Passthrough NIC - What are they?

[MiniKnight]

Seen lots around used but wondering what these are. Can they be used as a normal NIC? What is the difference? Anyone using them and how?

 

[dswartz]

Not sure where you are referring to, but the context I am familiar with: sometimes someone dedicates a specific NIC to a specific VM, so they (if the HW permits) pass the PCI device through to that guest, so it can manipulate it without any hypervisor interference. AFAIK, there is nothing 'passthrough' about the NIC itself.

 

[cactus]

My understanding is they are designed to fail closed(if the card dies two interfaces will be linked together). One would use one in an inline packet sniffer or IDS. If hardware fails for some reason the link will not go down.

 

[dswartz]

Oh, unfortunate use of the term passthrough then, from my POV anyway

 

[cactus]

Oh, unfortunate use of the term passthrough then, from my POV anyway

Bypass is the correct term.(Just spent half hour trying to remember that) Here is an example. I believe that is what miniknight was referring to. I know I have seen them on ebay before and thought WTH is that.

 

[MiniKnight]

Bypass is the correct term.(Just spent half hour trying to remember that) Here is an example. I believe that is what miniknight was referring to. I know I have seen them on ebay before and thought WTH is that.

Sorry bypass is what I meant. Those cards are cheaper sometimes.