Configuring PSTN Fallback
You can enable CRP to route emergency calls (or PSTN-intended calls) such as "911" from the Proxy server (IP Group #2 "CRP Proxy") to the PSTN (IP Group #3 "CRP Gateway"). In addition, for calls from the Proxy server to Users (IP Group #1 "CRP Users"), the device searches for a matching user in its Users Registration database and if not located, it sends the call to the PSTN (IP Group #3 "CRP Gateway") as an alternative route.
| ➢ | To enable CRP Gateway fallback: |
| 1. | Open the SBC General Settings page (Setup menu > Signaling & Media tab > SBC folder > SBC General Settings). |
| 2. | From the 'CRP Gateway Fallback' drop-down list, select Enable. |
| 3. | Click Apply; the alternative routing rule is added to row index #7 ("CRP Proxy" to "CRP Gateway" routing) in the IP-to-IP Routing table. |
| ● | Enabling this feature (this routing rule) may expose the device to a security "hole", allowing calls from the WAN to be routed to the Gateway. Thus, configure this feature with caution and only if necessary. |
| ● | This PSTN routing rule is not an alternative routing rule. In other words, if a match for a user is located in the database, this PSTN rule will never be used regardless of the state of the user endpoint (e.g., busy). |