Requests data to be transmitted to a specified signaling point.
DWORD NMSAPI MTP3SendData ( CTAHD ctahd, S16 sapId, U32 opc, U32 dpc, U8 lnkSel, U8 priority, U8 *data, S16 length, U8 srvInfo)
Argument |
Description |
ctahd |
Natural Access handle. |
sapId |
Service access point ID. Specify the same value used for ctaOpenServices. |
opc |
24-bit, 14-bit, or 16-bit originating point code to be inserted in the outgoing message. |
dpc |
24-bit, 14-bit, or 16-bit destination point code of the remote system. |
lnkSel |
Link selector used by MTP 3 to choose the link to send data over. Valid ranges are 0 through 15 for ITU-T and 0 through 31 for ANSI. |
priority |
Priority of the message. Valid range is 0 (lowest) through 3 (highest). |
data |
Pointer to the address of a buffer of data to transmit. |
length |
Length (in octets) of the data in the data field. |
srvInfo |
Service information octet (SIO) in which the application is interested. |
Return value |
Description |
MTP3_SUCCESS |
|
MTP3_INVBOARD |
Invalid board number. |
MTP3_NOT_BOUND |
ctaOpenServices not previously called. |
MTP3_OSERROR |
Lower-level drivers or task returned an error. |
MTP3_RESOURCE |
Host running out of buffers to send to the board. See the Details section for more information. |
Both opc and dpc are passed as 32-bit values. For example, the 24-bit point code 5.49.7 is passed as 0x053107.
For TUP only, all 8 bits are available to the application with no lnkSel range checking. For more information, refer to Outbound messages.
The user data sent is unique. The first byte corresponds to the first byte following the routing label in the underlying SS7 data message. For example, when constructing an ISUP message, the first byte of user data is the first byte of the circuit identification code (CIC). The MTP layer 3 constructs the routing label and SIO values from other parameters and bind information. The user application is responsible for any byte-order translation necessary for all data in the data field.
The SIO must be unique for each application. The service information field is composed of service indicator and network indicator fields. Only the service indicator field is used for routing of incoming messages.
If you receive an MTP3_RESOURCE error, perform one or more of the following tasks:
Increase the number of host buffers in ctaOpenServices. See Using ctaOpenServices.
Monitor MTP3EVN_CONGEST indications to determine when the number of available buffers is running low. Traffic could then be throttled before the buffer pool is exhausted. See Controlling congestion.
Reduce other host to board traffic, including management function traffic.
For more information, see Transferring data.