That's what happens when an Internet service provider finds its pipe plugged up by sudden huge bursts of traffic. In these cases, packets of data are bottlenecked and can't get through the routers. Now a fresh surge of packets flows all at once, this time completely swamping the router, which can only thrash and churn. With simple dial-up service, modems can't go faster than their advertised speed. But with wireless and other broadband equipment, all bets are off.
Broadband modems can request huge surges of transfer, well beyond the contracted amount.
If this swamps the pipe, even users who aren't making exorbitant demands find their service comes to a grinding halt. The only remedy is to shape the traffic so no individual user is starved for bandwidth. Dyband software, installed at the ISP's end, gives all users their contracted bandwidth allowance when traffic is normal. What's important is that the entire system will NOT grind to a halt. Those moderate users will be allowed to burst above their agreed bandwidth allowance, so long as this happens only occasionally.