Time interval over which the terms of a contract apply. Each contract includes a basic validity period. The actual validity period may be shorter (for example, due to an early cancellation) or longer (for example, because the customer extends the contract). The validity period consists of a start date and an end date. With regard to the validity period of a contract, there are two kinds of contract:

• Contracts of limited duration where the end date is automatically determined by the system or entered manually during processing
• Open-ended contracts for which there is only a start date. After a specified period, the contract may be cancelled or, if it is not cancelled, automatically extended. Open-ended contracts can only be ended if you or the service recipient cancel them under the terms specified in the contract.

The dates that define the validity period of a contract can be entered manually or determined indirectly by the system.

The contract start date can be used to determine the dates for the following contract-related activities:

• Billing plan
• Possible cancellation dates