There are a number of different factors that can affect the performance of your VPN. Some of these components will affect the client or server independently, but the overall VPN functionality will be influenced. Network conditions on the hosting Internet service provider, CPU and resource availability, and transport technology are but a few things to look at when troubleshooting performance problems.
In this chapter, I have illustrated some tools that can help determine performance as well as provided hints as to what can lead to performance degradation. At this juncture, you should be able to identify these items, along with many that were not mentioned.
Your troubleshooting should concentrate on the things you can quantitatively test and measure, followed by those components or variables you have control of.