volker hilt [email protected] bell labs/alcatel-lucent sip overload control ietf design team...
TRANSCRIPT
Slide 2 | 74 IETF Meeting | March 2009
SIP Overload Control Design Team
Team Members Eric Noel, Carolyn Johnson (AT&T Labs) Volker Hilt, Fangzhe Chang (Bell Labs/Alcatel-Lucent) Charles Shen, Henning Schulzrinne (Columbia University) Ahmed Abdelal, Tom Phelan (Sonus Networks) Mary Barnes (Nortel) Jonathan Rosenberg (Cisco) Nick Stewart (British Telecom)
Four independent simulation tools AT&T Labs, Bell Labs/Alcatel-Lucent, Columbia University, Sonus
Networks
Bi-weekly conference calls.
Slide 3 | 74 IETF Meeting | March 2009
draft-ietf-sipping-overload-design-01Changes to -00
Added new sections on: Fairness
Introduces fairness categories.
Performance Metrics Discusses metrics to compare overload control mechanisms
Message Priorization Selection of messages in overload condition.
Added text to Security Considerations section.
Minor edits throughout the text.
Slide 4 | 74 IETF Meeting | March 2009
draft-ietf-sipping-overload-design-00Next Steps
Discussion of overload control mechanisms needs to be structured along the identified performance metrics.
Document is close to completion.
Slide 5 | 74 IETF Meeting | March 2009
SIP Overload Control Design TeamSimulation Results
Four types of overload control Rate-based Overload Control Loss-based Overload Control Window-based Overload Control Overload Signal-based Overload Control
Summary of Steady-State Evaluation (presented at IETF ’73)
Performance of all overload control mechanisms under evaluation is similar in steady state.
Varying network conditions (i.e., delay, loss-rate) do not reveal significant differences.
Results for Transient Scenarios
Evaluation of transient behavior with respect to Changes in offered load changes in the number of neighbors Fairness
Slide 6 | 74 IETF Meeting | March 2009
Changes in Offered-Load (AT&T Labs) Rate-based and Window-based Overload Control
Simulations use the following overload control feedback types and algorithms:
Rate-based: queue delay Loss-based: SRED Window-based
Feedback conveyed in SIP responses.
Result: rate-, loss- and window-based controls respond well to transient stimulus.
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TheoreticalSRED control (fmin=0.03)
Slide 7 | 74 IETF Meeting | March 2009
Changes in Offered-Load (Bell Labs/Alcatel-Lucent) Loss-based and Rate-based Overload Control
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Overload control feedback type and algorithms used: SRED algorithm Loss- vs. rate-based feedback
SIP responses convey feedback from core to edge proxies.
Result: loss- and rate-based overload control perform well.
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Slide 8 | 74 IETF Meeting | March 2009
Changes in Offered-Load (Columbia University) Window-based and Rate-based Overload Control
23/4/19 Slide 8
Window- and rate-based controls perform well.
Slide 9 | 74 IETF Meeting | March 2009
Changes in Offered-Load (Sonus Networks) Loss-based and Overload-Signal-based Overload Control
Loss-based Overload Control
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Loss-based Overload Control
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Target Overload Signal Rate =10 Overload Signals /Sec
Overload Signal-based
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Slide 10 | 74 IETF Meeting | March 2009
Changes in the Number of Senders (Bell Labs/Alcatel-Lucent)Loss-based and Rate-based Overload Control
Edge proxies are turned on/off sequentially.
Each edge proxy sends the same amount of load while active.
Feedback-type and algorithms: Rate-fixed: core proxies are configured with a fixed number of senders.
The overall rate of a core proxy is divided through the sender number. Rate-aware: core proxies estimate the number of senders. The overall
rate of a core proxy is divided through the sender estimate.
Loss-based: same loss rate is sent to all edge proxies. All simulations use SRED algorithm.
Slide 11 | 74 IETF Meeting | March 2009
Fairness (Columbia University)Rate-based Overload Control
Slide 11
Provider-centric fairness: each source gets the same share
User-centric fairness: each source gets a share proportional to its original incoming load
Slide 12 | 74 IETF Meeting | March 2009
Conclusion & Next Steps
Simulation Results
The overload control performance seems to differ little between the type of feedback:
Rate-, Loss-, Window- and Signal-based mechanisms all performed well in steady-state as well as transient evaluations.
Of course, the performance does vary depending on the overload control algorithms used and parameter settings of these algorithms.
But: algorithms and parameter settings are likely to be out of scope for an overload control protocol specification.
Next Steps
Evaluate additional transient scenarios.
Finalize draft-ietf-sipping-overload-design-01
Work on a solution!!
Session Initiation Protocol (SIP) Overload
Controldraft-hilt-sipping-overload-06
Volker Hilt, Indra Widjaja, Henning Schulzrinne
A Session Initiation Protocol (SIP) Load Control Event
Packagedraft-shen-sipping-load-control-event-package-01
Charles Shen, Henning Schulzrinne, Arata Koike
Slide 14 | 74 IETF Meeting | March 2009 14
Service Provider B
Hotline Callee212-555-12349am-10am,
2009-1-1Service Provider A
Enterprise Network B
Enterprise Network A
Filter SpecID: To: +1-212-555-1234Time: 9am-10am 2009-1-1Act: accept rate= Nmax
Filter SpecID: To: +1-212-555-1234Time: 9am-10am 2009-1-1Act: accept rate=NSPA
Filter SpecID: To: +1-212-555-1234Time: 9am-10am 2009-1-1Act: accept rate=NEPA
Filter SpecID: To: +1-212-555-1234Time: 9am-10am 2009-1-1Act: accept rate=NSPB
Charles Shen, Henning Schulzrinne, Arata Koike, A Session Initiation Protocol (SIP) Load Control Event Package, draft-shen-sipping-load-control-event-package-01.txt, IETF SIPPING Working Group, Work in Progress. Nov 3, 2008
Filter-based SIP Server Overload Controldraft-shen-sipping-load-control-event-package-01
Slide 15 | 74 IETF Meeting | March 2009
Server S1 Server S2
Session Initiation Protocol (SIP) Overload Controldraft-hilt-sipping-overload-06
Overload control mechanism Enables proxies to send overload control feedback to upstream
neighbors. Feedback is conveyed in SIP responses
New Via Header Parameters
Supports different types of feedback. Currently defined: loss-based. Specifies the protocol semantics. Open to different overload control
algorithms.
Via: SIP/2.0/TCP ss1.example.com:5060 ;oc=20;oc_validity=500
OverloadReduces load