Basic Configuration Example
You need to configure both ingress trunk and egress trunk in order for the switch to sign calls with your Stir/Shaken certificate.
Ingress Trunk's Stir/Shaken configuration instructs the switch on "HOW" to sign the call.
Egress Trunk's Stir/Shaken configuration tells the switch "WHEN" to sign the call.
Most of the times, you want to use the most simple configuration, which is to have the switch to sign only incoming calls that are not previously signed by ingress clients.
In this case, you will configuration your ingress trunk as shown below:
The above configuration will sign all calls from a valid US caller ID.
Then, you will configure egress trunk to sign only calls that are not already signed.