SONiC¶

The SONiC implementation uses BGP EVPN with ingress-replication for BUM (Broadcast, Unknown unicast, Multicast) traffic handling.

Configuration Parameters¶

ngs_vtep_name - VXLAN tunnel endpoint interface name (required)
ngs_bgp_asn - BGP AS number (required)

Configuration Example¶

[genericswitch:sonic-switch]
device_type = netmiko_sonic
ip = 192.0.2.20
username = admin
password = password
ngs_physical_networks = datacenter1,datacenter2
ngs_vtep_name = vtep
ngs_bgp_asn = 65000

Prerequisites¶

Your SONiC switches must have BGP EVPN pre-configured with advertise-all-vni enabled in FRR.

Example FRR configuration:

router bgp 65000
  neighbor 10.0.0.2 remote-as 65000
  neighbor 10.0.0.2 update-source lo
  address-family l2vpn evpn
    neighbor 10.0.0.2 activate
    advertise-all-vni

Generated Configuration¶

For each VXLAN network, the driver automatically generates:

# BGP EVPN control plane (via FRR vtysh)
vtysh -c "configure terminal" \
      -c "router bgp 65000" \
      -c "address-family l2vpn evpn" \
      -c "vni 10100" \
      -c "rd auto" \
      -c "route-target import auto" \
      -c "route-target export auto"

# VXLAN map
config vxlan map add vtep 100 10100

Limitations¶

SONiC does NOT support multicast-based BUM replication. Only ingress-replication mode is available. If ngs_bum_replication_mode=multicast is configured, the driver will raise a GenericSwitchNetmikoConfigError.

According to the SONiC EVPN VXLAN HLD: “Support Ingress Replication for L2 BUM traffic over VXLAN tunnels. Underlay IP Multicast is not supported.”

For multicast-based BUM replication, consider using Cumulus NVUE, Arista EOS, or Cisco NX-OS.

SONiC