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Device Manager Guide, Cisco ACE 4700 Series Application Control Engine Appliance
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Chapter 7 Configuring Stickiness
Stickiness Overview
Figure 7-1 Buddy Sticky Groups: One-to-One Association
The ACE is configured to load balance HTTP requests to server farm http using either real server
1nx1:192.168.1.11:80 or 1nx2:192.168.1.12:80. The ACE is also configured to load balance HTTPS
requests using server farm https and either real server 1nx1:192.168.1.11:443 or 1nx2:192.168.1.12:443.
The buddy groups allow the ACE to stick a client to the same real server (for example, 1nx1) while
building a shopping cart using HTTP requests and then checking out using HTTPS.
In this example, the client hits VIP 172.16.1.100, destination port 80 with an HTTP request to begin to
build a shopping cart. The ACE load balances the request to server farm http, real server
1nx1:192.168.1.11:80 and creates a sticky entry based on the corresponding sticky group (for example,
source IP address) that sticks the client to the real server while the client builds their shopping cart.
When the client moves to the secured connection (port 443) for checkout, it hits the VIP with destination
port 443 and the ACE sends the client to server farm https. The ACE finds an existing sticky entry with
real server Inx1:192.168.1.11:80 and directs the client to 1nx1:192.168.1.11:443 because the two real
servers are buddied together under the blue buddy group.
Asymmetric Association Example
In an asymmetric buddy sticky group association, you create a buddy sticky group that sticks all Layer 7
traffic from a client to a specific real server even when some of the traffic does not match the Layer 7
class map. In the network example shown in Figure 7-2, the ACE is configured to include the following
server farms, their associated real servers, and real server buddy sticky groups.
Server Farm
http
(alpha)
Server Farm
https
(alpha)
1nx1
192.168.1.11:80
192.168.1.11:443
1nx2
192.168.1.12:80
192.168.1.12:443
Internet
Client
Multilayer
Switch
Feature Card
ACE
VLAN 20
VLAN 40
172.16.1.1
192.168.1.1
Int: 172.16.1.5
VIP 172.16.1.100
blue
red
332431
Server Farm
Server Farm
Buddy Member Group Real Server
Real Server
Buddy Group
foo bar alpha 1nx1 blue
1nx2 red
foo alpha 1nx1 blue
bar alpha 1nx2 red
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