This section discusses the high availability aspects of typical network scenarios for the SAP System and e-business.
As shown in the graphic below, a typical SAP system contains networked components from the following architecture levels:
· Database services
· Application services
· Presentation services
Typical Network Scenario for an SAP System
· The server network connects the application servers with the database server, which means that it is crucial for system availability. If the network fails, a connection to the database is no longer possible, so that the SAP system as a whole is unavailable.
· The access network connects the PCs to the application servers. For applications inside the company, this normally occurs using the existing intranet. If this fails, the system becomes unavailable to individual users or groups of users. Which high availability measures you choose to take here depends on the importance of system availability to particular users.
Due to the requirement to provide services on the internet, the role of the network infrastructure changes. The web-server network contains the servers that provide presentation services. However, access to these services is provided over the internet.
Since there is a connection to the internet, which means there is a danger of malicious access, a certain area of the network is defined as a demilitarized zone (DMZ). The DMZ is protected by firewalls, so preventing unauthorized access.
All the additional components above represent single points of failure, which you must consider for high availability protection.