Not failing over when network unplugged

I have two DSS servers, each has a dual port 10Gb nic card. Also two 1GB ports, on for mgmt and one for replication.
I have one vmware server with a dual port 10Gb nic card, which one is plugged into primary node and one is plugged into secondary node. The dss server have a virtual ip. Failover is configured and active, the iSCSI volume is replicated to the secondary node. All seems to work fine, except when I unplug the primary/active nodes data connection to the vmware host, it does not failover to the secondary node automatically. Would this be a ping node config problem on the 10Gb connections?

Simply unplugging iscsi path will not cause failover.
To test... unplug heartbeat link, and unplug links to ping nodes.

Thank you for the reply. After some thought, I suppose that makes sense.