DL_UNITDATA_REQ(7dlpi) DL_UNITDATA_REQ(7dlpi)
NAME
DL_UNITDATA_REQ - Message Type
SYNOPSIS
The message consists of one M_PROTO message block containing
the structure shown below, followed by one or more M_DATA
blocks containing at least one byte 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 {
ulong dl_primitive;
ulong dl_dest_addr_length;
ulong dl_dest_addr_offset;
dl_priority_t dl_priority;
} dl_unitdata_req_t;
DESCRIPTION
Conveys one DLSDU from the DLS user to the DLS provider for
transmission to a peer DLS user.
Because connectionless data transfer is an unacknowledged
service, the DLS provider makes no guarantees of delivery of
connectionless DLSDUs. It is the responsibility of the DLS
user to do any necessary sequencing or retransmission of
DLSDUs in the event of a presumed loss.
Parameters
dl_primitive conveys DL_UNITDATA_REQ.
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_priority indicates the priority value within the supported
range for this particular DLSDU.
Copyright 1994 Novell, Inc. Page 1
DL_UNITDATA_REQ(7dlpi) DL_UNITDATA_REQ(7dlpi)
State
The message is valid in state DL_IDLE.
New State
The resulting state is unchanged.
Response
If the DLS provider accepts the data for transmission, there
is no response. This does not, however, guarantee that the
data will be delivered to the destination DLS user, since the
connectionless data transfer is not a confirmed service.
If the request is erroneous, message DL_UDERROR_IND is
returned, and the resulting state is unchanged.
If for some reason the request cannot be processed, the DLS
provider may generate a DL_UDERROR_IND to report the problem.
There is, however, no guarantee that such an error report will
be generated for all undeliverable data units, since
connectionless data transfer is not a confirmed service.
Reasons for Failure
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_OUTSTATE The primitive was issued from an invalid state.
Mode
Connectionless-mode.
Copyright 1994 Novell, Inc. Page 2