Dial Plan

The Dial Plan is primarily intended for routing outbound calls if the Internet Gate is used as the SIP Server for the callers domain. If another SIP Server is used (the domain of the Request-URI) the call will automatically route to that server and the dial plan is not likely needed (however the Internet Gate can be configured to apply the dial plan to such calls as well).

When a call is processed in the dial plan, the table is scanned from top to bottom and the first line matching the callee and caller addresses/numbers is used for routing and policy decisions.

The dial plan can for example be used for:

Route certain calls to a PSTN service
Least Cost Routing (based on called numbers)
Secondary routes when the primary fails
SIP trunking, route calls through an internal B2BUA as a demarcation point or for interoperability reasons
Sharing a SIP ITSP account among many users
Add or remove leading digits in the called telephone number
Make ENUM lookups on the called number (find a SIP endpoint instead of routing a call to a PSTN service)

The following picture shows emergency number routed via SIPTRUNK1. Anonymous calls getting a #31# prefix. E.164 formatted numbers are changed to swedish national/international prefixes. Least cost routing, some international calls are routed via SIPTRUNK3, while national calls are routed using SIPTRUNK1. ENUM lookups performed prior to routing the call via the SIP trunks to search for alternative (non-cost) routes.

To be able to use the Dial Plan you need to purchase a license.