A Logical Approach To Extranet Design

IT Manager's Corner


Just For Fun



Extranet Design
Problem Definition
Requirements Analysis
Design & Prototyping
Development & Documentation
Test & Review
Deployment & Training
Help Desk
Extranets are a collection of interconnected intranets. They can be directly connected to form a large private network, such as financial institutions, or connected through the Internet. Security is normally handled by firewalls and encryption which prevent eavesdropping.
Managing the design, development, implementation, and operation of even a moderately sized extranet can be a long, difficult, and frustrating task. In this article, we present the primary steps to ensure a successful extranet development effort. Here, at Horsburgh.com, we have used this approach successfully on our client's extranet development projects.

Problem Definition

The definition and recording of the problem to be solved is one of the most often overlooked step of any development effort. A problem needs to be solved, so the tendency is to jump right in a solve it. For small, negligible cost efforts this is fine. For Extranet design, ignoring this step will lead to disaster. Write down and widely publish the answers to the following questions and all other questions that are appropriate for your specific effort. Remember to keep the questions targeted to DEFINING the problem NOT solving it.

Do We Need an Extranet?
This is an obvious question, but should be taken seriously. For some businesses the answer is an easy yes, but for others, there may be better solutions. It is wise to seek professional advice when answering this question. Having an outside professional examine this question may cost some money up-front, but they are far less costly early on the development.

What specific Problems will it solve?
Write down the four, five, ten, whatever, number of problems that having an Extranet will solve. The problems should be clearly stated, be very specific, and have testable criteria for success. Make sure you publicize these problems and get user and management feedback.

What are our available resources (time, money, and personnel)?
Knowing what your actual resources are at the beginning is critical for defining the development path. If your budget is low, consider down-scaling the effort. If time is short, consider using off-the-shelf products extensively. If your personnel resources are thin, consider outsourcing. Being realistic about your actual resources will help you prevent overruns and project disappointments. Promising a global communication when you only have resources for a toy telephone will always doom a project. Also, don't be afraid to tell upper management that the resources are too small for solving the problem. Believe me, they would rather know up front than get a surprise during deployment.

What criteria will we use to measure success?
This is an often overlooked step in the problem definition. For every problem stated, you must define a means for determining the success of the solution. If you can't think of a success criteria, then the problem is not defined specifically enough. Stay away from problem statements such as "We must tie all our remote offices together." Restate the problem in quantifiable terms, like: "We need 24x7 1Mbps sustained throughput to each regional office and 80% uptime with 256Kbps sustained throughput to each local office."

Should I outsource all, some, or none of the development and operation?
If you have in-house personnel that are under-utilized or have time to be assigned to the development process, then keeping most of the development in-house makes sense. If not, then you can either hire additional staff or outsource some or most of the development. I recommend that you do not outsource all of the development. You must have some in-house expertise available or at least strong upper management support. Otherwise you may end up with a very nice system that does not solve your problems. Strategic outsourcing make sense in most Extranet development projects. The outsourcing contractor can supply the needed expertise and personnel at the various development phases. And when a particular phase is finished, you are not left with a staff member looking for something to do. You will probably find the up-front costs of an outsourcing firm to be higher than hiring in-house personnel. But the long-term savings will be far greater with a professional outsourcing firm than by retaining in-house personnel. Remember to make sure you feel comfortable with the outsourcer's style and abilities. You will working with them very closely. Don't just choose the largest or best-known source. How you and your outsourcer "mesh" is far more important than their list of clients.

Am I upgrading an existing system, converting from a legacy system, or developing from scratch?
Developing a system from scratch, as strange as it sounds, is by far the easiest. If you are in this situation, count your blessings. If not, upgrading an existing system or converting from one or more legacy systems will be your lot. Fortunately, you will have a long list of "things that don't work right" to begin with. Make sure that you fully understand what systems will still be in place after the migration and how they will be integrated into your extranet. If your budget is low, then consider using middleware and "web-like" products to layer on top of the existing system. With a more moderate budget, you can replace inefficient systems with newer and more powerful ones. Remember that computer hardware and bandwidth are cheap. It's the software and operations that are expensive. Powerful hardware and networks can make even today's bloated software work faster. With a higher budget, consider replacing inefficient or outdated portions of the extranet with newer streamlined hardware and software. If you are not sure what the "latest and greatest" extranet products are, hire a professional extranet consultant. Their fee will be well worth it.

Are the local intranets sufficient to integrate into the extranet?
Try to separate the local intranet issues from the overall extranet. If you find an intranet that is not ready to be integrated, suggest an intranet enhancement project and integrate them into the extranet at a later time.


Requirements Analysis

Performing a requirements analysis is critical to the success of any project. Without a clear goal in mind, success is dubious. There are a number of different philosophies about requirements analysis: top down, bottom up, inside out, etc. The method I have found to work the best is as follows:
  1. Clearly state the problem(s) you wish to solve.
  2. Identify the users of the completed system.
  3. Formulate a specific budget - time, money, personnel.
  4. Ask identified users to specifically state what they expect the system to do.
  5. Ask management to specifically state their success criteria.
  6. Separate their requirements from their "desirements." Only design to requirements. The enhancement phase is where you address the "desirements."
  7. Group and "bubble-up" requirements.
  8. Generate a prioritized requirements table listing the requirement, where it came from, the success criteria, and priority. Keep this table high-level. A table with a dozen requirements will be much easier to manage than one with hundreds.
  9. Produce a detailed development schedule including hardware, software, personnel, documentation, and reviews. Include outsourcing requirements and long lead-time items.
  10. Get a sign-off of the requirements, resource allocation, and schedule from top management before you go any further.

Note that items 4 & 5 will be asked throughout the development cycle since their responses will change when they see prototypes and when they are being trained. Be sure to update items 6 through 9 each time.

Beware of getting caught in the cycle of

You: What are your requirements?

Them: I don't know, what can you do?

It's always best to ask very specific questions. Don't worry if their responses change each time you ask the question. It will happen, so plan for it.


Design & Prototyping

There are many design methodologies. The ones I've used most successfully are 1. Rapid Prototyping (for small to medium projects) and 2. Structured Development (for large or very complex projects).

Rapid Prototyping
There are five keys to a successful rapid prototyping methodology:

  1. Assemble a small, very bright team of programmers, hardware technicians, designers, quality assurance technicians, documentation and graphic artist specialists, and a single manager.
  2. Define and involve a small "focus group" consisting of users (both novice and experienced) and managers (both line and upper) from each location. These are the people who will provide the feedback necessary to drive the prototyping cycle. Listen to them.
  3. Generate a user's manual and user interface first. You will be amazed at what you will find out by producing a user's manual first!
  4. Use tools specifically designed for rapid prototyping. Stay away from C, C++, COBOL, etc. Instead use tools such as Visual Basic, HTML authoring, and similar development environments.
  5. Remember a prototype is NOT the final application. Prototypes are meant to be copied into production models. Once the prototypes are successful, then begin the development processing using development tools, such as C, C++, Java, etc.

Structured Development
When a project has more than 10 people involved or when multiple companies are performing the development, a more structure development management approach is required. Note that rapid prototyping can be a subset of the structured development approach. This approach applies a more disciplined approach to the extranet development. Documentation requirements are larger, quality control is critical, and the number of reviews increases. While some parts may seem like overkill at the time, they can save a project from overruns especially late in the development cycle. For more information about how the structured development approach works and detailed technical and management information, you can contact me via e-mail. (I've written a handbook on the topic :-)


Development & Documentation

Once the requirements analysis is well underway, the prototypes are working, and the focus groups are becoming happy, it's time to begin the development. Coordinating hardware and software purchases and upgrades, network and hardware installation, software development, documentation guides and manuals, reviews, and testing can become a full-time job. The key to keeping a handle on all of this to maintain a good written schedule that everyone can view and to have periodic "all-hands" reviews. Remember that working with vendors can be a frustrating experience. Hardware incompatibilities, software bugs, late deliveries, mistaken cabling requirements, etc. are more the norm than the exception. Outsourcing can help, but you must be continually involved to ensure success.

Test & Review

Testing and Reviews take place throughout the development cycle, including prototyping, development, deployment, operations, and enhancements. It never ends. It's wise to place a single individual in charge of testing and reviews. This is not a popular job, but it is critical for developing a system that works and meets each of the requirements. Be sure to empower this person (usually a quality assurance engineer) with the appropriate authority. Also, provide them with an appropriately sized staff. Testing is time consuming, tedious work and preparing for reviews and analyzing results can take much longer than you might think. Fortunately this person can save you from being surprised at budget review time and usually catches most problems before they become too big. If you outsource this task, make sure that you make it clear to the others on the team what the outsourcer's role is and what level of authority they have.

Deployment & Training

OK, the development is complete, quality assurance is satisfied, the documentation is ready, the regional, national, and global network connections are in place, and all the "off-the-shelf" products have arrived. Now it's time to put everything together. This can be a highly disruptive time. Make sure that you have full management support and that they understand the nature and effect of the installation and deployment disruption. Consider tying together the intranets using a clustered, incremental approach, testing each connection. Scheduling training sessions concurrently with the installation can be an effective use of time. Don't skimp on the training. Make sure you have training in the budget from the beginning and don't dip into it. The best way to ensure success is to effectively train the users so that they will actually use the system and possibly sing its praises. Also remember that training is ongoing. New employees or employees being moved or promoted will need to be trained. Each time enhancements are added, new training sessions must be scheduled.


Extranets usually contain many servers. Tasks such as backups, bug fixes, software updates, hardware maintenance and upgrades, print and media services, electronic mail account maintenance, security patches, and other similar tasks must be performed regularly. Operation and maintenance of such services require an operations staff. It is not enough to "let the users take care of it." If you are providing these services in-house then you will need on-site support from either an outsourcing agency or in-house staff. The current trend is to outsource most of these services including the actual servers to an extranet outsourcing firm. Outsourcing can result in a substantial savings, especially if the outsourcer stays current with the hardware, software, and network upgrades. Just make sure that your provider can supply the services you require and is available when you need them. Also, be sure to discuss security requirements with them before you hire them.


There is always one thing you can count on: "Requirements Creep." The more successful the system, the faster requirements creep will occur. As your users become more sophisticated they will want more and more capabilities. If you can respond quickly and efficiently, your users will again sing your praises (and upper management will definitely take notice :-). Make sure that you have designed in the ability to add features from the very beginning. Remember to design in scalability and flexibility at all phases of development.

Help Desk

You might think that good manuals and good training would be sufficient to effectively use your extranet. Not so. A knowledgeable, available, responsive help desk is critical to the overall success of the project. Users will always find new uses for a well-designed system and problems will inevitably occur. Without a help desk, an extranet can become dated and under-utilized. In my experience, deployment of an excellent help desk (with telephone, fax, online, and e-mail capabilities) is the single most important function that ensures the continued success of an extranet.
Copyright © 2000, Horsburgh.com. All Rights Reserved.