I had a conversation recently with one of our clients about what alarms the Metaswitch Call Feature Server (CFS) would produce if 911 calls were failing.
The simple answer is that if a trunk is out of service then that trunk would go into alarm, but later I started wondering whether we could do a better job of highlighting failures on 911 emergency calls.
So in this short article I wanted to throw out an idea for using Metaswitch threshold alarms on 911 trunk groups to give extra attention to any issues with 911 calls.
The Metaswitch statistics database allows you to configure specific warning levels or thresholds for a whole bunch of statistics – and configure the CFS to raise an alarm if that statistical value falls outside the acceptable thresholds.
These can be found by clicking on the statistics button on any SIP trunk or ISUP/MF media channel. From there you click on the configuration button (top right) and then use the “override defaults” option for the specific statistics of interest.
My idea is to set a few aggressive threshold alarms on the specific trunk groups that are used for 911 calls so your technicians can be quickly notified of any 911-related issues.
Suggested 911 warnings
This is a new idea, so I’m open to other suggestions, but I’m proposing setting the following threshold alarms on 911 trunks.
- Call appearances currently available: alarm if lower than 1
- Rejected circuit requests (per hour): alarm if higher than 1*
- Unconnected calls (failures) (per hour): alarm is higher than 0
Obviously you may want to change these values a little depending on your network and the frequency of 911 calls, but since many independent telcos have just a couple of 911 circuits and infrequent calls it would be useful to get an alarm for any failure, or anytime the number of circuits available drops to zero.
Note that the alarm itself wouldn’t tell you what was wrong – just that the threshold has been breached, so if an alarm is raised, you’d want to search for 911 calls in Metaswitch Service Assurance Server to figure it out.