SNAX/HLS Application Programming Manual

Response Protocols
SNAX/HLS Verbs
104707 Tandem Computers Incorporated 5–99
Response Protocols SNAX/HLS uses the BIND image to determine which response protocol to use. This
determination is modified by the application program's use of the NOTIFY–IND field
in the SEND-DATA and SEND-AND-RECEIVE-DATA verbs. Table 5-4 shows the
protocol actually used.
Table 5-4. Selection of Response Protocols
Response Protocol Specified in BIND Response Protocol Actually Used
NOTIFY –IND = N NOTIFY–IND=Y
None No response Illegal
Exception Exception Illegal
Definite Definite Definite
Definite or Exception Usually Exception Definite
The two cases marked as illegal are forbidden by the verb interface; you cannot ask for
notification if SNAX/HLS is prevented from demanding a response.
The case marked as usually exception is a case where SNAX/HLS attempts to
optimize the flows. Except under the conditions listed below, SNAX/HLS uses
exception response chains. The only condition under which SNAX/HLS selects
definite response chains is if all the following conditions hold:
The session is using brackets.
The session is between brackets.
You are using FM–PROFILE 2 (which does not support the BID message).
Under these conditions, the only way to bid for the bracket is by including the BBI
(begin bracket indicator) on the first element of the chain. This requires the use of
definite response chains.