"The Diameter base protocol specifies mechanisms whereby a given realm may advertise Diameter nodes and the supported transport protocol. However@ these mechanisms do not reveal the Diameter applications that each node supports. A peer outside the realm would have to perform a Diameter capability exchange with every node until it discovers one that supports the required application. This document updates RFC 3588@ ""Diameter Base Protocol""@ and describes an improvement using an extended format for the Straightforward-Naming Authority Pointer (S-NAPTR) application service tag that allows for discovery of the supported applications without doing Diameter capability exchange beforehand."