This Recommendation defines a protocol for the exchange of alternative address related information between a DTE and an address resolution entity as defined in Recommendation X.115. This Recommendation complements Recommendation X.115 which defines the address translation capability in public data networks. The protocol defined in this Recommendation enables DTEs to register alternative addresses (e.g. addresses in formats other than X.121 or E.164). The ARE stores the registered information along with the addresses where DTEs are reachable and provides this information when queried by a DTE or a switching system to enable call establishment.