SNAX/HLS Management Programming Manual

Standard SNAX/HLS Definitions
Common Definitions
104708 Tandem Computers Incorporated 6–31
ZSEND–RECV
controls the flow of chains in the session. This value is set when the BIND record
is processed.
This field can have the following enumerated values:
ZHLS–VAL–SEND–RECV–FDUX
specifies full–duplex transmission. Messages flow in each direction
independently.
ZHLS–VAL–SEND–RECV–HDUX–CONT
specifies half–duplex with contention. In this protocol, one session partner is
specified as the bidder or contention–loser, and the other as the first speaker or
contention winner. Session partners contend for the right to send a message.
Initially, both partners are in a contention state.
ZHLS–VAL–SEND–RECV–HDUX–FF
specifies half–duplex flip–flop. When brackets are in use, contention is used to
resolve the right to begin brackets and also to resolve which partner can send
messages. The right to send messages alternates, with the change direction
indicator (CDI) being sent by the current sender to indicate the change in
direction.
When no brackets are in use, the first sender is established based upon the
HDX–FF–RESET–STATE flag. The right to send data alternates with the use of
the CDI.
ZSEQNUM–USE
specifies whether sequence numbers are available for session recovery. It is used
for FM–profile 4 sessions only. This value is set when the BIND record is
processed.
ZSINGL–FMH
specifies whether FMHs can be continued, using the high–order bit of the second
byte of the FMH. Standard headers for LU types other than LU type 0 use the
convention. CICS communicating with an IBM 3600, however, is an example of
LU type 0 using a different continuation.
This option should be equal to ZSPI–VAL–TRUE when FMHs cannot be
continued.