gtps2m38ACF/SNA Data Communications Reference

SNA Message Protocol

Messages transmitted between TPF and a logical unit must adhere to SNA message protocol. In an SNA environment, messages are prefixed with a request-response header (RH). Within this header is a field that indicates to the receiver of the message the type of response the sender requires. SNA defines three response types:

Definite response:
Directs the receiver to respond without regard to the nature of the response. A response, either positive or negative, must be returned. A positive response is referred to as a +RSP. A negative response is referred to as a --RSP.

Exception response:
Directs the receiver to respond only if the request is unacceptable as received or cannot be processed. Only a negative response is returned.

No response:
Indicates to the receiver that no response is to be returned.