Networking

Communication with the highly available components takes place by using special IPaddresses, called relocatable IP addresses. They are handled by MC/ServiceGuard. Think of them as addresses of a package rather than host machine addresses.

Some of the SAP R/3 processes require that hostnames are not longer than eight characters and do not contain special characters.

One additional IP address is the minimum address requirement for the one package concept, two IP addresses are needed for the two package solution (one for each package). If you are planning to use a frontend LAN and a server LAN as suggested by SAP R/3, double the number of IP addresses, that is, use two or four.

You can reduce the number of additional IP addresses with the two package concept if you do not want to access the database directly through the frontend LAN. You can save another IP address, if you do not have frontends that directly connect to the central instance, but only access your SAP R/3 system through different application servers.

The reason for relocatable IP addresses on both networks is, that a switchover must remain transparent to both the frontends and the additional application servers.

The complete system is installed if there is no server LAN at all, that is, all profiles only refer to addresses of the frontend LAN. Static routing of the relocatable addresses from the client LAN to the server LAN redirect the communication traffic of the application servers and the database to the backend LAN.