I am looking at an automation element for a training environment.
We would like to be able to fail a cable without doing a shutdown on the interface or having an engineer physically remove the cable from the switch.
I would like this to be as transparent as possible. I've thought of the following:
1) Using a switch with Fa0/1 as input interface and Fa0/2 as end device. Put them on the same VLAN. These ports can both be shutdown which would simulate a cable failure at the switch and end device. The downside of this method is that both ports need shutdown otherwise you will black hole the traffic. Similarly the MAC Address seen by the original switch will see the MAC Address of the secondary switch, rather than the end device.
2) L2 Protocol Tunnelling. I looked at this on the Cisco switches but it seems to suffer from the same problems as 1). The MAC Address would not match.
3) Using a Linux box with multiple ethernet interfaces and forwarding traffic at a L2 level between two interfaces. Using some basic scripting the MAC Address could be spoofed such that the original switch would see the same MAC Address as if it were directly connected. I'm not clear on the details for this method but believe it would work but it is not an off the shelf solution.
4) Alternatively a simple mechanical on/off switch would suffice but I have yet to find one easily available. The only solution that I've found is on Youtube here: https://www.youtube.com/watch?v=u9Etvk5CnqM