I have a question on the interpretation of following paragraph from RFC 6733 section 2.1 "Transport":
A given Diameter instance of the peer state machine MUST NOT use more than one transport connection to communicate with a given peer, unless multiple instances exist on the peer, in which, case a separate connection per process is allowed.
My interpretation is that it refers to the possibility for two Diam. peers (each of them identified by its "valid" Diameter Identity - as set in section 5.1-) to establish more than one transport connections (i.e. several TCP connections or several SCTP associations -e.g. the "initiator/client" using different TCP/SCTP source ports for each of them-).
In line with this, also CER/CEA, DWR/DWA and DPR/DPA procedures must be managed per established TCP conn/SCTP assoc (as set in section 5.6) ... but (Diameter) Application specific request and answers can be sent from one peer to the other using whatever transport connection established among them (for the shared/common supported Application-Ids, of course).
Could you confirm this is the shared understanding?
A part from that, in that case, I got the following question: is it mandated that responses are sent through the same transport connection from where the (related) request-command was received?