SNAX/APN Application Programming Manual

The SNALU Interface
SNAX/APN Application Programming Manual—420111-001
4-22
SNALU Application Terminates Session With
Remote SLU
The SNALU application sends the UNBIND request to the SLU in the write portion of a
WRITEREAD call and accepts the response from the SLU in the read portion of the
same WRITEREAD call. The format of an UNBIND request, as it appears in the
application’s write buffer, is shown in Table 4-5.
Response Formats
The SNALU application accepts responses from the SLU by way of the read portion of a
WRITEREAD call. Positive responses to a BIND request occupy 10 bytes in the
application’s buffer; negative responses occupy 14 bytes.
Table 4-6 shows how a positive response appears to an UNBIND request in the
application’s buffer.
Figure 4-6. SNALU Application PLU Terminates Session With Remote SLU
Tandem Node Remote Node
SNALU Application (PLU) SLU Device or Program
Open the LU (OPEN call)
Send UNBIND request
(write portion of WRITEREAD call)
UNBIND Request
Receive response
(read portion of WRITEREAD call)
Positive Response
Close the remote LU (CLOSE call)
Table 4-5. Format of an UNBIND Request
Byte Description
0-8 SNAX header
(0-1) X’0100’ TC indicators field: EFI=1
(2-3) X’0000’ Status codes field
(4-5) Sequence number field
(6-8) X’6B8000’ RU category: session control
RH indicators: RRI=0, FI=BCI=ECI=1, DR1I=1
9 X’32’ (request code)
10 Type of UNBIND request (usually a PLU process on a Tandem system
specifies X’01’, indicating a normal end of session; other UNBIND
request type codes are defined in the IBM SNA Format and Protocol
Reference: Architectural Logic manual
and can be used if they are
supported by the particular SLU device).