Comment by jeffbee
1 day ago
Your comment, to me, only points out that the OSI layer model is nonsense. Envoy in DSR mode routes traffic based on application features, at "layer 7".
1 day ago
Your comment, to me, only points out that the OSI layer model is nonsense. Envoy in DSR mode routes traffic based on application features, at "layer 7".
Envoy calls it Layer 4
https://blog.envoyproxy.io/introduction-to-modern-network-lo...
That's fair. Of course that post also calls the OSI model "unfortunate" and "a poor approximation".
All models are wrong, some are useful.
Layer 4 to 7 is useful in this case, as layer 4 involves forging tcp/udp packets, which is vastly different than say a http level reverse proxy.
The model itself isn’t nonsense because it’s not a model of load balancers; it’s a model of network protocols. Load balancers might handle multiple levels of the stack for the same traffic, but so does any other networked program, eg handling cross-domain redirects.