Many Internet connections suffer from overload. The simultaneous use for the web access, the FTP download, email traffic and VPN often cause traffic to collapse completely. Here you need meaningful prioritization of Internet traffic. Before you buy expensive additional devices, you should check out the possibilities under Linux. Especially if you are already using a Linux firewall, the following options are available of QoS under Linux.
Prerequisites: Experience in the administration of a Linux system, knowledge of network protocols.