SNAX/HLS Application Programming Manual
OPEN-SESSION Verb
SNAX/HLS Verbs
5–50 104707 Tandem Computers Incorporated
VERIFY–SEQUENCE–NUMBERS–IND
dictates whether SNAX/HLS performs sequence number verification. This is
valid only if TS PROFILE 4 is in use on the SNA session. (The TS PROFILE level is
specified by a field in the SNA BIND request.)
If VERIFY–SEQUENCE–NUMBERS–IND is N, no sequence number verification
occurs. If SNAX/HLS is acting as the PLU, then as part of the (TS PROFILE 4)
session initiation, SNAX/HLS sends the sequence numbers supplied on the
HLS–OPEN verb request to the SLU. These become the starting sequence
numbers for the session. SNAX/HLS (as the PLU) synchronizes the numbers and
does not check with the SLU to determine that the numbers are appropriate. If
SNAX/HLS is the SLU, it receives the starting sequence numbers from the PLU
and does not test them against any supplied on the HLS–OPEN verb.
If VERIFY–SEQUENCE–NUMBERS–IND is Y, sequence number verification is
performed. If SNAX/HLS is acting as the PLU then as part of the (TS PROFILE 4)
session initiation, SNAX/HLS sends the sequence numbers supplied on the
HLS–OPEN verb request to the SLU. These become the starting sequence
numbers for the session. SNAX/HLS checks with the SLU to determine that the
numbers are what the SLU expects. If they are not, the RETURN–CODE is
RC–VERIFY–FAILURE. The values in the RECOVERY–TAGS field of the verb
reply are those returned by the SLU. Your application must decide what to do if
verification fails.
If SNAX/HLS is the SLU, it receives the starting sequence numbers that the PLU
wants to use to restart the session. These become the starting values. If they do
not match the values supplied on the HLS–OPEN verb, the RETURN–CODE of the
reply is RC–VERIFY–FAILURE and the received sequence numbers are in the
RECOVERY–TAGS field of the reply. Upon request of the PLU, the sequence
numbers supplied on the HLS–OPEN verb are sent to the PLU with the result of
the comparison.
FUTURE
is reserved for future use.
RECOVERY–TAGS
contains the two sequence numbers used in FM PROFILE 4 only, to resynchronize
sequence numbers. These values reflect the partner’s send and receive sequence
numbers to be sent at session establishment.
Reply Details
VERB–CODE
identifies the reply by an integer constant (of value 1), named as follows:
VERB–OPEN–SESSION (in SCOBOL)
VERB^OPEN^SESSION (in TAL)