Comment 16 for bug 1846285

@Miguel

Hi Miguel. For me, there is one obscure thing about routed network is how routed network assure L3 network connectivity between ToRs.

From the sentence of documents (https://docs.openstack.org/neutron/pike/admin/config-routed-networks.html), there is a sentence 'In the future, implementation of dynamic routing protocols may ease configuration of routed networks.' How was admin configure of infra network with/without dynamic routing protocol?

I think integration of L3 network into underlay(or infra?) network is key point to implement this extended routed network model because without it, I could not find ideal way to follow core concept of neutron.

My current naive idea is that
1. Abstract underlay network using current encapsulation(vxlan, gre...) mechanism, propagate routing entries to each hypervisors using tunnel. It looks like calico way except they does not encapsulate for tenant.

2. Pre configure ToR using BGP and hypervisor make some encapsulation(mpls..) between ToR and hypervisors. It looks like networking-bagpipe L3VPN implementation.

I think both way seems not to be easy since current neutron abstract underlay network considering them blackbox.

Any advice would be appreciated. Thanks.