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I've just set up a rack with a SFP input into a Dell N2024, with a /28 routed to the switch which I can then use as required for devices within the rest of the rack.

This is working fine from a single setup point of view, but I'd also bought an additional switch, under the guise that they'd be setup to redundantly fail over should the first switch fail. The network engineers haven't done this though as part of the original installation and now I've got to work out how to complete the redundancy setup. I've not had much experience with these switches though (or setting them up in a redundant fashion before)..

It looks like I've got two options:

  • Firstly, get the switch setup how we want it, then copy it's config to the second, although it's a critical service, I'd be happy with a manual move to the switch below (i.e in the unlikely case of complete switch failure some downtime whilst the switches were swapped wouldn't be a huge issue)
  • Secondly, work out how and what the process is, to set these switches up in a redundant fashion. Am I right in assuming, I'd need a second fibre in (for the SFP port the second switch), as well as dual outputs to each router/firewall? What are the technologies involved in this process?

Any help is much appreciated

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Since your switch is stackable, you could configure link aggregation between your devices and your switches, being one interface on one switch and another interface on the other switch.

Should any of the switches fail, all traffic would still be able to reach destination with a few packet drops but quick convergence without the need to reconfigure. As a bonus, you'd get double bandwidth.

This switch (as a stack) can be configured with up to 128 LAGGs.

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  • So this would require 2 incoming SFP connections, as well as 2 ethernet interfaces for every machine that connects to the switch(es)?
    – kwiksand
    Jul 30, 2014 at 13:54
  • Exactly. One to each switch
    – Pedro Brito
    Jul 30, 2014 at 14:01
  • Thankyou! I was under the mistaken impression that whilst stacked/linked the switch may use an input (i.e the fibre connection) from the other switch, but that really doesn't make sense, because if that switch dies, it wouldn't be 'stacked' any more
    – kwiksand
    Jul 31, 2014 at 12:47
  • You were not wrong. When they are stacked, they act as one and the traffic can arrive in an interface connected to SW1 and leave from SW2. It just isn't very useful for your purpose because you want to be able to quickly recover from hardware failure. In this case, it's better to have one connection to each switch, should any of them fail, you're covered.
    – Pedro Brito
    Jul 31, 2014 at 14:31

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