1. Muse confidential Broadband Europe 2007 We3A.4 Document:Emulation and Simulation Tool for Design and Optimization of IMS based FMC Networks Date:2007-12-05 Originator:Stefanie Braun, Stefan Wahl

2. Broadband Europe 2007 We3A.4 — 2 Agenda > Motivation of the Tool > Emulation and Simulation Tool > Usage and Output Results > Tool Appliances > Conclusions

3. Broadband Europe 2007 We3A.4 — 3 Motivation > Questions on Optimization and Deployment Alternatives for an IMS System What is the most efficient architecture of an IMS system? – central  any flavor between central/distributed  distributed How does the efficiency vary with the deployment and service scenarios? – size of the network – type of the services – the service usage and use case scenarios Which function grouping improves the efficiency? – grouping of functions may simplify the interface  less processing effort What is the best deployment strategy of (new) services on the architecture?  Development of Simulation and Emulation Tool

4. Broadband Europe 2007 We3A.4 — 4 > Emulation part used to emulate functions and interfaces at – application, call control and media transport layer – with different (selectable) abstraction levels whereby – each invocation of functions/interfaces adds a computational effort share validate the interworking of functions and interfaces > Simulator part applies the emulated functions and interfaces adds user agents and a traffic generator which – produce a mixtures of determinable services at offered loads accumulates the computational efforts provides statistics on average/peak/hot spot computational efforts effort analysis on function, node and architecture level Objective: Performance comparison, validation and verification of IMS like architectures and service scenarios. Emulation and Simulation Tool

5. Broadband Europe 2007 We3A.4 — 5 UA 2 P-CSCF S-CSCF UA I-CSCF UA 1 AS MRFP mobility logic … … NE 1 NE 2 NE 3 NE 4 NE 5 NE m UA UA n UA … … Emulation and Simulation Tool Architecture composition and output > Graphical or XML based network architecture composition: Provides means to configure easily the network size and the amount of network domains Network element (NE) are composed by application, call control and media layer functions Assignment of a number of User Agents (UA) to the NE for generation and termination of service calls Traffic generator

6. Broadband Europe 2007 We3A.4 — 6 UA 2 P-CSCF S-CSCF UA I-CSCF UA 1 AS MRFP mobility logic … … NE 1 NE 3 NE m NE 2 UAx UA n UA … … Traffic generator requests and releases independently network services and end2end calls Traffic Generator Graphical output of the simulator part peak or average computational effort per function or component over time setup video call to UAx release audio call setup teleVoting call e.g. Emulation and Simulation Tool Architecture composition and output per function or component per network element

7. Broadband Europe 2007 We3A.4 — 7 Research of Processing Effort Values Input parameters for the emulation/simulation tool Extraction of SIP processing effort values from performed tests and literature* Parsing  Consumes about 25% of total message processing time  Parsing time grows linearly with message size String and Memory Manipulation  Proprietary string operations and less processing stages reduce the impact on the total processing message time from 45% to 7%  Proprietary memory operations reduce processing message time from 18 to 3 % Parsing + string handling + memory allocation: take 33 - 83 % of total message processing time in SIP proxies * Articles : „On SIP Performance“, Cortes, Ensor, Esteban, Bell Labs Technical Journal 2004 „Measurement of the SIP Parsing Performance in the SIP Express Router“, S. Wanke et al., Proc. EUNICE 2007 Inter NE function (e.g. CSCF) interfaces could replace SIP protocol Replacing SIP protocol with more efficient inter NE protocols (e.g. binary, ordered) improves the message processing time

8. Broadband Europe 2007 We3A.4 — 8 Emulation and Simulation Tool Examples for architecture optimization > Performance gains due to grouping of IMS functions > Architecture and protocol investigations based on computational processing effort Scenario A: Call sessions with media processing Scenario B: TeleVoting with high signaling, AS and media load Scenario C: Trend analysis – increasing amount of AS services > Comparison between centralized and distributed AS server concept

9. Broadband Europe 2007 We3A.4 — 9 Emulation and Simulation Tool Performance gains due to grouping of IMS functions Standard IMS case for multi-domain with roaming Average =6.2 CSCF hops I-CSCF (S-P)-CSCF (P-S-I)-CSCF P-CSCF (S-I)-CSCF (P-S)-CSCF Simulation Result: Probability Histogram of combined CSC-Functions -10 IMS domains -Calls equally distributed across all domains -20% users in roaming Grouping IMS CSC-Functions in MS-ER Most advantageous CSCF combinations: SP-CSCF, PSI-CSCF, SI-CSCF, … Average CSCF hops:3.5 Reduction:43 % PSI UE ISP UE About 57 % of the simulated cases require 3 CSCF hops Current IMS MS-ER Solution SIIS PP UE I P Home-Home: 6 CSCF Instances I P UE Foreign-Foreign: 8 CSCF Instances P-CSCF I-CSCF S-CSCF Terminal / Peering Typical Example visited A home A home B visited B

10. Broadband Europe 2007 We3A.4 — 10 Emulation and Simulation Tool Examples for architecture optimization > Performance gains due to grouping of IMS functions > Architecture and protocol investigations based on computational processing effort Scenario A: Call sessions with media processing Scenario B: TeleVoting with high signaling, AS and media load Scenario C: Trend analysis – increasing amount of AS services > Comparison between centralized and distributed AS server concept

11. Broadband Europe 2007 We3A.4 — 11 Emulation and Simulation Tool Architecture investigations: Call sessions with media processing Scenario Description > 2 independent administrative domains > Clients are equally distributed across domains > No roaming clients > Clients establishes calls randomly > 80% standard calls > 20% calls use transcoding service > IMS SIP stack processing effort: 100% > Processing effort values for the inter and intra MS-ER protocol are varied Intra/Inter: 20% / 40% Intra/Inter: 50% / 70% Architecture Comparison S Home network UE S P... IMS UE AS MRF... S intra MS-ER protocol intra... UE P AS MRF intra... MS-ER S intra... P AS MRF MS-ER inter MS-ER protocol UE Test case: Typical IMS Test case: MS-ER 3GPP SIP... P

12. Broadband Europe 2007 We3A.4 — 12 Emulation and Simulation Tool Architecture investigations: Call sessions with media processing Test Results 100% -17% -4% -28% Typical IMS implementation with SIP based interfaces MS-ER implementation with optimized “inter” and “intra” interfaces

13. Broadband Europe 2007 We3A.4 — 13 Emulation and Simulation Tool Examples for architecture optimization > Performance gains due to grouping of IMS functions > Architecture and protocol investigations based on computational processing effort Scenario A: Call sessions with media processing Scenario B: TeleVoting with high signaling, AS and media load Scenario C: Trend analysis – increasing amount of AS services > Comparison between centralized and distributed AS server concept

14. Broadband Europe 2007 We3A.4 — 14 Emulation and Simulation Tool Architecture investigations: TeleVoting scenario Test Results Higher efficiency for co-locating call control, application layer and media transport functions to one MS-ER node Improved efficiency also for heavy load generating TeleVoting services Architecture Comparison S Home network... Central App. Server UE P S Home network P intra MS-ER protocol UE MS-ER 1 AS S MRF... MRF Vote App. CT Vote App. AS CT intra.. Vote result Basic Calls Televoting -28% 100% -28% -17% -16% Co-located App. Server 3GPP SIP... 3GPP SIP

15. Broadband Europe 2007 We3A.4 — 15 Emulation and Simulation Tool Examples for architecture optimization > Performance gains due to grouping of IMS functions > Architecture and protocol investigations based on computational processing effort Scenario A: Call sessions with media processing Scenario B: TeleVoting with high signaling, AS and media load Scenario C: Trend analysis – increasing amount of AS services > Comparison between centralized and distributed AS server concept

16. Broadband Europe 2007 We3A.4 — 16 Test Results The efficiency of the MS-ER concept increases with the increasing number of services applying AS functions Test Cases S UE AS P P UE MS-ER 1MS-ER 2 Home network S intra.. S Home network UE S P P intra MS-ER protocol intra.. inter MS-ER protocol UE MS-ER 1MS-ER 2 AS intra.. co-located AS central AS -17% -14% -11% -8% -5% 0% - 15% - 14% - 11% - 8% - 5% - 0% AS the MS-ER + AS histogram bars are used as effort references Emulation and Simulation Tool Architecture investigations: Increasing amount of AS services 3GPP SIP inter MS-ER protocol

17. Broadband Europe 2007 We3A.4 — 17 Emulation and Simulation Tool Examples for architecture optimization > Performance gains due to grouping of IMS functions > Architecture and protocol investigations based on computational processing effort Scenario A: Call sessions with media processing Scenario B: TeleVoting with high signaling, AS and media load Scenario C: Trend analysis – increasing amount of AS services > Comparison between centralized and distributed AS server concept

18. Broadband Europe 2007 We3A.4 — 18 Emulation and Simulation Tool Comparison co-located  central AS To maintain the peak effort gain for an increasing number of MS-ER nodes, the co-located AS MS-ER architecture requires a more performing intra MS-ER communication. Home network P MS-ER 1 S AS P MS-ER 2 S AS intra.. inter MS-ER protocol MS-ER architecture with co-located AS Home network MS-ER architecture with central AS MS-ER 3 AS P MS-ER 1 S AS P MS-ER 2 S AS intra.. 3GPP SIP intra.. inter MS-ER protocol intra.. inter MS-ER protocol Parameter: Inter MS-ER protocol effort = 40 % 40363228242016 Peak Computational Effort Estimation Intra MS-ER protocol effort [%] Effort [%] Break Event Points for co-located AS MS-ER + central AS MS-ER + co-located AS ≈ 20 MS-ER 4 MS-ER ≈ MS-ER co-located AS is more efficient MS-ER central AS is more efficient

19. Broadband Europe 2007 We3A.4 — 19 Emulation and Simulation Tool Further use cases > Resource Manager hardware, service-, signaling-, and media software components algorithm development > Network planning optimization of existing network (identification of hot spots) extension of the network > Distributed service execution evaluation of more advanced strategies

20. Broadband Europe 2007 We3A.4 — 20 Emulation and Simulation Tool Conclusion > Emulation features allow to integrate functions with required abstraction levels reduce the communication protocols to the relevant functions compare service introduction strategies into an IMS architecture > Computational effort evaluation to compare various variants of IMS network architectures identify processing effort values and hot spots at different levels: domains, network node and functions estimate performance dependencies and critical optimization parameters of a network architecture derive the influence of protocol and functional improvements check the influence of a resource management algorithm

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