communication lost

[DCIM_Support]

I am getting communication lost then restored alerts multiple time a day.  No other problems on network.

All other UPS have no problems.

Alert   Title:	Data   Center 40K UPS(192.168.20.232) - communication lost
Alert   Description:	Communication with 'Data Center 40K UPS(192.168.20.232)' has been lost.
Alert   Type:	Communication   Lost
Severity:	Failure
Alert   Level:	Email   action
Device:	Data   Center 40K UPS(192.168.20.232)
Time   Detected:	03/10/2016   09:20:34 am
Notification   Time:	03/10/2016   09:20:34 am
Action   Name:	Email   action
Location:	Data   Center
Primary   Contact:	ITS
Notes:	APC   Web/SNMP Management Card (MB:v4.1.0 PF:v6.3.2 PN:apc_hw05_aos_632.bin   AF1:v6.3.3 AN1:apc_hw05_sy3p_633.bin MN:AP9630 HR:05 SN: 5A1420T22114   MD:05/18/2014) (Embedded PowerNet SNMP Agent SW v2.2 compatible)
Alert   ID:	nbErrorCond_81CED112
Version:	7.2.6.24

(CID:105468389)

[DCIM_Support]

I get the same thing from time to time.  It seems to come and go.  Mine come from a remote 40K UPS that is monitored via a 45mb/s WAN link.  Does yours trigger all the time, or does it appear to be random?  If I remote into the IP address of the management interface of the UPS, it responds just fine, and then DCE stops alerting on it for a while.

Brian R.

(CID:105468392)

[DCIM_Support · Accepted solution]

Hi Jeffrey,

K-base FA226273 goes over a good deal of information and troubleshooting for SNMP communications issues. Intermittent issues can be some of the more difficult to diagnose. I would suggest first looking at the NMC itself to see if there are any issues shown in it's event log. If you can match the lost comms times with specific events on the device, perhaps it is unavailable when DCE is trying to poll it. You may also want to try and poll that same device when it is showing a lost comm.

Is the issue happening for an extended period of time or is it only for a 5 minute event? If your polling time is set to 5 minutes and it is just a single polling cycle, it is possible increasing timeouts and retries will help. Is this the only device with the issue? Is this device on the DCE private LAN? If there is a public and private LAN on this DCE system, are they both using the 192.168 IP scheme?

Steve

(CID:105468393)

[DCIM_Support]

Adjusting timeouts and retries seems to have solved it. No alarms since change. Crossing fingers! Jeff

(CID:105468492)

[DCIM_Support]

Hi Steven,

we have also getting the same error but only from particular model , to clear this  alarm we are resting the management interface of that ups for temp solution. I Would like to know what timeout and retries you are suggesting to a good monitoring.

 currently we are in time out of 5 Sec.

(CID:106210059)

[DCIM_Support]

Hi KKH,

Normally timeouts and retries of 5 seconds and 3 retries is good enough. If the comm is lost and does not regain until you reset the management interface on the device, it sounds like it is the device's SNMP stack hanging and these settings would make no difference. 

What device is it (APC, 3rd party, etc)?

When the device is in lost comm, have you tried polling it using another SNMP utility?

Is the firmware up to date?

Are you using SNMP version 1 or version 3?

There may be other pertinent questions but I'd start looking at these.

Steve

(CID:106210097)

[DCIM_Support]

Remember SNMP is a UDP connection, discard eligible.  check your wan links/network traffic to see if there has been a spike .  if on a wan link check router logs to see if there are any routing flaps this coincide with the loss of comm.

(CID:106891010)

[DCIM_Support]

We seem to have a similar issue. To safely edit the SNMP configs/settings, would it be possible for you guys to send me a link so that i can confirm what i am changing is correct.

Note, i only want a certain group of devices that we monitoring over the WAN to effect these changes.

Kind regards

(CID:110006161)

[DCIM_Support]

Hi Yusef, What exactly are you looking to change? If you're looking to change SNMP configurations on the devices, you need to go to the device if it's a non-APC device. f it's an APC device, you need to go to APC SNMP Device Configuration. You can change settings on one, many, or all devices here. This assumes of course that you have FTP or SCP communications with the devices and have not lost that communications option as well. device File Transfer settings can be altered if FTP/SCP configurations in DCE are failing to communicate with the APC devices. If you're looking to change the way DCE communicates with devices, changing community names as I just noted also changes the community names DCE uses to communicate with the devices. If you just want to change the community names DCE uses, go to SNMP device scan settings and you can change community names DCE uses to communicate with the device. If you're asking something else, again, please specify. Steve.

(CID:110006176)

[DCIM_Support]

We seem to have a similar issue. To safely edit the SNMP configs/settings, would it be possible for you guys to send me a link so that i can confirm what we editing is correct. Note, i only want a certain group of devices that we monitoring over the WAN to effect these changes. Kind regards

(CID:110006164)

[DCIM_Support]

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