stability analysis of tandem sip proxies
DESCRIPTION
Stability Analysis of Tandem SIP Proxies. IEEE ICC 2012 - Communication QoS , Reliability and Modeling Symposium Arthur: Seyed Vahid Azhari, Hani Nemati Presenter: 侯宗佑. Outline. Introduction Fluid Flow Model Lyapunov stability Stabilizing Algorithm Conclusion. SIP protocol. - PowerPoint PPT PresentationTRANSCRIPT
IEEE ICC 2012 - COMMUNICATION QOS, RELIABILITY AND MODELING SYMPOSIUM
ARTHUR: SEYED VAHID AZHARI , HANI NEMATI
PRESENTER: 侯宗佑
Stability Analysis of Tandem SIP Proxies
Outline
IntroductionFluid Flow ModelLyapunov stabilityStabilizing AlgorithmConclusion
SIP protocol
Signaling Communications ProtocolIETF,RFC 2543, latest RFC 3261Setup, modify, tear down multimedia sessionsText-based protocol (like http, smtp)Media stream use RTP protocol
SIP protocol(cont’d)
Lyapunov Stability
Mostly used for non-linear dynamic systemStay near Equilibrium point
Fluid Flow Model
Fluid Flow Model(Cont’d)
Assumption: Infinite queues, negligible packet loss and processing time, only Invite and OK message
State variable: weighted number of Invite message queues on proxy
Fluid Flow Model(Cont’d)
Fluid Flow Model
Lyapunov Stability
Equilibrium : (x1,x2) = (0,0)
Lyapunov Stability(Cont’d)
Lyapunov Stability(Cont’d)
Optimal rejection policy
P2,rej = 0 has max value
All rejection burden at upstream proxy
Stabilizing Algorithm
Idetical:
P1 >= 1:
Stabilizing Algorithm(Cont’d)
Stabilizing Algorithm(Cont’d)
Stabilizing Algorithm(Cont’d)
Maximum Withstand-able Overload
Conslusion
Modeled SIP topologyDerive Lyapunov stability conditionProposed a simple overload control algorithmOptimal rejection policy