Add EVPN ipv6 neighbor configuration to Arista template

[aeangel]

I'd like to propose an enhancement to the Arista device template to support automatic EVPN IPv6-neighbor configuration. Currently, when using EVPN with Arista, the template does not generate ipv6 BGP neighbor statements for EVPN peering.
I add this to netsim/ansible/templates/evpn/eos.j2 and seems ok

{% for n in bgp.neighbors if n.ipv6 is defined and n.evpn|default(False) %}
{%   set peer = 'ebgp_intf_' + n.local_if if n.local_if is defined else n.ipv6 %}
  neighbor {{ peer }} activate
{% endfor %}

full file

!
router bgp {{ bgp.as }}
 address-family evpn
{% if evpn.transport|default('vxlan') == 'mpls' %}
  neighbor default encapsulation mpls next-hop-self source-interface Loopback0
{% endif %}
!
{% for n in bgp.neighbors if n.ipv4 is defined and n.evpn|default(False) %}
{%   set peer = 'ebgp_intf_' + n.local_if if n.local_if is defined else n.ipv4 %}
  neighbor {{ peer }} activate
{% endfor %}
{% for n in bgp.neighbors if n.ipv6 is defined and n.evpn|default(False) %}
{%   set peer = 'ebgp_intf_' + n.local_if if n.local_if is defined else n.ipv6 %}
  neighbor {{ peer }} activate
{% endfor %}
{% if vlans is defined %}
{%   for v in vlans.values() if v.evpn.evi is defined and v.evpn.bundle is not defined %}
!
 vlan {{ v.id }}
  rd {{ v.evpn.rd }}
{%     for irt in v.evpn.import|default([]) %}
  route-target import {{ irt }}
{%     endfor %}
{%     for ert in v.evpn.export|default([]) %}
  route-target export {{ ert }}
{%     endfor %}
  redistribute learned
{%   endfor %}
{% endif %}
{% if vrfs is defined %}
{%   for n,v in vrfs.items() if v.evpn.vlans is defined %}
!
 vlan-aware-bundle {{ n }}
  rd {{ v.rd }}
  route-target import {{ v.import|join(' ') }}
  route-target export {{ v.export|join(' ') }}
  redistribute learned
  vlan {{ v.evpn.vlan_ids|join(',') }}
{%   endfor %}
{% endif %}
{% if vrfs is defined %}
{%   for n,v in vrfs.items() if v.af is defined %}
!
 vrf {{ n }}
  rd {{ v.rd }}
{%     for irt in v.import|default([]) %}
  route-target import evpn {{ irt }}
{%     endfor %}
{%     for ert in v.export|default([]) %}
  route-target export evpn {{ ert }}
{%     endfor %}
  redistribute connected
{%   endfor %}
{% endif %}
{% if vrfs is defined %}
{%   for n,v in vrfs.items() if v.evpn.transit_vni is defined %}
{%     if loop.first %}
!
interface vxlan 1
{%     endif %}
 vxlan vrf {{ n }} vni {{ v.evpn.transit_vni }}
{%   endfor %}
{% endif %}

[ipspace]

I'd like to propose an enhancement to the Arista device template to support automatic EVPN IPv6-neighbor configuration. Currently, when using EVPN with Arista, the template does not generate ipv6 BGP neighbor statements for EVPN peering.

That's because netlab (so far) implements EVPN only for IPv4 VTEPs.

I would love to see (a pointer to) a complete device configuration (or netlab topology file). Do you run an IPv6-only fabric and use IPv6 VTEPs? If not, how do you propagate the IPv4 VTEP reachability information?

[aeangel]

I’m practicing with dual-stack networking in the lab, using FRR and EOS devices. I noticed that after bringing up FRR, it establishes an IPv6 neighbor in af evpn, while EOS does not. topology.yml FRR(leaf) config EOS(spine) config
I’m not sure it’s a good idea to run dual-stack for EVPN AF, since the routes get duplicated and it’s unlikely anyone would deploy this in production. But I found it interesting to experiment with.

[ipspace]

I’m practicing with dual-stack networking in the lab

👍

I noticed that after bringing up FRR, it establishes an IPv6 neighbor in af evpn

That's the incorrect behavior. netlab should not enable AFs with IPv4 next hops over IPv6 sessions.

I’m not sure it’s a good idea to run dual-stack for EVPN AF

It is definitely not, more so if you try to touch the next hop 🤦‍♂️

Thanks a million for spotting this, opening an issue.

[aeangel]

I thought the bug was in Arista, but turns out it was in FRR 🤦