How do I learn VXLAN EVPN on SONiC?

The lab, in seven steps

1. 1

   Add the SONiC image once

   SONiC runs as a bring-your-own image. Add the community SONiC VS image in the NetPilot app under Images. From then on the assistant can deploy SONiC nodes in any lab on your VM.

2. 2

   Ask for the fabric in plain words

   Two leaves, one spine, the AS numbers, the loopbacks, one host per leaf. The assistant designs the topology, writes the config for each node and deploys the lab with containerlab.

3. 3

   Check the underlay

   The leaves must reach each other's loopback before any overlay exists. On a leaf, show ip bgp summary shows the spine session Established, and show ip route shows the other leaf's loopback learned over it.

4. 4

   Check the EVPN session

   BGP on SONiC is FRR, so the EVPN address family is read through vtysh. show bgp l2vpn evpn summary on each leaf shows the EVPN neighbour Established and a prefix count once the VNIs are advertised.

5. 5

   Map the VLAN to a VNI

   This is the step that teaches the SONiC way of doing things: config vlan add, config vlan member add, config vxlan add for the VTEP with the loopback as source, config vxlan evpn_nvo add to bind the VTEP to EVPN, and config vxlan map add for the VLAN to VNI mapping. show vxlan vlanvnimap and vtysh -c "show evpn vni" confirm it.

6. 6

   Send traffic and read the routes

   Ping from the host on leaf1 to the host on leaf2. show vxlan tunnel now lists the remote VTEP, show vxlan remotemac all lists the remote host's MAC learned over EVPN, and vtysh -c "show bgp l2vpn evpn route type macip" shows the type-2 route that carried it.

7. 7

   Save it the SONiC way

   config save -y writes the running state to /etc/sonic/config_db.json. show runningconfiguration all prints the same JSON, which is what you read when something does not come back after a reload.

What the output looks like

admin@leaf1:~$ vtysh -c "show bgp l2vpn evpn summary"
BGP router identifier 10.1.1.1, local AS number 65001 vrf-id 0
Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd   PfxSnt
10.0.1.0        4 65000     132     128        0    0    0 00:58:12            3        3

admin@leaf1:~$ show vxlan vlanvnimap
+---------+-------+
| VLAN    |   VNI |
+=========+=======+
| Vlan100 | 10100 |
+---------+-------+
Total count : 1

admin@leaf1:~$ show vxlan tunnel
vxlan tunnel name    source ip    destination ip    tunnel map name    tunnel map mapping(vni -> vlan)
-------------------  -----------  ----------------  -----------------  ---------------------------------
vtep1                10.1.1.1     10.1.1.2          map_10100_Vlan100  10100 -> Vlan100

admin@leaf1:~$ show vxlan remotemac all
+---------+-------------------+--------------+-------+---------+
| VLAN    | MAC               | RemoteVTEP   |   VNI | Type    |
+=========+===================+==============+=======+=========+
| Vlan100 | aa:c1:ab:12:34:02 | 10.1.1.2     | 10100 | dynamic |
+---------+-------------------+--------------+-------+---------+
Total count : 1