Dial Plan Transparency

Last Updated : Sep 29, 2026 |
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Dial Plan Transparency (DPT) preserves the dial plan when a gateway registers with a Survivable Remote server or when a port network registers with a Survivable Core server. Port network registers with a Survivable Core server due to the loss of contact with the primary controller. DPT establishes a trunk call and reroutes the call over the PSTN to connect endpoints that can no longer connect over the corporate IP network.
You need not activate DPT in the license file. DPT is a standard feature in Communication Manager Release 4.0 and later. DPT is similar to IGAR as both provide alternate call routing when normal connections are unavailable. A major difference is that DPT routes calls between endpoints that two independent servers control. IGAR routes calls between endpoints that a single server controls. The DPT and IGAR features are independent of each other, but you can activate both simultaneously.
Limitations of DPT:
  • DPT only handles IP network connectivity failures between network regions.
  • DPT calls are trunk calls. Therefore, Communication Manager does not support many station features.
  • For Release 4.0, DPT applies only to endpoints that are dialed directly. DPT cannot route redirected calls or calls to groups.
  • DPT cannot reroute calls involving a SIP endpoint that has lost registration with the Session Manager.
  • DPT works only when failover strategies for gateways and port networks, and alternate gatekeeper lists for IP stations are consistent.
For information about administering DPT, see Administering DPT.