This read-write enumerated value determines the type of address translation applied to calls exiting the network at this port, among disabled, tunnel-when-called-party-matches-prefix, replace-when-called-party-matches-prefix, translate-e164-native-to-nsap, or translate-e164-nsap-to-native, with the description explaining that tunneling mode screens the called address against configured prefixes and, if a remote gateway address is configured for a matching prefix, tunnels the called party as a called subaddress while inserting the remote gateway address as the new called party. This lets the network transparently interconnect E.164 and ATM-NSAP addressing domains, or redirect specific called-party ranges toward a designated gateway, without requiring the calling or called endpoints to be aware of the translation. An engineer bridging calls from an E.164-addressed access network toward an ATM-NSAP-addressed core would set svcConfigEgressAddrXlateMode to translate-e164-native-to-nsap(4) so outbound calls are automatically converted to the format the core network expects.