Response Modes

Each SNA message is either a request or a response. Every request from one LU elicits a matching response from the partner LU. Because the response carries the same transmission sequence number as the request, responses and requests can be matched by their sequence numbers.

When your application has received a request whose RH specifies a mandatory response, your application must generate and send a response message. The response mode rule determines when the response must be sent.

Under immediate response mode, your application must send a response to a request before it sends any request of its own. Under delayed response mode, however, responses can be sent at any time after a request is received.