You need to understand your existing network infrastructure to determine how well it can meet the needs of your deployment goals. By examining your existing infrastructure, you identify if you need to upgrade existing network components or purchase new network components. You should build up a complete map of the existing network by covering these areas:
Physical communication links, such as cable length, grade, and so forth
Server information, including:
Locations of devices on your network, including:
Routers and bridges
Number of users at each site, including mobile users
After completing this inventory, you need to review that information in conjunction with your project goals to determine what changes are required so that you can successfully deliver the deployment.