The Internet NG Project

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WU5: Internet accounting

An important subject to be investigated by WU5 of the Internet NG project is "provider based accounting". This form of accounting, which is very similar to accounting within the POTS of 900 numbers, can be used for accounting of contents as well as transport. Payments within a provider based accounting system involves three steps:

• The client pays its own Internet provider.
• The Internet provider of the client pays the Internet provider to which the server is connected. Because of the large number of possible trust relationships between Internet providers, it may be necessary to introduce a Thrusted Third Party (TTP). Such TTP, which may be bank, takes care of the financial balance between all associated Internet providers.
• Finally the server gets paid by its own Internet provider.

The basic architecture, which is shown in the figure below, includes a client who is connected to one provider, and a server who is connected to another Internet provider. Both providers may be connected via zero, one or more backbone providers.

The process starts with a request from the client to the server (1) to deliver content. The server answers with an accounting request message (2), indicating that the client should pay for the content to the client's provider. The parameters of the accounting request message are:

• server information, including a readable string identifying the owner of the server, an authentication key as well as the server's IP / DNS address.
• price, which may be a single value or, in case of multiple components, a chain of values. The currency should also be specified, as well as a time-stamp to allow determination of the exact exchange rate to cover cases where the client wants to pay in, for example, euros whereas the server wants to receive dollars. The time-stamp is also needed to ensure that information can not be reused (replay protection).
• content type, which may take the value streaming or atomic. In case of streaming, the price is actually a price per unit, and can for example be expressed in MBytes or minutes. Other differences between both types of content are explained later.
• accounting server information, which includes the authentication key as well as the IP / DNS address of the accounting server within the server's Internet provider.

In case the client agrees to receive charged content, it forwards the information within the accounting request message to the accounting server of its own Internet provider (3). To guarantee that no-one can change the information, protection is needed via message authentication codes. Such codes can be generated using algorithms like MD5 or SHA1. If the client has paid all previous bills, the accounting server within the client's provider stores the information for future billing purposes and forwards the accounting accepted message to the server's provider (4). If this Internet provider is also willing to participate in the accounting process, it stores the information too and forwards the message to the content server (5).

It should be noted that this architecture is not only interesting for content accounting, but can also be used to charge for reverse traffic. In that case the accounting servers should configure the access routers such that the amount of traffic flowing between both users will be measured.

3^rd phase activities

The complexity of a provider based accounting system is significant and it is not easy to understand all decisions at an early stage of the design. A way to deal with this complexity is to follow a cyclic design approach. The idea of cyclic design is to distribute design problems over a sequence of design cycles, allowing to exploit design experience obtained in previous cycles while performing the next.

The figure below shows an example of a cyclic design process. In this example, four design cycles are performed in sequence. During the first design cycle only a subset of the user requirements will be considered. During the second design cycle additional requirements will be considered, and during subsequent design cycles more requirements will be taken into account. The experience that is obtained in each of the cycles is used as input to the subsequent cycles.

The first cycle, which was performed in the september - december 2000 period, focused on provider based accounting of streaming content. The design was very simple, in the sense that only a single customer could use the streaming server at a time and the interactions between the various components of the architecture were implemented as RPC calls.

The goal for 2001 is to perform three subsequent design cycles. Each of these cycles will take four months.

• The second cycle, which starts in january and runs till may, will enhance the simplistic streaming case of the first cycle. Among the improvements are support for: multiple simultaneous customers, multiple movies, different pricing schemes etc.. Also the simplistic RPC interactions will be mapped upon a more reliable underlying protocol. This underlying protocol may, for example, be TCP, BEEP and / or Corba.
• The third cycle will start in may and continue until august. It is anticipated that this cycle will focus on mobility. In particular it will investigate the accounting issues associated with roaming users who change between providers frequently (roaming).
• The fourth cycle will start in september and be completed in december. It is anticipated that this cycle will focus on security.

In addition to the above work on provider based accounting, there will also be an activity related to the further development of Netramet. Netramet, which is a public domain implementation of the IETF's meter MIB, can be used to gather accounting data from the network. The particular issue that will be tackled is the problem of visualizing traffic flows.

Information exchange between the various groups within the Netherlands that perform research in the area of accounting is important. WU5 of the Internet NG project therefore intends to organize in 2001 two workshops at which the groups within KPN Research, TI, Ericsson and CTIT can discuss their work. It is possible that also other groups will be invited.

Deliverables

D5.8 Provider based accounting architecture - cycle 2 (completion date: 15 may 2001).

The output of this cycle will be a design document, plus a working prototype. The design document will provide an overview of the architecture, a description of all interactions plus associated parameters, and a comparison between various underlying protocols / platforms (such as, for example, TCP, BEEP, Corba, Diameter). As compared to cycle 1, cycle 2 adds support for multiple simultaneous customers, multiple movies, different pricing schemes, error situations etc..

D5.9 Provider based accounting architecture - cycle 3 (completion date: 15 september 2001)

The output of this cycle will be a design document, plus a working prototype. As compared to cycle 2, cycle 3 is expected to add support for mobile and roaming users.

D5.10 Provider based accounting architecture - cycle 4 (completion date: 31 december 2001)

The output of this cycle will be a design document, plus a working prototype. As compared to cycle 3, cycle 4 is expected to add support for security and non-repudiation.

D5.11 Pre-study for cycle 3: adding mobility (completion date: 1 may 2001).

D5.12 Pre-study for cycle 4: adding security (completion date: 1 september 2001)

D5.13 Visualisation of traffic flows (completion date: 1 july 2001).

This deliver will be a piece of software (plus description) that can be used in conjunction with NeTraMet (or any other meter MIB implementation).

D5.14 Workshop 1 (organised before: 15 july 2001)

D5.15 Workshop 2 (organised before: 21 december 2001)

D5.16: Pre-study for cycle 3: charging of QoS (completion date: 30-4-2001)