Intel 1520 manual Using a layer 4-aware switch to filter transparency requests

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 requests

Layer 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.

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Intel NetStructure Cache Appliance

Figure 3 Using a layer 4-aware switch to filter HTTP requests

122Intel NetStructure Cache Appliance Administrator’s Guide