Editing Multilayer switch (section)

===Layer 4–7 switch, web switch, or content switch===
Some switches can use packet information up to OSI layer 7; these may be called layer 4–7 switches, '''{{vanchor|content switches|content switch}}''', '''{{vanchor|content services switches|content services switch}}''', web switches or application switches.

Content switches are typically used for [[Load balancer|load balancing]] among groups of servers.  Load balancing can be performed on [[HTTP]], [[HTTPS]], [[VPN]], or any TCP/IP traffic using a specific port.  Load balancing often involves [[destination network address translation]] so that the client of the load-balanced service is not fully aware of which server is handling its requests.  Some layer 4–7 switches can perform [[Network address translation]] (NAT) at wire speed.  Content switches can often be used to perform standard operations such as [[Secure Sockets Layer|SSL]] encryption and decryption to reduce the load on the servers receiving the traffic, or to centralize the management of [[digital certificate]]s. Layer-7 switching is a technology used in a [[content delivery network]] (CDN).

Some applications require that repeated requests from a client are directed at the same application server.  Since the client isn't generally aware of which server it spoke to earlier, content switches define a notion of stickiness. For example, requests from the same source IP address are directed to the same application server each time. Stickiness can also be based on SSL IDs, and some content switches can use [[HTTP cookie|cookies]] to provide this functionality.