-ack-N RQ Lost CK Timeout Frames 0-4 are retransmitted Frame Frame 2 Frame Frame 2 Frame 4 Frame 5 Frame 4 CK CK CK 5 Frames and 4 are discarded 21 Selective-Repeat RQ Similar to Go-ack-N RQ. However, the sender only retransmits frames for which a NK is received dvantage over Go-ack-N: Fewer Retransmissions. Disadvantages: More complexity at sender and receiver Each frame must be acknowledged individually (no cumulative acknowledgements) Receiver may receive frames out of sequence 22 11

12 Selective-Repeat RQ Lost Frame only Frame 4 is retransmitted Frame Frame 2 Frame 7 Frame 4 Frame 6 Frame 5 Frame 4 CK 1 CK 2 CK CK 4 CK 6, NK 4 CK 7 CK 5 CK 0 CK 1 Frames 5 and 6 are buffered 2 Example of Selective-Repeat RQ Frames waiting for CK/NK Frames received 2 1 CK2 frame 1 is correct, send CK 2 4 NK2 frame 2 is in error, send NK retransmit frame Receiver must keep track of `holes in the sequence of delivered frames Sender must maintain one timer per outstanding packet 24 12

CSE331: Introduction to Networks and Security. Lecture 9 Fall 2006

CSE331: 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 information

Stop And Wait. ACK received; transmit frame 2 CS 455 3

Stop And Wait. ACK received; transmit frame 2 CS 455 3 Data Link Layer, Part 5 Sliding Window Protocols These slides are created by Dr. Yih Huang of George Mason University. Students registered in Dr. Huang's courses at GMU can make a single machine-readable

More information

Computer Networks. Data Link Layer

Computer Networks. Data Link Layer Computer Networks The Data Link Layer 1 Data Link Layer Application Transport Network DLL PHY 2 What does it do? What functions it performs? Typically: Handling transmission errors, a.k.a., error control.

More information

CMPE 150 Winter 2009

CMPE 150 Winter 2009 CMPE 150 Winter 2009 Lecture 6 January 22, 2009 P.E. Mantey CMPE 150 -- Introduction to Computer Networks Instructor: Patrick Mantey mantey@soe.ucsc.edu http://www.soe.ucsc.edu/~mantey/ / t / Office: Engr.

More information

Data Link Layer(1) Principal service: Transferring data from the network layer of the source machine to the one of the destination machine

Data Link Layer(1) Principal service: Transferring data from the network layer of the source machine to the one of the destination machine Data Link Layer(1) Principal service: Transferring data from the network layer of the source machine to the one of the destination machine Virtual communication versus actual communication: Specific functions

More information

Computer Networks. Chapter 5 Transport Protocols

Computer Networks. Chapter 5 Transport Protocols Computer Networks Chapter 5 Transport Protocols Transport Protocol Provides end-to-end transport Hides the network details Transport protocol or service (TS) offers: Different types of services QoS Data

More information

Applied Data Communication Lecture 14

Applied Data Communication Lecture 14 Applied Data Communication Lecture 14 Character oriented Data Link Character-oriented data link control Asynchronous Synchronous Kristjan Sillmann reaalajasüsteemide õppetool TTÜ automaatikainstituut character-oriented

More information

Transport Layer Protocols

Transport 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 information

Protocols and Architecture. Protocol Architecture.

Protocols and Architecture. Protocol Architecture. Protocols and Architecture Protocol Architecture. Layered structure of hardware and software to support exchange of data between systems/distributed applications Set of rules for transmission of data between

More information

EKSAMEN / EXAM TTM4100 18 05 2007

EKSAMEN / EXAM TTM4100 18 05 2007 1.1 1.1.1...... 1.1.2...... 1.1.3...... 1.1.4...... 1.1.5...... 1.1.6...... 1.1.7...... 1.1.8...... 1.1.9...... 1.1.10.... 1.1.11... 1.1.16.... 1.1.12... 1.1.17.... 1.1.13... 1.1.18.... 1.1.14... 1.1.19....

More information

TCP in Wireless Mobile Networks

TCP 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 information

Lecture Objectives. Lecture 07 Mobile Networks: TCP in Wireless Networks. Agenda. TCP Flow Control. Flow Control Can Limit Throughput (1)

Lecture 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 information

Advanced Computer Networks Project 2: File Transfer Application

Advanced Computer Networks Project 2: File Transfer Application 1 Overview Advanced Computer Networks Project 2: File Transfer Application Assigned: April 25, 2014 Due: May 30, 2014 In this assignment, you will implement a file transfer application. The application

More information

Midterm Exam CMPSCI 453: Computer Networks Fall 2011 Prof. Jim Kurose

Midterm Exam CMPSCI 453: Computer Networks Fall 2011 Prof. Jim Kurose Midterm Exam CMPSCI 453: Computer Networks Fall 2011 Prof. Jim Kurose Instructions: There are 4 questions on this exam. Please use two exam blue books answer questions 1, 2 in one book, and the remaining

More information

Congestion Control Overview

Congestion Control Overview Congestion Control Overview Problem: When too many packets are transmitted through a network, congestion occurs t very high traffic, performance collapses completely, and almost no packets are delivered

More information

Names & Addresses. Names & Addresses. Hop-by-Hop Packet Forwarding. Longest-Prefix-Match Forwarding. Longest-Prefix-Match Forwarding

Names & 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 information

ECE 358: Computer Networks. Homework #3. Chapter 5 and 6 Review Questions 1

ECE 358: Computer Networks. Homework #3. Chapter 5 and 6 Review Questions 1 ECE 358: Computer Networks Homework #3 Chapter 5 and 6 Review Questions 1 Chapter 5: The Link Layer P26. Let's consider the operation of a learning switch in the context of a network in which 6 nodes labeled

More information

Chapter 3: Sample Questions, Problems and Solutions Bölüm 3: Örnek Sorular, Problemler ve Çözümleri

Chapter 3: Sample Questions, Problems and Solutions Bölüm 3: Örnek Sorular, Problemler ve Çözümleri Chapter 3: Sample Questions, Problems and Solutions Bölüm 3: Örnek Sorular, Problemler ve Çözümleri Örnek Sorular (Sample Questions): What is an unacknowledged connectionless service? What is an acknowledged

More information

Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks - III

Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks - III Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks - III CS: 647 Advanced Topics in Wireless Networks Drs. Baruch Awerbuch & Amitabh Mishra Department of Computer Science Johns Hopkins

More information

TCP 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) 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

Ethernet. Ethernet Frame Structure. Ethernet Frame Structure (more) Ethernet: uses CSMA/CD

Ethernet. Ethernet Frame Structure. Ethernet Frame Structure (more) Ethernet: uses CSMA/CD Ethernet dominant LAN technology: cheap -- $20 for 100Mbs! first widely used LAN technology Simpler, cheaper than token rings and ATM Kept up with speed race: 10, 100, 1000 Mbps Metcalfe s Etheret sketch

More information

0,2 D(0) A(1) D(1) 1,3 D(2) 0,2 D(0) A(1) D(1) 1,3 D(2) D(3) D(3) D(1) D(1) A(4) D(2) 4,6 D(3) A(4) 4,6 GO BACK 3 SELECTIVE REJECT WINDOW SLIDES

0,2 D(0) A(1) D(1) 1,3 D(2) 0,2 D(0) A(1) D(1) 1,3 D(2) D(3) D(3) D(1) D(1) A(4) D(2) 4,6 D(3) A(4) 4,6 GO BACK 3 SELECTIVE REJECT WINDOW SLIDES WASHINGTON UNIVERSITY DEPARTMENT OF COMPUTER SCIENCE CS423 Computer Communications: More Error Recovery Fall 1995 This is the fourth of probably 7 lectures on the Data Link Layer. In the last lecture we

More information

An enhanced TCP mechanism Fast-TCP in IP networks with wireless links

An enhanced TCP mechanism Fast-TCP in IP networks with wireless links Wireless Networks 6 (2000) 375 379 375 An enhanced TCP mechanism Fast-TCP in IP networks with wireless links Jian Ma a, Jussi Ruutu b and Jing Wu c a Nokia China R&D Center, No. 10, He Ping Li Dong Jie,

More information

ECE 333: Introduction to Communication Networks Fall 2002

ECE 333: Introduction to Communication Networks Fall 2002 ECE 333: Introduction to Communication Networks Fall 2002 Lecture 14: Medium Access Control II Dynamic Channel Allocation Pure Aloha In the last lecture we began discussing medium access control protocols

More information

TCP in Wireless Networks

TCP 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 information

Note! The problem set consists of two parts: Part I: The problem specifications pages Part II: The answer pages

Note! The problem set consists of two parts: Part I: The problem specifications pages Part II: The answer pages Part I: The problem specifications NTNU The Norwegian University of Science and Technology Department of Telematics Note! The problem set consists of two parts: Part I: The problem specifications pages

More information

LANs. Local Area Networks. via the Media Access Control (MAC) SubLayer. Networks: Local Area Networks

LANs. Local Area Networks. via the Media Access Control (MAC) SubLayer. Networks: Local Area Networks LANs Local Area Networks via the Media Access Control (MAC) SubLayer 1 Local Area Networks Aloha Slotted Aloha CSMA (non-persistent, 1-persistent, p-persistent) CSMA/CD Ethernet Token Ring 2 Network Layer

More information

3.4 SLIDING WINDOW PROTOCOLS

3.4 SLIDING WINDOW PROTOCOLS SEC. 3.3 SLIDING WINDOW PROTOCOLS 211 3.4 SLIDING WINDOW PROTOCOLS In the previous protocols, data frames were transmitted in one direction only. In most practical situations, there is a need for transmitting

More information

1. The subnet must prevent additional packets from entering the congested region until those already present can be processed.

1. 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 information

TCP Flow Control. TCP Receiver Window. Sliding Window. Computer Networks. Lecture 30: Flow Control, Reliable Delivery

TCP 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 information

CS268 Exam Solutions. 1) End-to-End (20 pts)

CS268 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 information

TCP for Wireless Networks

TCP 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 information

CS6956: Wireless and Mobile Networks Lecture Notes: 2/11/2015. IEEE 802.11 Wireless Local Area Networks (WLANs)

CS6956: Wireless and Mobile Networks Lecture Notes: 2/11/2015. IEEE 802.11 Wireless Local Area Networks (WLANs) CS6956: Wireless and Mobile Networks Lecture Notes: //05 IEEE 80. Wireless Local Area Networks (WLANs) CSMA/CD Carrier Sense Multi Access/Collision Detection detects collision and retransmits, no acknowledgement,

More information

Local Area Networks transmission system private speedy and secure kilometres shared transmission medium hardware & software

Local Area Networks transmission system private speedy and secure kilometres shared transmission medium hardware & software Local Area What s a LAN? A transmission system, usually private owned, very speedy and secure, covering a geographical area in the range of kilometres, comprising a shared transmission medium and a set

More information

[Prof. Rupesh G Vaishnav] Page 1

[Prof. Rupesh G Vaishnav] Page 1 Basics The function of transport layer is to provide a reliable end-to-end communications service. It also provides data transfer service for the user layers above and shield the upper layers from the

More information

Applying Active Queue Management to Link Layer Buffers for Real-time Traffic over Third Generation Wireless Networks

Applying Active Queue Management to Link Layer Buffers for Real-time Traffic over Third Generation Wireless Networks Applying Active Queue Management to Link Layer Buffers for Real-time Traffic over Third Generation Wireless Networks Jian Chen and Victor C.M. Leung Department of Electrical and Computer Engineering The

More information

CSE 473 Introduction to Computer Networks. Exam 2 Solutions. Your name: 10/31/2013

CSE 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 information

BCS THE CHARTERED INSTITUTE FOR IT. BCS HIGHER EDUCATION QUALIFICATIONS BCS Level 5 Diploma in IT COMPUTER NETWORKS

BCS THE CHARTERED INSTITUTE FOR IT. BCS HIGHER EDUCATION QUALIFICATIONS BCS Level 5 Diploma in IT COMPUTER NETWORKS BCS THE CHARTERED INSTITUTE FOR IT BCS HIGHER EDUCATION QUALIFICATIONS BCS Level 5 Diploma in IT COMPUTER NETWORKS Friday 2 nd October 2015 Morning Answer any FOUR questions out of SIX. All questions carry

More information

TCP and Wireless Networks Classical Approaches Optimizations TCP for 2.5G/3G Systems. Lehrstuhl für Informatik 4 Kommunikation und verteilte Systeme

TCP 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 information

Data Communications & Networks. Session 6 Main Theme Reliable Data Transfer. Dr. Jean-Claude Franchitti

Data Communications & Networks. Session 6 Main Theme Reliable Data Transfer. Dr. Jean-Claude Franchitti Data Communications & Networks Session 6 Main Theme Reliable Data Transfer Dr. Jean-Claude Franchitti New York University Computer Science Department Courant Institute of Mathematical Sciences Adapted

More information

The Problem with TCP. Overcoming TCP s Drawbacks

The 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 information

Operating Systems and Computer Networks / Datenverarbeitung 2 / Data Processing 2

Operating Systems and Computer Networks / Datenverarbeitung 2 / Data Processing 2 Computer Networks / Datenverarbeitung 2 / Data Processing 2 Exercise 7: Network Transmission & Code Efficiency Faculty of Question 7.1 Code Efficiency Block Length S S S Y Y O N N H 5 characters S T X

More information

Improving Throughput Performance of the IEEE 802.11 MAC Layer Using Congestion Control Methods

Improving Throughput Performance of the IEEE 802.11 MAC Layer Using Congestion Control Methods Improving Throughput Performance of the IEEE 802.11 MAC Layer Using Congestion Control Methods Song Ci CS Department University of Michigan-Flint Flint, MI48502 cisong@umich.edu Guevara Noubir College

More information

Performance Analysis of the IEEE 802.11 Wireless LAN Standard 1

Performance Analysis of the IEEE 802.11 Wireless LAN Standard 1 Performance Analysis of the IEEE. Wireless LAN Standard C. Sweet Performance Analysis of the IEEE. Wireless LAN Standard Craig Sweet and Deepinder Sidhu Maryland Center for Telecommunications Research

More information

Mobile Communications Chapter 9: Mobile Transport Layer

Mobile 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 information

ESPA 4.4.4 Nov 1984 PROPOSAL FOR SERIAL DATA INTERFACE FOR PAGING EQUIPMENT CONTENTS 1. INTRODUCTION 2. CHARACTER DESCRIPTION

ESPA 4.4.4 Nov 1984 PROPOSAL FOR SERIAL DATA INTERFACE FOR PAGING EQUIPMENT CONTENTS 1. INTRODUCTION 2. CHARACTER DESCRIPTION PROPOSAL FOR SERIAL DATA INTERFACE FOR PAGING EQUIPMENT CONTENTS 1. INTRODUCTION 2. CHARACTER DESCRIPTION 2.1 CHARACTER STRUCTURE 2.2 THE CHARACTER SET 2.3 CONTROL CHARACTERS 2.3.1 Transmission control

More information

COMP 361 Computer Communications Networks. Fall Semester 2003. Midterm Examination

COMP 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 information

28 Networks and Communication Protocols

28 Networks and Communication Protocols 113 28 Networks and ommunication Protocols Trend in computer systems: personal computing. Reasons why: ost: economies of scale. lso, avoids large initial investment in timesharing system. Performance:

More information

LLC: Frame Construction. Layer 2: Division into two Parts. Error-detecting and -correcting Codes. Error-correcting Codes

LLC: Frame Construction. Layer 2: Division into two Parts. Error-detecting and -correcting Codes. Error-correcting Codes Sicherungsebene Layer 2: Division into two Parts Logical Link Control (LLC) (Layer 2b) Organization of the data to be sent into frames Guarantee (if possible) an error free transmission between neighboring

More information

Access Control: Firewalls (1)

Access Control: Firewalls (1) Access Control: Firewalls (1) World is divided in good and bad guys ---> access control (security checks) at a single point of entry/exit: in medieval castles: drawbridge in corporate buildings: security/reception

More information

Review of Error Detection of Data Link Layer in Computer Network

Review of Error Detection of Data Link Layer in Computer Network Middle-East Journal of Scientific Research 18 (8): 1105-1110, 2013 ISSN 1990-9233 IDOSI Publications, 2013 DOI: 10.5829/idosi.mejsr.2013.18.8.11835 Review of Error Detection of Data Link Layer in Computer

More information

A Survey on Congestion Control Mechanisms for Performance Improvement of TCP

A 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 information

Higher Layer Protocols: UDP, TCP, ATM, MPLS

Higher Layer Protocols: UDP, TCP, ATM, MPLS Higher Layer Protocols: UDP, TCP, ATM, MPLS Massachusetts Institute of Technology Slide 1 The TCP/IP Protocol Suite Transmission Control Protocol / Internet Protocol Developed by DARPA to connect Universities

More information

Multiple Choice Questions

Multiple Choice Questions Comp18112: VoIP Examples/Revision 1 Barry 7/03/11 University of Manchester School of Computer Science COMP18112: Foundations of Distributed Computing 2011 Voice over Internet Protocol (VoIP) Questions

More information

Quectel Cellular Engine

Quectel Cellular Engine Cellular Engine GSM Multiplexer Application Notes GSM_MUX_AN_V1.00 Document Title GSM Multiplexer Application Notes Version 1.00 Date 2009-06-27 Status Document Control ID Release GSM_MUX_AN_V1.00 General

More information

Dynamic Source Routing in Ad Hoc Wireless Networks

Dynamic Source Routing in Ad Hoc Wireless Networks Dynamic Source Routing in Ad Hoc Wireless Networks David B. Johnson David A. Maltz Computer Science Department Carnegie Mellon University 5000 Forbes Avenue Pittsburgh, PA 15213-3891 dbj@cs.cmu.edu Abstract

More information

Outline. TCP connection setup/data transfer. 15-441 Computer Networking. TCP Reliability. Congestion sources and collapse. Congestion control basics

Outline. 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 information

Prefix AggregaNon. Company X and Company Y connect to the same ISP, and they are assigned the prefixes:

Prefix 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 information

Application Level Congestion Control Enhancements in High BDP Networks. Anupama Sundaresan

Application 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 information

Improving the Performance of TCP Using Window Adjustment Procedure and Bandwidth Estimation

Improving 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 information

Simulation-Based Comparisons of Solutions for TCP Packet Reordering in Wireless Network

Simulation-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 information

Solving complex performance problems in TCP/IP and SNA environments.

Solving complex performance problems in TCP/IP and SNA environments. IBM Global Services Solving complex performance problems in TCP/IP and SNA environments. Key Topics Discusses how performance analysis of networks relates to key issues in today's business environment

More information

3GPP TS 34.109 V3.10.0 (2004-09)

3GPP TS 34.109 V3.10.0 (2004-09) TS 34.109 V3.10.0 (2004-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Terminal logical test interface; Special conformance testing

More information

ARM Thumb Microcontrollers. Application Note. Software ISO 7816 I/O Line Implementation. Features. Introduction

ARM Thumb Microcontrollers. Application Note. Software ISO 7816 I/O Line Implementation. Features. Introduction Software ISO 7816 I/O Line Implementation Features ISO 7816-3 compliant (direct convention) Byte reception and transmission with parity check Retransmission on error detection Automatic reception at the

More information

Ring Local Area Network. Ring LANs

Ring Local Area Network. Ring LANs Ring Local Area Network Ring interface (1-bit buffer) Ring interface To station From station Ring LANs The ring is a series of bit repeaters, each connected by a unidirectional transmission link All arriving

More information

AN 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 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 information

Overview. Securing TCP/IP. Introduction to TCP/IP (cont d) Introduction to TCP/IP

Overview. Securing TCP/IP. Introduction to TCP/IP (cont d) Introduction to TCP/IP Overview Securing TCP/IP Chapter 6 TCP/IP Open Systems Interconnection Model Anatomy of a Packet Internet Protocol Security (IPSec) Web Security (HTTP over TLS, Secure-HTTP) Lecturer: Pei-yih Ting 1 2

More information

A study of Skype over IEEE 802.16 networks: voice quality and bandwidth usage

A study of Skype over IEEE 802.16 networks: voice quality and bandwidth usage Iowa State University Digital Repository @ Iowa State University Graduate Theses and Dissertations Graduate College 2011 A study of Skype over IEEE 802.16 networks: voice quality and bandwidth usage Kuan-yu

More information

Overview of Network Hardware and Software. CS158a Chris Pollett Jan 29, 2007.

Overview of Network Hardware and Software. CS158a Chris Pollett Jan 29, 2007. Overview of Network Hardware and Software CS158a Chris Pollett Jan 29, 2007. Outline Scales of Networks Protocol Hierarchies Scales of Networks Last day, we talked about broadcast versus point-to-point

More information

Computer Network. Interconnected collection of autonomous computers that are able to exchange information

Computer Network. Interconnected collection of autonomous computers that are able to exchange information Introduction Computer Network. Interconnected collection of autonomous computers that are able to exchange information No master/slave relationship between the computers in the network Data Communications.

More information

EECS 122: Introduction to Computer Networks Multiaccess Protocols. ISO OSI Reference Model for Layers

EECS 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 information

Digital Audio and Video Data

Digital Audio and Video Data Multimedia Networking Reading: Sections 3.1.2, 3.3, 4.5, and 6.5 CS-375: Computer Networks Dr. Thomas C. Bressoud 1 Digital Audio and Video Data 2 Challenges for Media Streaming Large volume of data Each

More information

The Qualcomm CDMA Digital Cellular System

The Qualcomm CDMA Digital Cellular System The Qualcomm CDMA Digital Cellular System Phil Karn Qualcomm, Inc 10555 Sorrento Valley Rd San Diego, CA 92121 karn@qualcomm.com Introduction Qualcomm, Inc. has developed and tested a digital spread spectrum

More information

Appendix B RCS11 Remote Communications

Appendix B RCS11 Remote Communications Appendix B RCS11 Remote Communications B.1 Host Computer Remote Communications Control and status messages are conveyed between the RCS11 and the host computer using packetized message blocks in accordance

More information

DATA COMMUNICATION AND NETWORKS

DATA COMMUNICATION AND NETWORKS DATA COMMUNICATION AND NETWORKS 1. Define the term Computer Networks. A Computer network is a number if computers interconnected by one or more transmission paths. The transmission path often is the telephone

More information

Mobile Computing/ Mobile Networks

Mobile Computing/ Mobile Networks Mobile Computing/ Mobile Networks TCP in Mobile Networks Prof. Chansu Yu Contents Physical layer issues Communication frequency Signal propagation Modulation and Demodulation Channel access issues Multiple

More information

A Transport Protocol for Multimedia Wireless Sensor Networks

A Transport Protocol for Multimedia Wireless Sensor Networks A Transport Protocol for Multimedia Wireless Sensor Networks Duarte Meneses, António Grilo, Paulo Rogério Pereira 1 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks Introduction Wireless

More information

Data Link Layer Overview

Data Link Layer Overview Data Link Layer Overview Date link layer deals with two basic issues: Part I How data frames can be reliably transmitted, and Part II How a shared communication medium can be accessed In many networks,

More information

LIN (Local Interconnect Network):

LIN (Local Interconnect Network): LIN (Local Interconnect Network): History: LIN (Local Interconnect Network) was developed as cost-effective alternate to CAN protocol. In 1998 a group of companies including Volvo, Motorola, Audi, BMW,

More information

Welcome to the Introduction to Controller Area Network web seminar My name is William Stuart, and I am a Applications Engineer for the Automotive

Welcome to the Introduction to Controller Area Network web seminar My name is William Stuart, and I am a Applications Engineer for the Automotive Welcome to the Introduction to Controller Area Network web seminar My name is William Stuart, and I am a Applications Engineer for the Automotive Products Group within Microchip. This web seminar today

More information

15-441: Computer Networks Homework 2 Solution

15-441: 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 information

Performance Measurement of TCP/IP Header Compression

Performance Measurement of TCP/IP Header Compression International Journal of Electronics and Communication Engineering. ISSN 0974-2166 Volume 4, Number 4 (2011), pp. 399-404 International Research Publication House http://www.irphouse.com Performance Measurement

More information

PROPERTY MANAGEMENT SYSTEM

PROPERTY MANAGEMENT SYSTEM PROPERTY MANAGEMENT SYSTEM COMMUNICATION INTERFACE SPECIFICATION NEC America, Inc. NDA-305-00 Revision.0 June, 998 Stock # 24727 LIABILITY DISCLAIMER NEC America reserves the right to change the specifications,

More information

B-2 Analyzing TCP/IP Networks with Wireshark. Ray Tompkins Founder of Gearbit www.gearbit.com

B-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 information

OSI Model. Application Presentation Session Transport Network Data Link Physical. EE156 Computer Network Architecture

OSI Model. Application Presentation Session Transport Network Data Link Physical. EE156 Computer Network Architecture OSI Model 7 6 5 4 3 2 1 Application Presentation Session Transport Network Data Link Physical Protocols Define a set of rules for communication. Specify the meaning and format of messages Define exchange

More information

802.11 Wireless LAN Protocol CS 571 Fall 2006. 2006 Kenneth L. Calvert All rights reserved

802.11 Wireless LAN Protocol CS 571 Fall 2006. 2006 Kenneth L. Calvert All rights reserved 802.11 Wireless LAN Protocol CS 571 Fall 2006 2006 Kenneth L. Calvert All rights reserved Wireless Channel Considerations Stations may move Changing propagation delays, signal strengths, etc. "Non-transitive"

More information

Note! The problem set consists of two parts: Part I: The problem specifications pages Part II: The answer pages

Note! The problem set consists of two parts: Part I: The problem specifications pages Part II: The answer pages Part I: The problem specifications NTNU The Norwegian University of Science and Technology Department of Telematics Note! The problem set consists of two parts: Part I: The problem specifications pages

More information

Congestions and Control Mechanisms n Wired and Wireless Networks

Congestions 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 information

Adaptive RTP/UDP/IP Header Compression for VoIP over Bluetooth

Adaptive RTP/UDP/IP Header Compression for VoIP over Bluetooth Adaptive RTP/UDP/IP Header Compression for VoIP over Bluetooth Luca Marzegalli 1, Mirco Masa 2, Mario Vitiello 3 1 marze@cefriel.it, 2 masa@cefriel.it, 3 vitiello@cefriel.it CEFRIEL / Politecnico di Milano

More information

Per-Flow Queuing Allot's Approach to Bandwidth Management

Per-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 information

CSMA/CA. Information Networks p. 1

CSMA/CA. Information Networks p. 1 Information Networks p. 1 CSMA/CA IEEE 802.11 standard for WLAN defines a distributed coordination function (DCF) for sharing access to the medium based on the CSMA/CA protocol Collision detection is not

More information

Networking Test 4 Study Guide

Networking Test 4 Study Guide Networking Test 4 Study Guide True/False Indicate whether the statement is true or false. 1. IPX/SPX is considered the protocol suite of the Internet, and it is the most widely used protocol suite in LANs.

More information

First Semester Examinations 2011/12 INTERNET PRINCIPLES

First Semester Examinations 2011/12 INTERNET PRINCIPLES PAPER CODE NO. EXAMINER : Martin Gairing COMP211 DEPARTMENT : Computer Science Tel. No. 0151 795 4264 First Semester Examinations 2011/12 INTERNET PRINCIPLES TIME ALLOWED : Two Hours INSTRUCTIONS TO CANDIDATES

More information

A Study on TCP Performance over Mobile Ad Hoc Networks

A 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 information

A DNP3 Protocol Primer

A DNP3 Protocol Primer A Protocol Primer Introduction This is a primer for people who want a quick understanding of without having to comb through the tedious details of a complex specification. The writing style is meant to

More information

CONTROL MICROSYSTEMS DNP3. User and Reference Manual

CONTROL MICROSYSTEMS DNP3. User and Reference Manual DNP3 User and Reference Manual CONTROL MICROSYSTEMS SCADA products... for the distance 48 Steacie Drive Telephone: 613-591-1943 Kanata, Ontario Facsimile: 613-591-1022 K2K 2A9 Technical Support: 888-226-6876

More information

Distributed Systems 3. Network Quality of Service (QoS)

Distributed Systems 3. Network Quality of Service (QoS) Distributed Systems 3. Network Quality of Service (QoS) Paul Krzyzanowski pxk@cs.rutgers.edu 1 What factors matter for network performance? Bandwidth (bit rate) Average number of bits per second through

More information

Homework 2 assignment for ECE374 Posted: 02/21/14 Due: 02/28/14

Homework 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 information

15-441: Computer Networks Homework 1

15-441: Computer Networks Homework 1 15-441: Computer Networks Homework 1 Assigned: January 29, 2008 Due: February 7, 2008 1. Suppose a 100-Mbps point-to-point link is being set up between Earth and a new lunar colony. The distance from the

More information

RFC 2544 Testing of Ethernet Services in Telecom Networks

RFC 2544 Testing of Ethernet Services in Telecom Networks RFC 2544 Testing of Ethernet Services in Telecom Networks White Paper Nigel Burgess Agilent Technologies Introduction The object of this paper is to discuss the use and testing of Ethernet services in

More information