how to keep sqlnet sqlplus connections alive in 12g

After a few minutes, my Toad or sqlnet drop its connecton and I i need to reconnect.

This is especially annoying with Toad, as it tries to use the connection and take a minute to timeout before getting an error no connection.

this a very noticable in 12g. Read oc ID 1591874.1 which is vague about location of config setting like :

TCP_KEEPALIVE_TIME (the amount of time until the first keepalive packet is sent)

TCP_KEEPCNT(the number of probes to send)

TCP_KEEPINTVL (the interval between keepalive packets)

Tried

connectid=

 (DESCRIPTION=

  (ENABLE=BROKEN)

nothing seems to work?