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Technical Reference: Communications, Volume 1
DL_TEST_REQ Primitive
Purpose
Conveys one test-command data link service data unit
(DLSDU) from the data link service (DLS) user to the DLS provider for transmission
to a peer DLS provider.
Structure
The message consists of one M_PROTO message block, which contains the following structure, followed by zero
or more M_DATA blocks containing zero or more bytes
of data:
typedef struct
{
ulong dl_primitive;
ulong dl_flag;
ulong dl_dest_addr_length;
ulong dl_dest_addr_offset;
} dl_test_req_t;
Description
The DL_TEST_REQ primitive conveys
one test-command DLSDU from the DLS user to the DLS provider for transmission
to a peer DLS provider.
A DL_ERROR_ACK primitive is always
returned.
Note
This primitive applies to XID and test operations.
Parameters
dl_primitive |
Specifies the DL_TEST_REQ primitive. |
dl_flag |
Indicates flag values for the request as follows:
- DL_POLL_FINAL
- Indicates whether the poll/final bit is set.
|
dl_dest_addr_length |
Specifies the length of the data link service access point (DLSAP)
address of the destination DLS user. If the destination user is implemented
using the Data Link Provider Interface (DLPI), this address is the full DLSAP
address returned on the DL_BIND_ACK primitive. |
dl_dest_addr_offset |
Indicates where the destination DLSAP address begins. The value of
this parameter is the offset from the beginning of the M_PROTO message block. |
States
Valid |
The primitive is valid in the DL_IDLE or DL_DATAXFER state. |
New |
The resulting state is unchanged. |
Acknowledgments
Unsuccessful |
The DL_ERROR_ACK primitive is returned for
an invalid test-command request. |
Note
It is recommended that the DLS user use a timeout procedure
to recover from a situation when the peer DLS user does not respond.
Error Code
DL_OUTSTATE |
The primitive was issued from an invalid state. |
DL_BADADDR |
The DLSAP address information was invalid or was in an incorrect
format. |
DL_BADDATA |
The amount of data in the current DLSDU exceeded the DLS provider's
DLSDU limit. |
DL_SYSERR |
A system error has occurred. The system error is indicated in the DL_ERROR_ACK primitive. |
DL_TESTAUTO |
Indicates the previous bind request specified automatic handling
of test responses. |
Related Information
The DL_BIND_ACK primitive, DL_ERROR_ACK primitive.
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