Novell SUSE LINUX ENTERPRISE SERVER 10 SP2 HEARTBEAT Manual page 17

Figure 1.6 Heartbeat Architecture
Messaging and Infrastructure Layer
The primary or first layer is the messaging/infrastructure layer, also known as the
Heartbeat layer. This layer contains components that send out the Heartbeat messages
containing "I'm alive" signals, as well as other information. The Heartbeat program
resides in the messaging/infrastructure layer.
Membership Layer
The second layer is the membership layer. The membership layer is responsible for
calculating the largest fully connected set of cluster nodes and synchronizing this view
Overview 9