Determining and Prioritizing Other Environmental Constraints

   

The final set of constraints to consider is those related to the environment in which the directory service is to be deployed. There are many of these potential constraints, and the list varies depending on the situation, but this section touches on a few of the most important areas.

Hardware and Software

A lot of information about existing systems was discussed earlier in this chapter in the section Analyzing Your Environment. When thinking about your directory service, consider the computer hardware and operating systems that it must support. The use of a standard protocol for directory access such as LDAP largely insulates you from the characteristics of any specific computer platform; as a practical consideration, however, your directory service may need to accommodate a variety of existing systems.

Some directory or directory-enabled application software is available for only one or two platforms. Ask yourself the following questions to make sure you take into account these system-related constraints:

  • Can you purchase new hardware and software to deploy the directory servers, or do they need to run on hardware you already own?

  • What kind of computer hardware and operating systems do your users have?

  • What kind of computer hardware and operating systems will your directory-enabled applications need to run on?

  • What up-and-coming computing platforms do you need to worry about?

Be sure to note any trends away from certain existing systems and toward others. For example, suppose that use of the Linux operating system is on the rise and Microsoft Windows 98 is on its way out. By the time your directory service is fully deployed, support for Linux may be much more important than support for Windows 98.

Another example is the trend toward wireless and handheld devices. The constraints imposed by these kinds of devices present interesting challenges to the directory designer. For example, connecting a wireless device to your directory infrastructure may require specialized directory access software (and perhaps custom development) because of the network bandwidth and hardware limitations of the device.

The Network

Another set of environmental constraints relates to your organization's network. As discussed earlier, the physical deployment of directory servers may be governed largely by the cost, reliability, and performance characteristics of the network that your directory service relies on. Even worse , if the network within your organization is managed by a completely separate group , you may be powerless to effect much change in the network. In that case you will need to design your directory service to fit the existing network constraints. If changes can be made to the network to accommodate your directory needs, so much the better. The physical deployment of directory servers throughout your network is covered in depth in Chapters 10, Topology Design, and 11, Replication Design.

Criticality of Service

Next think about whether your directory service must provide mission-critical services or whether things are a bit more relaxed . For example, if you're deploying a directory service that will be used in a hospital emergency room, the standards that your directory service will be held to may be very high indeed. In contrast, it may be acceptable for a software company's internal directory service to fail occasionally, because the users are familiar with and may be more tolerant of such failures.

Security

Some security and privacy constraints come from the directory users (as previously discussed), but some arise from the environment in which the service operates. For example, if a directory service operates in an open network environment such as the Internet, it is more likely to be attacked by malicious intruders. You do not want a breach of security within your directory service to occur and cause your e-commerce site to be mentioned on the front page of the Wall Street Journal , so appropriate steps must be taken. Similarly, if your organization is secretive by nature or deals with sensitive data, the value of breaking the directory service's security may be higher ”and the security-related expectations of users may be higher as well. Because privacy and security are so important, we devote all of Chapter 12, Privacy and Security Design, to those topics.

Coexistence with Other Databases and Directories

Finally, a directory service typically must coexist with a variety of directories and database systems. These external systems may be completely independent of your directory service or tightly integrated with it. In the latter case, these systems will impose additional constraints on your directory service, covering a wide range of areas. You can find more information about integrating with other directories and databases in Chapter 7, Data Design, and Chapter 23, Directory Coexistence, where we cover the topic of integration with other data sources.

Prioritizing Your Environmental Constraints

As you did for all the needs and constraints discussed earlier, list the remaining environmental constraints and assign priorities to each of them. Try to distinguish between absolute constraints that you cannot overcome and constraints that you may be able to work around or avoid. For example, it may be difficult and expensive to upgrade all the computer hardware and operating systems that users have, but you may be able to lobby successfully to purchase new systems on which to run the directory servers themselves .

   


Understanding and Deploying LDAP Directory Services
Understanding and Deploying LDAP Directory Services (2nd Edition)
ISBN: 0672323168
EAN: 2147483647
Year: 2002
Pages: 242

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