Charging and QoS Aspects for Service Outsourcing in Inter-Domain IMS Frameworks

1. Charging and QoS Aspects for Service Outsourcing in Inter-Domain IMS Frameworks Candidate: Vitalis G. Ozianyi Supervisor: Neco Ventura Electrical Engineering University of Cape Town South Africa

2. Introduction • Next Generation Networks (NGN) are characterized by wireless overlaps (WO) • Ubiquitous mobile computing required in NGN • Handoff decisions are mainly influenced by signal strength and network congestion • To achieve price-influenced ubiquitous mobile computing

3. Objectives • Maintain the same (predictable) charge for the user • Analyze financial implications of service outsourcing • Facilitate pricing in NGN for the success of the IMS

4. Service Outsourcing Basics • Provide services to users over a federated operator network • Home network experiencing congestion • Session QoS negotiated based on offer price • Several operators bid for outsourced service • UE directed to attach to specific network

5. Related Work • Roaming – higher and unpredictable charges • Dependent of signal strength and network congestion • Some recent work investigates user profiles and other context information for handover decisions

6. Useful Definitions • IMS registration and session setup • Network capacity and congestion • Service request blocking • Service outsourcing negotiations between custodian and candidate network • QoS and outsource offer price • Handover to candidate network • Session re-establishment: • Update registration • Re-invite • Start/resume media flow • Custodian network (home network) – Holds user subscriptions • Candidate network (visited network) – Federated to custodian X

7. Conditions and Requirements • Custodian network (N1) and candidate network (N2) would be federated • Access networks AN1 and AN2 are reachable by UE (Overlapping) • N2 can meet QoS requirements for the session

8. Financial Requirements • User Pricing function – satisfaction influenced by SLA • Network price functions – profit maximization Utility function Satisfaction Cost function Inter-domain resources (Less resources for off-peak times) – bought in blocks from ISP; price controlled by ISP Local resources in an Access Domain (Fixed capacity over medium time frames) – sold to users Profit Revenue Expenditure Time-frame users sessions

9. Financial Conditions • Profitability for custodian network: PN > 0 Revenue from user payments Cost of subsequent blocks Net Revenue Cost of 1st block

10. Financial Conditions • Extra block to service one user session – not profitable (More radio spectrum in AN) • Outsource new request to candidate network • Share user payments with candidate operator • Select cheapest candidate network in multi-operator scenarios

11. Outsourcing Triggers and Benefits • Triggers • Unserviceable requests from UE on AN1 • N1 wants to admit high profile requests on AN1 – outsource of low profile requests • Benefits • Ubiquitous service delivery to users – enhanced satisfaction • Retention of subscriptions – important for advertisement and AAA revenue in IMS

12. Financial Implications • Extra revenue due to outsourcing • PΣ > PN Net Revenue Outsource revenue

13. Deliverables • Extend the UCT IMS client to support and service outsourcing • Extend the Fokus OSIMS Core to support service outsourcing Questions and Suggestions are Welcome…!

14. Next Steps • Implement charging in OSIMS • Develop outsource messaging for IMS • Outsource signaling optimization through aggregated outsourcing

15. Published Work • Integrating pricing profiles in NGN – Elsevier journal paper • Use of the platinum, gold and silver pricing profiles to influence selection of access network • Virtual network capacity expansion – WCNC 2008 paper • Definition of generic user and network pricing functions for service outsourcing • Service outsourcing to support virtual home environments – LCN-P2MNet • Route selection impacts on achieving IMS QoS – SATNAC 2008