According to one aspect, the subject matter described herein includes a method for routing Diameter messages. The method includes steps occurring at a Diameter signaling router (DSR) comprising a plurality of Diameter message processors. The method also includes receiving, by a first of the plurality of Diameter message processors and from a first Diameter node, a Diameter message, wherein the Diameter message is received via a first Diameter connection. The method further includes determining, by the first Diameter message processor, a next-hop Diameter node for the Diameter message. The method further includes communicating, by the first of the plurality of Diameter message processors and to a second of the plurality of Diameter message processors, the Diameter message. The method further includes communicating, by the second Diameter message processor and to the next-hop Diameter node, the Diameter message, wherein the Diameter message is communicated via a second Diameter connection.