Introduction
This post introduces BGP EVPN from a high level and walks through getting it up and running quickly in a lab.
This is not a deep-dive — it is a fast-start guide you can build upon. I reference documents and notes from when I first learned this topic; I hope they help you too.
Lab Topology
The lab uses EVE-NG with Nexus 9000v (n9000-i-bin.boot), 2 vCPU and 12 GB RAM per instance, running NX-OS 7.0(3)I7(3). End devices are VPCs (Virtual PCs) rather than routers.
Methodology
The configuration is built in layers:
- Configure basic connectivity — interfaces, IP addressing, and routing protocol.
- Verify underlay reachability.
- Configure overlay networking and confirm switch-level connectivity.
Let’s build the EVPN setup step by step.
Building the Basic Configuration Out
Since the configuration is phased, each NX-OS feature is enabled only when it is needed — this makes it clear why each feature is used and when.
To configure the UNDERLAY (SVIs and routing), enable the interface-vlan and ospf features first.
Multicast for BUM Traffic
VXLAN requires a mechanism to handle BUM (Broadcast, Unknown unicast, and Multicast) traffic. In this lab, PIM sparse-mode multicast is used. Each VNI is mapped to a multicast group address (e.g., 239.1.1.10), which the NVE interface uses to flood BUM frames across the fabric. BGP EVPN then takes over for unicast MAC/IP learning, reducing reliance on multicast for known hosts.
Full Configuration
SPINE-1
version 7.0(3)I7(3)
hostname SPINE-1
nv overlay evpn
feature ospf
feature bgp
feature pim
feature interface-vlan
feature vn-segment-vlan-based
feature nv overlay
ip pim rp-address 192.168.9.9 group-list 224.0.0.0/4
ip pim ssm range 232.0.0.0/8
interface Ethernet1/1
no switchport
ip address 192.168.19.9/24
ip router ospf UNDERLAY area 0.0.0.0
ip pim sparse-mode
no shutdown
interface Ethernet1/2
no switchport
ip address 192.168.29.9/24
ip router ospf UNDERLAY area 0.0.0.0
ip pim sparse-mode
no shutdown
interface mgmt0
vrf member management
interface loopback1
ip address 192.168.9.9/32
ip router ospf UNDERLAY area 0.0.0.0
ip pim sparse-mode
cli alias name mac show system internal l2fwder mac
cli alias name wr copy running start
line console
line vty
boot nxos bootflash:/nxos.7.0.3.I7.3.bin
router ospf UNDERLAY
router bgp 65000
log-neighbor-changes
address-family ipv4 unicast
address-family l2vpn evpn
retain route-target all
template peer VTEP-PEERS
remote-as 65000
update-source loopback1
address-family ipv4 unicast
send-community
send-community extended
route-reflector-client
address-family l2vpn evpn
send-community
send-community extended
route-reflector-client
neighbor 192.168.11.11
inherit peer VTEP-PEERS
neighbor 192.168.22.22
inherit peer VTEP-PEERS
!
!end
VTEP-1
version 7.0(3)I7(3)
hostname VTEP-1
nv overlay evpn
feature ospf
feature bgp
feature pim
feature interface-vlan
feature vn-segment-vlan-based
feature nv overlay
fabric forwarding anycast-gateway-mac 0001.0001.0001
ip pim rp-address 192.168.9.9 group-list 224.0.0.0/4
ip pim ssm range 232.0.0.0/8
vlan 1,30,40,100,200
vlan 10
name L3_VNI
vn-segment 10000010
vlan 30
vn-segment 10000030
vlan 40
vn-segment 10000040
vrf context L3_VNI
vni 10000010
rd auto
address-family ipv4 unicast
route-target both auto
route-target both auto evpn
interface Vlan10
no shutdown
mtu 9216
vrf member L3_VNI
ip forward
interface Vlan30
no shutdown
mtu 9216
vrf member L3_VNI
ip address 172.16.30.1/24
fabric forwarding mode anycast-gateway
interface Vlan40
no shutdown
mtu 9216
vrf member L3_VNI
ip address 172.16.40.1/24
fabric forwarding mode anycast-gateway
interface nve1
no shutdown
host-reachability protocol bgp
source-interface loopback2
member vni 10000010 associate-vrf
member vni 10000030
mcast-group 239.1.1.10
member vni 10000040
mcast-group 239.1.1.20
interface Ethernet1/1
description Going to Spine
no switchport
ip address 192.168.19.1/24
ip router ospf UNDERLAY area 0.0.0.0
ip pim sparse-mode
no shutdown
interface loopback2
description Loopback for BGP
ip address 192.168.11.11/32
ip router ospf UNDERLAY area 0.0.0.0
ip pim sparse-mode
cli alias name wr copy runn start
cli alias name mac show system internal l2fwder mac
line console
line vty
boot nxos bootflash:/nxos.7.0.3.I7.3.bin
router ospf UNDERLAY
router bgp 65000
address-family ipv4 unicast
address-family l2vpn evpn
neighbor 192.168.9.9
remote-as 65000
update-source loopback2
address-family ipv4 unicast
address-family l2vpn evpn
send-community extended
evpn
vni 10000030 l2
rd auto
route-target import auto
route-target export auto
vni 10000040 l2
rd auto
route-target import auto
route-target export auto
!
!end
VTEP-2
version 7.0(3)I7(3)
hostname VTEP-2
nv overlay evpn
feature ospf
feature bgp
feature pim
feature interface-vlan
feature vn-segment-vlan-based
feature nv overlay
fabric forwarding anycast-gateway-mac 0001.0001.0001
ip pim rp-address 192.168.9.9 group-list 224.0.0.0/4
ip pim ssm range 232.0.0.0/8
vlan 1,10,30,40,100,200
vlan 10
name L3_VNI
vn-segment 10000010
vlan 30
vn-segment 10000030
vlan 40
vn-segment 10000040
vrf context L3_VNI
vni 10000010
rd auto
address-family ipv4 unicast
route-target both auto
route-target both auto evpn
interface Vlan10
no shutdown
mtu 9216
vrf member L3_VNI
ip forward
interface Vlan30
no shutdown
mtu 9216
vrf member L3_VNI
ip address 172.16.30.1/24
fabric forwarding mode anycast-gateway
interface Vlan40
no shutdown
mtu 9216
vrf member L3_VNI
ip address 172.16.40.1/24
fabric forwarding mode anycast-gateway
interface nve1
no shutdown
host-reachability protocol bgp
source-interface loopback2
member vni 10000010 associate-vrf
member vni 10000030
mcast-group 239.1.1.10
member vni 10000040
mcast-group 239.1.1.20
interface Ethernet1/1
description "Going to Spine"
no switchport
ip address 192.168.29.2/24
ip router ospf UNDERLAY area 0.0.0.0
ip pim sparse-mode
no shutdown
interface loopback2
description "Loopback for BGP"
ip address 192.168.22.22/32
ip router ospf UNDERLAY area 0.0.0.0
ip pim sparse-mode
cli alias name mac show system internal l2fwder mac
cli alias name wr copy runnin start
line console
line vty
boot nxos bootflash:/nxos.7.0.3.I7.3.bin
router ospf UNDERLAY
router bgp 65000
address-family ipv4 unicast
address-family l2vpn evpn
neighbor 192.168.9.9
remote-as 65000
update-source loopback2
address-family ipv4 unicast
address-family l2vpn evpn
send-community extended
evpn
vni 10000030 l2
rd auto
route-target import auto
route-target export auto
vni 10000040 l2
rd auto
route-target import auto
route-target export auto
!
!end
Troubleshooting Tips
root@VTEP-1#tcpdump -i eth8 icmp
tcpdump: WARNING: eth8: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth8, link-type EN10MB (Ethernet), capture size 65535 bytes
09:48:31.589679 IP 172.16.30.10 > 172.16.40.10: ICMP echo request,
show l2 route mac all
show bgp l2vpn evpn