In an 8500 Clustered NAS System there are several modules in the cluster communication architecture...

Agent-Agent monitors the resources of each system and provides the status to each machine's HAD

HAD Cluster service that monitors and manages the cluster's NAS

Under the management of the master node of the cluster, Gab sends the communication information between the cluster members to the point communication

LLT (Low-Latency Transport) sends information to all nodes in the cluster through a low-latency delivery protocol