Appendix C Application Programmer’s Interface 93
Call Setup

Tomake a call, send a SETUP message down to Q.93B and wait for a SETUP_ACK

from Q.93B. The SETUP message should include a Broadband Higher Layer

Information (BHLI) information element that contains a four-octet SAP identified as

User Specific Information. The SAP is used to identify the application on the

receiving host to which the Q.93B should direct the message. After receiving a

SETUP_ACK with a 0 error field, wait for a CALL_PROCEEDING, ALERTING,

TABLEC-3 qcc Functions
Name Functionality Input Output
qcc_bld_* Createsand encodes a message;
enables customization of a limited
set of values, depending on the
message type. Configurablevalues
arepassed in as parameters.
Parameter values Encoded Q.2931
message(in the format
shown in FIGUREC-2)
qcc_parse_* Extracts a definedset of values
froman encoded message Encoded Q.2931 message
(in the format shown in
FIGUREC-2)
Parameter values
qcc_len_* Returnsthe maximum length of the
bufferthat should be allocated for
the second strbuf in a Q.2931
message. Only applicable to user
space applications; the kernel API
allocates the buffersinside the
qcc_bld/qcc_pack functions.
none Maximumlength of
the message
qcc_create_* Createsa message structure with
the requiredvalues set. You can
further customize the structure
using qcc_set_ie.
Default parameter values Message structure
(definedin
<atm/qcctypes.h>)
qcc_set_ie Updates or inserts values for an
informationelement into a message
structure.
Message structureand IE
structure(defined in
<atm/qcctypes.h>)
Updated message
structure
qcc_pack_* Takesa message structure and
encodes it into an actual Q.2931
message, consisting of the two
mblks (or strbufs) illustrated in
FIGUREC-2.
Message structure(defined
in <atm/qcctypes.h>)Encoded Q.2931
message(in the format
shown in FIGUREC-2)
qcc_unpack_* The reverseof qcc_pack_*: takes
an encoded message and decodes
the data into a message structure.
Encoded Q.2931 message
(in the format shown in
FIGUREC-2)
Message structure
(definedin
<atm/qcctypes.h>)