8-2
User
Guide
for
the
Cisco
Application
Networking
Manager
5.2
OL-26572-01
Chapte
r
8
Configuring
Real
Servers
and
Server
Farms
Information
About
Server
Load
Balancing
Depending
on
t
he
load-balancing
al
gorithm
or
predictor
that
you
c
onfigure,
the
ACE
performs
a
se
ries
of
checks
and
calculations
to
determine
the
server
that
can
best
service
each
client
request.
The
ACE
bases
server
selection
on
several
factors,
including
the
server
with
the
fewest
connections
with
respect
to
load,
source
or
destination
address,
cookies,
URLs,
or
HTTP
headers.
ANM
al
lows
you
t
o
configure
load
balancing
using:
•
Virtual
servers—See
Configuring
Virtual
Servers,
page
7-2
.
•
Real
servers—See
Configuring
Real
Ser
vers,
page
8-5
.
•
Dynamic
Workload
Scaling—See
Configuring
Dynamic
Workload
Scaling,
page
8-26
.
•
Server
farms—See
Configuring
Ser
ver
Farms,
page
8-30
.
•
Sticky
groups—See
Configuring
Sticky
Groups,
page
9-7
.
•
Parameter
maps—See
Configuring
Parameter
Maps,
page
10-1
.
For
more
information
about
SLB
as
configured
and
performed
by
the
ACE,
see:
•
Configuring
Virtual
Servers,
page
7-2
•
Load-Balancing
Predictors,
page
8-2
•
Real
Servers,
page
8-3
•
Dynamic
Workload
Scaling
Overview,
page
8-4
•
Server
Farms,
page
8-5
•
Configuring
Health
Monitoring,
page
8-49
•
TCL
Scripts,
page
8-50
•
Configuring
Stickiness,
page
9-1
This
section
includes
the
following
topics:
–
Load-Balancing
Predictors,
page
8-2
–
Real
Servers,
page
8-3
–
Server
Farms,
page
8-5
Load-Balancing
Predictors
The
ACE
uses
the
following
predictors
to
select
the
best
server
to
satisfy
a
client
request:
•
Hash
Address—Selects
the
server
using
a
hash
value
based
on
either
the
source
or
destination
IP
address,
or
both.
Use
these
predictors
for
firewall
load
balancing
(FWLB).
Note
FWLB
allows
you
to
scale
firewall
protection
by
distributing
traffic
across
multiple
firewalls
on
a
per-connection
basis.
All
packets
belonging
to
a
particular
connection
must
go
through
the
same
firewall.
The
firewall
then
allows
or
de
nies
transmission
of
i
ndividual
packets
across
its
interfaces.
For
more
information
about
configuring
FWLB
on
the
ACE,
see
the
Cisco
4700
Series
Application
Control
Engine
Appliance
Server
Load-Balancing
Configuration
Guide
.
•
Hash
Content—
Selects
the
server
by
using
a
hash
value
based
on
the
specified
content
string
of
the
HTTP
packet
body
•
Hash
Cookie—Selects
the
server
using
a
hash
value
based
on
a
cookie
name.
•
Hash
Header—Selects
the
server
usi
ng
a
hash
value
based
on
the
HTTP
header
name.
