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I am not a network guy, but rather a general IT guru that knows just a small bit about networking in general (enough to get myself in trouble!).

My business has been growing over the last several years, and as it has grown my need for IP addresses has grown with it. As a result, I now have a total of 5 network drops that go to my various servers. For the sake of this question, lets just call them Drop1 - Drop5. Each Drop gives the server its plugged in to access to a single network subnet - some of my subnets are quite small, being the oldest (/224), but I also have 2 /128s and 1 /0

Now, My /0 is currently restricted to a single physical server owing to the fact that all 4 NICs on the other servers are being used. The smallest network also goes to a single server and is not really needed anywhere else. In my current environment this is ok, but I am about to expand my business yet again and move all my physical servers to Hyper-V Hosts and create a single private cloud where VMs can essentially move from one box to another as needed for our requirements... That means that I will need to have all of my network drops available on all my servers at the same time, and I am looking for ways to get out of buying additional NICs (and of course paying the higher per month fees from the datacenter for additional drops)

Now, as I said I am not a network guru... but it sure seems to me that even tho I have multiple subnets, it should be possible get all of them on a single network drop via CAT6 somehow.

I asked my datacenter this question about a year ago, and I was not happy with their answer... it was essentially "no". I suspect I talked to a guy that did not know what he was talking about and instead of forwarding the request on, he just gave me a bunch of BS lol.

So - there is my question. Is it possible to have multiple subnets delivered to a single server with a single CAT6 cable in such a way as to make all those subnets available to both the host OS and any VMs residing on Hyper-V on that box?

Is there a hardware option to simplify the process if the datacenter is unable or unwilling to perform whatever is needed to make this happen? Such as a device that allows X number of network connections coming in, then a single gigabit connection outbound to each of my servers from there?

Now, I also already have a private LAN connecting each of my servers (which of course takes up another of the NICs for each server). This will remain as I use it for secure server to server traffic.

I have heard of VLAN, but after reading an intro I am not sure if that will help me or not... ?

Any kick in the right direction here is greatly appreciated!

Dave

  • /224, /128, and /0?!? What exactly do you mean by that? Perhaps you should read up on proper CIDR notation? Or reply with what you mean and I can help you use the proper notation. – EEAA Dec 29 '15 at 23:04
  • Not all of us can be expert's in network notation mate. Thanks for the super helpful and friendly response tho. – David Borneman Dec 29 '15 at 23:38
  • Agreed, which is why I offered to help you sort out correct terminology. It would do you well to learn it, if only so that your datacenter techs take you more seriously when you're discussing things with them. – EEAA Dec 29 '15 at 23:39
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So - there is my question. Is it possible to have multiple subnets delivered to a single server with a single CAT6 cable in such a way as to make all those subnets available to both the host OS and any VMs residing on Hyper-V on that box?

Yes, this is exactly what trunked 802.1q VLAN interfaces are for. The datacenter configures their switch port to tag each ethernet frame that leaves the port with the appropriate VLAN tag and then you configure your Hyper-V host(s) to properly "unwrap" the tagged frames into whatever switch is assigned to that VLAN.

Is there a hardware option to simplify the process if the datacenter is unable or unwilling to perform whatever is needed to make this happen? Such as a device that allows X number of network connections coming in, then a single gigabit connection outbound to each of my servers from there?

A low-end managed, vlan-capable layer 2 switch would be able to do this very easily. Each "network drop" coming from your datacenter would connect to an untagged port for its VLAN and then your Hyper-V hosts would connected to tagged VLAN ports.

  • Excellent. I had hoped that was the answer, but got very confused by a roundabout answer from the datacenter tech. Thank you very much! – David Borneman Dec 29 '15 at 23:37

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