Author: Antxon Gonzalez

VM networks are Virtual Networks virtual networks that use a VLAN tag on top of the Hypervisorhypervisor's Network Interfaces network interfaces on the physical Networknetwork.

The Physical Network Interfaces physical network interfaces belong to a Network Service Type network service type (NST), which identifies the network segment that the interface is connected to.

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Racks

Before you add a Physical Machine to physical machine to a Datacenterdatacenter, you need to create the Rack rack it will belong to.

A rack is a logical set of Physical Machines physical machines providing the same level of compute service.

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This pool is used to provide Private private networks to Virtual Datacentersvirtual datacenters.

Network service type

Every time you add a Physical Machinephysical machine, you must choose its Rack rack and specify the Network Service Type network service type (NST) its network interfaces are connected to.

A An NST is a set of interfaces providing the same network service level. You may think that of each NST is as a different network segment.

VLANs inside a an NST have the same meaning for interfaces in the same rack, while VLANs will be different for interfaces in different NSTs or Racksracks.

This does not imply that VLANs inside a NST are interconnected, as this depends on the VLAN type.

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Cloud networks

Cloud Networks networks in Abiquo are defined by their type, network service type (NST), and VLAN tag. This means that all VMs using a network will run on hypervisors with NICs of the corresponding NST.

There will always be a default NST that we call the Service Network, which is the NST that will hold most of the networking workload.

There are three different kind of networks:

• Private: Bound to the Virtual Datacenter virtual datacenter (VDC) they were created in.
  The VLAN network tag is taken from the VLAN network tag pool of a rack automatically, bounding the network workload to it.

• External: Bound to a Datacenter and an Enterprisedatacenter and a cloud tenant (enterprise).
  This means that the network VLAN tag has the same meaning for all racks in the Datacenterdatacenter.

• Public: Bound to a Datacenter datacenter only.
  They are similar to external networks, but more than one enterprise may use them.

Private networks are bound to the rack they were defined in, and their VLAN network tags have no meaning outside this rack. This means that VDCs are bound to the rack their private networks are defined in.

External and public networks can be used in all racks in a datacenter. Their VLAN network tags must be defined in the infrastructure before you define them inside Abiquo.

VMs in the same enterprise may communicate through public and external networks, or private networks is if they belong to the same VDC.

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DHCP

There are two different approaches to get DHCP working in your environment: Regular DHCP infrastructure When using SDN systems, such as NSX-T, Abiquo will use the DHCP services of the SDN system.

When you are using standard networking, you can choose between a regular DHCP service or the Abiquo DNSMasq networking solutionservice. Both solutions require a DHCP service listening to must listen on the Abiquo virtual networks (with VLAN tags in their NSTs), meaning that the service will need a NIC in each network.

If you have a large number of networks, regular DHCP may require a Relay relay network infrastructure to deal with all networks depending on their number,  while the . The DNSMasq solution has no limits to the number of interfaces the server may be listening to.

Additionally, Regular DHCP just requires an OMAPI capable server, as this is the protocol that Abiquo will use to manage the leases for the network environment.When using SDN systems, such as NSX-T, Abiquo can use the DHCP services of the SDN system.

If your datacenter is configured without DHCP servicesdoes not have a DHCP service, you can use hypervisor tools or cloud-init to assign network addresses. See Guest setup