The equipment switch reason reflects the reason why the last switch occurred.

EswitchReason can take the following values:
- "NA", is used, if a more precise value is not available.
- "E_FAILURE", is used when an instance of equipment has failed.
- "MANUAL", indicates a switch that was requested by the operator and includes forced switches.

Readable by NMS? Yes
Writeable by NMS? No
Invariant? No
