1. A PUCI (protection against unsolicited communication for internet protocol multimedia subsystem) system including: a call session control function (CSCF) implementing a PUCI-aware routing logic; and a plurality of PUCI application servers with a dynamic call routing function based on PUCI information included in a signaling message included in an IMS (an IP multimedia subsystem) header of a SIP message or a SIP (a signal initiated protocol) header of the SIP message, wherein the CSCF causes each PUCI application server of the plurality of PUCI application servers, including a first PUCI application server, to perform an evaluation as to whether a received communication from a user equipment is regarded as an unsolicited communication, wherein the CSCF determines routing toward a second PUCI application server selected from among the plurality of PUCI application servers in accordance with the PUCI-aware routing logic when the received communication is regarded as the unsolicited communication, and wherein the evaluation as to the unsolicited communication is performed via each of the plurality of PUCI application servers until the CSCF is able to finalize the routing, thus dynamically chaining the plurality of PUCI application servers via the routing, wherein the evaluation is performed using a two-staged PUCI testing process comprising: forwarding an INVITE from the user equipment to the CSCF; executing a PUCI service in the CSCF; forwarding the INVITE in light of an initial filter criteria from the CSCF to the first PUCI application server; executing a first PUCI test in the first PUCI application server, thus producing a first PUCI score indicating a probability of occurrence of an unsolicited call; sending back the INVITE including the first PUCI score from the first PUCI application server to the CSCF; evaluating the first PUCI score so as to forward the INVITE to the second PUCI application server subjected to a second PUCI test; executing the second PUCI test in the second PUCI application server, thus producing a second PUCI score indicating a secondary probability of the occurrence of the unsolicited call; sending back the INVITE including the second PUCI score from the second PUCI application server to the CSCF; and evaluating the first PUCI score and the second PUCI score so as to reject the unsolicited call, wherein comparison of a value of a test result from a previous application server to a threshold value results in the PUCI information as the test result, and resulting in selection of a new application server, based on one or more of an operator policy and a customer policy, the PUCI information indicating a probability of unsolicited communication.