I am building a network with stacked switches for redundancy. The problem I have is that some of the machines connected to the network will only have one available network card. This card is not a dual port card so I will only have one port.

Do I have pseudo-network fault tolerance with a simple unmanaged switch? The reason I am doing this is because there are many machines on the network and if a managed switch goes down, all the machines should not go with it. If the unmanaged switch goes down it will only take the local machines access with it.

1 Answer 1


No. What you are proposing is to create a loop in your network with an unmanaged switch and then hoping it understands spanning-tree, or hoping that it forwards spanning-tree through itself so the two upstream managed switches can work out that there is a loop and block one of their downstream ports.

Best case for single-NIC servers is a highly available network switch (dual power supplies, possibly dual supervisors and/or some type of ISSU). Or you can add a second NIC or create some type of HA cluster with another single-NIC server attached to a different switch.

  • I have read a paper from cisco and its description of a redundant star network contradicts what you are saying. Am i misunderstanding it? cisco.com/web/strategy/docs/manufacturing/… its on page 11
    – DavyGravy
    Commented Nov 19, 2014 at 8:38
  • If you mean figures 4 or 5, the L2 switches they are using are not unmanaged, but full spanning-tree capable switches that will actively participate in STP and use standard loop-avoidance decision-making.
    – cpt_fink
    Commented Nov 19, 2014 at 8:41
  • Thanks for the answer! Now a cheeky question..do you have any recommendations? for en indstrial one(2 inputs) and a 8 port one? I'm off to look for them now it was only if you had a recommendation Im gratefull for the answers you already gave. edit I found this one I guess that should be good enough right? trendnet.com/langen/products/…
    – DavyGravy
    Commented Nov 19, 2014 at 11:36

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