7. SpeedReliabilityEfficiency In almost every case, content utilizing a CDN will be much closer to the end-user and that will result in faster delivery and a better user experience The CDN spreads out content, replicating that content across the globe, resulting in reduced demand on any given server The CDN optimizes for delivery, allowing the customer to focus on the quality of their content, not on the delivery of that content

10. 100ms 1,000ms 10,000ms

11. Does not replicate a representative CDN scenario Does not transmit TCP-based data Uses ICMP, which is for diagnosis, not testing Routers may give ICMP messages lower priority Routers may be configured to block ICMP messages entirely

12. TCP Connect DNS Lookup Content Download Time to first byte

14. the rate of successful message delivery over a channel the time required for a signal packet to travel from a specific source to a specific destination and back again the ratio of the number of cache hits to the number of misses

18. 1 Set your metrics and establish your baseline performance 2 Use publicly available reports like those available from a RUM testing provider like Cedexis to determine what major CDN provider performance should look like, all things being equal 3 Run an actual test of how those CDNs perform in your situation and compare the numbers, either through your own testing or through a custom testing provider like Gomez or Catchpoint 4 If your results (1) show improvement over your baseline and (2) are in line with the performances provided by generic testing, your scenario is probably close enough to the generic testing to depend on it for choosing your provider 5 If your result (1) show improvement over your baseline and (2) are NOT in line with the generic testing, you will want to drill into the details and determine what the variance is. This is usually one of the following or (a combination): file type, file size, time of day or geography. Then you will want to run tests specifically to see which provider performs best in the conditions you identify. 6 If your results do NOT show improvement over your baseline, you might be in a rare situation where a CDN is not going to help your performance and you may want to consider some alternate ways to address your goals than using the CDN

19. RUM stands for “Real User Measurements”. It depends not on using “virtual” end users or “synthetic" agents but on measurements taken from actual website and mobile application users, using real PCs, laptops and mobiles, to capture a real user’s experience. Synthetic monitoring utilizes a web browser emulation or scripted recordings of web transactions to test performance. Custom paths can be designed to test specific behaviors then repeated for a set number or duration to gather a meaningful dataset.

20. Identify ContentUpload to Origin Download via non-CDN URL Download via CDN URL Point to Origin