Content Switching

Key Point

A content switch load-balances requests to servers, content engines, or firewalls.

A content switch can be used in a data center environment, for example. Here the content switch can be used in front of a group of application servers to balance the connection requests sent to each, as illustrated in Figure 8-6.

Figure 8-6. A Content Switch Can Load-Balance Connections to a Server Farm

Content switches can be configured with various policies that define how messages are shared among devices. For example, when load-balancing across a set of servers, a policy might specify some of the following:^[5]

• That all connections from a single user will go to the same server

• That all connections from a specific type of device (for example, from a cell phone) will go to a subset of the servers that can handle that device type

• That all requests for specific file types (for example, video files) will be directed to a specific server

The load balancing can be based on a variety of algorithms, including distributing requests on a round-robin basis or distributing to the least-loaded device.

A content switch can also monitor the status of the devices and fail over to another if one should become unavailable.