Historically with capacity planning, once a link started running over a predetermined threshold on a regular basis it would be time to consider a bandwidth upgrade. WAN optimization devices removed some of the factors that prevented protocols from using all the available bandwidth, and as such, I have seen links that were running at around 30-50% now regularly run at close to 100% utilization after the addition of WAAS devices.

Whilst this is positive as the customer is now fully utilizing the WAN links (often more than the specified link bandwidth is available due to the use of techniques such as compression); it does prompt the question of when to upgrade the link?

Does anyone have any ideas, guidelines etc?

Thanks