Hereby you limit e.g. the entire or connection-related maximum bandwidth for server accesses.
An example:
You operate both a Web server and a local network on a shared Internet access.
To prevent that your productive network (LAN) is paralyzed by many Internet accesses to your Web server, all server accesses are limited to half of the available bandwidth. Furthermore, in order to guarantee that your server services are available equally to many users at the same time, a certain maximum bandwidth per each server connection is set.