ever heard of the new highway? some people built a new highway because the old road was getting too small for the amount of traffic on it. so everybody was happy when the new highway was done. while the highway was still new, everybody said it was great that they had that much space to run and cruise in it. so everybody's friends and families soon started driving on the new highway until eventually everybody was thinking the highway was now too small and they needed another new highway ...

moral of the story? if you do not have enough, you will soon be looking for some more. if you have more than enough, people will start filling it up sooner or later.


as i almost always had to guesstimate things because of the lack of access to network metrics, i look at current load and whether that load has increased over the years as well as whether there are plans to put in more network-hungry apps/devices (i.e., video conferencing). if current load has been increasing, i look at the amount and rate of the increase.

as an example: 10 users at a remote site using 5 applications at the corporate site at year 1 and 50 users (max capacity) at the remote site using same 5 applications at the corporate site at year 5 -- only the user base increased. minus any planned implementation of network-hungry apps/devices and no complaints of performance hits even with the increase in the user load, i will not be looking to upgrade within the next 2 years unless the company just wanted to spend money just because.

for a site with an unknown load, look at the kind and size of the population the site most likely will be hosting as well as the apps/devices they will be using and the planned infrastructure physically located at the site. if you have no other site that is currently comparable to the new site, check how many seats are planned in the space as well as how big is the data center/room and correlate that with the business and/or group that will be located there (i.e., software development, banking back-office, internet research, etc.). decide the approximate load and plan accordingly. if you are still at a loss and still cannot decide, ask the project manager how much they have budgeted for the whole project and just reasonably ask for as much as they can give you.