LLT and GAB
VCS uses two components, LLT and GAB, to share data over private networks among systems. These components provide the performance and reliability that VCS requires.
LLT (Low Latency Transport) provides fast, kernel-to-kernel communications, and monitors network connections. The system administrator configures LLT by creating the configuration files /etc/llthosts, which lists all the nodes in the cluster, and /etc/llttab, which describes the local system's private network links to the other nodes in the cluster.
GAB (Group Membership and Atomic Broadcast) provides the global message order required to maintain a synchronized state among the nodes. It monitors disk communications such as the VCS heartbeat utility. The system administrator configures the GAB driver by creating a configuration file (/etc/gabtab).
See Verifying LLT and GAB configuration files.