Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 239)

Brocade Virtual ADX Server Load Balancing Guide 223
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Miscellaneous health check settings
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FIGURE 24 Health check of remote server – learned MAC address is not used
In this example, the Brocade Virtual ADX sends the health check through its default gateway. The
default gateway sends the health check back to the Brocade Virtual ADX, because Router R1’s
route to the remote server lists the Brocade Virtual ADX as the next hop. Despite the unnecessary
trip through the default gateway, the health check still reaches the remote server. However, if you
want to eliminate unnecessary hops, you can enable the Brocade Virtual ADX to learn the MAC
address from which the remote server’s health check reply is received, and send subsequent
health checks directly through that MAC address.
Figure 25 shows the simplified health check
process.
FIGURE 25 Health check of remote server – learned MAC address is used
To enable the Brocade Virtual ADX to use learned MAC addresses for sending health checks to
remote servers, enter the following command.
Virtual ADX(config-rs-remote1)#use-learned-mac-address
Syntax: [no] use-learned-mac-address
NOTE
This command does not apply to local servers. Because local servers are attached at Layer 2, the
Brocade Virtual ADX does not need to use a gateway or otherwise route the health check to the
server.
Handling traffic initiated from remote server
Under normal conditions, traffic is always initiated from a client and return traffic is processed by
looking up the session table. However, a real server may have to initiate traffic to a client in some
complex protocols such as Active FTP. The Brocade Virtual ADX checks the source MAC to handle
the traffic initiated from the remote server.
To enable the Brocade Virtual ADX to check the source IP instead of source MAC to handle the
traffic from a remote server, enter the following command:
Virtual ADX(config)#server identify-server-by-ip