3.3.1.5.8 Multiplexed Connections

A client SHOULD<107> support concurrent multiplexing on a connection.

A client can indicate to the server that it wants to do concurrent multiplexing on a connection. It does that by setting the PFC_CONC_MPX bit, as specified in [C706] section 12. If the server also supports this capability, it responds with a PDU that also has the same bit set. At this point both the client and server MUST set the Connection Multiplex Flag to Yes. Once concurrent multiplexing on a connection is negotiated, a client is allowed to send another request on a connection before it receives a response on a previous request, provided that the server is in CONTEXT_NEGOTIATED or Dispatched state. A client still MUST send all request PDUs for a fragmented request before it can move on to the next. Each request on the connection MUST abide by the same rule.

If a client negotiates a connection that does not support concurrent multiplexing (also called an exclusive connection), a client MUST wait for all PDUs of a response to arrive before it can send a request PDU for the next call.