Explanation
This message is issued in response to the following
display commands when the associated device is congested:
- D NET TRL
- D NET,TRL,TRLE=trlename
- D NET,ID=trlename
** CONGESTED *** indicates that the associated
device trlename has an excessive amount of outbound
I/O work that is queued at the Data Link Control (DLC) layer. This
congestion might be related to system storage problems (such as storage
shortages) for this system.
System action
Operator response
When a device is marked congested, further
action is required to determine whether the congestion is related
to a system storage problem. The following steps should be taken:
- Review the system console for any messages related to current
storage shortage conditions.
- Issue the following display commands:
- VTAM® display commands:
- D NET,CSM
- D NET,BFRUSE
- D NET,STORUSE,POOL=*
- TCP/IP display command (if applicable):
- Issue D NET,TRL,TRLE= trlename to obtain more details about the
device congestion (reference message IST1802I).
- Activate VTAM tuning statistics
(TNSTAT) or RMF™ (or other monitoring
tools) to monitor this specific device.
- Display the active jobs in the system to determine whether new
work was recently started.
If the previous steps indicate a system storage shortage
is present, it might be necessary to obtain documentation (such as
a CONSOLE LOG and a DUMP) to diagnose the congestion related to this
device. This condition might be relieved by stopping the device (TCP/IP)
or inactivating the PU (SNA).
System programmer response
The following steps might be required
to isolate a system storage problem that is related to an I/O device:
- Review the network configuration related to this device or any
recent configuration changes for this system.
- Review or monitor (using the output from VTAM TNSTAT or RMF)
the network traffic related to this device. Compare the actual workload
to the I/O capacity of the hardware device.
- Determine if the congestion is related to a specific time of day,
job, application, or type of work load.
- Verify that Missing Interrupt Handler (MIH) is defined for the
write devices.
- Review or verify that the maintenance level for the hardware device
is current.
- Consider automating the necessary storage displays to monitor
system conditions.
Routing code
Descriptor code