When enabling EVPN L3VNI, L2 VNI info disappears

[ssasso]

When I assign VLANs to a VRF, for using them with Symmetric IRB, I still want to preserve L2 VNI info (RD, RT) for my VLANs (L3 VNI shall not exclude L2 VNI).

With this topology:

vrfs:
  tenant:
    evpn.transit_vni: True

vlans:
  red:
    vrf: tenant
  blue:
    vrf: tenant
  green:
    vrf: tenant

nodes:
  h1:
  h2:
  h3:
  h4:
  s1:
    vlans:
      red:
      blue:
      green:
  s2:
    vlans:
      red:
      blue:
      green:

links:
- h1:
  s1:
    vlan.access: red
- h2:
  s2:
    vlan.access: red
- h3:
  s1:
    vlan.access: blue
- h4:
  s2:
    vlan.access: green
- s1:
  s2:

The vlans structure does not have them anymore:

vlans:
  blue:
    bridge_group: 2
    id: 1001
    prefix:
      ipv4: 172.16.1.0/24
    vni: 101001
    vrf: tenant

The problem maybe seems to be here:
https://github.com/ipspace/netsim-tools/blob/2b24377717c3233ba830b4d2abebcc46d5e847f5/netsim/modules/evpn.py#L169

When the vrf key is present, it is assumed to use vlan_bundle (which may not be supported by all the devices)

[ipspace]

The real question is "do you want to configure end-to-end VLANs as VLAN bundle (within a VRF) or as independent VLANs?" Currently they are treated as a VLAN bundle and configured with the RD/RT from the VRF.

I guess there's no good answer to this question, so either we stick with an opinionated design (wouldn't be the first time) or make it configurable.

[ssasso]

The blocking point for me is that not all the devices support VLAN Bundle services :-(

[ipspace]

... and I'm positive someone will eventually start yammering if we exclude VLAN bundles, so here goes another nerd knob ;) Will do.

[ipspace]

Implemented in e0e5792