DLC commands are issued through a command control blocks. To issue a DLC command, call the AcsLan function, which receives two pointers to LLC_CCB structures representing command control blocks. The LLC_CCB structure contains information about the command to perform, an optional event handle, and a pointer to a parameter table. The parameter table contains information required by the command. The format of the parameter table varies from command to command.
The DLC commands fall into three functional groups.
Direct Interface Commands
The direct interface enables you to perform control functions on an adapter. It also enables you to open and close an adapter, obtain the error status, and set addresses. The following are the direct interface commands:
| LLC_DIR_CLOSE_ADAPTER |
| LLC_DIR_CLOSE_DIRECT |
| LLC_DIR_INITIALIZE |
| LLC_DIR_INTERRUPT |
| LLC_DIR_OPEN_ADAPTER |
| LLC_DIR_OPEN_DIRECT |
| LLC_DIR_READ_LOG |
| LLC_DIR_SET_EXCEPTION_FLAGS |
| LLC_DIR_SET_FUNCTIONAL_ADDRESS |
| LLC_DIR_SET_GROUP_ADDRESS |
| LLC_DIR_SET_MULTICAST_ADDRESS |
| LLC_DIR_STATUS |
| LLC_DIR_TIMER_CANCEL |
| LLC_DIR_TIMER_CANCEL_GROUP |
| LLC_DIR_TIMER_SET |
DLC (IEEE 802.2) Interface Commands
The DLC interface provides an interface to the logical link control (LLC) sublayer of the DLC protocol. It offers both connectionless and connection-oriented services. The following are the DLC interface commands:
| LLC_DLC_CLOSE_SAP |
| LLC_DLC_CLOSE_STATION |
| LLC_DLC_CONNECT_STATION |
| LLC_DLC_FLOW_CONTROL |
| LLC_DLC_MODIFY |
| LLC_DLC_OPEN_SAP |
| LLC_DLC_OPEN_STATION |
| LLC_DLC_REALLOCATE_STATIONS |
| LLC_DLC_RESET |
| LLC_DLC_SET_THRESHOLD |
| LLC_DLC_STATISTICS |
Transmit and Receive Commands
Data is exchanged between applications on the network in frames using transmit and receive commands. The protocol driver moves the contents of the transmit buffer to the adapter's work space for transmission. The protocol driver receives frames from the network and moves them to the application's buffers. The following are the transmit and receive commands:
| LLC_BUFFER_CREATE |
| LLC_BUFFER_FREE |
| LLC_BUFFER_GET |
| LLC_READ |
| LLC_READ_CANCEL |
| LLC_RECEIVE |
| LLC_RECEIVE_CANCEL |
| LLC_RECEIVE_MODIFY |
| LLC_TRANSMIT_DIR_FRAME |
| LLC_TRANSMIT_FRAMES |
| LLC_TRANSMIT_I_FRAME |
| LLC_TRANSMIT_TEST_CMD |
| LLC_TRANSMIT_UI_FRAME |
| LLC_TRANSMIT_XID_CMD |
| LLC_TRANSMIT_XID_RESP_FINAL |
| LLC_TRANSMIT_XID_RESP_NOT_FINAL |