How to Cheat at Securing a Wireless Network--Wireless Network Design--Part II

Identifying the design methodology
There are many ways to create a network design, and each method must be modified for the type of network being created. At the beginning of this chapter, we outlined the necessary phases for a sound design methodology (preliminary investigation analysis, preliminary design, detailed design implementation and documentation).Nevertheless, network types can vary from service provider to enterprise, to security and so on. As wireless networking becomes more commonplace, new design methodologies tuned specifically for the wireless environment will be created.

In this chapter, we give you an overview of the piece of the engagement methodology that provides Lucent consultants a framework for applying their technical expertise during the various stages of the network lifecycle. Referred to as the Network Engagement Methodology (NEM),it is a tool developed by the consultants of Lucent ESS and provides best practices, procedures, and tools from their most successful projects. What you will see in this chapter is the basis for what makes up the final network design (the other phases of NEM include business development, initiation and definition, planning, execution and control, and finally, close out.

This section provides information on the execution and control phase, specifically tuned for a service provider network. The execution and control phase has been broken down into five stages: plan, architect, design, implement, and operate. The next several sections provide a high-level description of what makes up the plan, architect, and design stages of NEM.

Creating the Network Plan
Every good network design begins with a well thought out plan. The network plan is the first step in creating a network design. It is where information regarding desired services, number of users, types of applications, and so forth is gathered. This phase is the brainstorming phase during which the initial ideas are put together. The planning stage can be one of the longest segments of a network design, because it is dependent on several factors that can be very time consuming. However, if each planning step is thoroughly completed, the architecture and design stages move along much more quickly.

Gathering the Requirements
The first and most important step in creating a network plan is to gather the requirements. The requirements will be the basis for formulating the architecture and design. If a requirement is not identified at the beginning of the project, the entire design can miss the intended goal of the network. The requirements include:

• Business Requirements--A few examples of possible business requirements are budget, time frame for completion, the impact of a network outage, and the desired maintenance window to minimize the negative effects of an outage.
• Regulatory Issues--Certain types of wireless networks (such as MMDS) require licenses from the FCC. If the wireless network is going to operate outside of the public RF bands, the regulatory issues need to be identified.
• Service Offerings--These are the primary justification for the design of a new network or migration of an existing network. Simply, these are services or functionality the network will provide to the end users.
• Service Levels--Committed information rate (CIR) is an example of a service level agreement (SLA).This involves the customer's expectation of what the service provider guarantees to provide.
• Customer Base--This establishes who the anticipated end users are, and what their anticipated applications and traffic patterns are.
• Operations, Management, Provisioning, and Administration Requirements--These identify how the new network will impact the individuals performing these job functions, and whether there will be a need to train these individuals.
• Technical Requirements--These can vary from a preferred equipment vendor to management system requirements.
• Additional Information--Any additional information that can affect the outcome of the design.

Once all of the requirements have been collected, it is recommended that a meeting be set up with the client to ensure that no key information is missing. This is important because it not only keeps the client involved, but also allows both the client and network architect to establish and understand the expectations of the other. Once you get client buy-off on the goals and requirements of the network, you can proceed with baselining the existing network.

Baselining the Existing Network
The reason you need to baseline the existing network is to provide an accurate picture of the current network environment. This information will be used later on to identify how the new design will incorporate/interface with the existing network. When conducting the baseline, be sure to include the following considerations:

• Business processes
• Network architecture
• IP addressing
• Network equipment
• Utilization
• Bandwidth
• Growth
• Performance
• Traffic patterns
• Applications
• Site identification/Surveys
• Cost analysis

With proper identification of these items, you will gain a good understanding of both the existing network and get an idea of any potential issues or design constraints. In the case of utilization--that is, overutilization--unless kept under a watchful eye, it can contribute to a less-than-optimized network. Therefore, by evaluating the health of the existing network, you can either eliminate or compensate for potential risks of the new network. In addition to monitoring network conditions, it is also a good idea to perform site surveys in this step ,to identify any possible problems that are not identified in either the requirements collection or the baseline monitoring.

Analyzing the Competitive Practices
When you compare the client's business and technology plan to the competitors' in the same industry, you can learn what has and hasn't worked and why. Once you have evaluated and understand the industry practices, you can identify what not to do as well. This is a potential opportunity for a network architect to influence the functionality, in terms of services and choice of technology, that will facilitate the desired network. The primary reason the architect is involved is because of his or her knowledge of the technology--not only how it works, but also how it is evolving.

Beginning the Operations Planning
The operations systems support daily activities of telecommunications infrastructures.

The purpose of this step is to identify all of the elements required for the operations system. Depending on the needs of the client, any or all of the following processes need to be identified:

• Pre-order
• Order management
• Provisioning
• Billing
• Maintenance
• Repair
• Customer care

If your client is not planning on offering any services with the new design, then this step can be skipped. Once the operations planning step is complete, you can move on to the gap analysis.

Performing a Gap Analysis
The gap analysis will be a comparison of the existing network to the future requirements. The information obtained through the gathering of requirements and baselining of the current network provide the data needed to develop a gap analysis.

The gap analysis is a method of developing a plan to improve the existing network, and integrate the new requirements. The documented result should include the following items:

• Baseline
• Future requirements
• Gap analysis
• Alternative technology options
• Plan of action