A method for screening Diameter messages within a Diameter signaling router, DSR, having a distributed message processor architecture, the method comprising: at a DSR comprising a plurality of Diameter message processors (204, 206, 208), each configured to perform at least one Diameter function: receiving, at an ingress Diameter message processor of the Diameter message processors, a Diameter message from a Diameter peer node; identifying, at a Diameter application message processor of the Diameter message processors, a Diameter message screening rule associated with the received Diameter message, wherein the identified Diameter message screening rule specifies a maximum receipt rate for Diameter messages associated with the Diameter message screening rule; and performing, at the Diameter application message processor of the Diameter message processors, a screening function associated with the identified Diameter message screening rule on the received Diameter message, wherein performing the screening function on the received Diameter message includes recording or updating one or more usage or measurement statistics associated with the identified Diameter message screening rule to account for the received Diameter message, wherein recording or updating the one or more usage or measurement statistics includes adjusting a current receipt rate of Diameter messages associated with the identified Diameter message screening rule to account for the received Diameter message, and; performing the screening function on the received Diameter message further includes performing an additional screening function in response to the current receipt rate of Diameter messages associated with the identified Diameter message screening rule exceeding the specified maximum receipt rate. at a DSR comprising a plurality of Diameter message processors (204, 206, 208), each configured to perform at least one Diameter function: receiving, at an ingress Diameter message processor of the Diameter message processors, a Diameter message from a Diameter peer node; identifying, at a Diameter application message processor of the Diameter message processors, a Diameter message screening rule associated with the received Diameter message, wherein the identified Diameter message screening rule specifies a maximum receipt rate for Diameter messages associated with the Diameter message screening rule; and performing, at the Diameter application message processor of the Diameter message processors, a screening function associated with the identified Diameter message screening rule on the received Diameter message, wherein performing the screening function on the received Diameter message includes recording or updating one or more usage or measurement statistics associated with the identified Diameter message screening rule to account for the received Diameter message, wherein recording or updating the one or more usage or measurement statistics includes adjusting a current receipt rate of Diameter messages associated with the identified Diameter message screening rule to account for the received Diameter message, and; receiving, at an ingress Diameter message processor of the Diameter message processors, a Diameter message from a Diameter peer node; identifying, at a Diameter application message processor of the Diameter message processors, a Diameter message screening rule associated with the received Diameter message, wherein the identified Diameter message screening rule specifies a maximum receipt rate for Diameter messages associated with the Diameter message screening rule; and performing, at the Diameter application message processor of the Diameter message processors, a screening function associated with the identified Diameter message screening rule on the received Diameter message, wherein performing the screening function on the received Diameter message includes recording or updating one or more usage or measurement statistics associated with the identified Diameter message screening rule to account for the received Diameter message, wherein recording or updating the one or more usage or measurement statistics includes adjusting a current receipt rate of Diameter messages associated with the identified Diameter message screening rule to account for the received Diameter message, and; performing the screening function on the received Diameter message further includes performing an additional screening function in response to the current receipt rate of Diameter messages associated with the identified Diameter message screening rule exceeding the specified maximum receipt rate.