SNAX/HLS Configuration and Control Manual

Step 3. Planning Session BINDs
Planning the SNAX/HLS Environment
104705 Tandem Computers Incorporated 2–7
For those applications where SNAX/HLS is used to control the primary half of the
session, the BIND message used to set up the session is derived from one of two
sources:
For Primary-Acquire sessions, the primary partner unilaterally issues a BIND. The
BIND information is based upon the name in the profile, which identifies one of
the BIND messages you've defined.
For Primary-Accept sessions the primary partner receives a CINIT. When the
CINIT does not contain a valid BIND message or the profile has not selected the
ACCEPT-BIND option, the BIND information is derived from the RDT table.
When the CINIT contains a valid BIND message and the profile has selected the
ACCEPT-BIND option, then the BIND information is derived from the CINIT.
The only change that occurs is in making sure that the primary and secondary
maximum RU sizes do not exceed 30720.
The last option can only occur when SNAX/HLS is used in conjunction with
SNAX/CDF.
FM and TS Profile Selection SNAX/HLS supports any combination of FM profiles 2, 3, 4, 7, 18 and TS profiles 2, 3,
4, and 7. Limitations on the PROFILE types imposed by LU-type considerations are
outside the scope of SNAX/HLS. The selection of an FM and TS Profile determines
which SNA requests are supported for the session and which BIND attributes are
allowed. For example, sequence-number verification at session establishment is
allowed only under TS Profile 4. (See the SNA references listed in the Preface.)
Primary and Secondary FM
Usage
Byte 4 of the BIND image contains information that pertains to the primary
half-session, and byte 5 contains information that pertains to the secondary half-
session.
Chaining Use Selection
This field determines whether SNAX/HLS is to break user messages into SNA chain
elements. Selection of some FM profiles can override the value of this field. If
chaining is not supported, the size of messages is limited to a value given in the BIND;
SEND-DATA verb messages cannot be larger than the maximum RU size specified for
the half-session in the BIND.
In the BIND message, this attribute is indicated in byte 4, bit 0 for the primary
half-session, and in byte 5, bit 0 for the secondary half-session. In HLSRDT, this
attribute is specified by the BIND attributes PRI-CHAIN-USE and SEC-CHAIN-USE,
respectively, where: SINGLE-RU corresponds to 0 in the BIND message and
MULTIPLE-RU corresponds to 1 in the BIND message.
Request Control Mode
This attribute determines SNAX/HLS verb behavior as follows:
Delayed-request mode— allows several messages to be outstanding at once even
though each message requests explicit acknowledgement (that is, definite
response). This means SEND verbs complete when the I/O to SNAX/XF or