I think the way Symbol’s architecture is being explained is a bit obscure, at least to me.
So the 4th layer is sdks/apps ? That’s a layer in any architecture with an API ever. No need to tout that as a 4th layer.
The 3rd layer is REST nodes and the 2nd API nodes? With all due respect, but do the people who write these things (especially on Twitter) understand what REST and API mean? REST really doesn’t give any insight into what these nodes do, other than that they provide a RESTful API. The exaplanations that are being given in most places don’t really help a lot, because they also just make it clear it’s an API.
But then there are separate API nodes (presumably not a RESTful API?), so they obviously have some API too. So where’s the distinction? Without searching for better explanations, this nomenclature, in my view, is rather useless.
Thankfully, I found a non-official source that seems to provide some insights and I’d like to make some suggestions if I may:
It’s probably to late to drop the 4th layer talk, so whatevs…
I would suggest to call REST nodes “Gateway Nodes”. This makes clear that they provide an interface to the “ouside world” i.e. the “4th layer”.
Gateway Nodes talk to the API Nodes which seem to be a layer between peer nodes and Gateway Nodes (haven’t been able to find any explanation as to why that layer was introduced, so I can only guess). Hard to suggest a better name, when there isn’t any proper explanation for why they exists (at least none that I could find in 5 minutes of Googling, which, let’s be honest, that’s about as long as anyone will spend on it). Maybe Internal API nodes?