Chapter -6 IMPROVED CONGESTION CONTROL MECHANISM FOR REAL TIME DATA TRANSMISSION
|
|
- Patrick Garrett
- 5 years ago
- Views:
Transcription
1 Chapter -6 IMPROVED CONGESTION CONTROL MECHANISM FOR REAL TIME DATA TRANSMISSION
2 Chapter 6 IMPROVED CONGESTION CONTROL MECHANISM FOR REAL TIME DATA TRANSMISSION 6.1 Introduction Supporting Quality of Service (QoS) is a very important parameter during message transmission in real time scenario. Many routing protocols for Mobile Adhoc Network (MANET) Supporting Real Time Applications have been developed that uses improved Real time framework for optimization of delay and power techniques, basic intention being extreme utilization of resource in resource limited environment, minimum power consumption using restricted residual battery power of the highly transferrable mobile stations. Here we discuss the issue of queuing delay during routing in the MANET and propose an improved technique to minimize delay based on congestion control by presenting an enhanced leaky bucket algorithm called Real-time Leaky Bucket (RLB) that avoids congestion at a node by regulating the burst flow of incoming packets using separate queues for real time and best effort packets. In case of congestion real time packets are given higher priority than the general packets hence avoiding congestion. 6.2 The Proposed Design In this research work, we have designed a QoS platform for congestion control at the transport layer which maintains handshaking approach with optimized Power and Delay AODV Protocol called PDO AODV at the network layer. A superior channel access mechanism has also been designed in the MAC layer for real time application prioritization and resource reservation that interacts with the improved AODV protocol based on a cross layer design foundation. Fig.6.1 shows the basic architecture of our proposed QoS platform with congestion control mechanism at the transport layer. In this paper we have elaborated functionality of the improved congestion control algorithm for real time applications. 99
3 Fig.6.1: Basic architecture of our proposed QoS Platform. While sending a video file during a multimedia application, the corresponding audio and video frames after being converted to packets and sent to the destination over a network. In a packet switched network, some packets sometimes get delayed due to congestion at various nodes. Therefore queuing delay takes place while the packets traverse through various routes. If the packets traverse through the same route, then also at specific nodes delay occurs depending on routing strategy of those nodes and sometimes due to processing complexity. Fig.6.2: Real time platform for video file transmission Fig.6.2 describes the new QoS mechanism employed in our scheme at every intermediate node during transmission of video file from a source to destination. At the intermediate node to control the congestion of traffic and to reduce the queuing delay an 100
4 enhanced RLB algorithm has been proposed which is explained in the next section. When a particular frame is being played during which few preceding frames arrive to the destination, that recently arrived frame is unnecessary so it will be discarded. Therefore, if a frame gets delayed by few seconds, then it is deleted by the receiver side instead of any processing done on it. Hard real time task provision is applicable on computer games, which are not safety critical, as a result of which if the time constraint is not satisfied, due to time mismatch of few nanoseconds, the game gets halt. 6.3 Queuing Delay in Real Time Transmission According to queuing theory, each node or station or router is called a queue and each packet is known as a job. A queue has a processing location and a memory buffer (or queue) where all the jobs wait before getting processed. According to the queuing policy (algorithm such as FIFO, FIFO etc) adopted by the queue and the packet execution time, the performance of that queue can be known. Throughput and delay performance can be measured by parameters such as type of packet, length of the packet, queuing policy and memory size at the queue Sources of Packet Delay Fig.6.3: Four sources of packet delay [181] As the figure 6.3 shows there are basically four sources of packet delay. Nodal processing delay At the node, the error bit pattern is checked for possible corruption of bits in the received data. The output link is checked as per the QoS requirement if it suits for specific bandwidth or not. Queuing delay This is the time taken by the packets to wait for their turn to come to be transmitted by the router. This delay is directly proportional to the congestion status of the router. Transmission delay If L is the length of the packet and 101
5 R is the bandwidth of the link in bps (bits per second), then transmission delay = L/R Propagation delay: Let d= length of the physical link, and s = propagation speed in the medium, then propagation delay = d/s Packet Loss Fig.6.4: Packet Loss in Queue Overflow [181] Fig.6.5:Packer drop due to queuing delay [181] Fig.6.4 explains that a buffer at a router has limited capacity, when many packets from different sources and different traffic reach at the buffer, and if the buffer is full at that time, then the packets are simply discarded resulting in packet loss. These lost packets are again re-transmitted upon request by the receiving side or as per the congestion control algorithm regulation. Therefore we have reduced the queuing delay of the real time frames at the node entry point using load shedding technique.fig.6.5 describes that When the rate of arrival of packets to the queue of the receiving node exceeds the rate of transmission of the link, for a particular period of time, the packets are queued while waiting to get transmitted and gradually when it gets late start to drop, lost in the medium without being received by any receiver, as their memory is already full. Fig.6.6: Queuing delay due to waiting [181] 102
6 As the above fig.6.6 shows when the incoming packets from the source arrive to the router memory buffers, if the rate of packets arrival, is more than the output link capacity, then the left out packets remain in a queue waiting their turn to come. In such case, queuing delay occurs. When a satellite captures pictures of an opponent territory and beams it to a ground station computing device sequence of frames, the base station computer executes all the frames to search the positional difference of objects that comes across in the preceding frames to examine the activity of the opponent enemy. In this case if the base computer gets overloaded, then while processing task of current frame is not over, another frame has already reached to the buffer. In such firm real time task, the associated time bounds typically ranges from a few mili seconds to several hundred mili seconds. 6.4 Real Time Leakey Bucket Algorithm with Congestion Control When number of packets sent to a particular network or sub-network is higher than the network capacity then it exceeds the link capacity, hence congestion takes place in the network. It is very much similar to a congested traffic scenario on a rushed road, as a result of which the performance of network slows down. The leaky bucket algorithm for congestion control has a bound on output flow through a bucket which has a hole, hence the water leaks in constant rate irrespective of the burst heavy incoming water flow. When there is no input, the system remains idle. The source inputs one packet per a single clock tick to the network. As in case of ATM (Asynchronous Transfer Mode) cells in case where the packet size are all same. In case of different packet size, it allows fixed number of bytes at a time, it may be fraction of a packet. This maintains uniformity in output traffic without heavy congestion. Fig.6.7: Functional Block diagram of proposed congestion control 103
7 Fig.6.8: Block diagram of RLB(Realtime leaky bucket ) But to have prioritized flow for real time applications we have designed improved congestion control mechanism, the functional block diagram of which has been presented in fig Detailed block diagram of our proposed Real time Leaky Bucket Algorithm has been presented in fig.6.8. Instead of a single burst flow of traffic coming to the bucket buffer, we have two parallel incoming flow, one for Real time and the other one for Best effort packets. When the queue at the router is full, the Best effort packets from the corresponding queue will be discarded and not the real time packets. Similarly there are two separate output flows for real time and best effort packets. The output bit rate remains constant but high constant rate for real time traffic and low constant rate for normal traffic. In this way prioritization of video files and other multimedia data traffic has been done ensuring improved real time data throughput in the network. This section of the research work focuses on one of the vital issues during real time data transmission in Mobile Adhoc Network. It solves the the challenging problem of queuing delay at the intermediate nodes and the congestion control strategy during multi-hop communication by offering an improved algorithm called Real Time Leaky Bucket for smooth control of incoming as well as outgoing traffic at the entry point of nodes. Using simulation results in a highly mobile environment, we have justified that the proposed scheme performs better in terms of congestion control and reducing queuing delay and in our future work we have planned 104
8 to implement our algorithm in real platform and to check the other related issues such as reliability and security while implementing the new proposal. 6.5 Improved Real Time Token Bucket Method Under open loop congestion control policies the re-transmission policy is important which is used when the sender feels that a sent packet is lost or its bits have been corrupted, and then it re-transmits the packets. This is one of the conventional ways which faces the issue of delaying in data transmission in window policy. The selective repeat window flow control policy is used than the go-back n windows policy for congestion control. Then there is an acknowledgement policy, in which a receiver may send an acknowledgement only if it has packet to be sent or a specially programmed timer gets expired, other cases it will not send an acknowledgement. It prevents congestion by not sending too many acknowledgement packets which create congestion in the traffic. In discarding method, the routers discard some packets randomly without any basic criteria simply to avoid congestion that can be retransmitted at a later stage. In admission method, there are different switches that regulate the flow by checking the resource requirements before admitting it to the network. Hence this way avoiding chance of congestion in future. The provision of back pressure technique is a controlling mechanism of congestion in which a congested node does not receive any data from its immediate upstream node. The provision of back pressure technique is a controlling mechanism of congestion in which a congested node does not receive any data from its immediate upstream node. Another Choke Packet method is used in which a package sent by a node to the source regarding the event of congestion, so that the source pauses for some time without continuously sending the packets, and it starts when the congestion at that particular node is under control. When there is no communication between the congested source node of the data transmission, the source assumes that a congestion event has occurred, so it stops sending more packets in this path and does not wait for receiving acknowledgement. This method is called implicit signalling. Similarly, in explicit signalling concept, the congested node explicitly sends a signal to the source computer. Congestion control also influences the Quality of Service during transmission which is a set of services that should be supported by a network, while transporting a packet from source to destination. By controlling and maintaining the flow characteristics of traffic, QoS can be achieved. The basic 105
9 characteristics of a flow are Reliability, Delay, Jitter and Bandwidth. Bandwidth is an important parameter which is considered during video and multimedia data transmission. Different applications need different bandwidths. In video conferencing we need to send millions of bits per second to refresh a color screen while the total number of bits in an e- mail may not reach even a million. 6.6 Improved Congestion Control In this section the congestion control technique has been discussed with prominence on shaping the traffic with improved token bucket based technique for real time applications. Fig.6.9: Basic architecture of our proposed policy Fig.6.10: Functional Block diagram This method checks the incoming traffic flow and streamlines it before inflowing to the network. The proposed method controls the rate of sending flow of traffic by introducing a set up time ( t) decided by negotiation among the sending station and the carrier which decide a traffic pattern. In Real Time Token Bucket (RTB) algorithm, there are two types of tokens generated by the system and the bucket holds the token. To transfer a packet, a station has to seize one token of its application type and delete it. As shown in fig. 4, the tokens are produced by the system at a rate of one token in every t second. 106
10 Fig.6.11: Token Bucket Mechanism According to our proposed Improved RTB (Real Time Token Bucket), in every alternative unit time, real time token and best effort tokens are produced. Stations which currently do not have anything to send, can capture the tokens and preserve for future transmission purpose when they have higher bursts of flow. But it is limited to extreme size of the bucket. Fig.6.12: Block diagram of RTB (Real Time Token Bucket) Leaky bucket discards the packets, but packets are not discarded in our proposed method RTB.Using RTB, a packet can only be communicated only if there is sufficient tokens to shelter its length. Leaky bucket directs the packets at an average constant rate. But improved RTB permits for bigger bursts to be sent quicker by more rapidly sending up 107
11 the output. RTB allows redeeming the tokens (authorizations) to send bulky bursts, which are not allowed in Leaky Bucket. 6.7 Performance Improvement in the Proposed Approach Leaky bucket algorithm has some limitation such as it does not profit a host that does not have anything to send. When a station has nothing to send, then its bucket turn into empty. In such case, if a station has burst data, there will be average data flow in leaky bucket. But the idle period in which the station was silent, will not be taken into account. But in token bucket algorithm, it is allowed for the silent stations to gather the acclaim for future in the means of token. For every clock tick, the system transmits n token to the bucket. This method eliminates one token for every bite of data transmitted. It can be understood that a station can transmit burst data s long as the bucket is not empty. As shown in fig. 6.4, the token bucket method can use a counter for implementation. As per our improved proposal in Token Bucket Algorithm for real time applications, there are three components, i.e. Interface Queue Real Time Token Queue and Release Queue.The Interface Queue receives the packets at a fixed rate, stores then as per SJF (Shortest Job First) scheduling method, and waits for the token bucket to fulfil the required tokens. When there are many tokens for one packet, it sends them to release queue and deletes those tokens which are already used. The server processes the received packets from the release queue in its own fixed rate. Every queue and the buckets have their own processing rate and the bucket of tokens has a fixed rate to store the tokens without overflow. Functionality of our Improved Real Time Token Bucket Method is explained in following algorithm. The algorithm consists of a bucket with a maximum capacity of N tokens which refills at a rate R tokens per second. Each token typically represents a quantity of whatever resource is being rate limited (network bandwidth, connections, etc.)this allows for a fixed rate of flow R with bursts up to N without impacting the consumer. 108
12 Fig.6.13: Code for consuming tokens Fig.6.14: Code for checking bucket capacity In this approach the output rate from release queue varies depending on the size of the burst flow. The bucket holds the token to transmit a packet, The clock timer produces the tokens one token in every t second. Silent stations with nothing to send currently, can capture and save in a later stage for transmitting large bursts. This method is Real Time token dependent. If the bucket becomes full, then the RT Tokens are discarded, and not the packets. When number of tokens is more, then the packets can transmit. Large burst flow can be sent quicker. Leaky bucket and token bucket concepts are merged in our approach. The two techniques have been combined to credit an idle host and at the same time regulate the traffic. The leaky bucket is applied after the token bucket; the rate of the leaky bucket needs to be higher than the rate of tokens dropped in the bucket. This part of the research work focuses on one of the vital issues during real time data transmission in Mobile Adhoc Network. It solves the challenging problem of queuing delay at the intermediate nodes and the congestion control strategy during multi-hop communication by offering an improved algorithm called Real Time Token Bucket for smooth control of incoming as well as outgoing traffic at the entry point of nodes. Using simulation results in a highly mobile environment, we have justified that the proposed scheme performs better in terms of congestion control and reducing queuing delay and in our future work we have planned to implement our algorithm in real platform and to check the other related issues such as reliability and security while implementing the new proposal. 109
13 6.8 Simulation and Results Network Simulator NS 2 is used for simulation and the and the simulation parameters are as given in Table1.We have simulated our approach with Optimized AODV protocol as part of the QoS architecture. Table 1 shows the network parameters considered during the simulation. Table 6.1: Simulation Parameters Parameter Name Parameter Value Channel Type Wireless Channel Radio Propagation Model Two Ray Ground Network Interface Type Wireless Phy Type of Traffic V B R Simulation Time 2 Minutes MAC Type Mac/802_11 Max Speed 50 m/s Network Size 1600 x 1600 Mobile Nodes 120 Packet Size 512 Kb Interface queue Type Queue/Droptail Protocol PDOAODV with RTB Simulator Ns2 Jitter can be termed as the variation is delay during packet arrival from source to destination. For real time packet delivery if there is non-uniform delay during packet arrival time, then the video streaming problem occurs during a video display. Fig.6.8 shows the comparison of jitter in video file transmission during packet arrival which has been calculated considering packet arrival time for different segments during the simulation process. Awk script has been used to extract the delay information from the output trace file that is generated after the simulation. 110
14 Fig Comparison of Jitter From fig it can be depicted that our proposed congestion control approach RT2B with PDO AODV protocol exhibits lesser delay between packet arrival with better jitter performance than the TBTS (Token Bucket Traffic Shaping) with AODV protocol in MANET. Fig.6.16 shows the comparative graph between the Token Bucket Congestion Control with Traffic Shaping and Our Proposed Improved RTB in terms of Packet Delivery Ratio(PDR) It clearly shows that our approach has a higher PDR percentage in a highly mobility scenario. Fig.6.16: Comparison of Packet Delivery Ratio(PDR) 111
15 Fig.6.17: Delay Comparison Fig.6.17 depicts that due to improved congestion control mechanism in our approach, the average delay in packet transmission reduces up to a greater extent in our approach. The above part of our research work concentrates on one of the dynamic concerns in real time data transmission in Mobile Adhoc Network. It resolves the stimulating difficulty of congestion due to queuing delay at the router interface during routing by proposing an enriched process called Real Time Token Bucket for fascinating control of inward as well as outbound traffic at the access point of the stations. This mechanism performs fantastically when embedded as a part of our original Multi-Layer Communication based QoS architecture. In our future work we have scheduled to device this procedure in real podium and to focus on the other related technical issues including performance appraisal under variable parameters. 6.9 Summary This research article focuses on one of the vital issues during real time data transmission in Mobile Adhoc Network. It solves the challenging problem of queuing delay at the intermediate nodes and the congestion control strategy during multi-hop communication by offering an improved algorithm called Real Time Leaky Bucket for smooth control of incoming as well as outgoing traffic at the entry point of nodes. Using simulation results in a highly mobile environment, we have justified that the proposed scheme performs better in terms of congestion control and reducing queuing delay and in our future work we have planned to implement our algorithm in real platform and to check the other related issues such as reliability and security while implementing the new proposal. 112
Chapter -5 QUALITY OF SERVICE (QOS) PLATFORM DESIGN FOR REAL TIME MULTIMEDIA APPLICATIONS
Chapter -5 QUALITY OF SERVICE (QOS) PLATFORM DESIGN FOR REAL TIME MULTIMEDIA APPLICATIONS Chapter 5 QUALITY OF SERVICE (QOS) PLATFORM DESIGN FOR REAL TIME MULTIMEDIA APPLICATIONS 5.1 Introduction For successful
More informationQuality of Service (QoS)
Quality of Service (QoS) The Internet was originally designed for best-effort service without guarantee of predictable performance. Best-effort service is often sufficient for a traffic that is not sensitive
More informationCHAPTER 3 EFFECTIVE ADMISSION CONTROL MECHANISM IN WIRELESS MESH NETWORKS
28 CHAPTER 3 EFFECTIVE ADMISSION CONTROL MECHANISM IN WIRELESS MESH NETWORKS Introduction Measurement-based scheme, that constantly monitors the network, will incorporate the current network state in the
More informationUnit 2 Packet Switching Networks - II
Unit 2 Packet Switching Networks - II Dijkstra Algorithm: Finding shortest path Algorithm for finding shortest paths N: set of nodes for which shortest path already found Initialization: (Start with source
More informationADVANCED COMPUTER NETWORKS
ADVANCED COMPUTER NETWORKS Congestion Control and Avoidance 1 Lecture-6 Instructor : Mazhar Hussain CONGESTION CONTROL When one part of the subnet (e.g. one or more routers in an area) becomes overloaded,
More informationQuality of Service in the Internet
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 informationWhat Is Congestion? Effects of Congestion. Interaction of Queues. Chapter 12 Congestion in Data Networks. Effect of Congestion Control
Chapter 12 Congestion in Data Networks Effect of Congestion Control Ideal Performance Practical Performance Congestion Control Mechanisms Backpressure Choke Packet Implicit Congestion Signaling Explicit
More informationQuality of Service in the Internet
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 informationIntroduction to Real-Time Communications. Real-Time and Embedded Systems (M) Lecture 15
Introduction to Real-Time Communications Real-Time and Embedded Systems (M) Lecture 15 Lecture Outline Modelling real-time communications Traffic and network models Properties of networks Throughput, delay
More informationLecture Outline. Bag of Tricks
Lecture Outline TELE302 Network Design Lecture 3 - Quality of Service Design 1 Jeremiah Deng Information Science / Telecommunications Programme University of Otago July 15, 2013 2 Jeremiah Deng (Information
More informationReal-Time Protocol (RTP)
Real-Time Protocol (RTP) Provides standard packet format for real-time application Typically runs over UDP Specifies header fields below Payload Type: 7 bits, providing 128 possible different types of
More informationQuality of Service in the Internet. QoS Parameters. Keeping the QoS. 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 informationKent State University
CS 4/54201 Computer Communication Network Kent State University Dept. of Computer Science www.mcs.kent.edu/~javed/class-net06f/ 1 A Course on Networking and Computer Communication LECT-11, S-2 Congestion
More informationOutline EEC-682/782 Computer Networks I. Midterm 1 Statistics. Midterm 1 Statistics. High 99, Low 34, Average 66
Outline EEC-682/782 Computer Networks I Lecture 12 Wenbing Zhao w.zhao1@csuohio.edu http://academic.csuohio.edu/zhao_w/teaching/eec682.htm (Lecture nodes are based on materials supplied by Dr. Louise Moser
More informationTraffic Access Control. Hamid R. Rabiee Mostafa Salehi, Fatemeh Dabiran, Hoda Ayatollahi Spring 2011
Traffic Access Control Hamid R. Rabiee Mostafa Salehi, Fatemeh Dabiran, Hoda Ayatollahi Spring 2011 Outlines Traffic Access Control Definition Traffic Shaping Traffic Policing The Leaky Bucket The Token
More informationResource allocation in networks. Resource Allocation in Networks. Resource allocation
Resource allocation in networks Resource Allocation in Networks Very much like a resource allocation problem in operating systems How is it different? Resources and jobs are different Resources are buffers
More informationCongestion Control Open Loop
Congestion Control Open Loop Muhammad Jaseemuddin Dept. of Electrical & Computer Engineering Ryerson University Toronto, Canada References 1. A. Leon-Garcia and I. Widjaja, Communication Networks: Fundamental
More informationCongestion in Data Networks. Congestion in Data Networks
Congestion in Data Networks CS420/520 Axel Krings 1 Congestion in Data Networks What is Congestion? Congestion occurs when the number of packets being transmitted through the network approaches the packet
More informationWhat Is Congestion? Computer Networks. Ideal Network Utilization. Interaction of Queues
168 430 Computer Networks Chapter 13 Congestion in Data Networks What Is Congestion? Congestion occurs when the number of packets being transmitted through the network approaches the packet handling capacity
More informationQUALITY of SERVICE. Introduction
QUALITY of SERVICE Introduction There are applications (and customers) that demand stronger performance guarantees from the network than the best that could be done under the circumstances. Multimedia
More informationUNIT IV TRANSPORT LAYER
Transport Layer UNIT IV TRANSPORT LAYER Congestion Control and Quality of Service Ref: Data Communication & Networking, 4 th edition, Forouzan IV-1 DATA TRAFFIC The main focus of congestion control and
More informationCSCD 433/533 Advanced Networks Spring Lecture 22 Quality of Service
CSCD 433/533 Advanced Networks Spring 2016 Lecture 22 Quality of Service 1 Topics Quality of Service (QOS) Defined Properties Integrated Service Differentiated Service 2 Introduction Problem Overview Have
More informationNetwork Management & Monitoring
Network Management & Monitoring Network Delay These materials are licensed under the Creative Commons Attribution-Noncommercial 3.0 Unported license (http://creativecommons.org/licenses/by-nc/3.0/) End-to-end
More informationCHAPTER 9: PACKET SWITCHING N/W & CONGESTION CONTROL
CHAPTER 9: PACKET SWITCHING N/W & CONGESTION CONTROL Dr. Bhargavi Goswami, Associate Professor head, Department of Computer Science, Garden City College Bangalore. PACKET SWITCHED NETWORKS Transfer blocks
More informationII. Principles of Computer Communications Network and Transport Layer
II. Principles of Computer Communications Network and Transport Layer A. Internet Protocol (IP) IPv4 Header An IP datagram consists of a header part and a text part. The header has a 20-byte fixed part
More informationLesson 14: QoS in IP Networks: IntServ and DiffServ
Slide supporting material Lesson 14: QoS in IP Networks: IntServ and DiffServ Giovanni Giambene Queuing Theory and Telecommunications: Networks and Applications 2nd edition, Springer All rights reserved
More informationQuality of Service II
Quality of Service II Patrick J. Stockreisser p.j.stockreisser@cs.cardiff.ac.uk Lecture Outline Common QoS Approaches Best Effort Integrated Services Differentiated Services Integrated Services Integrated
More informationQuality of Service (QoS)
CEN445 Network Protocols and Algorithms Chapter 5 Network Layer 5.4 Quality of Service Dr. Mostafa Hassan Dahshan Department of Computer Engineering College of Computer and Information Sciences King Saud
More informationChapter 24 Congestion Control and Quality of Service 24.1
Chapter 24 Congestion Control and Quality of Service 24.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-1 DATA TRAFFIC The main focus of congestion control
More informationAdvanced Computer Networks
Advanced Computer Networks QoS in IP networks Prof. Andrzej Duda duda@imag.fr Contents QoS principles Traffic shaping leaky bucket token bucket Scheduling FIFO Fair queueing RED IntServ DiffServ http://duda.imag.fr
More informationChapter 23 Process-to-Process Delivery: UDP, TCP, and SCTP
Chapter 23 Process-to-Process Delivery: UDP, TCP, and SCTP 23.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 23-1 PROCESS-TO-PROCESS DELIVERY The transport
More informationCEN445 Network Protocols & Algorithms. Network Layer. Prepared by Dr. Mohammed Amer Arafah Summer 2008
CEN445 Network Protocols & Algorithms Network Layer Prepared by Dr. Mohammed Amer Arafah Summer 2008 1 Congestion Control Algorithms General Principles of Congestion Control Congestion Prevention Policies
More informationInternet Services & Protocols. Quality of Service Architecture
Department of Computer Science Institute for System Architecture, Chair for Computer Networks Internet Services & Protocols Quality of Service Architecture Dr.-Ing. Stephan Groß Room: INF 3099 E-Mail:
More informationQoS Guarantees. Motivation. . link-level level scheduling. Certain applications require minimum level of network performance: Ch 6 in Ross/Kurose
QoS Guarantees. introduction. call admission. traffic specification. link-level level scheduling. call setup protocol. reading: Tannenbaum,, 393-395, 395, 458-471 471 Ch 6 in Ross/Kurose Motivation Certain
More informationLecture 4 Wide Area Networks - Congestion in Data Networks
DATA AND COMPUTER COMMUNICATIONS Lecture 4 Wide Area Networks - Congestion in Data Networks Mei Yang Based on Lecture slides by William Stallings 1 WHAT IS CONGESTION? congestion occurs when the number
More informationComputer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ
Computer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ 1 Lecture 5: Network Layer (cont ) Reference: Chapter 5 - Computer Networks, Andrew S. Tanenbaum, 4th Edition, Prentice Hall, 2003. 2
More informationCongestion Control in Communication Networks
Congestion Control in Communication Networks Introduction Congestion occurs when number of packets transmitted approaches network capacity Objective of congestion control: keep number of packets below
More informationBasics (cont.) Characteristics of data communication technologies OSI-Model
48 Basics (cont.) Characteristics of data communication technologies OSI-Model Topologies Packet switching / Circuit switching Medium Access Control (MAC) mechanisms Coding Quality of Service (QoS) 49
More informationConfiguring QoS CHAPTER
CHAPTER 34 This chapter describes how to use different methods to configure quality of service (QoS) on the Catalyst 3750 Metro switch. With QoS, you can provide preferential treatment to certain types
More informationH3C S9500 QoS Technology White Paper
H3C Key words: QoS, quality of service Abstract: The Ethernet technology is widely applied currently. At present, Ethernet is the leading technology in various independent local area networks (LANs), and
More informationNetwork Support for Multimedia
Network Support for Multimedia Daniel Zappala CS 460 Computer Networking Brigham Young University Network Support for Multimedia 2/33 make the best of best effort use application-level techniques use CDNs
More informationCS 344/444 Computer Network Fundamentals Final Exam Solutions Spring 2007
CS 344/444 Computer Network Fundamentals Final Exam Solutions Spring 2007 Question 344 Points 444 Points Score 1 10 10 2 10 10 3 20 20 4 20 10 5 20 20 6 20 10 7-20 Total: 100 100 Instructions: 1. Question
More informationChapter 7 CONCLUSION
97 Chapter 7 CONCLUSION 7.1. Introduction A Mobile Ad-hoc Network (MANET) could be considered as network of mobile nodes which communicate with each other without any fixed infrastructure. The nodes in
More informationJaringan Komputer. Network Layer. Network Layer. Network Layer. Network Layer Design Issues. Store-and-Forward Packet Switching
Network Layer Jaringan Komputer Network Layer Concerned with getting packets from the source all the way to the destination May require making many hops at intermediate routers along the way Contrasts
More informationRSVP 1. Resource Control and Reservation
RSVP 1 Resource Control and Reservation RSVP 2 Resource Control and Reservation policing: hold sources to committed resources scheduling: isolate flows, guarantees resource reservation: establish flows
More informationResource Control and Reservation
1 Resource Control and Reservation Resource Control and Reservation policing: hold sources to committed resources scheduling: isolate flows, guarantees resource reservation: establish flows 2 Usage parameter
More informationOverview Computer Networking What is QoS? Queuing discipline and scheduling. Traffic Enforcement. Integrated services
Overview 15-441 15-441 Computer Networking 15-641 Lecture 19 Queue Management and Quality of Service Peter Steenkiste Fall 2016 www.cs.cmu.edu/~prs/15-441-f16 What is QoS? Queuing discipline and scheduling
More informationThe Network Layer. Network Layer Design Objectives
1 next CITS3002 help3002 CITS3002 schedule The Network Layer The Data Link Layer had the responsibility of reliably transmitting frames across along a single wire (or wireless,...) link. The Network Layer's
More informationAdvanced Lab in Computer Communications Meeting 6 QoS. Instructor: Tom Mahler
Advanced Lab in Computer Communications Meeting 6 QoS Instructor: Tom Mahler Motivation Internet provides only single class of best-effort service. Some applications can be elastic. Tolerate delays and
More information3. Evaluation of Selected Tree and Mesh based Routing Protocols
33 3. Evaluation of Selected Tree and Mesh based Routing Protocols 3.1 Introduction Construction of best possible multicast trees and maintaining the group connections in sequence is challenging even in
More informationTELE Switching Systems and Architecture. Assignment Week 10 Lecture Summary - Traffic Management (including scheduling)
TELE9751 - Switching Systems and Architecture Assignment Week 10 Lecture Summary - Traffic Management (including scheduling) Student Name and zid: Akshada Umesh Lalaye - z5140576 Lecturer: Dr. Tim Moors
More informationImproving QOS in IP Networks. Principles for QOS Guarantees
Improving QOS in IP Networks Thus far: making the best of best effort Future: next generation Internet with QoS guarantees RSVP: signaling for resource reservations Differentiated Services: differential
More informationIntroduction to IP QoS
Introduction to IP QoS Primer to IP Quality of Service Aspects Queuing, Shaping, Classification Agenda IP QoS Introduction Queue Management Congestion Avoidance Traffic Rate Management Classification and
More informationCS244a: An Introduction to Computer Networks
Name: Student ID #: Campus/SITN-Local/SITN-Remote? MC MC Long 18 19 TOTAL /20 /20 CS244a: An Introduction to Computer Networks Final Exam: Thursday February 16th, 2000 You are allowed 2 hours to complete
More informationUNIT 2 TRANSPORT LAYER
Network, Transport and Application UNIT 2 TRANSPORT LAYER Structure Page No. 2.0 Introduction 34 2.1 Objective 34 2.2 Addressing 35 2.3 Reliable delivery 35 2.4 Flow control 38 2.5 Connection Management
More informationConfiguring QoS. Understanding QoS CHAPTER
29 CHAPTER This chapter describes how to configure quality of service (QoS) by using automatic QoS (auto-qos) commands or by using standard QoS commands on the Catalyst 3750 switch. With QoS, you can provide
More informationMultimedia Networking
CMPT765/408 08-1 Multimedia Networking 1 Overview Multimedia Networking The note is mainly based on Chapter 7, Computer Networking, A Top-Down Approach Featuring the Internet (4th edition), by J.F. Kurose
More informationATM Quality of Service (QoS)
ATM Quality of Service (QoS) Traffic/Service Classes, Call Admission Control Usage Parameter Control, ABR Agenda Introduction Service Classes and Traffic Attributes Traffic Control Flow Control Special
More informationSIMULATION OF PACKET DATA NETWORKS USING OPNET
SIMULATION OF PACKET DATA NETWORKS USING OPNET Nazy Alborz, Maryam Keyvani, Milan Nikolic, and Ljiljana Trajkovic * School of Engineering Science Simon Fraser University Vancouver, British Columbia, Canada
More informationLecture 17 Multimedia Transport Subsystem (Part 3)
CS 414 Multimedia Systems Design Lecture 17 Multimedia Transport Subsystem (Part 3) Klara Nahrstedt Spring 2010 Administrative MP2: deadline Monday, March 1, demos 5-7pm (sign up in class on Monday) HW1:
More informationUNIT IV -- TRANSPORT LAYER
UNIT IV -- TRANSPORT LAYER TABLE OF CONTENTS 4.1. Transport layer. 02 4.2. Reliable delivery service. 03 4.3. Congestion control. 05 4.4. Connection establishment.. 07 4.5. Flow control 09 4.6. Transmission
More informationIMPLEMENTATION OF CONGESTION CONTROL MECHANISMS USING OPNET
Nazy Alborz IMPLEMENTATION OF CONGESTION CONTROL MECHANISMS USING OPNET TM Communication Networks Laboratory School of Engineering Science Simon Fraser University Road map Introduction to congestion control
More informationConfiguring QoS. Finding Feature Information. Prerequisites for QoS
Finding Feature Information, page 1 Prerequisites for QoS, page 1 Restrictions for QoS, page 3 Information About QoS, page 4 How to Configure QoS, page 28 Monitoring Standard QoS, page 80 Configuration
More informationKommunikationssysteme [KS]
Kommunikationssysteme [KS] Dr.-Ing. Falko Dressler Computer Networks and Communication Systems Department of Computer Sciences University of Erlangen-Nürnberg http://www7.informatik.uni-erlangen.de/~dressler/
More informationLecture 14: Performance Architecture
Lecture 14: Performance Architecture Prof. Shervin Shirmohammadi SITE, University of Ottawa Prof. Shervin Shirmohammadi CEG 4185 14-1 Background Performance: levels for capacity, delay, and RMA. Performance
More informationComparing the bandwidth and priority Commands of a QoS Service Policy
Comparing the and priority s of a QoS Service Policy Contents Introduction Prerequisites Requirements Components Used Conventions Summary of Differences Configuring the Configuring the priority Which Traffic
More informationConfiguring QoS CHAPTER
CHAPTER 37 This chapter describes how to configure quality of service (QoS) by using automatic QoS (auto-qos) commands or by using standard QoS commands on the Catalyst 3750-E or 3560-E switch. With QoS,
More informationComputer Networking. Queue Management and Quality of Service (QOS)
Computer Networking Queue Management and Quality of Service (QOS) Outline Previously:TCP flow control Congestion sources and collapse Congestion control basics - Routers 2 Internet Pipes? How should you
More information(Refer Slide Time: 2:20)
Data Communications Prof. A. Pal Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture -23 X.25 and Frame Relay Hello and welcome to today s lecture on X.25 and
More informationFlow Control. Flow control problem. Other considerations. Where?
Flow control problem Flow Control An Engineering Approach to Computer Networking Consider file transfer Sender sends a stream of packets representing fragments of a file Sender should try to match rate
More informationConfiguring QoS CHAPTER
CHAPTER 36 This chapter describes how to configure quality of service (QoS) by using automatic QoS (auto-qos) commands or by using standard QoS commands on the Catalyst 3750 switch. With QoS, you can provide
More informationAdvanced Mechanisms for Available Rate Usage in ATM and Differentiated Services Networks
Advanced Mechanisms for Available Rate Usage in ATM and Differentiated Services Networks Roland Bless, Dirk Holzhausen, Hartmut Ritter, Klaus Wehrle Institute of Telematics, University of Karlsruhe Zirkel
More informationCongestion. Can t sustain input rate > output rate Issues: - Avoid congestion - Control congestion - Prioritize who gets limited resources
Congestion Source 1 Source 2 10-Mbps Ethernet 100-Mbps FDDI Router 1.5-Mbps T1 link Destination Can t sustain input rate > output rate Issues: - Avoid congestion - Control congestion - Prioritize who gets
More informationNetworking Quality of service
System i Networking Quality of service Version 6 Release 1 System i Networking Quality of service Version 6 Release 1 Note Before using this information and the product it supports, read the information
More informationBefore configuring standard QoS, you must have a thorough understanding of these items:
Finding Feature Information, page 1 Prerequisites for QoS, page 1 QoS Components, page 2 QoS Terminology, page 3 Information About QoS, page 3 Restrictions for QoS on Wired Targets, page 41 Restrictions
More informationToward a Reliable Data Transport Architecture for Optical Burst-Switched Networks
Toward a Reliable Data Transport Architecture for Optical Burst-Switched Networks Dr. Vinod Vokkarane Assistant Professor, Computer and Information Science Co-Director, Advanced Computer Networks Lab University
More informationModule objectives. Integrated services. Support for real-time applications. Real-time flows and the current Internet protocols
Integrated services Reading: S. Keshav, An Engineering Approach to Computer Networking, chapters 6, 9 and 4 Module objectives Learn and understand about: Support for real-time applications: network-layer
More informationA Preferred Service Architecture for Payload Data Flows. Ray Gilstrap, Thom Stone, Ken Freeman
A Preferred Service Architecture for Payload Data Flows Ray Gilstrap, Thom Stone, Ken Freeman NASA Research and Engineering Network NASA Advanced Supercomputing Division NASA Ames Research Center Outline
More information3. Quality of Service
3. Quality of Service Usage Applications Learning & Teaching Design User Interfaces Services Content Process ing Security... Documents Synchronization Group Communi cations Systems Databases Programming
More informationQoS Configuration. Overview. Introduction to QoS. QoS Policy. Class. Traffic behavior
Table of Contents QoS Configuration 1 Overview 1 Introduction to QoS 1 QoS Policy 1 Traffic Policing 2 Congestion Management 3 Line Rate 9 Configuring a QoS Policy 9 Configuration Task List 9 Configuring
More informationLecture 13. Quality of Service II CM0256
Lecture 13 Quality of Service II CM0256 Types of QoS Best Effort Services Integrated Services -- resource reservation network resources are assigned according to the application QoS request and subject
More informationA DiffServ IntServ Integrated QoS Provision Approach in BRAHMS Satellite System
A DiffServ IntServ Integrated QoS Provision Approach in BRAHMS Satellite System Guido Fraietta 1, Tiziano Inzerilli 2, Valerio Morsella 3, Dario Pompili 4 University of Rome La Sapienza, Dipartimento di
More informationQuality of Service. Traffic Descriptor Traffic Profiles. Figure 24.1 Traffic descriptors. Figure Three traffic profiles
24-1 DATA TRAFFIC Chapter 24 Congestion Control and Quality of Service The main focus of control and quality of service is data traffic. In control we try to avoid traffic. In quality of service, we try
More informationQoS Routing By Ad-Hoc on Demand Vector Routing Protocol for MANET
2011 International Conference on Information and Network Technology IPCSIT vol.4 (2011) (2011) IACSIT Press, Singapore QoS Routing By Ad-Hoc on Demand Vector Routing Protocol for MANET Ashwini V. Biradar
More informationLecture 21. Reminders: Homework 6 due today, Programming Project 4 due on Thursday Questions? Current event: BGP router glitch on Nov.
Lecture 21 Reminders: Homework 6 due today, Programming Project 4 due on Thursday Questions? Current event: BGP router glitch on Nov. 7 http://money.cnn.com/2011/11/07/technology/juniper_internet_outage/
More informationdifferent problems from other networks ITU-T specified restricted initial set Limited number of overhead bits ATM forum Traffic Management
Traffic and Congestion Management in ATM 3BA33 David Lewis 3BA33 D.Lewis 2007 1 Traffic Control Objectives Optimise usage of network resources Network is a shared resource Over-utilisation -> congestion
More informationETSF10 Internet Protocols Transport Layer Protocols
ETSF10 Internet Protocols Transport Layer Protocols 2012, Part 2, Lecture 2.2 Kaan Bür, Jens Andersson Transport Layer Protocols Special Topic: Quality of Service (QoS) [ed.4 ch.24.1+5-6] [ed.5 ch.30.1-2]
More informationLecture 5: Performance Analysis I
CS 6323 : Modeling and Inference Lecture 5: Performance Analysis I Prof. Gregory Provan Department of Computer Science University College Cork Slides: Based on M. Yin (Performability Analysis) Overview
More informationMultimedia Applications over Packet Networks
Multimedia Networking and Quality of Service Mario Baldi Technical Univeristy of Torino Computer Engineering Department mario.baldi@polito.it +39 011 564 7067 staff.polito.it/mario.baldi Nota di Copyright
More informationInstitute of Computer Technology - Vienna University of Technology. L73 - IP QoS Integrated Services Model. Integrated Services Model
Integrated Services Model IP QoS IntServ Integrated Services Model Resource Reservation Protocol (RSVP) Agenda Integrated Services Principles Resource Reservation Protocol RSVP Message Formats RSVP in
More informationNWEN 243. Networked Applications. Transport layer and application layer
NWEN 243 Networked Applications Transport layer and application layer 1 Topic TCP flow control TCP congestion control The Application Layer 2 Fast Retransmit Time-out period often relatively long: long
More informationEC1009 HIGH SPEED NETWORKS (ELECTIVE) (2 marks Questions and answers)
DEPARTMENT OF ECE EC1009 HIGH SPEED NETWORKS (ELECTIVE) (2 marks Questions and answers) FINAL YEAR 7 th SEMESTER UNIT I HIGH SPEED NETWORKS 1) What is common channel signaling? The data s and control signals
More informationPriority Traffic CSCD 433/533. Advanced Networks Spring Lecture 21 Congestion Control and Queuing Strategies
CSCD 433/533 Priority Traffic Advanced Networks Spring 2016 Lecture 21 Congestion Control and Queuing Strategies 1 Topics Congestion Control and Resource Allocation Flows Types of Mechanisms Evaluation
More informationDesign Intentions. IP QoS IntServ. Agenda. Design Intentions. L73 - IP QoS Integrated Services Model. L73 - IP QoS Integrated Services Model
Design Intentions Integrated Services Model IP QoS IntServ Integrated Services Model Resource Reservation Protocol (RSVP) The Internet was based on a best effort packet delivery service, but nowadays the
More informationMultimedia Traffic Management and Congestion Control in Satellite ATM Networks
Multimedia Traffic Management and Congestion Control in Satellite ATM Networks by S. Annukka Piironen Submitted to the Department of Electrical Engineering and Computer Science in partial fulfillment of
More informationStop-and-Go Service Using Hierarchical Round Robin
Stop-and-Go Service Using Hierarchical Round Robin S. Keshav AT&T Bell Laboratories 600 Mountain Avenue, Murray Hill, NJ 07974, USA keshav@research.att.com Abstract The Stop-and-Go service discipline allows
More informationConfiguring Advanced Radio Settings on the WAP371
Article ID: 5069 Configuring Advanced Radio Settings on the WAP371 Objective Radio settings are used to configure the wireless radio antenna and its properties on the wireless access point (WAP) device
More informationRouting & Congestion Control
WIDE AREA NETWORK Routing & Congestion Control Introduction Congestion control and routing are major issues to be handled in Wide Area Networks. Congestion is handled at transport layer and routing is
More information"Filling up an old bath with holes in it, indeed. Who would be such a fool?" "A sum it is, girl," my father said. "A sum. A problem for the mind.
We were doing very well, up to the kind of sum when a bath is filling at the rate of so many gallons and two holes are letting the water out, and please to say how long it will take to fill the bath, when
More informationCS244 Advanced Topics in Computer Networks Midterm Exam Monday, May 2, 2016 OPEN BOOK, OPEN NOTES, INTERNET OFF
CS244 Advanced Topics in Computer Networks Midterm Exam Monday, May 2, 2016 OPEN BOOK, OPEN NOTES, INTERNET OFF Your Name: Answers SUNet ID: root @stanford.edu In accordance with both the letter and the
More information