1 Pertemuan 04 Proxy/Cache Matakuliah: H0491/Praktikum Jaringan Komputer Tahun: 2005 Versi: 1/0

2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Menghubungkan LAN dengan INTERNET menggunkan Proxy

3 Proxy Servers Proxy services sit between user on the inside and server on the outside. Instead of talking directly, user and server talk through proxy.

4 Proxy Servers Advantages –Can be good at logging –Can provide caching –Can do intelligent filtering based on “content” –Can perform user level authentication Disadvantages –Not all services have proxied versions –May need different proxy server for each service –Require modification of client

5 Topology of proxies How many proxies we should use Where we should place them Define the relationships between proxies

6 Web Cache Placed between Data Server and Web Clients Saves copies of objects requested from a client Use the copies when a cached object is requested again

7 Type of Web Caches Browser Caches Proxy Caches Web Server Caches Application Server Caches DBMS Caches

8 Web Cache Use Reduce Latency Reduce Traffic

9 Updates Push Function Update to the database ->Immediately triggers the deletion and recalculation of the materialized data invalidated by the update Pull function Materialized data periodically checked for freshness

10 Current search topics Internet protocol and connection General Architectures used from Data intensive Web-Sites Cache Protocols Can we make true the communication between caches and materialized data with the existing protocols? Where, what and when is cached. Create a case tool.