Load Balancing Building Blocks - L4 & L7 Proxies
The Reverse Proxy type of load balancer is probably the most common one - it is Good Enough for most applications. The differences between the L4 and L7 proxy variants come from which level of the OSI model they deal with. L4 load balancers deal with individual connection flows (think TCP/UDP packets, plain bytes), while L7 load balancers deal with individual requests (think HTTP requests, GETs or POSTs). In the proxy design, incoming connections are terminated on the load balancer, and the request passed on to one of the backend servers, either by opening a new connection or using an already established one....