The Transparent Network Substrate (TNS) allows peer-to-peer connectivity where no machine-level connectivity can occur. It provides a user-transparent layer that enables a heterogeneous network consisting of different protocols to function as a homogeneous network. TNS forms a transparent layer to which different network protocols can connect. It provides a network of applications above the existing networks of computers.
Oracle Corporation typically relies on TNS to provide generic network connectivity to and between Oracle databases, regardless of underlying protocols.
If you are working with Oracle and is a beginner with Oracle, you will find lots of new protocols defined by Oracle to be used. One of them is TSN. TSN is short for Transparent Network Substrate. As Wikipedia says it is: