Network card with relay in case of power failure

Joel Jaeggli joelja at
Wed Jun 17 21:17:09 UTC 2020

> On Jun 17, 2020, at 13:14, Dovid Bender <dovid at> wrote:
> Hi,
> I am sorry if this is off topic.I was once demoed a network device that had two interfaces. The traffic would go through the device. If there was a power cut or some other malfunction there would be a relay that would physically bridge the two network interfaces so the traffic would flow as if it was just a network cable. Is anyone aware of such a network card or device?

that kind of device is an ethernet bypass tap.  the device is relay driven and closes when it loses power bypassing the in-band device.

there are others which require that they remain powered, but use a heatbeat of some flavor to detect failures and switch the path accordingly.

copper tap infrastructure has kind of fallen out of favor as ports have gotten faster (vs just spanning on a switch or router or passive optical taps) but it still exists.

gigamon / niagra and a number of white-box  tap manufactures make device that would be referred to as active bypass taps.

> TIA.

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