Cumulus NVUE VLAN use cases: Mixed trunk

[jbemmel]

I'm working on a PR that enables Cumulus NVUE to support all VLAN use cases, including the 5 that are currently not supported

• Need to change vlan.model to router in order to support 63-vlan-mixed-native
  => This alters the YAML that gets generated, trunk_ids are replaced by sub interfaces
• 63-vlan-mixed-native requires the native VLAN to be configured on interface.bridge as an untagged vlan, plus a subinterface with tag and IP - unlike case 61-vlan-routed-native where there is no bridge involved, and the native VLAN IP is on the parent interface.

I've added a quirk that adds the correct subinterface ifname for the mixed trunk use case, but I was wondering if there could be a more elegant way to handle this in the core model ( e.g. always create a subinterface for the native vlan instead of combining it with the trunk port )

[ipspace]

Some things are not worth solving ;) Trying to make the VLAN-aware Linux bridge act like a router is definitely in the "hammering star-shaped pegs into heptagonal holes" category.

However, if you insist, you could probably use something similar to what @ssasso had to do with Juniper interfaces.

[ipspace]

Implemented as far as @jbemmel could push it ;)