SAP NetWeaver Architecture and Various Components
SAP NetWeaver Portal, we will look at the portal platform, its SAP NetWeaver architecture, and various components that form part of SAP NetWeaver Portal.
The SAP NetWeaver Portal is a Java Enterprise Edition (EE) application that runs on the SAP Web Application Server Java stack and provides an environment for the portal components to run. SAP NetWeaver Portal is comprised of the following parts:
SAP NetWeaver Portal
EE Portal Runtime (PRT)
Portal Runtime is the container that runs the portal applications and generates the HTML response that is sent back to the client.
EE Portal Content Directory (PCD)
Portal Content Directory is the repository for portal content objects, such as iViews, pages, roles, worksets, and systems. Information about all of the PCD objects is stored in the Application Server (AS) database.
EE Application Server Java (AS Java)
AS Java is the platform on which SAP NetWeaver Portal runs. This chapter discusses all of these components and their architecture in detail so that you can develop an understanding of the SAP NetWeaver Portal platform and how it works. We start by discussing the SAP NetWeaver Portal architecture in terms of the various components that make up the platform.
Then we move to discussing various administration tools that the platform provides along with the usage scenarios of each tool. We will then discuss the SAP NetWeaver Portal Runtime in terms of how client requests to SAP NetWeaver Portal are handled by the portal at runtime.
SAP NetWeaver architecture
AS Java Architecture
This section focuses on the architecture, administration, and configuration of SAP AS Java, on which SAP NetWeaver Portal runs. It introduces you to the general architecture of a Java application server.
Cluster Architecture
AS Java is based on cluster architecture. An AS Java server cluster consists of many parts: one or more Java instances, a central instance, and a database. Figure shows various parts of the cluster. The general architecture of an AS Java cluster, which can typically contain more than one Java instance.
The main criterion driving the number of Java instances in a cluster is the scalability requirement; when the demands from the system are high, more instances are added. Individual Java instances can be deployed on the same box or on different boxes, and each Java instance can als have multiple server nodes.
Java Instance
The Java instance is the actual runtime environment that AS Java provides for running the applications. The Java instance consists of an Internet Communication Manager (ICM) and one or more server processes, which are also known as server nodes. The ICM handles the requests from clients and sends these requests to the individual work processes; after processing, it returns the response to the clients,
Central Instance
The central instance is an important part of an AS Java cluster. Every AS Java cluster has one central services instance. This instance is responsible for exchanging lock administration messages between the instances, and load balancing within the cluster. Central services run on one physical machine and have a separate instance number.
The SAP central instance is comprised of the message server and enqueue serve both of which are described next.
Message Server
The message server maintains a list of all server processes in the AS Java cluster and provides information about their availability to the ICM. It also represents the infrastructure for data exchange between the participating server processes.
The message server is responsible for the following tasks in the AS Java cluster:
- Notification of events that arise in the cluster (e.g., when a server process is started or stopped)
- Communication between different server processes
- Forwarding of messages and requests to all participants
- Preparation of login information for the SAP Web Dispatcher
- Exchange of cache information in the cluster