Support for VLAN networks in Distributed Virtual Router (DVR)

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With Juno deployment, users of openstack neutron can deploy distributed virtual routers as referred in [1].

DVRs enable routing between tenant VMs without the need to deploy a centralized node to host tenant routers. Tenants can create distributed routers and such routers are made available on-demand basis on the compute servers that have tenant VMs on subnets hosted by the router.

However, in Juno release of neutron, distributed router interfaces that are managed can belong only to VXLAN (or) GRE network types.

The capability to host VLAN network types as distributed router interfaces was not available.

Problem Description

As explained in the introduction section above, Juno release of openstack makes available distributed virtual routers. However, the implementation available is functional only for network_types for VXLAN and GRE.

This blueprint will address the following gaps:

1. Enables VLAN Networks to be hosted as distributed router interfaces More specifically, if two networks are attached as interfaces of a dvr, of which both the networks are VLAN type, then VMs on such network can route traffic between each other transparent to the tenant, via this blueprint.

2. Enables a distributed router to route packets between a VLAN network, VXLAN network and GRE network. More specifically, if two networks are attached as interfaces of a dvr, of which one is a VLAN network and another is a VXLAN network, then VMs on such network can route traffic between each other transparent to the tenant, via this blueprint. Similarly, this blueprint also enables routed communication between one interface of the dvr being on VLAN network and another interface being on GRE network. Also, this blueprint also enables routed communication between one interface of a dvr being on a VXLAN network and another interface being on a GRE network.

We are intending to clarify here that this blueprint would enable only routed traffic to pass through disparate network types (only VLAN, VXLAN, GRE). This blueprint does not propose a gateway to switch traffic across disparate networks.

Proposed Change

We will be making changes to the following components of the Openstack Neutron as part of implementation of this blueprint:

a. The DVR RPCs serviced by the ML2 Plugin will be enhanced to provide physical network information that will be used by the OVS Neutron Agent to plumb VLAN network-type ports as DVR interfaces.

b. The OVS DVR Neutron Agent will be enhanced to embrace VLAN network-type thereby allowing tenant VMs that are on VLAN networks to communicate via distributed router. Also it will be enhanced to enable tenant VMs (one on VLAN and other on VXLAN/GRE network) to communicate via distributed router. By enhancement, we want to refer that OVS Rules will be added to integration-bridge and physical-bridges by the OVS DVR Neutron Agent in order to enable routing between VMs on different VLAN networks and also to enable routing between VMs that each reside on a VLAN network and a VXLAN/GRE network.

So, the blueprint will enable DVR openvswitch implementation to embrace VLAN network-types.

Data Model Impact




Security Impact


Notifications Impact


Other End User Impact


Performance Impact


IPv6 Impact

This change will not have impact on IPv6 in Neutron.

The Distributed Virtual Router (dvr) in [1] does not support IPv6 networks. And, so the DVR feature must first be enhanced to support IPv6 as a separate blueprint. Until then IPv6 tenant networks will not able to take advantage of the DVR feature in neutron.

Other Deployer Impact


Developer Impact


Community Impact

The Neutron community embraced the DVR feature in the intent that it resolves parity issues with nova-network. This blueprint will further close gaps to bring-in more parity.





The author of this blueprint will be posting code for reviews by the community.

Primary assignee:
Other contributors: (kevin benton) (review) (review) (review)

Work Items

The following are the work items involved for execution of this blueprint:

1. Primary code-piece development in Neutron to enhance existing DVR logic to embrace VLAN networks (in addition to retaining the functionality to host VXLAN/GRE networks).

  1. Unit test cases development to ensure test coverage for this feature.

3. There will be functional test cases that will be added in initial commits to test the feature.

4. In the longer term (in next release), the existing DVR CI would be enhanced to embrace VLAN-type networks as DVR interfaces.


Depends on the Distributed Virtual Router blueprint as in [1].


As mentioned in Work Items, initially functional tests will be made available to test this feature. Later the existing DVR CI (available at gate) will be enhanced to embrace testing VLAN networks with DVR.

Tempest Tests


Functional Tests

Functional tests cases would be provided to test this feature.

API Tests


Documentation Impact

There will be documentation impact as we need to include in the openstack neutron manual, that DVR is capable of supporting VLAN network-type. The auther and the extended existing DVR team will work with neutron documentation in including this feature.

User Documentation

Openstack Networking Administration Guide will be updated to reflect the capability brought in by this blueprint into DVR.

Developer Documentation