MSTP (多生成树) 每个VLAN或者几个VLAN拥有一颗生成树，基于实例的生成树。instance 1、instance 2 每个实例拥有一颗生成树。MSTP可以实现多VLAN 的负载分担，可以实现多厂商对接。

VRRP虚拟路由冗余协议(Virtual Router Redundancy Protocol)是由IETF提出的解决局域网中配置静态网关出现单点失效现象的路由协议。

注意：当MSTP 和VRRP共同存在时，我们必须要做MSTP的区域设置以及实例优先级，网络中二层MSTP的Vlan主根和三层VRRP的master网关要放在同一台设备上。在下面的图中，我们把Vlan10的instance 1的根桥设置为LSW1，Vlan10的网关设备也设置为LSW1。Vlan20的instance 2的根桥设置为LSW2，Vlan20的网关设备也为LSW2。

如图，PC1、PC2是企业内网的主机，分别属于VLAN10和VLAN20，LSW1和LSW2之间的g0/0/2口和g0/0/3口之间形成链路聚合。AR1是企业边界路由器，用于和外网通信。AR1、LSW1和LSW2之间运行ospf协议。LSW1、LSW2和LSW3之间运行MSTP协议。要让PC1、PC2出去和回来的流量方向一致，且形成第一跳网关冗余，且负载均衡。如下是配置

PC1

PC>ipconfig

IPv4 address......................: 192.168.10.10
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.10.254
Physical address..................: 54-89-98-55-50-74
VLAN..............................: 10

PC2

PC>ipconfig

IPv4 address......................: 192.168.20.10
Subnet mask.......................: 255.255.255.0
Gateway...........................: 192.168.20.254
Physical address..................: 54-89-98-85-59-50
Vlan..............................: 20

LSW1

[LSW1]display current-configuration
#
vlan batch 10 20 100
#
stp instance 1 priority 4096
stp instance 2 priority 8192
#
stp region-configuration
 region-name MSTP
 instance 1 vlan 10
 instance 2 vlan 20
 active region-configuration
#
interface Vlanif10
 ip address 192.168.10.1 255.255.255.0
 vrrp vrid 10 virtual-ip 192.168.10.254
 vrrp vrid 10 priority 150
 vrrp vrid 10 preempt-mode timer delay 10
 vrrp vrid 10 track interface GigabitEthernet0/0/4 reduced 60
 vrrp vrid 10 authentication-mode md5 GX2lR,}C+Ky~t+Byca8YR#(#
#
interface Vlanif20
 ip address 192.168.20.1 255.255.255.0
 vrrp vrid 20 virtual-ip 192.168.20.254
 vrrp vrid 20 authentication-mode md5 L>YK#S.jKJu:|l#3M^#3"$f#
#
interface Vlanif100
 ip address 192.168.30.1 255.255.255.0
#
interface Eth-Trunk1
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/2
 eth-trunk 1
#
interface GigabitEthernet0/0/3
 eth-trunk 1
#
interface GigabitEthernet0/0/4
 port link-type access
 port default vlan 100
#
ospf 100 router-id 192.168.30.1
 import-route direct route-policy POLICY
 area 0.0.0.0
  network 192.168.30.1 0.0.0.0
#
route-policy POLICY permit node 10
 if-match ip-prefix F
 apply cost 10
#
route-policy POLICY permit node 20
 if-match ip-prefix F2
 apply cost 20
#
ip ip-prefix F index 10 permit 192.168.10.0 24
ip ip-prefix F2 index 10 permit 192.168.20.0 24
#

LSW2

[LSW2]display current-configuration
#
vlan batch 10 20 100
#
stp instance 1 priority 8192
stp instance 2 priority 4096
#
stp region-configuration
 region-name MSTP
 instance 1 vlan 10
 instance 2 vlan 20
 active region-configuration
#
interface Vlanif10
 ip address 192.168.10.2 255.255.255.0
 vrrp vrid 10 virtual-ip 192.168.10.254
 vrrp vrid 10 authentication-mode md5 CN7EFU,9+,'eKRQqbl+O/%;#
#
interface Vlanif20
 ip address 192.168.20.2 255.255.255.0
 vrrp vrid 20 virtual-ip 192.168.20.254
 vrrp vrid 20 priority 150
 vrrp vrid 20 preempt-mode timer delay 60
 vrrp vrid 20 track interface GigabitEthernet0/0/4 reduced 60
 vrrp vrid 20 authentication-mode md5 :||$@<`|wYu:|l#3M^#36%L#
#
interface Vlanif100
 ip address 192.168.40.2 255.255.255.0
#
interface Eth-Trunk1
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/2
 eth-trunk 1
#
interface GigabitEthernet0/0/3
 eth-trunk 1
#
interface GigabitEthernet0/0/4
 port link-type access
 port default vlan 100
#
ospf 100 router-id 192.168.40.2
 import-route direct route-policy POLICY
 area 0.0.0.0
  network 192.168.40.2 0.0.0.0
#
route-policy POLICY permit node 10
 if-match ip-prefix F
 apply cost 20
#
route-policy POLICY permit node 20
 if-match ip-prefix F2
 apply cost 10
#
ip ip-prefix F index 10 permit 192.168.10.0 24
ip ip-prefix F2 index 10 permit 192.168.20.0 24
#

LSW3

[LSW3]display current-configuration
#
vlan batch 10 20
#
stp region-configuration
 region-name MSTP
 instance 1 vlan 10
 instance 2 vlan 20
 active region-configuration
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 10 20
#
interface GigabitEthernet0/0/3
 port link-type access
 port default vlan 10
 stp edged-port enable
#
interface GigabitEthernet0/0/4
 port link-type trunk
 port trunk allow-pass vlan 20
 stp edged-port enable
#

AR1

[AR1]display current-configuration
#
interface GigabitEthernet0/0/0
 ip address 192.168.30.2 255.255.255.0
#
interface GigabitEthernet0/0/1
 ip address 192.168.40.1 255.255.255.0
#
ospf 100 router-id 111.1.1.1
 area 0.0.0.0
  network 192.168.30.2 0.0.0.0
  network 192.168.40.1 0.0.0.0
#

附上ensp源文件：链接: https://pan.baidu.com/s/1WhN79Z7b8XviOmmFAi5WyQ 密码: 8qkg