My lab network design

Inspired by Chris Wahls blog post “Building a New Network Design for the Lab”, I want to describe how my lab network designs looks like.

The requirements

My lab is separated from my home network, and it’s focused on the needs of a lab. A detailed overview about my lab can be found here. My lab is a lab and therefore I divided it into a lab, and an infrastructure part. The infrastructure part of my lab consists of devices that are needed to provide basic infrastructure and management. The other part is my playground.

While planning my lab, I focused on these requirements:

  • Reuse of existing equipment
  • Separation of traffic within the lab and to the outer world
  • Scalable, robust and predictable performance

The equipment

To meet my requirements, I had the following equipment available:

  • HP 1910-24G switch
  • HP 1910-8G switch
  • Juniper 5GT firewall

The design

The HP 1910 switch is an awesome product with a very good price / performance ratio. Especially because the can do IP routing, which was important for my lab design. Each of my ESXi hosts has 4x 1 GbE interfaces, plus one interface for ILO. In sum 20 ports are necessary to connect my ESXi hosts to my network. The 1910-24G and 1910-8G were connected with a 1 GbE RJ45 SFP. The 1910-8G is used to connect the firewall and client devices, e.g. a Thin Client or a laptop. No other devices are connected to my lab. Because storage is delivered by a HP StoreVirtual VSA, no ports are needed for a NAS or similar.

To separate the traffic, I created a couple of VLANs. Unlike Chris, I’m still using VLAN 1 in my lab. In a customer environment, I would avoid the use of VLAN 1.

VLAN ID Name Usage
1 Access (Default) Client connectivity
2 Management ILO, Management VMkernel ports
3 Infra VMs and devices for the lab infrastructure
4 Lab 1 Lab VLAN
5 Lab 2 Lab VLAN
6 Lab 3 Lab VLAN
7 Temp temporary connectivity
10 iSCSI 1 iSCSI
11 iSCSI 2 iSCSI
200 vMotion vMotion VMkernel ports

VLAN 1 (Default) and 3 are carried to the 1910-8G. All VLANs are carried to the ESXi hosts using trunk ports on the 1910-24G. The Juniper 5GT is connected to the 1910-8G and the trusted interface is connected to an access port in VLAN 3. The untrusted port is connected to the outer world.

The routing is a bit complex on the first look. I configured a couple of switch virtual interfaces (SVI) on the 1910-24G. I configured a SVI for the VLANs 1, 2, 3, 7, 10, 11 and 100. But how do I get traffic in and out of my lab VLANs? I use a small firewall VM that is housed in VLAN 3 (Infra). It has interfaces (vNICs) in VLAN 4, 5 and 6. With this VM, I can carry traffic in and out of my lab VLANs, as long as a policy allows the traffic.

I use  /27 subnets for VLAN 1 to 7, two /28 for VLAN 100 (NFS) and 200 (vMotion), and two /24 for VLAN 10 and 11 (both iSCSI).

VLAN ID Name IP Subnet
1 Access (Default)
2 Management
3 Infra
4 Lab 1
5 Lab 2
6 Lab 3
7 Temp
10 iSCSI 1
11 iSCSI 2
100 NFS
200 vMotion

I don’t use a routing protocol inside my lab. It looks complex, but with this design I can easily separate the traffic for my three lab VLANs. iSCSI is routed, but I don’t route iSCSI traffic. The same applies for NFS. This drawing gives you an overview about the routing.

Patrick Terlisten/ Creative Commons CC0

Patrick Terlisten/ Creative Commons CC0

To simplify address assignment, I use a central DHCP on VLAN 3 with several scopes. The HP 1910-24G and my firewall VM act as DHCP relay and forward DHCP requests to my DHCP. For each VLAN only a small number of dynamic IPs are available. Usually, the servers get a fixed IP.

1 Access (Default)
3 Infra
4 Lab 1
5 Lab 2
6 Lab 3
7 Temp

The VLAN 10 is used to carry iSCSI from the HP StoreVirtual VSA to my ESXi hosts. The second iSCSI VLAN (ID 11) can be used for tests, e.g. to simulate routed iSCSI traffic. The VLANs 4, 5 and 6 are used for lab work. Until I add a  rule on my firewall VM, no traffic can enter or leave VLAN 4, 5 and 6. When deploying a new VM, I add the VM to VLAN 1 or 3. The VM is installed using MDT and PXE. After applying all necessary updates (MDT uses WSUS during the setup), I can add the VM to VLAN 4, 5 or 6.

Final words

Sure, a lab network design could be easier. The IP subnets can be a pitfall, if you’re not familiar with subnetting. The routing seems to be complex, if you’re not an expert in IP routing. Until today, the network has done exactly what I expected.