Understanding Directory Services
Novice or experienced network administrator? You need to understand the intricacies of directory services.
- By Warren E. Wyrostek
- August 01, 2000
Whether you're a novice network administrator,
a systems engineer with 20 years experience, or a career changer
anticipating the rewards of network certification, you need to understand
the intricacies of directory services. Understanding Directory Services
is a superb, comprehensive overview of the various contemporary
directory service implementations and their predecessors.
This book takes the reader through the design,
evaluation, assessment, concepts, and terminology of directory service
technologies from X.500 to Active Directory Services. In a fair,
easy-to-understand format LDAP, DNS, NDS, X.500, and ADS are individually
explained and historically delineated. Active Directory Services
is not only explained, for example, but the evolution and implementation
of ADS from DNS, LDAP, and NT4 is examined in a succinct manner.
The authors address each directory service technology in a logical
manner with a good balance of description, comparative tables, and
professional quality graphics.
In nine, well-designed chapters the authors take
the reader from an introduction to directory services to an examination
of the architecture and operations of Active Directory. Chapter
1 gives a complete overview of directory services. The operations
of directory services within a network are defined, their integration
explored and benefits examined.
Chapter 2 discusses the evolution of directory
structures. The basic information structures used in directory services
are examined, as is directory service operation and design. Application-specific
directories, network operating system directories, limited-use directories,
general-purpose directories and meta-directories are discussed and
compared. A high point of this chapter is the description of physical
and logical naming conventions.
Chapter 3 focuses on distributed directory services
and the distribution and storage of information. Partitioning and
replication are looked at with excellent graphical examples.
Chapters 4 through 6 look at X.500, LDAP, and
DNS—one standard per chapter with each chapter building on
the previous one. Chapter 4 is the foundation of the three with
its discussion of X.500, exploring both the X.500 model and the
collection of standards that comprise it. The schema, object definitions,
and naming methods are clearly defined.
Chapter 5 explores the world of LDAP, and Chapter
6 the realm of DNS. Through comparative tables the language of X.500
is correlated with LDAP and DNS in their respective chapters. Following
the pattern used in the chapter devoted to X.500, the methods and
conventions used in LDAP and DNS are presented. These three chapters
are the heart of the book.
Chapter 7 presents the business considerations
of directory services, helping the reader to evaluate a directory
service for a network environment.
Chapter 8 examines Novell Directory Services,
NDS, including the latest version NDS 8, while Chapter 9 examines
how Microsoft has implemented Active Directory Services. Both chapters
cover the core concepts used in their respective directory service
technology in an easy to understand fashion. I find the discussion
of NDS and ADS a must read for anyone wrestling with deploying a
directory service in a network environment.
The main weakness of the text is the placement
of chapter 7 between the heart of the book and the discussion of
NDS and ADS—a position that seems disjointed. This chapter
should either be the concluding chapter or come before the presentation
of the X.500 material.
As the whole, this is the best overview text
I have found on the topic of directory services in a network environment,
and have recommended it to my clients and students without reservation.
I would also highly recommend it to all network professionals who
are encountering or who will be encountering directory services
in their network environments.
Warren E. Wyrostek, M.Ed., MCNI, MCT, MCSE+Internet, CIW CI, CCNP is devoted
to technology education. Warren's main joy comes as a Contract Trainer in Prosoft,
Microsoft, and Novell technologies. At heart he is a teacher who loves what education offers.