Performance analysis and simulation in wireless mesh networks

Size: px
Start display at page:

Download "Performance analysis and simulation in wireless mesh networks"

Transcription

1 Performance analysis and simulation in wireless mesh networks Roberto Cusani, Tiziano Inzerilli, Giacomo Di Stasio University of Rome Sapienza INFOCOM Dept. Via Eudossiana 8, 84 Rome, Italy Abstract Wireless Mesh Networks (WMNs) can be used as convenient replacements of wireline networks in the context of emergency scenarios. WMNs technologies can be advantageously exploited to quickly set-up a new communication infrastructure to recover from terrestrial network collapse. However, in order to enable effectively operative communications through a WMN infrastructure, traffic control measures are generally needed, as wireless communications especially in mesh network configurations can be affected by significant congestion and channel impairments problems. In this work, we are focusing on performance assessment and enhancement in WMNs. In particular we are examining traffic control design aided by simulation. Experimental results are presented from simulation models of IEEE8.b technology obtained through the open source INET framework of OMNET++. Index Terms Wireless Mesh Networks, traffic control, IP QoS I. INTRODUCTION IEEE 8. is a largely adopted technology for deployment of wireless local area networks (LANs)[]. In this context, IEEE 8. is often configured to operate in the infrastructure mode, where a set of access points (APs) serve as communication hubs for mobile stations and provide entry points to the Internet and the current role of IEEE 8. is limited to direct communications between mobile clients with a single AP. As an alternative, IEEE 8. can be used to interconnect form a full wireless mesh network (WMN) by means of two additional modes of operation. The ad-hoc mode can be used to form a single-hop ad-hoc network where nodes communicate with each other directly without the use of APs and the wireless distribution system (WDS) mode allows forming point-to-point AP relay links where each AP acts also as a wireless relay node. Such WMN, however, does not possess satisfactory levels of QoS, for various reasons. The intrinsic unreliability of the wireless medium along with the potentially high number of traversed hops, make it difficult to provide bandwidth guarantees as in all WMNs. In addition, the contention based MAC scheme, i.e. CSMA/CA [] operated with the DCF (Distributed Coordination Function), poses serious challenges This work is partially supported by the Italian National project Wireless 8O.6 Multi-antenna mesh Networks (WOMEN)[] under grant number in the control of the end-to-end delay [4, 5], as it does not assure time-bounded access. In order to support real-time multimedia communications in a IEEE8. WMN, one can compensate for the lack of effective traffic control strategy at the IP layer. Before IP traffic is relayed to the IEEE8. NIC (network interface card) for transmission [6] bandwidth and buffer management strategies can be applied. In addition, the alternative timebounded PCF (Point Coordination Function) [] MAC scheme can be adopted along with the DCF based on CMSA/CA. In this work we are presenting traffic control analysis and design in a IEEE8. WMN using simulation models, which have been developed using OMNET++ tool. In particular, we are concentrating on bandwidth allocation and control of packet transfer delays in nodes receiving multiple real-time and non-real-time IP flows with a CSMA/CA MAC. In section II we introduce the simulation models which we have used to study IEEE8. mesh networks. In section III a theoretical estimation of available bandwidth in a IEEE8. link is developed. Finally, in section IV we show esperimental results obtained with the OMNET++ simulator. II. SIMULATION MODELS OMNeT++ [7] is an open-source simulation tool, which can be freely used for academic research. Within OMNET, the INET framework provides support for most common network protocols, including TCP/IP and ethernet networks. Instead, the Mobility framework includes simulation models for wireless channels and mobile nodes, including IEEE8.b (currently work in progress). We have used these two frameworks as the basis for building our traffic control models for IEEE8. networks. Fig. shows a possible network configuration for a WMN, obtained by interconnecting two AP nodes heading two wireless cells. AP relay stations are critical nodes for QoS as they aggregate and dispatch traffic. In APs traffic control policies are needed in order to control end-to-end delays and bandwidth allocation. In our simulation models we have then provided such nodes with traffic control. Fig. depicts the traffic control model along with the NIC (Network Interface Card) model it interacts with. The traffic control is based on an EDFPS (Earliest Deadline First Packet Scheduler) model in the AP node consists of the following components:

2 S Cell_ S EDFPS S4 NIC AP 8. AP D4 Fig. WMN scenario example CLASS. LB LB LB LB mac AP Cell_ FIFO decider snreval FIFO FIFO FIFO Fig. traffic control architecture in an AP relay station D D SERVER (i) A CLASSIFIER separating IP packets into distinct flows (ii) FIFO queues for storing packets of different service classes. (iii) LBs (Leaky Buckets) used to limit bandwidth allocations to each service class (iv) A SERVER implementing the EDF[8] scheduling and PQ (Priority Queuing) scheduling The FIFO queues containing UDP traffic can operate a delay jitter regulation by dropping packets reaching queuing delays beyond a certain threshold value, while, a RED/RIO [9] dropping strategy can be set for queues storing TCP traffic. In the wireless link, channel errors have been modelled using the Gilbert-Elliot wireless channel model [,]. OMNET++ supports a number of applications and protocols which can be generated and conveyed in a generic network scenario. Including TCP and UDP, RTP, HTTP, FTP. In the following section we are analysing performance of UDP and TCP flows conveyed in a IEEE8.b link. Using OMNET++ it is then possible to simulate performance of anelastic traffic on UDP and elastic traffic conveyed with TCP and assess the impact of the CSMA/CA MAC. III. ESTIMATING MAXIMUM COMMUNICATION THROUGHPUT IN AN IEEE8. MULTIHOP LINK Overall capacity experienced in a IEEE 8.b link decreases from its nominal value on account of various factors, including (i) channel impairments, determined by locationdependent errors due to multipath fading. (ii) overhead introduced by control information added to each packet at the various architectural levels, which is strictly related to the packet size. (iii) link contention, which is strongly dependent on the nodes contending the wireless medium bandwidth for transmission. Effective capacity which is available in a IEEE8. link contended by N source nodes can be derived from [], which we briefly summarize. Let us consider a single host transmitting one data frame in a IEEE8.b link. The overall transmission time, i.e. T, is given by: T = t tr + t ov where t tr is a MAC PDU (protocol data unit) transmission time and t ov is a fix overhead introduced by the CSMA/CA protocol, including fixed intervals of time during which the medium is sensed prior sending a MAC frame and prior returning the corresponding acknowledgment respectively, the transmission time for an acknowledgment and the fix time for sending the PLCP preamble and header prior each MAC PDU. When there are N- other hosts, further delay needs to be accounted for medium contention. In this case, an additional N t cont N can be delay t cont ( ) (an analytical formula for ( ) found in [, 4]) will have to be considered, corresponding to the time spent during contention among the N nodes. The overall transmission time becomes as follows: T ( N ) t + t t (N) tr ov + cont () = () Hence, the actual MAC capacity which is used for transmission in the IEEE8.b will be given by C ( N ) C t T tr = max () ( N ) where C max is the nominal capacity of the link IEEE8.b, equal to Mbps. We are now deriving an approximate formula for assessment of throughput in multi-hop scenario, which will be validated through simulations. In Fig. is depicted the dynamics of a multi-hop transmission from a source node S to a destination node D, through intermediate relay stations R, R and R, which are used to interconnect nodes that are not in visibility.

3 PHASE PHASE PHASE PHASE In order to validate eq. (4) we have collected statistics of throughput from two scenarios where link capacity is completely saturated (Fig. 4, scenarios and ). Namely, two nodes (scenario, N max = ) and four nodes (scenario, N max = 4) transmit UDP video streams to a destination node through an intermediate relay station respectively. PHASE 4 PHASE 5 PHASE 6 PHASE 7 Fig. multi-hop transmission flow (Mbps) 4 analytical simulation As non-adjacent nodes cannot interfere with each other, they are allowed to transmit simultaneously. Therefore, in order to maximize the overall throughput, each relay station should alternate intervals of transmission and reception as in see Fig. and dedicate 5% of their time for each of them. The maximum throughput at MAC layer can be then estimated at half of the link capacity in eq. (). Each application level PDU which is transmitted in the IEEE8. link include an overhead OV introduced by MAC, IP and UDP/TCP headers. Hence, the maximum throughput, i.e. Beff for a multi-hop link which can be observed at application layer is given by C( Nmax ) L ( BER) ( L, BER, Nmax ) ( L + OV ) = (4) where L is the length in bytes of the transmitted application PDU, BER the average bit error rate experienced along the multi-hop path and N max the biggest number of contending nodes within each hop. IV. EXPERIMENTAL RESULTS A. Maximum throughput with anelastic traffic..5 BER 5 L(byte) Fig. 5 Multi-hop throughput assessment vs. packet length L and BER (scenario, N max= ) (Mbps)..5 BER 5 analytical simulation L(byte) 5 5 Scenario Scenario S S S S4 R R Fig. 6 Multi-hop throughput assessment vs. packet length L and BER (scenario, N max= 4) In Fig. 5 and Fig. 6, the theoretical results obtained with eq. (4) are compared with the results obtained through simulation. In both scenarios the analytical plane as for eq. (4) approximate well the simulation plane obtained through OMNET++ models. The maximum difference between the two planes is of 5% (scenario N max =, Fig. 4) and 7% (scenario N max =4, Fig. 5). This provides an overall validation and assessement of eq. (4). Eq. (4) can be used for an overall dimensioning of a multihop network rather then to provide accurate estimate of throughput, which in general can be hardly provided. Fig. 4 Multi-hop scenarios

4 B. Throughput in presence of elastic and anelastic traffic It is worth highlighting that theoretical throughput calculated as in eq. (4) can be approached only when the link is saturated with sessions running on UDP, which conveys anelastic traffic. If we instead transport TCP sessions in the link, throughput can be significantly reduced on account of packet loss due to contention as well as channel impairments. TCP, unlike UDP, react to packet loss by considerably reducing the throughput. As a consequence when bandwidth is contended between UDP and TCP sessions, UDP sessions tend to prevail over TCP sessions as their throughput is insensitive to packet loss. This behaviour has been observed and commented in the work [5]. We have then considered scenario in Fig. 4 with a mix of UDP and TCP sources. Namely, we have considered two UDP video streaming sources along with an HTTP and an FTP session. The BER has been set to % and packet size for all the sessions set to 4 byte. We have then observed a reduction of the throughput from, Mbps experience with 4 UDP video sources (Fig. 6) to,54 Mbps with mixed UDP and TCP sessions, which accounts for a loss of throughput of %, with video sources maintaining a mean throughput of 58 Kbps. This result shows that in order to improve performance of TCP traffic in a IEEE8. link, it is necessary to separate contention of UDP sessions with TCP sessions, e.g. using PCF window for UDP flows and DCF window for TCP flows. B. End-to-end delay performance Mean end-to-end delay(sec) FTP HTTP Video Video Fig. 7 Mean end-to-end (ee) packet delay in scenario with mixed UDP and TCP sources without traffic control Fig. 7 shows delay performance of the four traffic sources in scenario. If we compare delay statistics of the two TCP sources (FTP and HTTP flow) with the UDP ones (video and video) we observe that performance of TCP transport is generally better than that of UDP transport. As no traffic control strategy is applied, delay differentiation between UDP and TCP can only depend on the interaction of UDP and TCP protocols with channel errors and the CSMA/CA MAC. This demonstrates that a traffic control strategy is required, first of all, to invert delay performance of TCP and UDP flows, so that UDP packets are generally delivered in shorter time than TCP packets. Mean ee delay(sec) Mean ee delay(sec) HTTP Video Video FTP Fig. 8 Mean end-to-end (ee) packet delay in scenario with mixed UDP and TCP sources with traffic control Figure 8 shows delay statistics in the previous scenario when traffic control is used in the AP node to implement differentiated QoS management of UDP and TCP flows. The traffic control which is used consists of two EDF [REF] schedulers, i.e. EDF and EDF, and a PQ (priority queuing) scheduler [REF]. EDF is used to schedule packets of UDP flows and EDF packets for TCP flows. The PQ scheduler imposes that packets can be extracted from TCP queues only when UDP queues are empty. In addition, UDP flows are regulated by LB prior EDF so as to assure that TCP traffic is not starved by excessive consumption of resources by UDP traffic, which are given absolute priority over TCP traffic by the PQ scheduler. Table I shows priority parameters used in the simulation, which sets approximate target values to be reached by the end-to-end delay of the various traffic sources. TABLE I EDF PRIORITY PARAMETERS EDF EDF Video.4 s HTTP.8 s Video. s FTP. s It can be noticed from figure 8 that the incorporated traffic control has allowed to reduce the dependency of delay performance on the IEEE8. MAC and invert performance of UDP and TCP flows as required. In addition, adoption of traffic control has also resulted into performance differentiation among flows transported with the same protocol. Namely, end-to-end delay for one video source has been reduced from roughly 5 ms to 5 ms. In turn, end-toend delay for HTTP and FTP flows from initial values of 4 ms for both has been increased to ms and s respectively.

5 The delay differentiation introduced by the traffic control has to regarded particularly good considering that the overall load of video sources corresponds to 75% of the total traffic (i.e. throughput of each video source is roughly 58 Kbps, while the total throughput of the four sources,54 Mbps, as discussed in subsection A). CONCLUSION In this work we have dealt with performance analysis of IP flows transport over an IEEE8. mesh network. We have developed simulation models of traffic control for an IEEE8.b network using the OMNET++ tool to carry out extensive simulations of various WMN scenarios. Basing on [] we have first developed a theoretical approach to estimate effective capacity in a IEEE8.b link, where the medium is contended by N nodes. Statistics collected with the simulation models has shown that the throughput which is reached when using UDP sources well approximate the effective link capacity estimated theoretically. Formulas in the theoretical approach can be used for an overall dimensioning of a WMN. As observed also in [5], when TCP sources contend the medium with UDP sources, generally exhibit lower performance. Namely, we have measured significant throughput loss in TCP flows with respect to UDP flows, which can be avoided scheduling UDP and TCP flows in separate PCF and DCF windows. Conversely, when we observed end-to-end delay statistics, UDP flows has exhibited slightly worse performance. Using a traffic control strategy in relay nodes, we have showed how to invert UDP and TCP delay performance in favour of UDP traffic and determine further delay differentiation within UDP sources and TCP sources. [] E. O. Elliot. Estimates of error rates for codes on burst-noise channels. Bell Systems Technical Journal, vol. 4, pp , September 96, vol, pag. [] M. Heusse, et al, "Performance Anomaly of 8.b," Proceedings of Infocom, date, location, pages, volume. [] F. Cali, et al, "IEEE 8. Wireless LAN: Capacity Analysis and Protocol Enhancements," Proceedings of Infocom, month 998 [4] G. Bianchi, "Performance Analysis of the IEEE 8. Distributed Coordination Function," IEEE Journal on Selected Area on Communications, volume, pp , March. [5] Raffaele Bruno, Marco Conti, Enrico Gregori, Throughput Analysis of UDP and TCP Flows in IEEE 8.bWLANs: A Simple Model and its Validation IEEE Computer Society Proceedings of the 5 Workshop on Techniques, Methodologies and Tools for Performance Evaluation of Complex Systems (FIRB-PERF 5), vol.,pag.,date. REFERENCES [] R. Bruno, M. Conti, and E. Gregori, Mesh networks: commodity multihop ad hoc networks, IEEE Communications Magazine, vol. 4, pp., March 5. [] [] IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, ISO/IEC 88-: 999. [4] O. Tickoo, B. Sikdar, Queueing analysis and delay mitigation in IEEE 8. random access MAC based wireless networks. In Proc. of IEEE INFOCOM 4, rd Annual Joint Conference of the IEEE Computer and Communications Societies, pp Vol., 7- March 4, location. [5] C. Hoene, A. Guenther, and A. Wolisz, Measuring the impact of slow user motion on packet loss and delay over IEEE 8.b wireless links, in Proc. of IEEE Workshop on Wireless Local Networks (WLN), Bonn, Germany, October, vol., pages. [6] Chou and A. Misra, Low latency multimedia broadcast in multi-rate wireless meshes, in Proc. of the First IEEE Workshop on Wireless Mesh Networks, September 5, vol.,pag.,location. [7] [8] D. Ferrari and D. Verma, A scheme for real-time channel establishment in wide-area networks, IEEE J. Selected Areas Commun., Vol. 8, pp , month 99. [9] K. Xu, M. Gerla, L. Qi, Y. Shu. Enhancing TCP Fairness in Ad Hoc Wireless Networks Using Neighborhood RED, in Proc. of ACM MOBICOM, month, vol,pag,location. [] E. N. Gilbert, Capacity of a burst-noise channel. Bell Systems Technical Journal, vol. 9, pp. 5-65, September 96, vol, pag.

Can I add a VoIP call?

Can I add a VoIP call? Can I add a VoIP call? Sachin Garg Avaya Labs Basking Ridge, NJ 07920 Email: sgarg@avaya.com Martin Kappes Avaya Labs Basking Ridge, NJ 07920 Email: mkappes@avaya.com Abstract In this paper, we study the

More information

Real-Time Communication in IEEE 802.11 Wireless Mesh Networks: A Prospective Study

Real-Time Communication in IEEE 802.11 Wireless Mesh Networks: A Prospective Study in IEEE 802.11 : A Prospective Study January 2011 Faculty of Engineering of the University of Porto Outline 1 Introduction 2 3 4 5 in IEEE 802.11 : A Prospective Study 2 / 28 Initial Considerations Introduction

More information

IEEE 802.11 Ad Hoc Networks: Performance Measurements

IEEE 802.11 Ad Hoc Networks: Performance Measurements IEEE 8. Ad Hoc Networks: Performance Measurements G. Anastasi Dept. of Information Engineering University of Pisa Via Diotisalvi - 56 Pisa, Italy Email: g.anastasi@iet.unipi.it E. Borgia, M. Conti, E.

More information

Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc

Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc (International Journal of Computer Science & Management Studies) Vol. 17, Issue 01 Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc Dr. Khalid Hamid Bilal Khartoum, Sudan dr.khalidbilal@hotmail.com

More information

Throughput Analysis of WEP Security in Ad Hoc Sensor Networks

Throughput Analysis of WEP Security in Ad Hoc Sensor Networks Throughput Analysis of WEP Security in Ad Hoc Sensor Networks Mohammad Saleh and Iyad Al Khatib iitc Stockholm, Sweden {mohsaleh, iyad}@iitc.se ABSTRACT This paper presents a performance investigation

More information

VoIP in 802.11. Mika Nupponen. S-72.333 Postgraduate Course in Radio Communications 06/04/2004 1

VoIP in 802.11. Mika Nupponen. S-72.333 Postgraduate Course in Radio Communications 06/04/2004 1 VoIP in 802.11 Mika Nupponen S-72.333 Postgraduate Course in Radio Communications 06/04/2004 1 Contents Introduction VoIP & WLAN Admission Control for VoIP Traffic in WLAN Voice services in IEEE 802.11

More information

An Experimental Study of Throughput for UDP and VoIP Traffic in IEEE 802.11b Networks

An Experimental Study of Throughput for UDP and VoIP Traffic in IEEE 802.11b Networks An Experimental Study of Throughput for UDP and VoIP Traffic in IEEE 82.11b Networks Sachin Garg sgarg@avaya.com Avaya Labs Research Basking Ridge, NJ USA Martin Kappes mkappes@avaya.com Avaya Labs Research

More information

EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Mathematics and Computer Science

EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Mathematics and Computer Science EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Mathematics and Computer Science Examination Computer Networks (2IC15) on Monday, June 22 nd 2009, 9.00h-12.00h. First read the entire examination. There

More information

Improving Quality of Service

Improving Quality of Service Improving Quality of Service Using Dell PowerConnect 6024/6024F Switches Quality of service (QoS) mechanisms classify and prioritize network traffic to improve throughput. This article explains the basic

More information

then, we require that, in order to support the offered load, (1)

then, we require that, in order to support the offered load, (1) Capacity of an IEEE 802.11b Wireless LAN supporting VoIP To appear in Proc. IEEE Int. Conference on Communications (ICC) 2004 David P. Hole and Fouad A. Tobagi Dept. of Electrical Engineering, Stanford

More information

Latency on a Switched Ethernet Network

Latency on a Switched Ethernet Network Application Note 8 Latency on a Switched Ethernet Network Introduction: This document serves to explain the sources of latency on a switched Ethernet network and describe how to calculate cumulative latency

More information

Establishing How Many VoIP Calls a Wireless LAN Can Support Without Performance Degradation

Establishing How Many VoIP Calls a Wireless LAN Can Support Without Performance Degradation Establishing How Many VoIP Calls a Wireless LAN Can Support Without Performance Degradation ABSTRACT Ángel Cuevas Rumín Universidad Carlos III de Madrid Department of Telematic Engineering Ph.D Student

More information

6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches?

6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches? TUTORIAL 2 (EKT 332) 6.1. Why do LANs tend to use broadcast networks? Why not use networks consisting of multiplexers and switches? Why broadcast network? -The computers in a LAN are separated by a short

More information

Introduction VOIP in an 802.11 Network VOIP 3

Introduction VOIP in an 802.11 Network VOIP 3 Solutions to Performance Problems in VOIP over 802.11 Wireless LAN Wei Wang, Soung C. Liew Presented By Syed Zaidi 1 Outline Introduction VOIP background Problems faced in 802.11 Low VOIP capacity in 802.11

More information

Performance Evaluation of VoIP Services using Different CODECs over a UMTS Network

Performance Evaluation of VoIP Services using Different CODECs over a UMTS Network Performance Evaluation of VoIP Services using Different CODECs over a UMTS Network Jianguo Cao School of Electrical and Computer Engineering RMIT University Melbourne, VIC 3000 Australia Email: j.cao@student.rmit.edu.au

More information

VoIP Network Dimensioning using Delay and Loss Bounds for Voice and Data Applications

VoIP Network Dimensioning using Delay and Loss Bounds for Voice and Data Applications VoIP Network Dimensioning using Delay and Loss Bounds for Voice and Data Applications Veselin Rakocevic School of Engineering and Mathematical Sciences City University, London, UK V.Rakocevic@city.ac.uk

More information

IJMIE Volume 2, Issue 7 ISSN: 2249-0558

IJMIE Volume 2, Issue 7 ISSN: 2249-0558 Evaluating Performance of Audio conferencing on Reactive Routing Protocols for MANET Alak Kumar Sarkar* Md. Ibrahim Abdullah* Md. Shamim Hossain* Ahsan-ul-Ambia* Abstract Mobile ad hoc network (MANET)

More information

Final for ECE374 05/06/13 Solution!!

Final for ECE374 05/06/13 Solution!! 1 Final for ECE374 05/06/13 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam taker -

More information

Real-Time Traffic Support in Heterogeneous Mobile Networks

Real-Time Traffic Support in Heterogeneous Mobile Networks Real-Time Traffic Support in Heterogeneous Mobile Networks Yuan Sun Elizabeth M. Belding-Royer Department of Computer Science University of California, Santa Barbara {suny, ebelding}@cs.ucsb.edu Xia Gao

More information

Investigation and Comparison of MPLS QoS Solution and Differentiated Services QoS Solutions

Investigation and Comparison of MPLS QoS Solution and Differentiated Services QoS Solutions Investigation and Comparison of MPLS QoS Solution and Differentiated Services QoS Solutions Steve Gennaoui, Jianhua Yin, Samuel Swinton, and * Vasil Hnatyshin Department of Computer Science Rowan University

More information

Measuring Data and VoIP Traffic in WiMAX Networks

Measuring Data and VoIP Traffic in WiMAX Networks JOURNAL OF TELECOMMUNICATIONS, VOLUME 2, ISSUE 1, APRIL 2010 Measuring Data and VoIP Traffic in WiMAX Networks 1 Iwan Adhicandra Abstract Due to its large coverage area, low cost of deployment and high

More information

Performance Evaluation of The Split Transmission in Multihop Wireless Networks

Performance Evaluation of The Split Transmission in Multihop Wireless Networks Performance Evaluation of The Split Transmission in Multihop Wireless Networks Wanqing Tu and Vic Grout Centre for Applied Internet Research, School of Computing and Communications Technology, Glyndwr

More information

Analysis of IP Network for different Quality of Service

Analysis of IP Network for different Quality of Service 2009 International Symposium on Computing, Communication, and Control (ISCCC 2009) Proc.of CSIT vol.1 (2011) (2011) IACSIT Press, Singapore Analysis of IP Network for different Quality of Service Ajith

More information

An Efficient QoS Routing Protocol for Mobile Ad-Hoc Networks *

An Efficient QoS Routing Protocol for Mobile Ad-Hoc Networks * An Efficient QoS Routing Protocol for Mobile Ad-Hoc Networks * Inwhee Joe College of Information and Communications Hanyang University Seoul, Korea iwj oeshanyang.ac.kr Abstract. To satisfy the user requirements

More information

Express Forwarding : A Distributed QoS MAC Protocol for Wireless Mesh

Express Forwarding : A Distributed QoS MAC Protocol for Wireless Mesh Express Forwarding : A Distributed QoS MAC Protocol for Wireless Mesh, Ph.D. benveniste@ieee.org Mesh 2008, Cap Esterel, France 1 Abstract Abundant hidden node collisions and correlated channel access

More information

TCP Behavior across Multihop Wireless Networks and the Wired Internet

TCP Behavior across Multihop Wireless Networks and the Wired Internet TCP Behavior across Multihop Wireless Networks and the Wired Internet Kaixin Xu, Sang Bae, Mario Gerla, Sungwook Lee Computer Science Department University of California, Los Angeles, CA 90095 (xkx, sbae,

More information

Transport layer issues in ad hoc wireless networks Dmitrij Lagutin, dlagutin@cc.hut.fi

Transport layer issues in ad hoc wireless networks Dmitrij Lagutin, dlagutin@cc.hut.fi Transport layer issues in ad hoc wireless networks Dmitrij Lagutin, dlagutin@cc.hut.fi 1. Introduction Ad hoc wireless networks pose a big challenge for transport layer protocol and transport layer protocols

More information

A TCP-like Adaptive Contention Window Scheme for WLAN

A TCP-like Adaptive Contention Window Scheme for WLAN A TCP-like Adaptive Contention Window Scheme for WLAN Qixiang Pang, Soung Chang Liew, Jack Y. B. Lee, Department of Information Engineering The Chinese University of Hong Kong Hong Kong S.-H. Gary Chan

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

Communications and Computer Networks

Communications and Computer Networks SFWR 4C03: Computer Networks and Computer Security January 5-8 2004 Lecturer: Kartik Krishnan Lectures 1-3 Communications and Computer Networks The fundamental purpose of a communication system is the

More information

Efficient Load Balancing Routing in Wireless Mesh Networks

Efficient Load Balancing Routing in Wireless Mesh Networks ISSN (e): 2250 3005 Vol, 04 Issue, 12 December 2014 International Journal of Computational Engineering Research (IJCER) Efficient Load Balancing Routing in Wireless Mesh Networks S.Irfan Lecturer, Dept

More information

Performance evaluation of QoS in wireless networks using IEEE 802.11e

Performance evaluation of QoS in wireless networks using IEEE 802.11e Performance evaluation of QoS in wireless networks using IEEE 802.11e Laio B. Vilas Boas, Pedro M. C. Massolino, Rafael T. Possignolo, Cintia B. Margi and Regina M. Silveira Abstract The increase demand

More information

Seamless Congestion Control over Wired and Wireless IEEE 802.11 Networks

Seamless Congestion Control over Wired and Wireless IEEE 802.11 Networks Seamless Congestion Control over Wired and Wireless IEEE 802.11 Networks Vasilios A. Siris and Despina Triantafyllidou Institute of Computer Science (ICS) Foundation for Research and Technology - Hellas

More information

QoS-aware MPDU Aggregation of IEEE 802.11n WLANs for VoIP Services

QoS-aware MPDU Aggregation of IEEE 802.11n WLANs for VoIP Services QoS-aware MPDU Aggregation of IEEE 802.11n WLANs for VoIP Services Shinnazar Seytnazarov and Young-Tak Kim Department of Information and Communication Engineering, Graduate School, Yeungnam University

More information

Quality of Service (QoS) on Netgear switches

Quality of Service (QoS) on Netgear switches Quality of Service (QoS) on Netgear switches Section 1 Principles and Practice of QoS on IP networks Introduction to QoS Why? In a typical modern IT environment, a wide variety of devices are connected

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

IP videoconferencing solution with ProCurve switches and Tandberg terminals

IP videoconferencing solution with ProCurve switches and Tandberg terminals An HP ProCurve Networking Application Note IP videoconferencing solution with ProCurve switches and Tandberg terminals Contents 1. Introduction... 3 2. Architecture... 3 3. Videoconferencing traffic and

More information

Adaptive DCF of MAC for VoIP services using IEEE 802.11 networks

Adaptive DCF of MAC for VoIP services using IEEE 802.11 networks Adaptive DCF of MAC for VoIP services using IEEE 802.11 networks 1 Mr. Praveen S Patil, 2 Mr. Rabinarayan Panda, 3 Mr. Sunil Kumar R D 1,2,3 Asst. Professor, Department of MCA, The Oxford College of Engineering,

More information

QoS Tools in the WAN. Need for QoS on WAN Links. Need for QoS in the WAN

QoS Tools in the WAN. Need for QoS on WAN Links. Need for QoS in the WAN QoS Tools in the WAN Need for QoS on WAN Links This topic defines the need for QoS in a WAN. Need for QoS in the WAN Voice must compete with data. Voice is real-time and must be sent first. Overhead should

More information

Denial of Service Attacks at the MAC Layer in Wireless Ad Hoc Networks

Denial of Service Attacks at the MAC Layer in Wireless Ad Hoc Networks Denial of Service Attacks at the MAC Layer in Wireless Ad Hoc Networks Vikram Gupta +, Srikanth Krishnamurthy, and Michalis Faloutsos Abstract Department of Computer Science and Engineering, UC Riverside,

More information

Assessment of Traffic Prioritization in Switched Local Area Networks Carrying Multimedia Traffic

Assessment of Traffic Prioritization in Switched Local Area Networks Carrying Multimedia Traffic Assessment of Traffic Prioritization in Switched Local Area Networks Carrying Multimedia Traffic F. A. Tobagi, C. J. Fraleigh, M. J. Karam, W. Noureddine Computer Systems Laboratory Department of Electrical

More information

other. A B AP wired network

other. A B AP wired network 1 Routing and Channel Assignment in Multi-Channel Multi-Hop Wireless Networks with Single-NIC Devices Jungmin So + Nitin H. Vaidya Department of Computer Science +, Department of Electrical and Computer

More information

SBSCET, Firozpur (Punjab), India

SBSCET, Firozpur (Punjab), India Volume 3, Issue 9, September 2013 ISSN: 2277 128X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com Layer Based

More information

Analysis of QoS parameters of VOIP calls over Wireless Local Area Networks

Analysis of QoS parameters of VOIP calls over Wireless Local Area Networks Analysis of QoS parameters of VOIP calls over Wireless Local Area Networks Ayman Wazwaz, Computer Engineering Department, Palestine Polytechnic University, Hebron, Palestine, aymanw@ppu.edu Duaa sweity

More information

Modeling and Simulation of Queuing Scheduling Disciplines on Packet Delivery for Next Generation Internet Streaming Applications

Modeling and Simulation of Queuing Scheduling Disciplines on Packet Delivery for Next Generation Internet Streaming Applications Modeling and Simulation of Queuing Scheduling Disciplines on Packet Delivery for Next Generation Internet Streaming Applications Sarhan M. Musa Mahamadou Tembely Matthew N. O. Sadiku Pamela H. Obiomon

More information

A Routing Metric for Load-Balancing in Wireless Mesh Networks

A Routing Metric for Load-Balancing in Wireless Mesh Networks A Routing Metric for Load-Balancing in Wireless Mesh Networks Liang Ma and Mieso K. Denko Department of Computing and Information Science University of Guelph, Guelph, Ontario, Canada, N1G 2W1 email: {lma02;mdenko}@uoguelph.ca

More information

Enhancing WLAN MAC Protocol performance using Differentiated VOIP and Data Services Strategy

Enhancing WLAN MAC Protocol performance using Differentiated VOIP and Data Services Strategy IJCSNS International Journal of Computer Science and Network Security, VOL.9 No.12, December 2009 89 Enhancing WLAN MAC Protocol performance using Differentiated VOIP and Data Services Strategy S.Vijay

More information

WhitePaper: XipLink Real-Time Optimizations

WhitePaper: XipLink Real-Time Optimizations WhitePaper: XipLink Real-Time Optimizations XipLink Real Time Optimizations Header Compression, Packet Coalescing and Packet Prioritization Overview XipLink Real Time ( XRT ) is a new optimization capability

More information

CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING

CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING CHAPTER 6 CROSS LAYER BASED MULTIPATH ROUTING FOR LOAD BALANCING 6.1 INTRODUCTION The technical challenges in WMNs are load balancing, optimal routing, fairness, network auto-configuration and mobility

More information

CHAPTER 6. VOICE COMMUNICATION OVER HYBRID MANETs

CHAPTER 6. VOICE COMMUNICATION OVER HYBRID MANETs CHAPTER 6 VOICE COMMUNICATION OVER HYBRID MANETs Multimedia real-time session services such as voice and videoconferencing with Quality of Service support is challenging task on Mobile Ad hoc Network (MANETs).

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

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

Modeling and Simulation of Quality of Service in VoIP Wireless LAN

Modeling and Simulation of Quality of Service in VoIP Wireless LAN Journal of Computing and Information Technology - CIT 16, 2008, 2, 131 142 doi:10.2498/cit.1001022 131 Modeling and Simulation of Quality of Service in VoIP Wireless LAN A. Al-Naamany, H. Bourdoucen and

More information

Computer Networks CS321

Computer Networks CS321 Computer Networks CS321 Dr. Ramana I.I.T Jodhpur Dr. Ramana ( I.I.T Jodhpur ) Computer Networks CS321 1 / 22 Outline of the Lectures 1 Introduction OSI Reference Model Internet Protocol Performance Metrics

More information

An Active Packet can be classified as

An Active Packet can be classified as Mobile Agents for Active Network Management By Rumeel Kazi and Patricia Morreale Stevens Institute of Technology Contact: rkazi,pat@ati.stevens-tech.edu Abstract-Traditionally, network management systems

More information

Enhancement of VoIP over IEEE 802.11 WLANs by Adapting Transmitting Interval

Enhancement of VoIP over IEEE 802.11 WLANs by Adapting Transmitting Interval Enhancement of VoIP over IEEE 82.11 WLANs by Adapting Transmitting Interval Zhuo Chen, Lingyun Wang, and Xinbing Wang School of Electronic, Information and Electrical Engineering Shanghai Jiao Tong University

More information

Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic.

Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic. Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic. A Network and Data Link Layer infrastructure Design to Improve QoS in Voice and video Traffic Jesús Arturo Pérez,

More information

Faculty of Engineering Computer Engineering Department Islamic University of Gaza 2012. Network Chapter# 19 INTERNETWORK OPERATION

Faculty of Engineering Computer Engineering Department Islamic University of Gaza 2012. Network Chapter# 19 INTERNETWORK OPERATION Faculty of Engineering Computer Engineering Department Islamic University of Gaza 2012 Network Chapter# 19 INTERNETWORK OPERATION Review Questions ٢ Network Chapter# 19 INTERNETWORK OPERATION 19.1 List

More information

An Experimental Performance Analysis of MAC Multicast in 802.11b Networks for VoIP Traffic

An Experimental Performance Analysis of MAC Multicast in 802.11b Networks for VoIP Traffic An Experimental Performance Analysis of MAC Multicast in 82.11b Networks for VoIP Traffic Martin Kappes DoCoMo Euro-Labs Landsberger Str. 312, 8687 Munich, Germany kappes@docomolab-euro.com Keywords: IEEE

More information

Enhanced Power Saving for IEEE 802.11 WLAN with Dynamic Slot Allocation

Enhanced Power Saving for IEEE 802.11 WLAN with Dynamic Slot Allocation Enhanced Power Saving for IEEE 802.11 WLAN with Dynamic Slot Allocation Changsu Suh, Young-Bae Ko, and Jai-Hoon Kim Graduate School of Information and Communication, Ajou University, Republic of Korea

More information

Supporting VoIP in IEEE802.11 Distributed WLANs

Supporting VoIP in IEEE802.11 Distributed WLANs Supporting VoIP in IEEE802.11 Distributed WLANs Zuo Liu Supervisor: Dr. Nick Filer July 2012 1 Voice VoIP Applications Constant Streaming Traffic Packetize interval usually 10-30 ms 8 160 bytes each packet

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

TECHNICAL CHALLENGES OF VoIP BYPASS

TECHNICAL CHALLENGES OF VoIP BYPASS TECHNICAL CHALLENGES OF VoIP BYPASS Presented by Monica Cultrera VP Software Development Bitek International Inc 23 rd TELELCOMMUNICATION CONFERENCE Agenda 1. Defining VoIP What is VoIP? How to establish

More information

Student, Haryana Engineering College, Haryana, India 2 H.O.D (CSE), Haryana Engineering College, Haryana, India

Student, Haryana Engineering College, Haryana, India 2 H.O.D (CSE), Haryana Engineering College, Haryana, India Volume 5, Issue 6, June 2015 ISSN: 2277 128X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com A New Protocol

More information

EXPERIMENTAL STUDY FOR QUALITY OF SERVICE IN VOICE OVER IP

EXPERIMENTAL STUDY FOR QUALITY OF SERVICE IN VOICE OVER IP Scientific Bulletin of the Electrical Engineering Faculty Year 11 No. 2 (16) ISSN 1843-6188 EXPERIMENTAL STUDY FOR QUALITY OF SERVICE IN VOICE OVER IP Emil DIACONU 1, Gabriel PREDUŞCĂ 2, Denisa CÎRCIUMĂRESCU

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

Chapter 3 ATM and Multimedia Traffic

Chapter 3 ATM and Multimedia Traffic In the middle of the 1980, the telecommunications world started the design of a network technology that could act as a great unifier to support all digital services, including low-speed telephony and very

More information

NOVEL PRIORITISED EGPRS MEDIUM ACCESS REGIME FOR REDUCED FILE TRANSFER DELAY DURING CONGESTED PERIODS

NOVEL PRIORITISED EGPRS MEDIUM ACCESS REGIME FOR REDUCED FILE TRANSFER DELAY DURING CONGESTED PERIODS NOVEL PRIORITISED EGPRS MEDIUM ACCESS REGIME FOR REDUCED FILE TRANSFER DELAY DURING CONGESTED PERIODS D. Todinca, P. Perry and J. Murphy Dublin City University, Ireland ABSTRACT The goal of this paper

More information

Requirements of Voice in an IP Internetwork

Requirements of Voice in an IP Internetwork Requirements of Voice in an IP Internetwork Real-Time Voice in a Best-Effort IP Internetwork This topic lists problems associated with implementation of real-time voice traffic in a best-effort IP internetwork.

More information

ECE/CS 372 introduction to computer networks. Lecture 13

ECE/CS 372 introduction to computer networks. Lecture 13 ECE/CS 372 introduction to computer networks Lecture 13 Announcements: HW #4 hard copy due today Lab #5 posted is due Tuesday June 4 th HW #5 posted is due Thursday June 6 th Pickup midterms Acknowledgement:

More information

4 Internet QoS Management

4 Internet QoS Management 4 Internet QoS Management Rolf Stadler School of Electrical Engineering KTH Royal Institute of Technology stadler@ee.kth.se September 2008 Overview Network Management Performance Mgt QoS Mgt Resource Control

More information

AN OVERVIEW OF QUALITY OF SERVICE COMPUTER NETWORK

AN OVERVIEW OF QUALITY OF SERVICE COMPUTER NETWORK Abstract AN OVERVIEW OF QUALITY OF SERVICE COMPUTER NETWORK Mrs. Amandeep Kaur, Assistant Professor, Department of Computer Application, Apeejay Institute of Management, Ramamandi, Jalandhar-144001, Punjab,

More information

QoS in Axis Video Products

QoS in Axis Video Products Table of contents 1 Quality of Service...3 1.1 What is QoS?...3 1.2 Requirements for QoS...3 1.3 A QoS network scenario...3 2 QoS models...4 2.1 The IntServ model...4 2.2 The DiffServ model...5 2.3 The

More information

Multimedia distribution system for rural communities

Multimedia distribution system for rural communities Multimedia distribution system for rural communities Tiziano Inzerilli, Roberto Cusani, Riccardo Salvatori University of Rome Sapienza INFOCOM Dept. Via Eudossiana 18, 00184 Rome, Italy Abstract - Wireless

More information

Internet Traffic Performance in High Speed Trains 1

Internet Traffic Performance in High Speed Trains 1 Internet Traffic Performance in High Speed Trains 1 Dmitry Sivchenko a, Bangnan Xu a, Gerd Zimmermann a, Sven Hischke b a T-Systems, Technologiezentrum, Am Kavalleriesand 3, D-64295 Darmstadt, Germany

More information

RT-QoS for Wireless ad-hoc Networks of Embedded Systems

RT-QoS for Wireless ad-hoc Networks of Embedded Systems RT-QoS for Wireless ad-hoc Networks of Embedded Systems Marco accamo University of Illinois Urbana-hampaign 1 Outline Wireless RT-QoS: important MA attributes and faced challenges Some new ideas and results

More information

Top-Down Network Design

Top-Down Network Design Top-Down Network Design Chapter Four Characterizing Network Traffic Copyright 2010 Cisco Press & Priscilla Oppenheimer Network Traffic Factors Traffic flow unidirectional, bidirectional symmetric, asymmetric

More information

Service Level Analysis of Video Conferencing over Wireless Local Area Network

Service Level Analysis of Video Conferencing over Wireless Local Area Network Service Level Analysis of Video Conferencing over Wireless Local Area Network B.O. Sadiq, E. Obi, A.S. Abubakar, Y. Ibrahim & S. Saidu Department of Electrical and Computer Engineering Ahmadu Bello Unicersity

More information

Admission Control for VoIP Traffic in IEEE 802.11 Networks

Admission Control for VoIP Traffic in IEEE 802.11 Networks Admission Control for VoIP Traffic in IEEE 802.11 Networks Sachin Garg Avaya Labs Basking Ridge, NJ 07920 Email: sgarg@avaya.com Martin Kappes Avaya Labs Basking Ridge, NJ 07920 Email: mkappes@avaya.com

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

Clearing the Way for VoIP

Clearing the Way for VoIP Gen2 Ventures White Paper Clearing the Way for VoIP An Alternative to Expensive WAN Upgrades Executive Overview Enterprises have traditionally maintained separate networks for their voice and data traffic.

More information

Quality of Service. Traditional Nonconverged Network. Traditional data traffic characteristics:

Quality of Service. Traditional Nonconverged Network. Traditional data traffic characteristics: Quality of Service 1 Traditional Nonconverged Network Traditional data traffic characteristics: Bursty data flow FIFO access Not overly time-sensitive; delays OK Brief outages are survivable 2 1 Converged

More information

Performance Analysis of VoIP Codecs over BE WiMAX Network

Performance Analysis of VoIP Codecs over BE WiMAX Network Performance Analysis of VoIP Codecs over BE WiMAX Network Muhammad Imran Tariq, Muhammad Ajmal Azad, Razvan Beuran, Yoichi Shinoda Japan Advanced Institute of Science and Technology, Ishikawa, Japan National

More information

Dr. Irfan S. Al-Anbagi and Prof. Hussein T. Mouftah

Dr. Irfan S. Al-Anbagi and Prof. Hussein T. Mouftah Dr. Irfan S. Al-Anbagi and Prof. Hussein T. Mouftah School of Electrical Engineering and Computer Science University of Ottawa Email: ialan055@uottawa.ca Cyber Physical Systems (CPSs) integrate communication

More information

Performance Analysis of AQM Schemes in Wired and Wireless Networks based on TCP flow

Performance Analysis of AQM Schemes in Wired and Wireless Networks based on TCP flow International Journal of Soft Computing and Engineering (IJSCE) Performance Analysis of AQM Schemes in Wired and Wireless Networks based on TCP flow Abdullah Al Masud, Hossain Md. Shamim, Amina Akhter

More information

VoIP Performance Over different service Classes Under Various Scheduling Techniques

VoIP Performance Over different service Classes Under Various Scheduling Techniques Australian Journal of Basic and Applied Sciences, 5(11): 1416-1422-CC, 211 ISSN 1991-8178 VoIP Performance Over different service Classes Under Various Scheduling Techniques Ahmad Karim Bahauddin Zakariya

More information

Network Considerations for IP Video

Network Considerations for IP Video Network Considerations for IP Video H.323 is an ITU standard for transmitting voice and video using Internet Protocol (IP). It differs from many other typical IP based applications in that it is a real-time

More information

Application Note Telephony Service over Satellite

Application Note Telephony Service over Satellite Voice over Application Note Telephony Service over Satellite January 2012 Data Sells but Voice Pays In the early years of the industry, networks were deployed primarily for telephony services. As time

More information

Optimizing Converged Cisco Networks (ONT)

Optimizing Converged Cisco Networks (ONT) Optimizing Converged Cisco Networks (ONT) Module 3: Introduction to IP QoS Introducing QoS Objectives Explain why converged networks require QoS. Identify the major quality issues with converged networks.

More information

Analysis of Effect of Handoff on Audio Streaming in VOIP Networks

Analysis of Effect of Handoff on Audio Streaming in VOIP Networks Beyond Limits... Volume: 2 Issue: 1 International Journal Of Advance Innovations, Thoughts & Ideas Analysis of Effect of Handoff on Audio Streaming in VOIP Networks Shivani Koul* shivanikoul2@gmail.com

More information

II. IEEE802.11e EDCA OVERVIEW

II. IEEE802.11e EDCA OVERVIEW The 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC'7) CACITY IMPROVEMENT OF WIRELESS LAN VOIP USING DISTRIBUTED TRANSMISSION SCHEDULING Kei Igarashi,

More information

H.323 Traffic Characterization Test Plan Draft Paul Schopis, pschopis@itecohio.org

H.323 Traffic Characterization Test Plan Draft Paul Schopis, pschopis@itecohio.org H.323 Traffic Characterization Test Plan Draft Paul Schopis, pschopis@itecohio.org I. Introduction Recent attempts at providing Quality of Service in the Internet2 community have focused primarily on Expedited

More information

FORTH-ICS / TR-375 March 2006. Experimental Evaluation of QoS Features in WiFi Multimedia (WMM)

FORTH-ICS / TR-375 March 2006. Experimental Evaluation of QoS Features in WiFi Multimedia (WMM) FORTH-ICS / TR-375 March 26 Experimental Evaluation of QoS Features in WiFi Multimedia (WMM) Vasilios A. Siris 1 and George Stamatakis 1 Abstract We investigate the operation and performance of WMM (WiFi

More information

3. TMT for IEEE 802.11g Networks

3. TMT for IEEE 802.11g Networks 136 IJCSNS International Journal of Computer Science and Network Security, VOL.11 No.4, April 2011 The Theoretical Maximum Throughput Calculation for the IEEE802.11g Standard Alex V. Barbosa, Marcos F.

More information

Optimized Load Balancing Mechanism Using Carry Forward Distance

Optimized Load Balancing Mechanism Using Carry Forward Distance Optimized Load Balancing Mechanism Using Carry Forward Distance Ramandeep Kaur 1, Gagandeep Singh 2, Sahil 3 1 M. Tech Research Scholar, Chandigarh Engineering College, Punjab, India 2 Assistant Professor,

More information

Achieving Load Balancing in Wireless Mesh Networks Through Multiple Gateways

Achieving Load Balancing in Wireless Mesh Networks Through Multiple Gateways Abstract Achieving Load Balancing in Wireless Mesh Networks Through Multiple Gateways Deepti Nandiraju, Lakshmi Santhanam, Nagesh Nandiraju, and Dharma P. Agrawal Center for Distributed and Mobile Computing,

More information

UPPER LAYER SWITCHING

UPPER LAYER SWITCHING 52-20-40 DATA COMMUNICATIONS MANAGEMENT UPPER LAYER SWITCHING Gilbert Held INSIDE Upper Layer Operations; Address Translation; Layer 3 Switching; Layer 4 Switching OVERVIEW The first series of LAN switches

More information

VoIP codec adaptation algorithm in multirate 802.11 WLANs : distributed vs centralized performance comparison

VoIP codec adaptation algorithm in multirate 802.11 WLANs : distributed vs centralized performance comparison VoIP codec adaptation algorithm in multirate 82.11 WLANs : distributed vs centralized performance comparison Anna Sfairopoulou, Carlos Macián, Boris Bellalta Network Technologies and Strategies (NeTS)

More information

Wireless VoIP at Home: Are We There Yet?

Wireless VoIP at Home: Are We There Yet? Wireless VoIP at Home: Are We There Yet? Gerardo Rubino, Martín Varela and Jean Marie Bonnin th May 00 Abstract Over the last few years, and especially since the advent of wireless technologies such as

More information