The Easy Connect naming method eliminates the need to look up service names in the
tnsnames.ora file or other repository for TCP/IP environments.
With Easy Connect, clients use a connect string for a simple TCP/IP address, which consists of a host name, and an optional port and service name. If you use this method, then no naming or directory system is required.
Networking elements for the Oracle Database server and clients are preconfigured for most environments. The Easy Connect naming method is enabled by default and does not require a repository. If you use a naming method other than Easy Connect, then additional configuration of Oracle Net Services may be required.
Oracle recommends against using the easy connect method with SCAN as it provides no high availability support.