This document specifies requirements for Open Caching System (OCS) for Logging data to help track data acquisition and delivery of it to the end user. The information logging is critical for the Open Caching Nodes as well as the upstream CDN and the Content Provider (CP). Logging information helps OCS track key performance metrics such as, data acquisition, delivery success and failures, measuring of effective throughput, cache hits and for troubleshooting fault and performance degradation. The logging data provided to the CDN by the OCS is also used by CDNs for auditing, billing and SLA purposes. The information logging will also be used by Open Caching Nodes (making up an OCS) for ensuring its compliance of SLAs with CDNs and measuring and assuring
Quality of Experience (QoE) for an end user.