Extreme Networks Px Series - Manual (Page 12)

1-2 Px Series Application Switch Installation and Configuration Guide
The Px series application switch can examine actual user requests, rather than simply
forwarding the requests to the servers. You can use the powerful array of tools provided
by the Px series application switch to scale websites by:
• Creating special purpose servers
• Making better use of web caches
• Allowing movement of web content without extensive re-linking of the site
Terms
The Px series application switch creates a level of abstraction between the real servers
and the Internet, by configuring a virtual IP (VIP) address and port on the application
switch. The VIP has a globally-reachable public IP address, and corresponds to the DNS
entry for the website. All traffic for the website is sent to the application switch, which
applies policies to decide how to forward the traffic to a real server.
Figure 1-1 shows several Internet users all connecting to the website www.busy.com.
Figure 1-1: Conceptual view of server load balancing
WS_012
Real Server 1
10.1.1.3
Virtual Server
www.busy.com
64.10.10.100
Real Server 2
10.1.1.4
Real Server 3
10.1.1.5
235.19.10.1
101.1.35.2
64.64.6.4
193.16.1.36
Internet clients