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<body class='hmmessage'><div dir='ltr'>Hello Folks.<br> <br>SIP faces with overload issue recently due to its popularity. Build-in overload mechanism cannot prevent overload effectively. Therefore, IETF SIP Overload Control (soc) Working Group works on IETF RFC "SIP Overload Control" currently.<br><a href="http://tools.ietf.org/html/draft-ietf-soc-overload-control-13">http://tools.ietf.org/html/draft-ietf-soc-overload-control-13</a><BR> <BR>Control theorectic approaches have been applied to model the interactions between an overloaded SIP server and its upstream servers as a feedback control system in two different scenarios - round trip delay control (IEEE ICC 2011) and redundant retransmission ratio control (IEEE Globecom 2010).<BR> <BR> <BR>Journal paper (SIP Overload Control) published by Springer Telecommunication Systems online today not only conducts more theoretical analysis of Round trip delay control (RTDC) and Redundant retransmission ratio control (RRRC), but also discusses how to apply RTDC algorithm to mitigate SIP overload for both SIP over UDP and SIP over TCP (with TLS).<br><BR>Y. Hong, C. Huang, and J. Yan, "Applying control theoretic approach to mitigate SIP overload", Telecommunication Systems, DOI: 10.1007/s11235-013-9744-8 Online First, July 2013. <br><a href="http://link.springer.com/article/10.1007/s11235-013-9744-8">http://link.springer.com/article/10.1007/s11235-013-9744-8</a> <BR> <BR> <BR>Round trip delay control: "Design Of A PI Rate Controller For Mitigating SIP Overload," Proceedings of IEEE ICC, Kyoto, Japan, June 2011. <br><a href="https://www.researchgate.net/publication/224249824_Design_of_a_PI_Rate_Controller_for_Mitigating_SIP_Overload">https://www.researchgate.net/publication/224249824_Design_of_a_PI_Rate_Controller_for_Mitigating_SIP_Overload</a><br><a href="http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5963029">http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5963029</a><BR> <BR>This implicit SIP overload control algorithm has been recommended as Industry Standard Protocol by TechRepublic (CBS Interactive)<br><a href="http://www.techrepublic.com/whitepapers/design-of-a-pi-rate-controller-for-mitigating-sip-overload/25142469">http://www.techrepublic.com/whitepapers/design-of-a-pi-rate-controller-for-mitigating-sip-overload/25142469</a><BR> <BR>This implicit SIP overload control algorithm has also been recommended as a Skype story by Road Runner (Time Warner Cable Inc.). <br><a href="http://features.rr.com/article/01vBgtc8TR17z?q=Skype">http://features.rr.com/article/01vBgtc8TR17z?q=Skype</a><BR> <BR> <BR>Redundant retransmission ratio control: "Mitigating SIP Overload Using a Control-Theoretic Approach," Proceedings of IEEE Globecom, Miami, FL, U.S.A, December 2010.<br><a href="https://www.researchgate.net/publication/221284946_Miigating_SIP_Overload_Using_a_Control-Theoretic_Approach">https://www.researchgate.net/publication/221284946_Miigating_SIP_Overload_Using_a_Control-Theoretic_Approach</a><br><a href="http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5683124">http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5683124</a><BR> <BR>This implicit SIP overload control algorithm has been quickly adopted by The Central Weather Bureau of Taiwan for their early earthquake warning system.<br>"An Efficient Earthquake Early Warning Message Delivery Algorithm Using an in Time Control-Theoretic Approach", 2011.<br><a href="http://link.springer.com/chapter/10.1007%2F978-3-642-23641-9_15">http://link.springer.com/chapter/10.1007%2F978-3-642-23641-9_15</a>#<br><a href="http://www.ipv6.org.tw/docu/elearning8_2011/1010004798p_3-7.pdf">http://www.ipv6.org.tw/docu/elearning8_2011/1010004798p_3-7.pdf</a><BR> <BR>Short review and comments on this implicit SIP overload control algorithm by former IEEE TAC Associate Editor S. Mascolo: "Local SIP Overload Control", Proceedings of WWIC, June 2013.<br><a href="http://link.springer.com/chapter/10.1007%2F978-3-642-38401-1_16">http://link.springer.com/chapter/10.1007%2F978-3-642-38401-1_16</a>#<BR> <BR> <BR>A survey on SIP overload control algorithms (including IETF RFC "SIP Overload Control") can be downloaded from the following link free of charge.<br>Y. Hong, C. Huang, and J. Yan, “A Comparative Study of SIP Overload Control Algorithms,"Network and Traffic Engineering in Emerging Distributed Computing Applications, Edited by J. Abawajy, M. Pathan, M. Rahman, A.K. Pathan, and M.M. Deris, IGI Global, 2012, pp. 1-20.<br><a href="http://www.researchgate.net/publication/231609451_A_Comparative_Study_of_SIP_Overload_Control_Algorithms">http://www.researchgate.net/publication/231609451_A_Comparative_Study_of_SIP_Overload_Control_Algorithms</a><br><a href="http://arxiv.org/abs/1210.1505">http://arxiv.org/abs/1210.1505</a><br><a href="http://www.igi-global.com/chapter/comparative-study-sip-overload-control/67496">http://www.igi-global.com/chapter/comparative-study-sip-overload-control/67496</a><BR> <BR>IETF-RFC "SIP Overload Control" discussion archive <br><a href="http://www.ietf.org/mail-archive/web/sip-overload/current/msg00919.html">http://www.ietf.org/mail-archive/web/sip-overload/current/msg00919.html</a><br> <br>In addition, implicit SIP overload control solution using control theorectic approaches can be regarded as an engineering applications of control theory, as shown by the most popular answers to the following 2 recent ResearchGate(RG) questions. ResearchGate is the largest social network for research scientists and engineers in the world.<br> <br>Yang Hong's answers for the two RG questions have been recommended by ResearchGate as the most popular answers as shown in the following two links.<br> <br>RG Question #1: "What are trends in control theory and its applications in physical systems (from a research point of view)?"<br><a href="https://www.researchgate.net/post/What_are_trends_in_control_theory_and_its_applications_in_physical_systems_from_a_research_point_of_view2">https://www.researchgate.net/post/What_are_trends_in_control_theory_and_its_applications_in_physical_systems_from_a_research_point_of_view2</a><br> <br>RG Question #2: "What are the new trends in control engineering?"<br><a href="https://www.researchgate.net/post/What_are_the_new_trends_in_control_engineering">https://www.researchgate.net/post/What_are_the_new_trends_in_control_engineering</a><BR> <BR> <br>Best regards,<br> <br>Winston Hong<br>Software Engineer<br>InBay Technologies Inc.<br>Ottawa, Ontario<br>Canada K2K 1Y3<br><a href="http://www.inbaytech.com/">http://www.inbaytech.com/</a><BR> </div></body>
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