Matakuliah
Tahun
Versi
: H0451/Praktikum Jaringan Komputer
: 2006
: 1/0
Pertemuan 04
Proxy/Cache
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Menghubungkan LAN dengan INTERNET menggunkan
Proxy
2
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.
Firewall
Dual
homed
Host
Internet
www.google.com
216.239.57.99
Proxy Server
Ethernet
3
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
4
Topology of proxies
• How many proxies we should use
• Where we should place them
• Define the relationships between proxies
5
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
6
Type of Web Caches
•
•
•
•
•
Browser Caches
Proxy Caches
Web Server Caches
Application Server Caches
DBMS Caches
7
Web Cache Use
• Reduce Latency
• Reduce Traffic
8
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
9
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.
10