SNAX/HLS Management Programming Manual

Standard SNAX/HLS Definitions
Common Definitions
6–12 104708 Tandem Computers Incorporated
def ZHLS–DDL–HS–PROTO.
05 ZMAX–RU type ZSPI–DDL–INT.
05 ZPACING–WINDOW type ZSPI–DDL–INT.
05 ZCHAIN–PROTO type ZSPI–DDL–ENUM.
05 ZCHAIN–USE type ZSPI–DDL–ENUM.
05 ZCMPRSS–IND type ZSPI–DDL–BOOLEAN.
05 ZEB–SEND type ZSPI–DDL–BOOLEAN.
05 ZRQ–MODE type ZSPI–DDL–ENUM.
05 ZTWO–PHASE–COMMIT type ZSPI–DDL–BOOLEAN.
ZMAX–RU
records the maximum–sized RU that can be sent by the half session. Note that the
actual value in bytes is indicated, not the encoded value used in the BIND request.
Only selected values are possible, as shown in Appendix A, “Table of RU Sizes,”
in the SNAX/HLS Configuration and Control Manual. The largest allowed value is
4,096.
When an application is not using the large message option (LMO), this value
affects only the efficiency of the data transfers, because SNAX/HLS breaks
outbound messages into ZMAX–RU–sized segments and combines inbound
segments into complete messages.
When an application is using the LMO, the ZMAX–RU value limits the size of
message segments that can move between the application and SNAX/HLS. For
primary half sessions, the ZMAX–RU value in ZHLS–MAP–INFO–SESS–PRI limits
the size of transfers (and the size of FMHs) sent, whereas the ZMAX–RU value in
ZHLS–MAP–INFO–SESS–SEC limits the size of received segments. For secondary
half sessions, the restrictions apply in the reverse direction.
ZPACING–WINDOW
records the size of the pacing window on the outbound flow. That is, in
ZHLS–MAP–INFO–SESS–PRI, this field defines the primary–to–secondary pacing.
In ZHLS–MAP–INFO–SESS–SEC, this field defines the secondary–to–primary
pacing. A value of 0 (zero) means no pacing.
The actual value that appears here corresponds to the window size—that is, the
number of message segments that can be sent without requesting and being
granted permission to send another window–sized batch of segments. Session–
level pacing is transparent to the SNAX/HLS application. The other partner,
however, might require pacing due to small buffering capabilities.