Determining if the WAN needs to be upgraded or if I need QOS enabled. I have a site which uses a 10mb WAN link. The users are complaining about slow network. Looking at MRTG, I can see the bandwidth does peak a couple of times a day. (explaining the users complains). But on average, it runs around 4mb. To my surprise, when I ran Iperf for about 2 minutes non-stop, I can fill up the 10mb link. I'm deducing that if a user starts a huge file transfer, he will eventually fill up the link as well. That explains the peaks. My question is by enabling QOS, will I be able to lower the priorty of file transfer and increase the priority for applications (office suite).