Technical data

54 Brocade ServerIron ADX Advanced Server Load Balancing Guide
53-1003441-01
Other transparent cache switching options
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In this example, return traffic from the cache servers passes through the ServerIron ADX to the
border access router (BAR) because the BAR is the default gateway for the cache servers. However,
the traffic is destined for the clients on the other side of the remote access server (RAS). The
ServerIron ADX can switch the traffic at wire-speed, causing no perceivable response delays for the
clients even if their return traffic must pass through the ServerIron ADX twice. However, the client
return traffic might add noticeable overhead to the BAR, especially if the BAR is also the default
gateway for other devices on the network.
You can reduce the burden on the BAR by enabling cache route optimization. This feature
configures the ServerIron ADX to use the information in its Layer 4 session table to recognize that
the return traffic actually should go to the RAS instead of the BAR, and send the return traffic
directly to the RAS. Thus, the return traffic does not needlessly add overhead to the BAR.
FIGURE 10 Cache route optimization