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1 Demystifying QoS Peter Thompson Chief Scientist U4EA Technologies Peter.Thompson@u4eatech.com
© U4EA Technologies 2006 2 www.u4eatech.com What is QoS? Quality of Service – many meanings Service availability –E.g PSTN backup for VoIP Service reliability –Even when subject to interference (accidental or malicious) Service observability –For SLAs
© U4EA Technologies 2006 3 www.u4eatech.com Why is QoS Necessary? Jitter of VoIP stream mixed with TCP over a T1 link
© U4EA Technologies 2006 4 www.u4eatech.com Why is QoS Necessary? PESQ score of G711 subject to packet loss and jitter
© U4EA Technologies 2006 5 www.u4eatech.com QoS is Affected at Many Levels Layer 1: S/N ratio Layer 2: protocol overheads Layer 3: buffer overflow, queuing delays Layer 4: error correction, jitter buffers Layer 5: session management
© U4EA Technologies 2006 6 www.u4eatech.com QoS: Reliable Packet-based Services Dynamic sharing of resources makes packet- based services –Flexible –Efficient –Potentially unreliable! Making packet-based services reliable requires giving the right resources to the right amount of the right packets
© U4EA Technologies 2006 7 www.u4eatech.com Elements of QoS Admission control Packet classification Packet queuing and scheduling Allocate the right resources Identify the right packets Ensure the right amount
© U4EA Technologies 2006 8 www.u4eatech.com Is Standard QoS Enough? Bursts for which loss and delay are increased Offered load Time Average Capacity Can manage with standard techniques e.g. 802.1p
© U4EA Technologies 2006 9 www.u4eatech.com Is Standard QoS Enough? Bursts where loss and/or delay become excessive Offered load Time Capacity Needs an advanced multi-media QoS solution Average
© U4EA Technologies 2006 10 www.u4eatech.com Summary: Reliable IP-based Services 1.Make sure the lower layers dont cause trouble 2.Use session control to limit the amount of traffic needing protection 3.Use standard techniques (802.1p, Diffserv etc.) to protect/prioritize traffic where the average load is low 4.Look for advanced mechanisms to make efficient use of more loaded links 5.Manage the congestion where it occurs
Quality of Service CCDA Quick Reference.
GH Telstra Internet 1 Capacity Measurement for IP Networks Geoff Huston Technical Manager Telstra Internet.
Congestion Control and Fairness Models Nick Feamster CS 4251 Computer Networking II Spring 2008.
VoIP Models for System Performance Evaluation Farooq Khan IEEE Interim Meeting Vancouver, BC, Canada January 12-16, 2004.
QoS Strategy in DiffServ aware MPLS environment Teerapat Sanguankotchakorn, D.Eng. Telecommunications Program, School of Advanced Technologies Asian Institute.
ITU-T Workshop on IP/Optical Chitose, 9-11 July 2002 Session Network Performance N eal Seitz, Chair SG 13/WP 4 IP Performance Specifications: Progress.
Streaming Video over the Internet
Submission doc.: IEEE 11-14/0xxx March 2014 Giwon Park, LG ElectronicsSlide 1 Discussion on power save mode for real time traffic Date: Authors:
© R. Jayanthan, K. Gunasakera 1999 Quality of Service in Multiservice Networks for Digital Economy R. Jayanthan & Kithsiri Gunasakera National IT Conference.
QoS Scheduling in Cable and Broadband Wireless Networks
Flow Aware Networking © 2007 Katedra Telekomunikacji AGH Flow Aware Networking Router model lead by prof. dr hab. inż. Andrzej Jajszczyk.
© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—8-1 MPLS TE Overview Introducing the TE Concept.
William Stallings Data and Computer Communications 7 th Edition Chapter 13 Congestion in Data Networks.
Engineering Internet QoS
© 2006 Cisco Systems, Inc. All rights reserved. Optimizing Converged Cisco Networks (ONT) Module 2: Cisco VoIP Implementations.
Playback-buffer Equalization For Streaming Media Using Stateless Transport Prioritization By Wai-tian Tan, Weidong Cui and John G. Apostolopoulos Presented.
© 2006 Cisco Systems, Inc. All rights reserved. Module 4: Implement the DiffServ QoS Model Lesson 4.8: Understanding WAN Link Efficiency Mechanisms.
Yi Liang Department of Electrical Engineering Stanford University April 19, 2000 Loss Recovery and Adaptive Playout Control for Packet Voice Communications.
Streaming Video over the Internet: Approaches and Directions Dapeng Wu, Yiwei Thomas Hou et al. Presented by: Abhishek Gupta
A Case for Relative Differentiated Services and the Proportional Differentiation Model Constantinos Dovrolis Parameswaran Ramanathan University of Wisconsin-Madison.
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