Envoy ACP/XF Application Programming Manual

Normal Response Mode (NRM) Protocols
EnvoyACP/XF Application Programming Manual–132179
3-7
Timers and Number of Retries
EnvoyACP/XF retries an operation that times out a maximum of retry count times before
the application process receives an error. Note that if EnvoyACP/XF retries an operation
the maximum number of times without receiving the proper response, EnvoyACP/XF
removes the erroneous WRITE request (and all subsequent pending WRITE requests to
the same station) from the queue and completes them with CCL and file-system error
162.
When EnvoyACP/XF times out on the transmission of an I-frame, EnvoyACP/XF
transmits an RR frame with the P/F bit set (Figure 3-1
). If a response returns,
EnvoyACP/XF retransmits the I-frame. If no response returns, EnvoyACP/XF transmits
another RR frame with the P/F bit set. This process repeats until one of the following
events occur:
•
I-frame is successfully transmitted.
•
I-frame is retransmitted retry count times without a proper response.
•
RR-frame with the P/F bit set is sent retry count times in succession without a
proper response.
If the application process issues an AWAITIO call (that includes a specified time limit)
and the time limit expires before the process has attempted the configured number of
retries, the AWAITIO call may terminate the operation prematurely.
.5 seconds IDLETIME
R
SETMODE
16
For a primary or supervisor
station, T1TIMER determines
the interval between polling
cycles.
Retry count 3 retries L1RETRY SETMODE
15
Determines the retry count for
level-1 error recovery attempts
such as WRITE operation
failures and DSR failures.
L2RETRY SETMODE
15
Determines the retry count for
station protocol-level, error-
recovery attempts, such as
frames not acknowledged and
poll response timeouts.
L2RETRY does not apply to
mode-setting commands
(SNRM, SNRME, SIM, DISC).
Note. Other errors can cause timeouts, so the user application may receive a different error
number, such as error 140 (modem or link error).
Table 3-1. Timers and Number of Retries (continued)
Features
Default
Value Modifier
SETMODE
procedure Description