In the section "Deploying Variable-Length On-Net Dial Plans with Flat Addressing"
in the subsection "Outgoing PSTN and IP WAN Calls"
It states "Option 1: Eight-Digit Numbers Only
This option relies on a single route pattern that matches all eight-digit ranges (8XXXXXXX) and points to a route list or route group that contains only a gatekeeper-controlled intercluster trunk. The gatekeeper is configured to use the site codes as zone prefixes.
This solution is simple and easy to maintain because no information is needed about other clusters' site codes or E.164 ranges. However, no automatic PSTN failover is provided when the IP WAN is unavailable, and users are expected to redial manually using the PSTN access code and the E.164 address of the destination"
My question why it can not automatically re-route to PSTN if IP wan is down, can't we just the route list to include gk as the 1st rg and local pstn as 2nd rg as we do usually?