Connecting both ends of an Ethernet Cable to a Switch? DoS??

Question

I was wondering what would happen if both the ends of a ethernet cable are connected to a switch. Recently a friend told me that it causes high bandwidth from the switch and could cause instability in the network. I was wondering if someone could give me more of a technical explanation

Answer 1

If both ends of a ethernet cable are connected to a switch, your switch will busy in a loop and the switch performance could causes instability in the network.

Answer 2

I'll assume you have basic networking knowledge.

connecting both ends of the cable to the switch could  cause "broadcast storm" , that's when one pc in the network sends a broadcast the switch will forward it on both ports of the cable and receive it again and forward it again to all ports and so on, at the same time the MAC address of the original PC  that sent the broadcast will appear at the all 3 ports , the original port and the other 2 connected to the cable which cause the switch to forward more frame to the wrong direction