As we have services like netcpa on esxi which communicates with Controllers and vsfwd communicates with NSX MP rabbitMQ service similar what services do we have in NSX-T ?
In NSX-T we have our NSX-RPC; which is two streams between the NSX Manager and the transport Node [ESXi and Edges]
Starting from NSXT 2.5 onwards [Till now ]
The answer is RPC channel for Management plane, another one for the Control plane
For Management the ESXI is connected to the 3 [I am giving an example that you have 3 Nodes cluster]
For Control it would be only one Manager Node doing the control; the other 2 would be as a standby; should any Node goes down the cluster will takeover to distribute the job of the failed one(S)
Please note that The unified appliance [NSXT Manager Node] is doing both mgmt + ctrl.
For the Firewall if I remember correct ATM; it's vSIP built-in to ESXi
Please feel free to ask more; and kindly mark as resolved if that answer your question(S).