/mcpSource: Cisco Unified Border Element Configuration Guide - Cisco IOS XE 17.6 Onwards In addition to voice class URI, administrators can use a dial-peer provision-policy (DPP) to match an in-leg URI for an outbound dial-peer match. This feature was added in Cisco IOS 15.4(2)T and Cisco IOS XE 3.12S. A dial-peer provision-policy requires defining a primary match attribute with a secondary match attribute being optional. The provision-policy is applied to an inbound dial-peer, and when that dial-peer is selected for use on an inbound call-leg, the policy is invoked. The result is an outbound dial-peer selection based on the attribute from the dial-peer provision-policy. The outbound match can be a single header or multiple headers which all must be true in order to match the dial-peer. In the example, there is a voice class uri for the From and To headers. For an OR match, a dial-peer provision-policy is configured which contains two preferences. The From header is the first preference, and the To header is the backup preference. Dial-Peer 1234 is built to apply the provision policy for inbound matching. Then built dial-peer 11111 and 22222 which apply the destination uri-from and destination uri-to commands respectively. These commands point back to their voice class URI. For the call, you can receive the Invite, match dial-peer 1234 and check the provision-policy. The device can then try to route on the From header first which as an applicable match on dial-peer 11111. If this fails, you can also try to route on the to header with 22222. The example also details how to achieve an And match with dial-peer provision-policies. Assuming the same Invite is received, you can define two headers under one preference and apply this to the inbound dial- peer. Now when the invite is received, it can check for eligible outbound dial-peers which satisfy both matching criteria defined in the provision-policy. So in this example, your outbound dial-peer needs to be defined with both the TO and FROM header in order to be matched. If either are not a valid match, this dial-peer 12345 is not used.