UCT-COE SeminarPage 1 May 3, 2023

Vitalis G.ONeco Ventura

Charging QoS-Enabled Services in Inter-domain IMS Frameworks

Department of Electrical EngineeringUniversity of Cape Town

UCT-COE SeminarPage 2 May 3, 2023

Introduction

• QoS requirements in IMS Frameworks• Inter-domain service brokering• Pricing IMS services• Policy and charging control – 3GPP approach• Relevant Protocols• Execution plan• Work in standards

UCT-COE SeminarPage 3 May 3, 2023

IMS QoS Requirements

PDF

Mw

Mw

Gq

Go

Cx

Cx

Mw

Application Plane

Control Plane

Intermediate Plane

Media plane

Application servers

P-CSCF

I-CSCF

HSS

PEP2

P-CSCF

I-CSCF

S-CSCF

Mm

PEP1AN1

AN2

CN1

CN2

ISP

IM1

IM2

IM3

• QoS for media plane: delay, jitter, and throughput

• QoS for IMS signaling• Pricing and charging

relates to QoS• Policy and charging

control done together

UCT-COE SeminarPage 4 May 3, 2023

Inter-domain Service Brokering

PDF

Mw

Mw

Gq

Go

Cx

Cx

Mw

Application Plane

Control Plane

Intermediate Plane

Media plane

Application servers

P-CSCF

I-CSCF

HSS

PEP2

P-CSCF

I-CSCF

S-CSCF

Mm

PEP1AN1

AN2

CN1

CN2

ISP

IM1

IM2

IM3

• AD1 = AN1:CN1AD1 = AN1:CN1

• AD2 = AN2:CN2AD2 = AN2:CN2

• AD1 outsources AN1 users to AD2 AD1 outsources AN1 users to AD2 on AN2on AN2

• QoS or price triggeredQoS or price triggered

• Inter-domain signalling between Inter-domain signalling between IM1 and IM2 on Mm reference pointIM1 and IM2 on Mm reference point

UCT-COE SeminarPage 5 May 3, 2023

Pricing the IMS

• Which traffic to charge? What model to use?– Flat rate for IMS session traffic– Usage based charges for bearer plane traffic

• Predictable access network-dependent charges• Retain low Internet charges for core network traffic

UCT-COE SeminarPage 6 May 3, 2023

Core Network Prices

PDF

Mw

Mw

Gq

Go

Cx

Cx

Mw

Application Plane

Control Plane

Intermediate Plane

Media plane

Application servers

P-CSCF

I-CSCF

HSS

PEP2

P-CSCF

I-CSCF

S-CSCF

Mm

PEP1AN1

AN2

CN1

CN2

ISP

IM1

IM2

IM3

• AD1 and AD2 provision resources AD1 and AD2 provision resources from different ISPs using long term from different ISPs using long term SLAsSLAs

• Abstraction: ISP sells bandwidth in Abstraction: ISP sells bandwidth in aggregate blocks to AD1 and AD2aggregate blocks to AD1 and AD2

•

• Admission cost component rises Admission cost component rises with no. of sold BW blockswith no. of sold BW blocks

B

b

T

tb

nt

T

tbA dtVxdtVP

2

)(

UCT-COE SeminarPage 7 May 3, 2023

Profitable Condition

1 2 N

Cong

estio

n p

rice

n>1

No. of Resource blocks

• PPNN ≥ 0≥ 0

• I = sessionsI = sessions

• J = CoSJ = CoS

• N = usersN = users

• T = timeT = time

• V = volume of trafficV = volume of traffic

• B = bandwidth blocksB = bandwidth blocks

N

n

J

j

I

i

T

t

V

v

T

t

B

b

T

tb

ntbN dtVxdtVxdvdtP

2

)(

UCT-COE SeminarPage 8 May 3, 2023

Outsource Triggers

• Link failure: calls dropped, blocked, failed

• Revenue vs. cost imbalance: provisioned resources to cost more than revenue from extra users

PDF

Mw

Mw

Gq

Go

Cx

Cx

Mw

Application Plane

Control Plane

Intermediate Plane

Media plane

Application servers

P-CSCF

I-CSCF

HSS

PEP2

P-CSCF

I-CSCF

S-CSCF

Mm

PEP1AN1

AN2

CN1

CN2

ISP

IM1

IM2

IM3

UCT-COE SeminarPage 9 May 3, 2023

Benefits and Conditions for Outsourcing

Conditions• PΣ > PN

• Candidate network must offer lower per flow charges for outsourced sessions

Benefits• Increased revenue for both operators• Boosted user satisfaction

I

i

J

j

T

t

V

v

N

n

M

Nn

T

t

B

b

T

t

nt VdtxVdtxdvdtxdvdtP

1 1 2

)(}{

UCT-COE SeminarPage 10 May 3, 2023

Requirements for Outsourcing

PDF

Mw

Mw

Gq

Go

Cx

Cx

Mw

Application Plane

Control Plane

Intermediate Plane

Media plane

Application servers

P-CSCF

I-CSCF

HSS

PEP2

P-CSCF

I-CSCF

S-CSCF

Mm

PEP1AN1

AN2

CN1

CN2

ISP

IM1

IM2

IM3

HSS

PCRF

Gq

Go

Control Plane

Intermediate Plane

Traffic Plane

P-CSCF S-CSCF

PCEFAN

CN

• Inter-domain policy and charging control message Inter-domain policy and charging control message interaction over the Mm reference pointinteraction over the Mm reference point

UCT-COE SeminarPage 11 May 3, 2023

Outsourcing Transactions

• SDP negotiation (request) between client and custodian network

• SDP request (required QoS, preferred access network etc.) and price offer to candidate network

• SDP answer and AA parameters for client from candidate network

• SDP answer to client with instruction to attach to candidate network

• Registration on candidate network: subscriber information exchange

• IMS session setup continuation via candidate network• Accounting session initiation for IMS and media traffic

UCT-COE SeminarPage 12 May 3, 2023

Relevant Protocols and Specifications

• SIP - IETF RFC3261• DIAMETER – IETF RFC3588• SDP – IETF RFC3264• DiffServ – IETF RFC2475• 3GPP TS 23.203– Policy and charging control

UCT-COE SeminarPage 13 May 3, 2023

Questions and Comments