User`s guide

4: ADCCP NRM Operations
DC 900-1317J 95
On the other hand, if a primary station only periodically polls its secondary stations and
withholds I-frame acknowledgment until after the secondary station sends its final
frame, a maximum transmit window size of 7 may not be sufficient to utilize the link. If
the application uses a satellite relay in a geosynchronous orbit, a 0.25-second propaga-
tion delay occurs each way, and acknowledgment of data reception is delayed at least 0.5
second. In these cases, ADCCP option 10 may be required to allow the use of a large
enough transmit window to compensate for delays in I-frame acknowledgment.
4.3 Handling Special Conditions
The client application must implement logic to correctly handle special conditions
reported by the ICP. This includes handling
DLI_PROT_RESP_UNBIND_ACK,
DLI_PROT_RECV_STATION_RESET, and DLI_PROT_RECV_LINK_EXCEPTION packets.
The client application must also process other packets associated with specific enabled
ADCCP options. For example, ADCCP option 1 allows
DLI_PROT_RECV_EXCHANGE_ID
packets, option 4 allows DLI_PROT_RECV_UNNUMBERED_DATA packets, and option 5 allows
both
DLI_PROT_RECV_STATION_INIT and DLI_PROT_RECV_UNFORMATTED_DATA packets.
4.3.1 ICP Station Inactive Condition
The client application may receive an unsolicited DLI_PROT_RESP_UNBIND_ACK packet at
any time. This event may occur for any of the following reasons:
• A remote primary or combined station sends DISC, and the ICP replies UA
• A remote secondary station sends RD, and a DISC/UA exchange follows
• A remote secondary station sends DM
Once the ICP reports a station inactive, the station remains inactive unless the client
application successfully re-enables it. As a minimum, the client application should
assume that all unacknowledged data remains unacknowledged and either initiate
higher level data recovery procedures or report an application-level error.