Cluster Control Link Interfaces and Network

You can use any physical interface or EtherChannel for the cluster control link. You cannot use a VLAN subinterface as the cluster control link. You also cannot use the Management interface.

Each cluster control link has an IP address on the same subnet. This subnet should be isolated from all other traffic, and should include only the cluster control link interfaces.

Note

For a 2-member cluster, do not directly-connect the cluster control link from one node to the other node. If you directly connect the interfaces, then when one unit fails, the cluster control link fails, and thus the remaining healthy unit fails. If you connect the cluster control link through a switch, then the cluster control link remains up for the healthy unit. If you need to directly-connect the units (for testing purposes, for example), then you should configure and enable the cluster control link interface on both nodes before you form the cluster.