IMS Decoys

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
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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

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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

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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

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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

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Useful Definitions

• Custodian network (home network) Holds user
  subscriptions
• Candidate network (visited network) Federated
  to custodian

• 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

X
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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

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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
Revenue
Profit
Expenditure
Time-frame
users
sessions
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Financial Conditions

• Profitability for custodian network PN gt 0

Revenue from user payments
Cost of subsequent blocks
Cost of 1st block
Net Revenue
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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

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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

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Financial Implications

• Extra revenue due to outsourcing
• PS gt PN

Net Revenue
Outsource revenue
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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!
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Next Steps

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

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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