Uniform format for RD

[ssasso]

Fighting again with Dell's implementations ;)

Right now in netlab we are using two different RD encoding, one for VRF and one for L2VNI.

vlans:
  blue:
    bridge_group: 2
    evpn:
      evi: 1001
      export:
      - 65000:1001
      import:
      - 65000:1001
      rd: 10.0.0.5:1001
    id: 1001
    prefix:
      ipv4: 172.16.1.0/24
    vni: 101001
    vrf: tenant

vrfs:
  tenant:
    af:
      ipv4: true
    evpn:
      transit_vni: 200000
    export:
    - '65000:1'
    import:
    - '65000:1'
    rd: '65000:1'
    vrfidx: 100

Can we uniform this to use Encoding Type 1 everywhere? https://www.rfc-editor.org/rfc/rfc4364#section-4.2

Dell OS10 is expecting this, for L3VNI RD:

s1(config-evpn-vrf-tenant)# rd 65000:1
% Error: Illegal parameter.
s1(config-evpn-vrf-tenant)# rd
  A.B.C.D:[1..65535]  4-octet-ipv4addr:2-octet-number

The workaround I am using right now is:

rd {{ rd_0|ipaddr('address') }}:{{ rd_1 }}

[ipspace]

L3VPN traditionally used AS:XX RD to prevent route duplication on every PE-router.

That doesn't matter so much in the EVPN world as it seems no route duplication is taking place. It makes no sense to compare two MAC addresses to see which one is better -- if you have two of them, you have a problem.

I could add a nerd knob that would influence L3VPN RD format, but if someone thinks they need that they could always write a plugin ;)

OTOH, using the workaround creates RDs incompatible with other implementations anyway (so we'd get route duplication no matter what), so just give up, create RD locally from {{ loopback }}:{{v.vrfidx}} or something similar and document it in caveats.

[ssasso]

I'll use bgp.router_id instead of loopback, so it will work also on IPv6-only stuff (when IPv6-only EVPN will work ;) )

[jbemmel]

On SR Linux, the easiest way is to let the platform handle it (i.e. by not specifying a RD explicitly).
It could support either format, but I'm currently ignoring the generated parameter

[ipspace]

That's been solved with the EVPN module rewrite