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Chapter 2. Host Software Component Functions 73
1st ed., 6/30/04 - 312579601
Recovering TCP/IP Communications
StorageTek suggests either performing a normal HSC shutdown or changing the
HSC state to the base service level prior to recycling TCP/IP or taking TCP/IP down
for any extended period of time.
Note: Please refer to “Recovery Maintenance Requirements” on page 70 to see PTFs that
must be applied before recovery processes discussed in this section can be implemented.
Unlike 3270 station protocol, TCP/IP station protocol requires the socket interface to be
reopened (restarted) by the HSC before communication to the LMU can be reestablished.
If the LMU station connection is lost, the HSC begins network recovery to the station.
During recovery, the HSC continues trying to reestablish the connection between its
socket and the remote station socket every 10 seconds for 30 minutes. Once the network
problem is resolved, the next time the HSC attempts network connectivity, it reestablishes
communication to the LMU.
Note: When 30 minutes is exceeded, no further reconnection attempts are made, and
operator intervention is required.
In a dual LMU environment, users can switch to the standby station if other host
processing is not greatly impacted. If connectivity is lost to both LMU stations, network
recovery is simultaneous.
When the HSC detects TCP/IP interface errors or timeout conditions, message SLS6012E
is issued.
SLS6012E ACS AA recovery of network connection to station C...C is now
active
When the HSC successfully recovers network connectivity, message SLS6013I is issued
and all outstanding LMU requests are redriven.
SLS6013I ACS AA recovery of network connection to station C...C
successful
If the HSC network recovery times out, message SLS6014E is issued, the station is
considered in error, no further reconnection attempts are made, and operator intervention
is required.
SLS6014E ACS AA unable to reestablish connection to station C...C
Caution: During network recovery or timeout situations, only use the Display Acs
command to view ACS and station status. The Display Cap and Display LSM commands
involve LMU requests and will not execute.