Hi,
it seems nobody is explaining why it cannot be in another way.
The SEP communication is based on a server-client model, it is not a peer-to-peer network.
The SEP Manager is the server and it is listening on port 8014 (or 80) for client connections.
The SEP client is the client and it does not listen on any port because it is just a client.
In this model, it is clear that only the SEP client can start a communication with the manager by opening a TCP connection to [SEPM_IP]:8014, the SEPM cannot connect to the clients because the clients, by definition, are not listening on any port.
Once the connection is established, Server and clients can exchange data, including commands.
In push mode the connection is always kept alive and the commands can be sent to the clients in real time through the already open channel. In pull mode the connection is pulled at regular intervals, between the heartbeats there is no established connection therefore the commands are just stored in the outbox waiting for the clients to get them. It cannot work in any other way.
This does not need any detailed document, it is just the server-client model.