Chapter 6. Planning for Coexistence

One of the most important aspects of planning for a deployment of Windows 2000 and Active Directory is developing a plan for coexistence with the existing network operating system (NOS) and infrastructure. No matter how quickly you are planning on integrating and migrating your existing legacy environment, it is necessary to coexist for a time. In many cases, it might be necessary to coexist for several months and possibly years.

So, what do we mean by the term coexistence? Specifically, coexistence is defined as two systems existing in the same place and having to interoperate in a cooperative way. If considering Active Directory, we are talking about coexistence with legacy NOS, such as NetWare, Windows NT, and UNIX. There are tools available for interoperating with all these environments. The keys to success in coexisting with these environments are

• Developing a comprehensive plan for coexistence

• Understanding the limitations of the tools used during coexistence

Because of the limitations in the tools, more work is required up front in designing scripts and secondary applications to provide the functionality required for coexistence.

This chapter, addresses coexistence with Windows NT and NetWare. To a lesser degree, we also discuss coexistence with UNIX. The reason for the limited focus on UNIX is two-fold: First, there are limited tools available for integrating the two environments, and second, it is not likely that there will be a wholesale migration from UNIX to Windows 2000. As much as Microsoft would like to believe that they are ready to displace UNIX as the operating system of choice for enterprise applications, it is not likely that it will be happening in the immediate future. Consequently, organizations that have a large UNIX infrastructure in place will most likely not be integrating a Windows 2000 environment with their UNIX environment. That said, however, it is important to note that Windows 2000 and Active Directory are based on standards, including Lightweight Directory Access Protocol (LDAP) and SMTP, which facilitates interoperability with UNIX-based systems.

Before examining some of the technical details of planning for coexistence, we discuss the methodology and process involved in planning for coexistence.