Envoy ACP/XF Application Programming Manual

Asynchronous Balanced Mode (ABM) Protocols
EnvoyACP/XF Application Programming Manual–132179
2-7
Timers and Number of Retries
Timers and Number of Retries
When transmission errors occur, EnvoyACP/XF always retries the requested operation.
HDLC and ADCCP-ABM use timeouts to detect errors. EnvoyACP/XF supports these
timeouts as follows:
If the T1TIMER elapses before EnvoyACP/XF receives a response to a transmitted
I-frame and if the modifiers L2HEARTBEAT and IDLECMDRR are enabled,
EnvoyACP/XF transmits an RR frame with the P/F bit set (Figure 2-3
) to check that the
other side is alive on the link. If EnvoyACP/XF receives no response, EnvoyACP/XF
sends another RR frame with the P/F bit set, up to retry count times (L2RETRY), at
which point HDLC and ADCCP complete the WRITE operation and return file-system
error 162 (operation timed out).
Features
Default
Value Modifier
SETMODE
procedure Description
Timeout 5 seconds T1TIMER SETMODE 15 Determines the period that
EnvoyACP/XF waits for an
acknowledgment from the remote
station after sending any frame.
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.
Retry count 3 retries 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 (SABM, SABME, 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).