Should routed interfaces created from a VLAN with mode 'route' honor the prefix assigned to that VLAN?

[jbemmel]

Acknowledging all the caveats around 'route' mode VLANs, an example (trying to showcase all options):

vlans:
  bridge:
    mode: bridge
    links: [ s1-h1, s2-h2 ]
    # isis.metric: 20
  irb:
    mode: irb
    id: 32
    links: [ s1-h3, s2-h4 ]
    pool: vlan32
    gateway: True
  route:
    mode: route
    prefix:
      ipv4: 172.31.1.0/24
    links: [ s1-h5, s2-h6 ]

The route VLAN is created as a subinterface, but its IP address is not taken from 172.31.1.0/24

[ipspace]

If all devices connected to a link use a routed VLAN, the link becomes an independent subnet, and we could have many of those in some scenarios (example: VRF lite running over VLAN trunks). Such independent subnets need unique IP prefixes or you'd get duplicate subnets.

Described in the last two paragraphs of https://netlab.tools/module/vlan/#vlan-addressing

[jbemmel]

ok, so should we issue a warning that the given prefix will not be used?

[ipspace]

We could do that.