Installation guide

7-7
Device Manager Guide, Cisco ACE 4700 Series Application Control Engine Appliance
OL-26645-02
Chapter 7 Configuring Stickiness
Stickiness Overview
• Many-to-One Association Example, page 7-9
Guidelines and Restrictions
Observe the following guidelines and restrictions when using the buddy sticky group feature:
• When two sticky groups with different timeout values are buddied together, the ACE uses the
shortest timeout value for the buddy group.
• Sticky groups that are buddied together must of the same type, such as all IP-sticky, all http-cookie,
and so forth. The ACE does not support different types of sticky groups buddied together.
• When two sticky groups are buddied together and one of them is configured for timeout active
connections, the member group is also configured for timeout active connections.
• When two sticky groups are configured with different IP netmask (IPv4) or prefix-length (IPv6), the
ACE uses the one with the most granular netmask or prefix-length.
• When a static entry is created under a buddy sticky group, its behavior is unchanged and it sticks to
the same real server configured regardless of the buddy group that real server is associated with.
• Before you can configure a sticky group as a member, you must have a server farm configured under
that sticky group and all the real servers that belong to that server farm have buddy group configured
under them. This requirement prevents invalid configurations.
• The ACE does not support configuring the following types of sticky groups as buddy sticky group
members:
– SSL
– RTSP Header
• The ACE supports PTMP sticky group such as SIP sticky; however, you must make sure that the
configuration is the same across both sticky groups for the buddy sticky group feature to work.
• For real server backup applications:
– We recommend only one level of backup-rserver with buddy sticky.
– If you add a buddy group to the primary real server, the backup server inherits this buddy group.
However, if you remove the buddy group from the primary real server, the buddy group is not
removed from the backup real server and vice versa.
One-to-One Association Example
In a one-to-one buddy sticky group association, you create a buddy sticky group that sticks a client to
the same physical server instances in two different server farms. In the network example shown in
Figure 7-1, the ACE is configured with the following server farms, their associated real servers, and the
buddy sticky groups that group both items:
Server Farm
Server Farm
Buddy Member Group Real Server
Real Server
Buddy Group
http
(for HTTP requests)
alpha 1nx1:192.168.1.11:80 blue
1nx2:192.168.1.12:80 red
https
(for HTTPS requests)
alpha 1nx1:192.168.1.11:443 blue
1nx2:192.168.1.12:443 red