Service_names

Type:String
Syntax:SERVICE_NAMES =db_service_name [, db_service_name [ ... ] ]
DefaultB_UNIQUE_NAME.DB_DOMAIN if defined
Modify:ALTER SYSTEM
Range:Any ASCII string or comma-separated list of string names
Basic:No
Raco not set the SERVER_NAMES parameter for Real Application Clusters
(RAC). Instead, define services using Database Configuration Assistant (DBCA) and manage services using Server Control (SRVCTL) utility.
Notes:SERVICE_NAMES specifies one or more names by which clients can connect to the instance. The instance registers its service names with the listener. When a client requests a service, the listener determines which instances offer the requested service and routes the client to the appropriate instance.You can specify multiple service names in order to distinguish among different uses of the same database. For example:
SERVICE_NAMES = sales.acme.com, widgetsales.acme.com
You can also use service names to identify a single service that is available from two different databases through the use of replication.If you do not qualify the names in this parameter with a domain, Oracle qualifies them
with the value of the DB_DOMAIN parameter. If DB_DOMAIN is not specified, then no domain will be applied to the non-qualified SERVICE_NAMES values.