122 Intel NetStructure Cache Appliance Administrator’s Guide
appliance, or routers or switches feeding it, is often deployed at a major artery or
aggregation pipe to the Internet.
The following sections provide more details about the Intel NetStructure Cache
Appliance’s transparency routing solutions.
Using a layer 4-aware switch to filter transparency requestsLayer 4-aware switches can rapidly redirect supported protocols to the Intel
NetStructure Cache Appliance, while passing all other Internet traffic through
directly to its destination. Figure 3 illustrates this scenario for HTTP.
Layer 4-aware switches offer the following features, depending on the particular
switch:
✔A layer 4-aware switch can sense downed hosts on the network and redirect
traffic.
✔Single layer 4-aware switches that feed several appliances balance loads
among the nodes. Different switches might use different load-balancing
methods, such as round-robin or hashing. If a node goes down, the switch
automatically redistributes the load. When the node returns to service, some
switches automatically return the node to its previous workload, so that the
node cache need not be repopulated; this feature is called cache affinity.
Intel recommends that you do not enable the virtual IP failover in this
situation, because layer 4-aware switch failover is already in operation.
Figure 3 Using a layer 4-aware switch to filter HTTP requests
end users
Intel NetStructure Cache Appliance
Internet
L4 switch
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