In most cases, EC/EB systems are not developed independently of an existing hardware and software infrastructure. Usually, the EC/EB systems have to be integrated into that infrastructure by exchanging data with it. However, the exchange of data between the EC/EB system and existing software systems may not always be sufficient - sometimes, the use of existing functionality is necessary. Thus, the IPSI electronic commerce portal exchanges data with its subsystems as well as with the database systems of the client (e.g. UDS, BS2000). This way, the portal can supply the data of insured persons and their contracts to the insurance agent. Furthermore, the portal needs the functionality of a complex tariff computation module, e.g. for a life insurance. Existing software systems like the latter one are termed legacy systems. In order to realize each subsystem, it must be decided if existing software systems fulfill the client's requirements, and if an existing software system can be integrated or if it is necessary to develop new software.

For the IPSI electronic commerce portal, it was decided to integrate existing software systems for most subsystems. This decision was followed by a market analysis to determine which existing systems should be used. The analysis took into account non-functional criteria such as price, availability, support and platform and led to the selection of MS Outlook 2000, Pirobase 4.0, SmartStore 2.0 and JavaMail 1.1 for the subsystems office, content management, procurement and communications (see Figure 3).

Figure 3. Subsystems of the electronic commerce portal.

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