User`s guide

3: ADCCP NRM DLI Functions
DC 900-1317J 63
NRM secondary station and the station’s transmit window is still open, the ICP trans-
mits the data in a response I-frame with the F-bit reset to zero.
For NRM primary stations, bits 1 and 2 in the iProtModifier field indicate the frame
addressing mode requested by the client. If both bits 1 and 2 are reset to zero, the ICP
uses normal individual station addressing. If bit 1 is set to one and bit 2 is reset to zero,
the ICP uses selective broadcast addressing. If bit 1 is reset to zero and bit 2 is set to one,
the ICP uses general broadcast addressing. If both bits 1 and 2 are set to one, the ICP
returns a
DLI_PROT_RESP_ERROR packet to the client.
When selective or global addressing is used, the client must specify the link ID and zero
the station ID, since the data is intended for multiple stations on the link. Prior to using
the selective broadcast addressing mode, the client must set the multipoint list (see
Section 3.4.13).
The ADCCP protocol does not define data flow control for unnumbered information
frames. Therefore, the client is responsible for not swamping the ICP with
DLI_PROT_SEND_UNNUMBERED_DATA packets. If the client does overload the ICP, the ICP
simply stops accepting input from the client; the client cannot send additional control
packets to the ICP until the ICP’s buffer congestion clears. If buffer congestion occurs
on the ICP, an application in the client attempting to write a control packet to the ICP
experiences delayed I/O completion, but no packet is actually lost.
3.4.11 DLI_PROT_RECV_UNNUMBERED_DATA Packet
This packet is valid only if the client has enabled ADCCP option 4 (see Section 3.4.20.2)
for the specified station. The ICP specifies the
usProtCommand field
(
DLI_PROT_RECV_UNNUMBERED_DATA), the iProtModifier field, the link ID, the
usProtXParms[0] field (station ID), the usProtXParms[1] field (data size), and the data
field contents.
For NRM secondary stations, bits 1 and 2 in the iProtModifier field indicate the frame
addressing mode used. If both bits 1 and 2 are reset to zero, normal individual station