DC_Heartbeats are not the heartbeats after which Heartbeat[1] is named (layer1 heartbeats).
These are specially constructed HeartbeatMessages[2] and only have any effect or meaning at the ClusterResourceManager[3] layer (layer3).
| [1] | http://www.linux-ha.org/HeartbeatProgram |
| [2] | http://www.linux-ha.org/HeartbeatMessages |
| [3] | http://www.linux-ha.org/ClusterResourceManager |
This information provided courtesy of the Linux-HA project at http://linux-ha.org/