Previously only 2-port QSFP+ 40 Gigabit or 4-port QSFP+ 40 Gigabit interface module can be used for failover in NS9500 Sensors stack.
With release 10.1, you can use 2-port QSFP28 100 Gigabit Network interface module along with 2-port QSFP+ 40 Gigabit or 4-port QSFP+ 40 Gigabit interface module for failover in NS9500 Sensors stack.