Content distribution networks (CDNs) are IP network-based servers that provide caching of content near the requesting end user device. CDN servers generally have unique IP addresses, so the techniques described herein can detect redirected packet streams to a CDN server and be able to determine the normal response/transmission times. Unlike other servers, the response time provided by a CDN or cache server is dependent upon whether the desired content is found within the CDN or cache, or if the request must be forwarded to another IP-based network server. Note that because the request from the CDN/cache is forwarded opaquely to the requesting end user device, the response/transmission time for packets routed to a CDN/cache may vary significantly. The database mechanism described above supports an IP address by IP address jitter value, which may be set to a large number to account for the varying packet flows. A similar approach may be used to account for content that is mirrored on multiple IP-based servers, where the packet stream path to the servers may vary opaquely to the end point device. This occurs when the mirrored servers are behind a load-balancing device that opaquely routes IP message traffic to one of a plurality of IP-based server(s).