Trouble shooting Management Agent Lost alarms in Spectrum

Products

• DX NetOps

Issue/Introduction

We are seeing Management Agent Lost alarms in Spectrum.

How do we trouble shoot the root cause?

Environment

Release : Any
Component: SpectroSERVER

Cause

Management Agent Lost alarms a asserted when Spectrum loses SNMP contact with a model.

By default, when Spectrum send out an SNMP request to a model, it will wait 3 seconds for a response. If a response is not received within three seconds, Spectrum will resend the SNMP request. Spectrum will resend the SNMP request 3 times by default waiting 3 seconds between retries.

If no response is received from the retries, Spectrum will ping the model. If a ping response is received, Spectrum will assert the Management Agent Lost alarm which indicates the device is still responding to ping but not SNMP.

Some common root causes:

- Spectrum is not using a correct SNMP Community String for this model

- There is an access list on this model preventing Spectrum from getting SNMP

- The is a network latency where the device is responding to SNMP, however, it is taking longer than 3 seconds for the response to reach Spectrum.

- The device is taking longer than 3 seconds to respond to the SNMP request

- The device is to busy to respond to SNMP

Resolution

The BEST tool to trouble shoot a Management Agent Lost alarm is to use a sniffer (Wireshark on Windows. tcpdump on Linux) to sniff the SNMP request leaving the SpectroSERVER to the device and if/how the device is responding.

Then, based on the analysis of the sniffer trace, take appropriate action to correct.