1. A New Prefetch Cache Scheme Shun-Zheng Yu; Kobayashi, H. Department of Electrical Engineering E-Quad, Princeton University. Proceedings of IEEE Conference on Global Telecommunications, 2000. GLOBECOM '00. IEEE, Volume: 1, 2000 Page(s): 350 -355

2. Outline 1.Introduction 2.Some Preparation 3.A New Prefetch Scheme 4.Numerical Result

3. 1.Instruction Conventional: --probability of each document --popularity of the document New: --average latency --hit probability --cache capacity --required bandwidth

4. Instruction(cont.) Classification of prefetch: --predictive prefetching (client’s access history,links between the contents) --popularity-based prefetching (frequency) --interactive prefetching (client  proxy) The goal that we want to achieve --minimizing the latency --maximizing the hit ratio

5. 2.Some preparation HTTP header support

6. Some preparation(cont.) Entry_is_fresh=(freshness_lifetime > current_age) Not_Modified=(Validator=Last_Modified time)

7. Some preparation(cont.)

9. (A) min latency

10. Some preparation(cont.) (B) max hit ratio

11. Some preparation(cont.) (C) min require bandwidth

12. 3.A New Prefetch Scheme Four Constraints --Increased cache capacity ΔC: --Increased bandwidth usage ΔB:

13. A New Prefetch Scheme --Tolerable latency Lo: --Minimum hit probability required Po:

14. A New Prefetch Scheme How to operate this scheme 1.Determine the Rn,R,μn,Sn,ΔTn 2.To calculate 3.Sort in the descending order 4.Determine the number r of prefetching documents(by 4 constraints) 5.Choose the largest r documents, and prefetch them. 6.Repeat the procedure from 1 to 5 with a given statistical cycle (hours,days)

15. 4.Numerical Result

16. Numerical Result(cont.)