Layer 4-7 Switch, Web-switch, Content-switch
Some switches can use up to OSI layer 7 packet information; these may be called layer 4-7 switches, content-switches, content services switches, web-switches or application-switches.
Content switches are typically used for 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 NAT so that the client of the load balanced service is not fully aware of which server is handling its requests. Some of the layer 4-7 switches can perform NAT at wirespeed. Also, content switches can often be used to perform standard operations such as SSL encryption/decryption to reduce the load on the servers receiving the traffic, or to centralise the management of digital certificates. Layer 7 switching is the base technology of a content delivery network.
Some types of 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 even use cookies to provide this functionality.
Read more about this topic: Multilayer Switch
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