One of the most important factors in determining the size of a Service Assurance deployment is quantity of devices and applications that must be managed. Estimate all managed devices in a network once. Include the following types of devices:
All routers, including virtual routers
Hosts that will be managed, including virtual machines
Any other devices that will be managed
All managed applications should also be counted: if an application consists of component processes, count each process.
VMware, Inc. has determined that even in well-managed large networks, administrators can underestimate the quantities of devices and applications that they intend to manage.
If possible, validate the estimated quantities for some portion of the network. If the estimate does not match, try to obtain an improved estimate for another part of the network and then validate again. If improving the estimates is not possible, determine the percentage error and use it to adjust all the other estimates.
As a final step in estimating the quantities of managed devices and applications, account for growth of the organization’s network and for planned application deployments.
Your Service Assurance deployment design should account for network growth over the expected life of the design. The network growth rate will relate to the vertical market environment and the organization’s plans, so the organization must provide you with growth estimates.
Information on the future deployment of business applications may be more difficult to obtain. For example, an organization’s budgetary plans may provide useful information, but may not be available to you. Interviews with IT staff may be your best source of information.