环境情介绍：
Underlay通过OSPF互联，Overlay通过BGP EVPN建立隧道
Leaf1和Leaf2分别与Spine建立IBGP邻居关系，Spine作为路由反射器RR
Leaf1，Leaf2和Spine分别使用lo b接口地址作为VTEP地址和BGP EVPN源地址
Leaf1的VTEP地址为1.1.1.1/32
Leaf2的VTEP地址为2.2.2.2/32
Spine的VTEP地址为3.3.3.3/32
Vlan10的子网范围为192.168.10.0/24，网关地址为192.168.10.1
Vlan20的子网范围为192.168.20.0/24，网关地址为192.168.20.1
网关部署在spine上
Vlan10子网对应的VNI为10
Vlan20子网对应的VNI为20
双方Vlan20子网设备（PC2和PC3）能够直接通过Leaf1和Leaf2建立的VXLAN隧道通信
最终实现效果：
PC2和PC3上都没有写网关，可以直接ping通对方，并不需要网关的介入。
SPIne结点配置：
evpn-overlay enable
interface GE1/0/0
undo portswitch
undo shutdown
ip address 10.0.12.1 255.255.255.0
ospf network-type p2p
interface GE1/0/1
undo portswitch
undo shutdown
ip address 10.0.13.1 255.255.255.0
ospf network-type p2p
interface LoopBack0
ip address 3.3.3.3 255.255.255.255
bgp 100
peer 1.1.1.1 as-number 100
peer 1.1.1.1 connect-interface LoopBack0
peer 2.2.2.2 as-number 100
peer 2.2.2.2 connect-interface LoopBack0
ipv4-family unicast
undo peer 1.1.1.1 enable
undo peer 2.2.2.2 enable
l2vpn-family evpn
undo policy vpn-target
peer 1.1.1.1 enable
peer 1.1.1.1 reflect-client
peer 2.2.2.2 enable
peer 2.2.2.2 reflect-client
ospf 1 router-id 3.3.3.3
area 0.0.0.0
network 3.3.3.3 0.0.0.0
network 10.0.12.1 0.0.0.0
network 10.0.13.1 0.0.0.0
Leaf1节点配置：
evpn-overlay enable
bridge-domain 20
vxlan vni 20
evpn
route-distinguisher 20:1
vpn-target 20:1 export-extcommunity
vpn-target 20:2 import-extcommunity
interface GE1/0/0
undo portswitch
undo shutdown
ip address 10.0.12.2 255.255.255.0
ospf network-type p2p
interface GE1/0/1
undo shutdown
interface GE1/0/1.20 mode l2
encapsulation dot1q vid 20
bridge-domain 20
interface LoopBack0
ip address 1.1.1.1 255.255.255.255
interface Nve1
source 1.1.1.1
vni 20 head-end peer-list protocol bgp
bgp 100
peer 3.3.3.3 as-number 100
peer 3.3.3.3 connect-interface LoopBack0
ipv4-family unicast
undo peer 3.3.3.3 enable
l2vpn-family evpn
policy vpn-target
peer 3.3.3.3 enable
ospf 1 router-id 1.1.1.1
area 0.0.0.0
network 1.1.1.1 0.0.0.0
network 10.0.12.2 0.0.0.0
Leaf2节点配置：
evpn-overlay enable
bridge-domain 20
vxlan vni 20
evpn
route-distinguisher 20:2 //RD两边可以不一致
vpn-target 20:2 export-extcommunity //RT一出一入必须反过来要一致
vpn-target 20:1 import-extcommunity //RT一出一入必须反过来要一致
interface MEth0/0/0
undo shutdown
interface GE1/0/0
undo portswitch
undo shutdown
ip address 10.0.13.3 255.255.255.0
ospf network-type p2p
interface GE1/0/1
undo shutdown
interface GE1/0/1.20 mode l2
encapsulation dot1q vid 20
bridge-domain 20
interface LoopBack0
ip address 2.2.2.2 255.255.255.255
interface Nve1
source 2.2.2.2
vni 20 head-end peer-list protocol bgp
bgp 100
peer 3.3.3.3 as-number 100
peer 3.3.3.3 connect-interface LoopBack0
ipv4-family unicast
undo peer 3.3.3.3 enable
l2vpn-family evpn
policy vpn-target
peer 3.3.3.3 enable
ospf 1 router-id 2.2.2.2
area 0.0.0.0
network 2.2.2.2 0.0.0.0
network 10.0.13.3 0.0.0.0
bgp evpn邻居查看：
vxlan隧道查看:
bgp路由查看：
