HP 800 HP DLPI Programmer's Guide - Page 105

Chapter 2 DLPI Primitives Connectionless-mode Service Primitives Connectionless-mode Service Primitives This section describes the connectionless-mode service primitives. DL_UNITDATA_REQ Conveys one DLSDU from the DLS user to the DLS provider for transmission to a peer DLS user. DLPI requires applications using this primitive to run as root. 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. Format 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; Parameters dl_primitive DL_UNITDATA_REQ dl_dest_addr_length 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 105