CER - Switch Changes That Affect CER

[RL5901]

CER System Version: 11.5.4.50000-6

Single appliance implementation (no HA). 

Switch model 3850

This is my first year working with Cisco Emergency Responder (10 months, so far). I have found that it can be rather finicky and is high maintenance. Does anyone know of a document that lists what changes to a switch will cause CER to lose the ERL assigned to the switch and/or ports? I have found through experience that the following changes to a switch may drop the ERL association in CER:

* IOS upgrade/change - always disassociates the ERL, sometimes drops the communication between the switch and CER (switch disappears under "Switch Port Details")

* adding a switch to a switch stack - either disassociate the ERL or drops the communication between the switch and CER altogether (disappears under "Switch Port Details")

* changing the hostname of a switch - sometimes drops the communication between the switch and CER altogether (disappears under "Switch Port Details")

The switches in our environment are using a configuration template that standardizes the config. We standardized our IOS on our switches, as well. 

I have not found any correlation between the switch IOS version and any of the above situations, and with SNMP the IOS should not matter. 

[Chris Deren]

I have never seen these issues you list nor should that be expected behavior unless you encounter a software bug.  If a switch model and IOS version is compatible with the CER version theses changes should not affect CER configuration.  Have you tried scanning through Cisco bug toolkit?  Did you review CER logs for clues after this happened? Those logs are very good and detailed and should provide some clues.

[RL5901]

I assumed this was normal behavior for CER. This behavior is reproducible every time.

I can understand that this behavior may be expected if we swap one switch for another of a different model (the sysOID will be different for different models). I am surprised when changes occur that do not change the sysOID (e.g., IOS upgrade, adding a new switch to a switch stack). But you're saying this is also not normal behavior if both switch models are compatible with CER (which they are). 

My daily routine involves reviewing Event Viewer logs for switches that fall out of CER (I also have alerts sent to my email inbox). My workaround has been to remove/add the switch(es) that fall out of tracking and this happens at least once a week. 

I found this doc on How to Collect Logs for CER. Now that I know this is not normal behavior for CER I will dig deeper into why this is happening. Thank you, Chris. 

[RL5901 · Accepted solution]

It's possible that we're hitting this Bug CSCvo82994. 

Bug Id: CSCvo82994
Title: CER is not updating switch information, if we change the same IP/Hostname to other model switch
Status: Open
Severity: 6 Enhancement
Description: Symptom:
Unable to discover new switch hardware using the same IP and hostname as the original hardware unless the original entry is deleted first. Error "CoreSortSeedDevices isSuccefullyAddedInD This Device is earlier discovered as C3750"

Conditions:
Existing 3750 switch will be replaced by a new 9300, using the same IP and Hostname. Customer must delete the old switch entry add a new entry for the replacement switch since the OID and config are stored in cache. CER will see an OID mismatch and throw an error ?CoreSortSeedDevices isSuccefullyAddedInD This Device is earlier discovered as C3750?. The new switch and phones will not be recognized until a Selective Discovery is run or Major Discovery occurs at midnight. Selective discovery cannot be run while a Major Discovery or Incremental Discovery is in progress.

Workaround:
Delete the original switch entry. Recreate the switch entry with the same IP and hostname and new switch hardware.
Replace switch hardware.
Run selective discovery immediately or complete the first two steps for all new hardware prior to the Major Discovery.

[scheived]

I found this issue still happends on version 14, running switch-port and phone update does nothing. After a reboot of CER it then started tracking phones on the replaced switches.

[RL5901]

That is good to know because we are planning to upgrade to version 14 soon.