NAME

DL_DATA_ACK_REQ (dl_data_ack_req_t) - this request is passed to the Data Link Provider to request that a DLSDU be sent to a peer DLS User using acknowledged connectionless mode data unit transmission procedures.

SYNOPSIS

Consists of one M_PROTO message block containing the structure shown below, followed by one or more M_DATA blocks containing one or more bytes of data. The amount of user data that may be transferred in a single DLSDU is limited. This limit is conveyed by the parameter dl_max_sdu in the DL_INFO_ACK primitive.

typedef struct {
    t_uscalar_t  dl_primitive;
    t_uscalar_t  dl_correlation;
    t_uscalar_t  dl_dest_addr_length;
    t_uscalar_t  dl_dest_addr_offset;
    t_uscalar_t  dl_src_addr_length;
    t_uscalar_t  dl_src_addr_offset;
    t_uscalar_t  dl_priority;
    t_uscalar_t  dl_service_class;
} dl_data_ack_req_t;

PARAMETERS

dl_primitive

conveys DL_DATA_ACK_REQ

dl_correlation

conveys a unique identifier which will be returned in the DL_DATA_ACK_STATUS_IND primitive to allow the DLS User to correlate the status to the appropriate DL_DATA_ACK_REQ primitive.

dl_dest_addr_length

conveys the length of the DLSAP address of the destination DLS User. If the destination user is implemented using DLPI, this address is the full DLSAP address returned on the DL_BIND_ACK.

dl_dest_addr_offset

conveys the offset from the beginning of the M_PROTO message block where the destination DLSAP address begins.

dl_src_addr_length

conveys the length of the DLSAP address of the source DLS User.

dl_src_addr_offset

conveys the offset from the beginning of the M_PROTO message block where the source DLSAP address begins.

dl_priority

indicates the priority value within the supported range for this particular DLSDU.

dl_service_class

specifies whether or not an acknowledge capability in the medium access control sublayer is to be used for the data unit transmission.

DL_RQST_RSP

request acknowledgement service from the medium access control sublayer if supported

DL_RQST_NORSP

no acknowledgement service requested from the medium access control sublayer.

STATE

This message is valid in state DL_IDLE.

NEW STATE

The resulting state is unchanged.

RESPONSE

If the request is erroneous, message DL_ERROR_ACK is returned, and the resulting state is unchanged. If the DLS Provider accepts the data for transmission,a DL_DATA_ACK_STATUS_IND is returned. This indication will indicate the success or failure of the data transmission. Although the exchange service is connectionless, in-sequence delivery is guaranteed for data sent by the initiating station.

ERRORS

DL_BADADDR

The destination DLSAP address was in an incorrect format or contained invalid information.

DL_BADDATA

The amount of data in the current DLSDU exceeded the DLS provider's DLSDU limit.

DL_NOTSUPPORTED

Primitive is valid, but not supported.

DL_OUTSTATE

The primitive was issued from an invalid state.

DL_UNSUPPORTED

Requested service or priority not supported by Provider (Request with response at the Medium Access Control sublayer).