Some tools and applications on Linux take up all the available bandwidth. Even if there is a lot of bandwidth available, they take all of it. They have no built-in traffic throttling feature.
A small GUI tool that allows to assign a bandwidth limit to tools and applications would allow to manage the traffic.
For example one could assign a maximum value of kb/s or kbit/s to an application or one could assign a maximum percentage of the total bandwidth to an application.