Depends on platform's QoS features.
Traffic shaping often supported on Cisco routers, not as often on Cisco switches.
When traffic shaping supported, often can be targeted to a specific IP (not so sure about a MAC).
That said, as you ask about downloading from the Internet, shaping is applied, only, on egress from your device. Another option is rate-limiting/policing, which can be applied egress or ingress (if platform supports).
Lastly, controlling an inbound flow's rate, will fully control its rate as it passes through the controlling device, but how the "offered" rate is impacted, might not be as well controlled as desired. I mention this, because in cases where you want to control Internet download usage, even when you control ingress rate on your device, the Internet link may still be congested by the "limited" traffic.
