1. Proxy-Based Acceleration of Dynamically Generated Content on the World Wide Web: An Approach and Implementation Anindya Dutta et al

2. WEB CACHING SOLUTIONS BACKGROUND BACK-END CACHING PROXY-BASED CACHING

3. BACK-END CACHING DATABASE CACHING(OR RESULTS OF QUERIES) PRESENTATION LAYER CACHING (CACHE HTML FRAGMENTS) COMPONENT LEVEL CACHING(CACHE ARBITRARY OBJECTS)

4. PROXY-BASED CACHING Page Level Caching Both at forward and backward proxy Improves –Delays associated with generation of content –Packet filtering –Bandwidth

5. DRAWBACKS URL BASED CACHING INCORRECT PAGES. VERY LITTLE REUSABILITY OF FULL HTML PAGES(PERSONIZATION) INVALIDATION

6. DYNAMIC PAGE ASSEMBLY DYNAMIC WEB PAGE APPROACH ESTABLISH A TEMPLATE FOR EACH DYNAMICALLY GENERATED PAGE EACH PAGE IS FACTORED INTO A NUMBER OF FRAGMENTS ASSEMBLE FRAGMENT HTML AT PROXY

7. DRAWBACKS CHANGE THE DESIGN OF WEBSITE(USE ONLY TEMPLATES) NO SEMANTIC INTERDEPENCE BETWEEN FRAGMENTS

8. AIM “Holy GRALE” of content caching has being a solution that can provide both bandwidth Saving, like proxy-based approaches and as well as server-side acceleration.

10. DYNAMIC PROXY CACHE OUTSIDE SITE’S INFRA (reverse- PROXY) OR AT NETWORK EDGE STORES CONTENT FRAGMENTS BEM(BACK END MONITOR) GENERATES THE LAYOUT FORWARD-PROXY FORWARD-PROXY –Request routing –Cache coherency

11. GRANULAR PROXY BASED CACHING CACHE DYNAMIC CONTENT FRAGMENT ON THE PROXY CACHE LAYOUT INFORMATION FROM SOURCE SITE QUERY TO DYNAMIC PROXY PUSH INTO SERVER SERVER RESPONDS WITH LAYOUT

12. Technical Details SYSTEM INITIALIZATION –Identify fragments and Tag them RUN-TIME OPERATION –Example –http://.../catalog.jsp?categoryID=fiction http://.../catalog.jsp?categoryID=fiction –Lookup fragID in BEMs cache dir –Insert GET /SET in the code

13. Back End Monitor MANAGE DPC CACHE –cache directory –Frags of DPC and metadata(ID,Key,valid,ttl) –Invalid fragment?? CACHE INTERMEDIATE OBJECTS

14. ANALYTICAL RESULTS Comparing average bytes served = B B = sum(Sci x n(t)) ncSci = sum(Sei) + f cSci = sum(Xj[(hxg) + (1-h)(sei + 2g)] + (1- Xj)(sei) + f] Plot ratio cB/ncB with fragment size Vary hit ratio and observe

16. Hit Ratio V/s Saving in Bytes

17. Cost Due to Cache No cache scan cost = ncB * y Cache Scan cost = cB*2y ncB > 2cB “It is preferable to dynamic proxy cache when the expected bytes served with no cache are more than the twice the expected bytes served with cache”

20. LIMITATIONS For forward proxy cache –Request Routing –Cache Coherency –Cache Management –Scalability