A system includes a first database to associate a sub-interface identifier with customer information, a second database to store a history of customer usage records, and a first device. The first device may receive information from a routing device, where the information includes the sub-interface identifier for a sub-interface of the routing device and information identifying an amount of network traffic received at or transmitted from the sub-interface over a time period, use the sub-interface identifier to obtain the associated customer information from the first database, associate the customer information with the information identifying an amount of network traffic received at or transmitted from the sub-interface over a time period to create a new customer usage record, and store the new customer usage record in the second database.