Telephone Charging System Helsinki University of Technology Yao - - PowerPoint PPT Presentation

Telephone Charging System

Helsinki University of Technology

Yao Yanjun Petteri Tulikoura

Agenda

Introduction Traditional telephone charging system Outdated Charging Charging Nowadays Future scenarios for charging Case: IP Telephony Towards pure-IP networks

Introduction

What is “charging”? “ A function whereby information related to a chargeable operation is formatted and transferred in

• rder to make it possible to determine usage for

which the charged party may be billed. ” What does it focus on?

the generation, formatting and transfer of data records,

which provide details relating to the usage of a service or consumption of an item of content.

Traditional Charging System

Charging Systems in the Past

Charging a telephone system with telephone

• perators.

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

“pulse is a rapid change in some characteristic of a signal”

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:

• the identities of sources (points of origin),
• the identities of destinations (endpoints),
• the duration of each call,
• the amount billed for each call,
• the total usage time in the billing period,
• the total free time remaining in the billing period,
• the running total charged during the billing period.
• CDRs may be output to a file, may be sent as packets on a network,
• r may be output from a serial port on a piece of telecom hardware.

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 Call Detail Record

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,

number of events) , corresponds to a real-time process

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):

charging on time and/or traffic

• ADSL:

month-charged, no charging on time and traffic

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:

• Call divert
• Toll free calls
• Prepaid calling
• Private number plans
• Call screening

Future Scenarios for Charging – Case: VoIP

VoIP

Consumer VoIP

• Software-based
• Skype, MSN, Yahoo
• Hard phone
• IP telephony service providers
• Over broadband Internet services
• Normal phone connected through an analog

telephone adapter (ATA)

• FON is a VoIP service formed by a community
• Share your home WiFi with other community

members

• Get access to VoIP through others’ WiFi when you

are on the move Corporate

• Corporate bridging

Wireless VoIP

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

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
• f the voice packets
• Qos, high availability, and
• verall network capability

crucial

Application Layer

• Voice mail
• Faxing
• Call forwarding
• Directory services

VoIP Benefits for Corporations

Traditionally voice traffic through circuit-switched PSTN

Many organizations may also have

their own internal telephone systems using a private branch exchange (PBX)

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

• Reduced costs and complexity

because there is only a single network to manage

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

people around because phone numbers are all provisioned in software rather than “hardswitch” connections

• Reduced long-distance charges

(toll bypass)

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

services should also differ, and if so, how?

VoIP Displacing Traditional PBX Equipments?

Source: Gartner (2004)

Gartner’s forecasts for 2008

55% of all Premises Switching

Equipment (PSE) lines will be pure-IP

TDM/ PBX/KTS lines are

expected to drop to a 10% market share by the end of the 2008

The remaining 90% will be a

mixture of pure IP-PBX and IP- enabled shipments

Worldwide Shipments by Technology Type

TDM Line IP Line

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

Traditional solutions will continue

to decline rapidly

IP enabled solutions will

dominate

Pure IP solutions will enjoy rapid

growth, but will account only 35%

• f line shipments 2007

Conclusions

Telephone systems have evolved from analog

circuit-switched networks to IP-based solutions

Telecoms have huge investments in circuit-

switched networks

But IP-based solutions are more cost efficient

Reference

• Sudhir Dixit, Tao Wu: Content Networking in the Mobile

Internet, chapter 12.2

• http://en.wikipedia.org/wiki/Call-detail_record
• http://en.wikipedia.org/wiki/Pstn
• http://en.wikipedia.org/wiki/Intelligent_network
• 3GPP TS 32.240, Charging Architecture and Principles,

09.2004

• http://www.ida.gov.sg/idaweb/media/PressRelease_LeadSto

ry_Main.jsp?leadStoryId=L153&versionId=3

Global spending on IP technology will overtake TDM by 2008