What makes a CDR invalid?

A valid CDR must comply with the roaming protocol specifications and include: the used kWh volume and price per kWh, all tariff components with unit, volume, and price per unit as agreed, and a unique roaming session ID that matches the invoice CDR session ID. Missing or incorrectly formatted mandatory fields will result in the CDR being rejected for payment. 

In addition, CDRs are deemed invalid if the consumption values are considered not feasible or plausible by DCS.