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the host, and you should not overthink the architecture of this simple network. Think of the
virtual switch as a simple pass-through, a simple linking mechanism that connects the physical
NIC to the virtual NICs in the virtual machines and is configured as an external type of vir-
tual switch. The host's NIC is then connected to the port assigned to the specific VLAN that
the virtual network needs to be a part of, and that's it. There is no special configuration; it is
as if you just plugged your machine to a switch port assigned it to a specific VLAN.
Multiple VLAN Using Multiple NICs with Virtual Switch Binding
In a more complicated networking scenario, we have two sets of virtual networks, each con-
nected to an external-type virtual switch. This is the same method as the previous one only
multiplied. Because only one external-type virtual switch can bind with a physical NIC, the
host must have two NICs installed and two different ports on the physical switch configured
for each VLAN and then connected to the appropriate NICs on the host via cables.
If you want to add more VLAN segments, then more NICs will be required on the host.
But this time we can change the settings a bit by setting the VLAN configuration and assign-
ment of the VLAN ID on the virtual switch and then setting the ports on the physical switch
as trunk ports, which are not tied to specific VLANs. This means that you can plug any of
the NICs to any port because they are configured as trunks and will not do VLAN tagging;
this will be done by the virtual switches. However, this presents an obvious limitation, which
can be solved by the method described in the next section.
VLAN ID Setting on VM
The method described in the preceding section has a major limitation in regard to the
number of NICs and VLANs, but this next one can address this problem properly. You
can create as many VLANs as you want using only a single virtual switch, which also
means only one NIC on the host and one port on the physical switch will be required. The
configuration for the VLAN and assignment of the VLAN ID will be transferred to the
virtual machines themselves, so now they will associate themselves with a specific VLAN,
and you would not need to do anything on the virtual switch. Simply set the physical
switch's port to trunk mode. You can configure the VLAN IDs on the virtual machine's
virtual NIC console.
Assigning IDs
Based on the preceding scenarios, there are several ways for assigning the VLAN ID in
order to create a VLAN or assign a device to it.
You can assign the VLAN ID to the ports of the physical switch, which converts them
all to access ports. Any device attached to those ports automatically becomes part of
that specific VLAN.
With this method, you need another group of virtual machines to be part of a different
VLAN segment; then they would need to be connected to a different virtual switch,
which would also require an additional physical NIC on the host because an external-
type virtual switch binds to a host NIC in a one-to-one manner.
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