OSPF Network Design Solutions

Adaptability

Adaptability refers to your network’s capability to respond to changes. In most cases, adaptability refers to your network’s capability to embrace new technologies in a timely and efficient manner. This becomes extremely important as the network ages because change within networking is racing forward at breakneck speeds. Though it is not necessary to always be on the leading or bleeding edge—there is a lot to be said for letting others find the bugs!

Manageability

To provide “true” proactive network management is the goal here. The network must have the proper tools and design to ensure you are always aware of its operation and current status.

Cost Effectiveness

In this case, I have saved the true bottom line of network design for last. The reality of life is that budgets and resources are limited, and building or expanding the network while staying within the predetermined budget is always a benefit to your career and proper network design.

Although there are five basic goals of network design that can be followed in any situation, I think there also should be a certain mindset during the process. This mindset is regarding the actual technology you will be using. It is very important to use state-of-the-art technologies whenever possible, though this does not mean to use unproven or inadequately tested technology. The reasoning behind this is that by spending a little extra money up front, you are investing with an eye to the future knowing that the network you are building will be able to grow, from a technological standpoint, longer than otherwise possible.

Network Design Issues

Up until this point, the various network design goals and the methodology needed to make the goals become a reality have been discussed. There are also certain design issues that you must consider when working through the network design process:

•  Reliability. When designing networks, reliability is usually the most important goal, as the WAN is often the backbone of any network.

•  Latency. Another big concern with users occurs when network access requests take a long time to be granted. Users should be notified about a latency problem in the network.

•   Cost of WAN resources. WAN resources are expensive, and as such, frequently involve a tradeoff between cost efficiency and full network redundancy. Usually cost efficiency wins.

•  Amount of traffic. This is a very straightforward consideration. You must be able to accurately determine the amount of traffic that will be on the network in order to properly size the various components that will make it up. As you implement the network, you should also develop a baseline that can be used to project future growth.

•  Allowing multiple protocols on the WAN. The simplicity of IP is of great benefit to any network. For example, by only allowing IP-based protocols on the network you will avoid the unique addressing and configuration issues relating to other protocols.

•  Compatibility with standards or legacy systems. Compatibility is always going to be an issue within your network throughout its life. As a network designer, you need to always keep this in mind as you proceed.

•  Simplicity and easy configuration. Having been a network engineer for many years and involved in network management, this feature is doubly important to me. You might only be involved in the design and implementation of the network and not the management. In that case, the knowledge you will develop will need to be passed on to those who will manage the network. Ensure that you keep the ideas of simplicity and ease of configuration in mind while you develop your design documents for the network.

•  Support for remote offices and telecommuters. In today’s telecommunications environment, remote satellite offices are becoming commonplace and require network connectivity, so you must plan accordingly. The estimates say that every day you will see companies increase the number of telecommuters. You must keep this in mind as you determine the placement of network components to ensure that they can handle this requirement when it becomes a priority for your organization.

Network Design Methodology

There are six common steps that can be used to design your OSPF network, or any network for that matter. This are not set in stone and will not guarantee the “perfect” network, but they will provide you with realistic steps and considerations that if taken into account will make for well designed network. These steps will also help you avoid getting caught up in all the “bells and whistles” available in the new-enhanced-ultra-secret- turbo-series-network-equipment which is the answer to all your networking needs.

These steps to designing a network have been proven not only over time, but also through countless networks that have been designed and implemented based upon this standard.

1.  Analyze the requirements.

2.  Develop the network topology.

3.  Determine addressing and naming conventions.

4.  Provision the hardware.

5.  Deploy protocol and IOS features.

6.  Implement, monitor, and maintain the network.

Although your network might not have the technology du jour, it might not really need it if you objectively determine the needs of a network by following this design methodology (as shown in Figure 7-2).

Figure 7-2  Network design methodology.