What This Chapter Is About

In preparation for the implementation of an SAP system, your network must be able to support TCP/IP and the corresponding address structures. Given the success of the Internet, this is the case for most enterprises. Because of the high impact of Internet technologies on SAP systems, we will review some of the underlying technologies in the first part of the chapter. The addressing and naming structure of a system landscape has to be determined before starting installation of the systems. SAP does not support a host name change after installation, and changes to the IP address structure cause downtime and additional costs. Therefore, the network addressing concept has to be structured and wide enough to support future growth without making fundamental changes.

Designing an IP network is a series of tasks from determining the hierarchical IP address structure to managing the running network. The first step in network design should be to gather data such as the corporate structure, the current topology, and the applications already in use, as well as the information flows within the company. Based on this information, together with the demands of the SAP system already discussed in the last chapter, the structure of the new network can be developed. The factors that influence network design (business, technical, economical, and political) are often conflicting. The objective of a good design is to achieve a balance between them. Any change of an in-place IP address structure causes downtimes and incurs costs. Designing networks requires broad, and often in-depth, theoretical and practical experience. This book does not intend to teach IP network design. However, it presents some methods to structure the IP addresses and describes some best practices. In this chapter, we present the following topics:

• Basic principles of logical and physical network architectures,

• Concepts of host names for SAP systems, and

• Configuration of multiple network interface cards in a single server (multi-homed host).

If you already have a sufficient IP-based network infrastructure in place, you can skip the first part of this chapter. We do recommend, however, that you review the second part of the chapter, which covers multi-homed hosts and other more specific SAP topics.