How to limit download speed per port on the network?
Solution 1:
Some routers can limit bandwidth per port or per client or per address block using QoS. The exact method of doing it (if at all) would depend on the model of router you have. If you are only using switches in a parallel configuration with static IPs then no, unless you can talk your ISP into setting it up for you (which some will per IP or IP block for a price).