How many concurrent connections allowed to a particular teradata box?
How many maximum instances are allowed OR is there any calculation need to be done to get it?
Can anyone please help me on this?
What do you mean by connections and instances?
By default there are 2 Parsing Engines per node, each supports up to 120 sessions, so usually it's 240 sessions * number of nodes.
There is one, and only one, TCP socket connection per Teradata Database session.
However, note that a "JDBC connection" is a different concept from a "TCP socket connection".
In particular, with a JDBC FastLoad or JDBC FastExport connection, the Teradata JDBC Driver will log on multiple Teradata Database sessions "behind the scenes" for each FastLoad or FastExport operation.