Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 112)

96 Brocade Virtual ADX Server Load Balancing Guide
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Policy-based SLB
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Policy-based SLB
Policy-based server load balancing (PBSLB) is the Brocade Virtual ADX ability to direct requests to a
server group based on the source IP address of the request.
When policy-based SLB is enabled for a port on a virtual server, the Brocade Virtual ADX examines
the source IP address of each new connection sent to the VIP on the port. The Brocade Virtual ADX
looks up the source IP address of the request in an internal policy list. The policy list is a table that
associates IP addresses with real server groups. If an entry for the IP address is found in the policy
list, then the Brocade Virtual ADX forwards the request to the associated real server group. If no
entry for the IP address is found, the Brocade Virtual ADX directs the request to a server group
specified as the "default" server group.
Figure 21 shows a sample policy-based SLB configuration.
FIGURE 21 Policy-based SLB configuration
The policy list contains three entries: one associating IP address 10.10.10.10 with Real Server
Group 1, another associating network address 20.20.0.0/16 with Real Server Group 2. In addition,
Real Server Group 3 is specified as the default server group.
In this example, policy-based SLB works as follows:
• When a request from address 10.10.10.10 is received on the VIP, the Brocade Virtual ADX
forwards the request to one of the load-balanced servers in Real Server Group 1.
• When a request from network 20.20.0.0/16 is received, it is forwarded to the real server in
group 2.