Recently, I was asked to implement vPC connections over Dark Fiber between two data centers. Is this possible, and, if it is possible, does it have any drawbacks or limitations? I'm asked to encrypt the data involved in the vPC using MACsec. I know it is a very hard task, but any help would be useful.

  • Which sort of VPC do you mean (Virtual Private Cloud, Virtual Port Channel, or something else)?
    – Ron Maupin
    Oct 4, 2015 at 13:48
  • Virtual Port Channel
    – Gadeliow
    Oct 4, 2015 at 13:49
  • 1
    This sounds like a case of management reading a term and saying "implement that!". While I'm sure VPC over two data centers is technically possible, I don't think there's a reason you should. You may want to look at some sort of a data center interconnect protocol, or get the reasons and scope of what management wants out of connecting both data centers.
    – Theo
    Oct 4, 2015 at 17:42
  • i just do what i asked for as you know customer allwes right think godness it wasn't OTV
    – Gadeliow
    Oct 5, 2015 at 0:16
  • 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 12, 2017 at 19:04

1 Answer 1


Three words: Don't do it.

There are many reasons why, but the most important is that instead of making resilient links, you have made both data centers vulnerable to the same problem. If the VPC link goes down, both data centers will think they're active. That almost certainly means that nothing will work until you restore the link. Not exactly a robust system is it?

  • may i can cofigure vpc autorecovery
    – Gadeliow
    Oct 5, 2015 at 0:14
  • Oh, I'm sure you can make it work. I just predict a day will come when you wish you hadn't.
    – Ron Trunk
    Oct 5, 2015 at 1:22
  • 1
    Also too, depending on the length of your dark fiber, and if you're using DWDM - you would almost definitely (eventually) see your VPC go split brained, without seeing any of the physical links flap. Microflaps can break networks. AND if it's provided via a third party and you're leasing it (Zayo, Level3, whoever) you're at their mercy for maintenance. They will perform maintenance whenever they want, very rarely will you or your company pushing back do anything, you'll also be lucky if they tell you. Oct 5, 2015 at 14:09
  • Why not suggest making it redundant instead of just saying it's all out a bad idea?
    – kll
    Oct 27, 2015 at 14:06
  • @kll Because it is a bad idea. You are just complicating a bad design. There are other ways to achieve redundancy that don't have such catastrophic failure modes.
    – Ron Trunk
    Oct 27, 2015 at 14:08

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