Welcome to Tech TopX. My name is Jason, and today we're going to talk about
virtual machine networking in the Acropolis Hypervisor. We've introduced a
new feature called VLAN trunking, but before we go into the details of that
let's talk about how Access mode works for virtual machine networking. So in our
Acropolis Hypervisor, we have an Open vSwitch bridge0. This Open vSwitch
bridge0 allows us to connect to a regular switch. So this switch is going
to be trunking many VLANs up to the Acropolis Hypervisor. So in this diagram
right now, we have just a single connection and a single VLAN trunked up
to the hypervisor and connected to the bridge0. So we would have a virtual
machine connected to the bridge0 as well. So in this sort of environment, we
would have a VLAN tag coming from the switch. Let's call this TAG100. The
bridge0 in the OVS switch is going to take off this VLAN TAG100 and pass
it, untagged, up to the virtual machine. When a virtual network is created and
connected to a virtual machine, the access mode is the default mode. Untagged
packets are passed to the virtual machine and there's one virtual network
assigned to that virtual NIC. In this case, VLAN 100 would be passed up
untagged to the virtual machine. If we wanted to add an additional network,
let's say we have
VLAN TAG200, we would have to create a new virtual NIC inside the virtual
machine. So now we're passing up two untagged networks - network 100 and network 200 - and
there are two virtual NICs inside of the virtual machine that that deal with this
traffic. The default configuration is called Access mode. Starting in Acropolis
Hypervisor 4.6, we've added a new feature called VLAN trunking for virtual machine
networking. In a VLAN trunked mode, we have our Acropolis Hypervisor and an Open
vSwitch bridge0. This is connected to a switch. And we have still our TAG100
packets and another network of TAG200 packets, and these networks go up to the
virtual machine, but we have a VM created with a port type of 'trunk'. So with a
trunk port type, you select the native VLAN - and in this case the native VLAN is
going to be 100; there's going to be no tag on this VLAN. So this will be just
simple untagged traffic passed up on the native VLAN 100. So as far as the virtual
machine is concerned, there's no VLAN tag on this packet. We've added a trunked
VLAN to this NIC though, and this NIC does get TAG200 traffic sent up to
it. So from the switch through the OVS, traffic will be sent on VLAN 200 with a
VLAN tag. The virtual machine can also send traffic
and put the VLAN 200 tag on the packet, and the Open vSwitch will
recognize it. This is really useful in scenarios when we have a virtual machine
running an application that might want to have multiple networks but only a
single network adapter. Some instance of this could be things like virtual
firewalls. So, as we can see, compared to the Access environment, we have to have
two virtual NICs. In the trunked environment, we have one virtual NIC and
it can have multiple networks. So let's see what that looks like when we have
more than just one network. So we'll create another virtual machine. We're
going to say that 100, no tags - so that's our native VLAN - and we might have
multiple VLANs such as 200, and we could even have VLAN 300 trunked up to the
machine as well. These would all be on a single NIC. The VLAN trunking feature
allows us a lot more flexibility in bringing virtual networks up to a
virtual machine. We can still use the Access mode of networking where
individual VLANs are sent untagged to separate network adapters, or we can use
the trunk mode where we have one native VLAN sent without a tag and potentially
multiple networks sent tagged up to the virtual machine. For more information on
configuring trunked VLANs up to a virtual machine, check out the Acropolis
Hypervisor administration guide. Thank you for watching Tech TopX.