Telephone Charging System

Transcription

1 Telephone Charging System Helsinki University of Technology Yao Yanjun Petteri Tulikoura

2 Agenda Introduction Traditional telephone charging system Outdated Charging Charging Nowadays Future scenarios for charging Case: IP Telephony Towards pure-ip networks

3 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? 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.

4 Traditional Charging System

5 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 pulse is a rapid change in some characteristic of a signal

6 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, or may be output from a serial port on a piece of telecom hardware.

7 Telephone Network Transit switch Interconnect switch Operator B callee Operator A caller Charging system Residential switch Call Detail Record Calling party Called party Call start : Call end : Recording unit 22 Record type 01 Egress circuit 244 Egress port 37

8 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

9 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

10 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

11 Future Scenarios for Charging Case: VoIP

12 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)

13 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 Application Layer Voice mail Faxing Call forwarding Directory services Infrastructure Layer Responsible for the delivery of the voice packets Qos, high availability, and overall network capability crucial

14 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)

15 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?

16 VoIP Displacing Traditional PBX Equipments? Worldwide Shipments by Technology Type Gartner s forecasts for % 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 IPenabled shipments Source: Gartner (2004) TDM Line IP Line

17 VoIP Displacing Traditional PBX Equipments? 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% of line shipments 2007 PBX Traditional Lines IP-Enabled PBX Traditional Lines IP-Enabled PBX IP Lines Pure IP PBX Lines Source: Gartner Dataquest (2004)

18 Conclusions Telephone systems have evolved from analog circuit-switched networks to IP-based solutions Telecoms have huge investments in circuitswitched networks But IP-based solutions are more cost efficient

19 Reference Sudhir Dixit, Tao Wu: Content Networking in the Mobile Internet, chapter GPP TS , Charging Architecture and Principles, ry_main.jsp?leadstoryid=l153&versionid=3

20 Global spending on IP technology will overtake TDM by 2008