Networking Capabilities (IPv4, IPv6, Dual Stack)

StarlingX OpenStack supports IPv4, IPv6, and dual-stack networking across platform networks and project networks. Administrators configure the IP version per network, giving each deployment the flexibility to match its addressing requirements without redesigning the underlying infrastructure.

Most platform networks accept either IPv4 or IPv6 addressing. The one exception is the PXE boot network, which requires IPv4 because the platform does not support IPv6-based host booting. Project networks go further by supporting dual-stack operation — both address families active on the same network simultaneously — through OpenStack Neutron.

The following platform networks support both IPv4 and IPv6:

  • Internal Management network — Carries inter-host communication between controller, compute, and storage nodes.

  • |OAM| network — Provides external administrative access to the platform.

  • Cluster Host network — Handles Kubernetes cluster communication between nodes.

  • |VXLAN| Data networks — Carry encapsulated tenant traffic between compute nodes. The underlay addressing for VXLAN tunnels supports both IPv4 and IPv6. Flat and VLAN data networks operate at Layer 2 and are address-family agnostic.

Project Networks

Neutron project networks support IPv4 subnets, IPv6 subnets, and dual-stack configurations where a single network carries both address families concurrently. Virtual machines communicate over IPv4 and IPv6 simultaneously without requiring separate network segments.

IPv6 capabilities on project networks include:

  • DHCPv6 — Neutron’s built-in DHCP service provides stateful and stateless address assignment on IPv6 subnets.

  • IPv6 routing — Neutron routers route IPv6 traffic between project subnets and toward external networks.

  • Router Advertisement (RA) — Neutron emits Router Advertisements on IPv6 subnets to support SLAAC for virtual machine interfaces.

Note

IPv6 is not supported for access to the Nova metadata service, SNAT, or Floating IPs. These functions remain IPv4-only. In dual-stack deployments, virtual machines that require metadata access or inbound Floating IP connectivity must retain an IPv4 subnet on the project network.

Dual Stack

In a dual-stack configuration, a Neutron network carries both an IPv4 subnet and an IPv6 subnet. Virtual machine ports receive addresses from both subnets, enabling the guest operating system to communicate over either protocol.

Dual-stack operation addresses common deployment scenarios:

  • Migrating workloads from IPv4 to IPv6 incrementally without requiring a hard cutover.

  • Supporting applications that must be reachable by both legacy IPv4 clients and IPv6-native clients.

  • Operating in environments where external routing policy or upstream connectivity determines which address family is preferred.

The guest operating system’s address-selection rules (RFC 6724) and the routing configuration of the attached Neutron router determine which address family carries a given flow.