Monitoring availability of content delivery networks

A computer implemented availability checking system and method is provided for use with a service provider configured to communicate with one or more client devices and with a content provider. The system includes a computer storage device operative to store an availability data store comprising a list of a plurality of potential endpoints of the service provider and a corresponding plurality of availability information for the plurality of potential endpoints. The plurality of potential endpoints is distributed across a plurality of resource cache components. The system further includes an availability query component operative to transmit a plurality of queries to the plurality of potential endpoints and to receive a plurality of responses from the plurality of potential endpoints. The system further includes an availability analysis component operative to analyze the plurality of responses, to generate the plurality of availability information, and to update the availability data store.