A NetScaler cluster provides link redundancy for LACP to ensure that all nodes have the same partner key.
To understand the need for link redundancy, let us consider the example of the following cluster setup along with the accompanying cases (with attention to case 3):
In this setup, interfaces I1, I2, I3 and I4 are bound to LACP channel with KEY 5. On the partner side, I1 and I2 are connected to Switch 1 to form a single LA channel with KEY 1. Similarly, I3 and I4 are connected to Switch 2 to form a single LA channel with KEY 2.
Now let us consider the following cases to understand the need for link redundancy:
set channel CLA/1 -linkRedundancy ON -lrMinThroughput <positive_integer>