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

Developing the Network Architecture
The network architecture is also referred to as a high-level design. It is a phase where all of the planning information is used to begin a conceptual design of the new network. It does not include specific details to the design, nor does it provide enough information to begin implementation.(This will be explained in greater detail in the following sections.) The architecture phase is responsible for marrying the results of the planning phase with the client's expectations and requirements for the network.

Reviewing and Validating the Planning Phase
The first step in developing a network architecture is to review and validate the results of the planning phase. Once you have thoroughly gone through the results of the planning phase, and you understand and agree to them, you are finished with this step and can move on to creating a high level topology. The reason that this step is included here is that many times teams on large projects will be assembled but the architecture team can consist of people that were not in the plan team.This step is to get everyone familiar with what was completed prior to his or her participation.

Creating a High-Level Topology
A high-level topology describes the logical architecture of a network. The logical architecture should describe the functions required to implement a network and the relationship between the functions. The logical architecture can be used to describe how different components of the network will interoperate, such as how a network verifies the authentication of users. The high-level topology will not include such granularity as specific hardware, for example; rather, it illustrates the desired functionality of the network. Some of the components to include in the high-level topology are:

• Logical network diagrams
• Functional network diagrams
• Radio frequency topology
• Call/Data flows
• Functional connectivity to resources
• Wireless network topology

Creating a Collocation Architecture
Once the collocation plan has been complete, a more detailed architecture needs to be created. The architecture should include information that will be used as part of the requirements package that you give to vendors for bids on locations. Information to include in the requirements includes:

• Power requirements in Watts
• Amperage requirements
• Voltage (both AC and DC) values
• BTU dissipated by the equipment
• Equipment and cabinet quantity and dimensions
• Equipment weight
• Equipment drawings (front, side, top, and back views)
• Environmental requirements

The intention of this type of architecture is to provide information to assist in issuing either a request for information (RFI) or a request for proposal (RFP) to a vendor(s).It is in the best interest of the client to include enough information about the network requirements to evoke an adequate response from the vendor, but not give away information that potentially could be used for competitive intelligence.

Defining the High-Level Services
The services that the client plans on offering their customers will usually help determine what the necessary equipment requirements will be. These services should match up with the services identified in the risk portion of the plan phase. Once the services have been identified, they need to be documented and compared against the risk matrix to determine what services will be offered. The client typically will already have identified the types of services they are interested in providing, but this is an opportunity to double-check the client's intentions. Any services that will not be offered need to be removed from the architecture. Once you have presented the documented services and get the client's service offering list, you can move on to creating a high-level physical design.

Creating a High-Level Physical Design
The high-level physical design is the most important step in the architecture phase and is usually the most complicated and time consuming. A lot of work, thought, and intelligence go into this step. It defines the physical location and types of equipment needed throughout the network to accomplish its intended operation. It does not identify specific brands or models of equipment, but rather functional components such as routers, switches, access points, etc. The high-level physical design takes the RF topology, for example, completed in the high-level topology step, and converts that to physical equipment locations. Due to the many unknowns with RF engineering, several modifications and redesigns may be necessary before this step is complete. Upon acceptance of the high-level physical design, the operations services needs to be defined.

Defining the Operations Services
The purpose of defining the operations services is to identify the functionality required within each operations discipline. Some of the more common operations disciplines include:

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

Once the functionality for each discipline has been defined, documented, and accepted, you are ready to create a high-level operations model.

Creating a High-Level Operating Model
If a network can't be properly maintained once built, then its success and even its life can be in jeopardy. The purpose of creating a high-level operating model is to describe how the network will be managed. Certainly a consideration here is how the new network management system will interoperate with the existing management system. Some of the steps that need to be considered when creating a high-level operating model include:

• Leveraging technical abilities to optimize delivery of management information
• Providing an easily managed network that is high quality and easy to troubleshoot
• Identifying all expectations and responsibilities