Capacity Planning and Architecture - Expert Oracle RAC Performance Diagnostics and Tuning - page 30

Figure 2-3 illustrates the various components of a clustered configuration.

Network Switch

Public Network

Cluster Interconnect

ORADB1 ORADB2 ORADB3 ORADB4

VIP VIP VIP VIP

SSKY1 SSKY2 SSKY3 SSKY4

IPC IPC IPC IPC

Comm. Layer
Listeners | Monitors

Comm. Layer
Listeners | Monitors

Comm. Layer
Listeners | Monitors

Comm. Layer
Listeners | Monitors

Clusterware
Operating System

Clusterware
Operating System

Clusterware
Operating System

Clusterware
Operating System

SAN switch

AV1 AVL9 AV10 AV11 AV12 AV13 AV14 AV15 AV16 AV17 AV18

GRID_DATA PRD_DATA PRD_FRA

Figure 2-3. Cluster components

In Figure 2-3 , the nodes are identified by a node name oradb1 , oradb2 , oradb3 , and oradb4 ; and the database
instances are identified by an instance name SSKY1 , SSKY2 , SSKY3 , and SSKY4 . The cluster components are

• Operating system

• Communication software layer

• Interprocess communication (IPC) protocol

• Oracle Clusterware or cluster manager

The communication software layer manages the communication between the nodes. It is also responsible for
configuring and passing messages across the interconnect to the other nodes in the cluster. Although the Oracle
Clusterware uses the messages returned by the heartbeat mechanism, it is the responsibility of the communication
layer to ensure the transmission of the message to the Oracle Clusterware.