Building Enterprise JavaScript Applications

Layer 7 load balancing

A Layer 7 (L7) load balancer is similar to an L4 load balancer, but uses information from the highest layer on the OSI model – the application layer. For web services like our API, the Hypertext Transfer Protocol (HTTP) is used.

An L7 load balancer can use information from the URL, HTTP headers (for example, Content-Type), cookies, contents of the message body, client's IP address, and other information to route a request.

By working on the application layer, an L7 load balancer has several advantages over an L4 load balancer:

• Smarter: Because L7 load balancers can base their routing rules on more information, such as the client's geolocation data, they can offer more sophisticated routing rules than L4 load balancers. ...