Planning Your Proxy Server Implementation

By Donald Rohrbacher

Planning Your Proxy Server Implementation

A key factor in determining the success of any installation is planning. Planning involves several phases-from understanding your current capabilities, to determining your current needs, anticipating your future needs, and, ultimately, finding a viable solution. We have all been in situations where the immediate need surpassed the need for planning and the installation was rushed. More often than not, the installation had to be repeated to correct problems. Microsoft stresses successful planning techniques, both to ease the initial installation and as a preventative troubleshooting task.

The Site Analysis Process
A key consideration of planning future network capacity is determining what services, users, and data will be present on the network. Take the time to complete a thorough site analysis. A bit of formal analysis now will ease the process of upgrading and configuring the system later. Don\'t succumb to the "easy way out." Planning can be a long and arduous task that is overlooked far too often, but one that pays off ultimately. Network Capacity Analysis

The capacity of a network is that network\'s ability to support the amount of data transmitted over it. A network that can support the activity of your organization today may not be able to support the increased activity level when Internet access is offered via Proxy Server. You need to carefully consider the performance ramifications of adding new information services to an already overtaxed network.

Although Proxy Server\'s ability to cache resources saves on performance over the Internet communication link, it does not decrease the amount of data ultimately transferred to the client. Even if 100 percent of requested data is stored in the proxy server\'s cache, it will still be sent across your local network to the client computer, increasing network traffic significantly.

The first step in network capacity analysis is to define a baseline profile of the performance levels of your current network by using Performance Monitor and Network Monitor. This involves sampling various aspects of your network over several days. Examine these readings to decipher what is normal and abnormal about how your network performs. This includes pinpointing which areas of your network experience the heaviest load, which users or applications cause the most traffic, and if there are failure points (for example, broken cables, bad connectors, failed links, or misconfigured protocols). Compare the actual traffic and performance levels on your network with the known capacity of the hardware that composes your network.
For example, if you\'re using 10Mbps NICs and hubs on your network and the average network load is around 7 or 8Mbps, you have little room for additional traffic. A network consistently operating at 70 percent of available capacity would experience severe performance degradation if Internet information services were added to the existing system.
As mentioned earlier, adding one or more Internet services to your current network will increase network traffic levels significantly. Often, adding Internet services requires an increase in the capacity of your network. Some considerations involved in expanding the capacity of your network include the following:
ä The number and type of services provided by the proxy server
ä The number of users accessing those services
ä The restrictions that will be implemented (particular users or groups, time of day, or amount of data)
ä The number of users that may be added in the next year

Needs Analysis
Determining your current needs involves making a list of services and features required on your network to improve or expand its current capabilities. This list can range from information services, to security restrictions, to content sources. To help you focus on this process, the following questions related to this process have been included. The needs analysis questions are divided into three categories:
ä Why do you need Internet access?
ä Connectivity What hardware do you have? Does it need to be up-graded?
ä Security What type of access will you allow through Proxy Server?

Why Grant Internet Access?
If you\'ve come to this section of the book, you\'ve probably already decided to connect to the Internet using Microsoft Proxy Server. However, the following are some questions to help you justify this implementation:
ä What are the top three reasons you need to add Internet access to your network?
ä How will your products and/or services be improved with Internet access?
ä Is Internet access just today\'s latest business