Layer 4 (L4) load balancing is mostly related to the network, IP addresses, network address translation or NAT, and packets. Layer 7 (L7) operates at the highest level of the OSI model. The HTTP protocol will be the most dominant protocol in that layer. HTTP comes with lots of features that you can use as a factor to make a decision about where to route each incoming request. Basically speaking, in the L7 we can create a rule based on URL, we can determine what content type comes with our request, and create rules based on its value.