Oracle SQL*Net version 2 features

Enhancements to SQL*Net version 2 include multiple “community” access  (i.e. TCP/IP to LU6.2), where databases can connect across diverse protocols, and the multi-threaded server that allows all communications to a database to be handled through a single dispatcher, rather than with separate processes on each database.

A Community is a group of computers that share a common protocol (TCP/IP, LU6.2).  SQL*Net v 2 is able to cross between different communities, such that the remote request is specified by database name, and all protocol conversion is automatically managed by the SQL*Net software.

In the example above we see the differences between connections with SQL*Net v 1 and SQL*Net v2.  Notice that the connect strings for SQL*Net v 1 requires the specification of the protocol and host name (e.g. t:host:database), while SQL*Net v 2 allows a single TNS service name.  Also, SQL*Net v2 uses the tnsnames.ora file to get the protocol and IP address before passing the request to the network.