3.9.5.2.2.1 Ringing Primary Targets

If in the processing of the INVITE based on the routing rules, the proxy decides to ring the primary targets, the following actions MUST be taken:

  • If the forward_immediate flag is set in the protocol client flags:

    • The call SHOULD be routed to the destination in the forwardto list or voice mail depending on whether the enablecf flag is set.

    • If a simultaneous_ring target exists, it MUST NOT be honored if the forward_immediate flag is set.

    • If the call was routed to the target in the forwardto list, the call forwarding timer MUST be started. If the call cannot be routed because of the Ms-Sensitivity header field value considerations described in section 3.9.5.2.1, a response indicating failure SHOULD be returned.

  • Otherwise, if the forward_immediate flag is not set in the protocol client flags:

    • The call MUST be forked to the registered endpoints whose address-of-record matches the address-of-record in the Request-URI field.

    • If the simultaneous_ring flag is set, the INVITE MUST be routed to the target specified in the simultaneous_ring list. The proxy MUST then start the registered endpoints timer.