Extreme Networks Px Series - Page 69

Px Series Application Switch Installation and Configuration Guide 6-11
Persistence Modes
Unlike self-identifying cookie persistence and hashed cookie persistence, learned cookie
persistence does not require the website administrator to make any changes to the
website. Learned cookie persistence is a best-effort persistence mode that creates a
short-term stickiness between the client and the web server.
Figure 6-4 illustrates learned cookie persistence mode.
Figure 6-4: Learned cookie persistence mode
The following transactions occur in Figure 6-4:
• The website administrator configures the Px series application switch to use learned
cookie persistence mode, and configures the name of the cookie to be tracked.
• The client at IP address 65.11.11.11 transmits its first TCP request (A) to
www.buystuff.com at its publicly-known VIP address, 64.1.1.7.
• The Px series application switch responds (B) on behalf of 64.1.1.7, and the three-way
TCP handshake is established between the client and the Px series application
switch.
• Using its configured load balancing policy, the Px series application switch selects
one of the web server. In this example, server 3 at IP address 10.1.1.3.
WS_004
Client
65.11.11.11
Cookie:
sessionID=37654
Server 1
10.1.1.1
Server 2
10.1.1.2
Server 3
10.1.1.3
64.1.1.7
www.buystuff.com
A
C
D
B
E
E
F
F