High availability (HA) refers to an active-standby operational mode of a NetScaler device pair. Each device has its own dedicated management IP address. All other IP addresses are owned by the active device in the pair.
While there are multiple connectivity options for aNetScaler HA pair, the most recommended one is depicted in the following diagram:
In the above diagram, the N+1 red links between each T1000 and the respective switch imply N+1 redundancy - as explained in Connectivity. For instance, considering a 45 Gbps Gi-LAN N=5 is an appropriate value, with 6x10GbE LACP channels between each switch and the respective T1000 as well as between the two switches.
An extra pair of links is recommended between the NetScaler pair, to provide for HA communication isolation from the OAM network.