Oracle RAC connectivity problems.  Works on either IP but not on both

I'm having problems connecting from my Oracle Application server into my Oracle 10g RAC database.

It works when I use the TNSNAMES definition of either:
QA.WORLD = (DESCRIPTION = (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ###.###.125.147)(PORT = 1521)))
    (CONNECT_DATA = (SERVICE_NAME=qa.world)(sid = QA.world)))
or
QA.WORLD = (DESCRIPTION = (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ###.###.125.148)(PORT = 1521)))
    (CONNECT_DATA = (SERVICE_NAME=qa.world)(sid = QA.world)))

It only works half of the time when I use the following entry.  I get an "ORA-12170:TNS:Connect Timeout Occurred" error.

QA.world =
  (DESCRIPTION =
    (LOAD_BALANCE=on)
    (FAILOVER=on)
    (ADDRESS = (PROTOCOL = TCP)(HOST = ###.###.125.147)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = ###.###.125.148)(PORT = 1521))
    (LOAD_BALANCE = yes)
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = qa.world)
      (FAILOVER_MODE=
        (TYPE=select)
        (METHOD=basic))))

And a TNSPING works for all 3 different TNSNAMES entries without fail.

Any thoughts?Start Free Trial