OSI/AS Programming Manual

Sending and Retrieving User Data
APS Procedures Programming Concepts
056783 Tandem Computers Incorporated 2–43
User Data Encoding Examples
The following examples illustrate the encoding of user data on an ACSE connection
using OSI/AS.
Example 1. This example performs an FTAM F-INITIALIZE operation using the ACSE
service provided by OSI/AS.
FTAM builds an F-INIT FPDU (with a PCID of 7), encoding all parameters according
to the BER transfer syntax, and includes the EXTERNAL in the user data element.
Any data from the user of FTAM (with a PCID of 9) is encoded as an EXTERNAL in a
new user data element. (The data from the user of FTAM could be included in the
second user data element.)
Note that PCIDs 7 and 9 must have been entered in the presentation context definition
list, along with the PCIDs for any other presentation contexts that may be needed
during the association. (In the case of FTAM, another PCID—for example, 11—would
be needed for data from an FTAM document type.)
The following set of structures shows the encoding given to ACSE:
data header [
ZNUM-ELEMENTS = 2
] -- end data header
data element 0 [
ZLEN = ??
ZTYPE = ZAPS-VAL-DATA-TYPE-VALUE
ZPCID = don’t care
(F-INIT FPDU)
28 [EXTERNAL]
?? [length]
02 01 [INTEGER, length of 1]
07 (F-INIT PCID)
80 [single-asn1-type]
?? [length]
94 [user-info]
] -- end data element 0
data element 1 [
ZLEN = ??
ZTYPE = ZAPS-VAL-DATA-TYPE-VALUE
ZPCID = don’t care
(user data from FTAM user)
28 [EXTERNAL]
?? [length]
02 01 [INTEGER, length of 1]
09 [user data PCID]
80 [single-asn1-type]
?? [length]