VXLAN：使用EVPN建立分布式网关配置（跨子网通信）

实验摘要：

CE2是PC1和PC2的网关设备，CE3是PC3和PC4的网关设备 ，对VXLAN数据进行封装。CE1作为CE2和CE3的反射器，只对VXLAN数据进行转发。CE2和CE3的网关IP地址是一样的，因为要实现虚拟机的热迁移。

使用EVPN的方式动态的建立VXLAN分布式网关。

实现分布式跨子网通信相对于同子网通信，就多配置了一个三层VNI和EVPN实例。

本端的ERT要和对端的IRT一样来实现同子网互访，本端ERT和对端eIRT一样实现跨子网互访。

最后实现：
PC1和PC2本地跨子网通信，PC3和PC4本地跨子网通信，
PC1和PC3同子网通信，PC2和PC4同子网通信，
PC1和PC4跨子网通信，PC2和PC3跨子网通信。

实验拓扑：

配置命令：

CE2：

#
sysname ce2
#
evpn-overlay enable
#
ip vpn-instance A
 ipv4-family
  route-distinguisher 1:100
  vpn-target 1:100 evpn
 vxlan vni 1
#
bridge-domain 10
 vxlan vni 10
 evpn
  route-distinguisher 1:1
  vpn-target 1:1 both
  vpn-target 1:100 export-extcommunity
#
bridge-domain 20
 vxlan vni 20
 evpn
  route-distinguisher 1:2
  vpn-target 1:2 both
  vpn-target 1:100 export-extcommunity
#
interface Vbdif10
 ip binding vpn-instance A
 ip address 192.168.1.254 255.255.255.0
 arp distribute-gateway enable
 arp collect host enable
#
interface Vbdif20
 ip binding vpn-instance A
 ip address 192.168.2.254 255.255.255.0
 arp distribute-gateway enable
 arp collect host enable
#
interface GE1/0/0
 undo portswitch
 undo shutdown
 ip address 10.1.12.2 255.255.255.0
#
interface GE1/0/1
 undo shutdown
#
interface GE1/0/1.10 mode l2
 encapsulation dot1q vid 10
 bridge-domain 10
#
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 10 head-end peer-list protocol bgp
 vni 20 head-end peer-list protocol bgp
#
bgp 100
 peer 1.1.1.1 as-number 100
 peer 1.1.1.1 connect-interface LoopBack0
 #
 l2vpn-family evpn
  policy vpn-target
  peer 1.1.1.1 enable
  peer 1.1.1.1 advertise irb
#
ospf 1
 area 0.0.0.0
  network 2.2.2.2 0.0.0.0
  network 10.1.12.2 0.0.0.0

CE3：

#
sysname ce3
#
evpn-overlay enable
#
ip vpn-instance A
 ipv4-family
  route-distinguisher 1:100
  vpn-target 1:100 evpn
 vxlan vni 2
#
bridge-domain 10
 vxlan vni 10
 evpn
  route-distinguisher 1:1
  vpn-target 1:1 both
  vpn-target 1:100 export-extcommunity
#
bridge-domain 20
 vxlan vni 20
 evpn
  route-distinguisher 1:2
  vpn-target 1:2 both
  vpn-target 1:100 export-extcommunity
#
interface Vbdif10
 ip binding vpn-instance A
 ip address 192.168.1.254 255.255.255.0
 arp distribute-gateway enable
 arp collect host enable
#
interface Vbdif20
 ip binding vpn-instance A
 ip address 192.168.2.254 255.255.255.0
 arp distribute-gateway enable
 arp collect host enable
#
interface GE1/0/0
 undo portswitch
 undo shutdown
 ip address 10.1.13.3 255.255.255.0
#
interface GE1/0/1
 undo shutdown
#
interface GE1/0/1.10 mode l2
 encapsulation dot1q vid 10
 bridge-domain 10
#
interface GE1/0/1.20 mode l2
 encapsulation dot1q vid 20
 bridge-domain 20
#
interface LoopBack0
 ip address 3.3.3.3 255.255.255.255
#
interface Nve1
 source 3.3.3.3
 vni 10 head-end peer-list protocol bgp
 vni 20 head-end peer-list protocol bgp
#
bgp 100
 peer 1.1.1.1 as-number 100
 peer 1.1.1.1 connect-interface LoopBack0
 #
 l2vpn-family evpn
  policy vpn-target
  peer 1.1.1.1 enable
  peer 1.1.1.1 advertise irb
#
ospf 1
 area 0.0.0.0
  network 3.3.3.3 0.0.0.0
  network 10.1.13.3 0.0.0.0

CE1：

#
sysname ce1
#
evpn-overlay enable
#
interface GE1/0/0
 undo portswitch
 undo shutdown
 ip address 10.1.12.1 255.255.255.0
#
interface GE1/0/1
 undo portswitch
 undo shutdown
 ip address 10.1.13.1 255.255.255.0
#
interface LoopBack0
 ip address 1.1.1.1 255.255.255.255
#
bgp 100
 peer 2.2.2.2 as-number 100
 peer 2.2.2.2 connect-interface LoopBack0
 peer 2.2.2.2 reflect-client
 peer 3.3.3.3 as-number 100
 peer 3.3.3.3 connect-interface LoopBack0
 peer 3.3.3.3 reflect-client
 #
 l2vpn-family evpn
  undo policy vpn-target
  peer 2.2.2.2 enable
  peer 2.2.2.2 advertise irb
  peer 2.2.2.2 reflect-client
  peer 3.3.3.3 enable
  peer 3.3.3.3 advertise irb
  peer 3.3.3.3 reflect-client
#
ospf 1
 area 0.0.0.0
  network 1.1.1.1 0.0.0.0
  network 10.1.12.1 0.0.0.0
  network 10.1.13.1 0.0.0.0

SW1:

#
sysname sw1
#
vlan batch 10 20
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/2
 port link-type access
 port default vlan 10
#
interface GigabitEthernet0/0/3
 port link-type access
 port default vlan 20

SW2:

#
sysname sw2
#
vlan batch 10 20
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/2
 port link-type access
 port default vlan 10
#
interface GigabitEthernet0/0/3
 port link-type access
 port default vlan 20

实验效果：