Telephone Charging System

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Telephone Charging

System

Helsinki University of Technology

Yao Yanjun

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Agenda

|

Introduction

|

Traditional telephone charging system

z

Outdated Charging

z

Charging Nowadays

|

Future scenarios for charging

z

Case: IP Telephony

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Introduction

|

What is “charging”?

“ A function whereby information related to a

chargeable operation is formatted and transferred in

order to make it possible to determine usage for

which the charged party may be billed. ”

|

What does it focus on?

z

the generation, formatting and transfer of data records,

which provide details relating to the usage of a

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Charging Systems in the Past

|

Charging a telephone system with telephone

operators.

|

Counting the number of “pulses” generated

per call within the telephone exchanges

involved in the setup, routing and control of

these calls

|

The pulse generated per call varied in

relation to the location of the callee

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Current Charging Systems

| Call Detail Record (CDR) (also Call Detail Recording) or Station

Message Detail Recording (SMDR) is a record containing information about recent system usage:

z the identities of sources (points of origin),

z the identities of destinations (endpoints),

z the duration of each call,

z the amount billed for each call,

z the total usage time in the billing period,

z the total free time remaining in the billing period,

z the running total charged during the billing period.

| CDRs may be output to a file, may be sent as packets on a network,

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Telephone Network

caller

Operator A

Operator B

callee

Residential

switch

Transit

switch

Charging

system

Interconnect

switch

37 Egress port 244 Egress circuit 01 Record type 22 Recording unit 02022006:101703 Call end 02022006:101007 Call start 05564123444 Called party 01023422315 Calling party

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Concepts

Charging:

| Offline charging: charging mechanism where charging information

does not affect, in real-time, the service rendered.

| Online charging: charging mechanism where charging information

can affect, in real-time, the service rendered and therefore a direct interaction of the charging mechanism with bearer/session/service control is required.

Billing:

| Postpaid billing: pay an insurance payment in advance, the

installation or setup fees, be invoiced (receive a bill) to pay for his usage of the service.

| Prepaid billing: buys a given amount of credits (duration, volume,

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Charging for Data

|

Charging data record: a formatted collection of information

about a chargeable event (e.g. time of call set-up, duration of

the call, amount of data transferred, etc) for use in billing and

accounting.

|

56k modem (nearly obsolete):

z charging on time and/or traffic

|

ADSL:

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Intelligent network

|

The Intelligent Network is a network architecture for both fixed

and mobile telecommunication networks. It allows operators to

differentiate themselves by providing value-added services in

addition to the standard telecoms services.

For example:

z Call divert

z Toll free calls

z Prepaid calling

z Private number plans

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Future Scenarios for

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VoIP

Consumer VoIP

| Software-based

z Skype, MSN, Yahoo

| Hard phone

z IP telephony service providers

z Over broadband Internet services

z Normal phone connected through an analog telephone adapter (ATA)

| FON is a VoIP service formed by a community

z Share your home WiFi with other community members

z Get access to VoIP through others’ WiFi when you are on the move

Corporate

| Corporate bridging Wireless VoIP

| Unregulated (802.11x) | Regulated (3G)

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IP Telephony System

Client Layer

• Analog-to-digital conversion and compression

Call Processing Layer

• An IP version of PBX

• Performs call setups and tear-downs • Also performs CAC and conference management

Infrastructure Layer

• Responsible for the delivery of the voice packets

• Qos, high availability, and overall network capability crucial

Application Layer

• Voice mail • Faxing • Call forwarding • Directory services

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VoIP Benefits for Corporations

Traditionally voice traffic through circuit-switched PSTN

z Many organizations may also have their own internal telephone

systems using a private branch exchange (PBX)

z Means deploying a separate

network for data traffic as well as to pay long-distance charges for calls to remote branches or partners

Especially organizations could benefit from IP-based systems

z Reduced costs and complexity because there is only a single network to manage

z More efficient use of bandwidth z Ease of adding and or moving

people around because phone numbers are all provisioned in software rather than

“hardswitch” connections

z Reduced long-distance charges (toll bypass)

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Challenges in Charging for

VoIP Services

|

Quality of service (QoS) is important in IP telephony as it is

critical for voice packets to arrive in the correct order with

minimal delay

|

Efficient pricing mechanisms coupled with traditional

congestion control protocols as a solution to congestion

control

|

There are great differences among the services offered by

the QoS capable networks

|

Therefore, one might ask whether the prices of these

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VoIP Displacing Traditional

PBX Equipments?

Source: Gartner (2004) Gartner’s forecasts for 2008

z 55% of all Premises Switching Equipment (PSE) lines will be pure-IP

z TDM/ PBX/KTS lines are expected to drop to a 10% market share by the end of the 2008

z The remaining 90% will be a mixture of pure PBX and IP-enabled shipments

Worldwide Shipments by Technology Type

TDM Line IP Line

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VoIP Displacing Traditional

PBX Equipments?

PBX Traditional Lines IP-Enabled PBX Traditional Lines IP-Enabled PBX IP Lines Pure IP PBX Lines

Source: Gartner Dataquest (2004)

Expected mix of solutions by technology type over the forecast period

PSE Extension Line Forecast

zTraditional solutions will continue to decline rapidly

zIP enabled solutions will dominate

zPure IP solutions will enjoy rapid growth, but will account only 35% of line shipments 2007