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I have two servers with two Ethernet ports each. I also have two managed Cisco switches.

Is it remotely possible to have each server connect to each switch in a way to make the switches automatically handle one of the switches dying?

I know very little of networking, but it seems to me like there would be a way to do something like LAGG across both switches and have the switches communicate with each other in a master/slave failover way.

I'm not looking for the best way to handle this necessarily, more just wanting to know if a method exists and a possible light description of it and how it COULD work.

  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 8 '17 at 20:35
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What models are those Cisco switches?

If you can stack them, then yes - You can connect them in stack and aggregate ports from both of them to the servers, and connections will work.

If you can't stack them, but you can connect them together, you can still connect the servers to both of them, but you won't be able (propably) aggregate ports from both of them, as this requires features like VSS and/or mLACP. Still - rather higher-end gear.

At the worst possible case, you connect server to two different switches and pray Spanning Tree will work correctly, closing one of the connections for forwarding the traffic. Otherwise, you may end up with loop in the network, or periodic loop, and they're hard to troubleshoot or nail down in non-trivial topologies given limited instrumentation on the host with two NICs (this assumes NIC driver can actually participate in the SPT, some of them can't and you'll end up with two separate links to both switches - which will work also, but isn't what you've asked for).

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You want to implement NIC teaming on the server. Depending on the server and OS there are drivers assoicated with the NICs, or if you run windows 2012 that feature is built into the OS. There may be other OSes that support NIC teaming (I know esx does) but I am not familiar with ,NIX. Or you can try to 'dual home' the server that is give each NIC its own IP address and have the default gateway point out both switches.

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