Echelon OpenLDV - Manual (Page 86)

78 Sending and Receiving Messages with the OpenLDV API
enumeration type definition NI_QueueCmd used in the field NI_Hdr.q.q_cmd of
the application layer header, and the queue codes are defined by the enumeration
type definition NI_Queue used in the field NI_Hdr.q.queue. The OpenLDV
Developer Example contains a utility function, COpenLDVni::msgHdrInit(),
that computes the correct value for the command/queue byte based on the
address type (local or remote), the service type, and the priority attribute of the
message.
Literals for the supported immediate commands are defined in the OpenLDV
Developer Example by the enumeration type definition NI_NoQueueCmd used
in the field NI_Hdr.q of the application layer header.
Table 33. Network Interface Commands
Network Interface
Command Value Direction Description
niL2_INCOMING 0x1A Uplink Specifies a Layer 2 incoming
packet.
niL2_INC_M1 0x1B Uplink Specifies a Layer 2 Mode 1
incoming packet.
niL2_INC_M2 0x1C Uplink Specifies a Layer 2 Mode 2
incoming packet.
niCOMM + niTQ 0x12 Downlink Used for downlink non-priority
messages using acknowledged,
request and repeated services. For
Layer 2 devices, also used for
unacknowledged messages.
This command specifies niCOMM
(for messages sent to and received
from the network) as the queue
value and niTQ as the command
value.
Applies to Layer 2 or Layer 5
devices. The command format is
different for Layer 2 and Layer 5.