配置四台pc的IP（不同网段）、子网掩码、网关
10.0.1.2 255.255.255.0 10.0.1.1
10.0.2.2 255.255.255.0 10.0.2.1
10.0.3.2 255.255.255.0 10.0.3.1
10.0.4.2 255.255.255.0 10.0.4.1
中间层两台交换机命令如下（例：左）
vlan 10
vlan 20
region-name yh
instance 1 vlan 10
instance 2 vlan 20
instance 3 vlan 30
instance 4 vlan 40
active region-configuration
stp global enable
interface GigabitEthernet1/0/1
port link-mode bridge
port access vlan 10
interface GigabitEthernet1/0/2
port link-mode bridge
port access vlan 20
interface GigabitEthernet1/0/3
port link-mode bridge
port link-type trunk
port trunk permit vlan 1 10 20
interface GigabitEthernet1/0/4
port link-mode bridge
port link-type trunk
port trunk permit vlan 1 10 20
上层两台交换机配置命令如下（例：左）
vlan 10
vlan 20
vlan 30
vlan 40
stp region-configuration
region-name yh
instance 1 vlan 10
instance 2 vlan 20
instance 3 vlan 30
instance 4 vlan 40
active region-configuration
stp instance 1 3 root primary
stp instance 2 4 root secondary
stp global enable
interface Bridge-Aggregation1
port link-type trunk
port trunk permit vlan 1 10 20 30 40
link-aggregation mode dynamic
interface GigabitEthernet1/0/1
port link-mode bridge
port link-type trunk
port trunk permit vlan 1 10 20
interface GigabitEthernet1/0/2
port link-mode bridge
port link-type trunk
port trunk permit vlan 1 30 40
interface GigabitEthernet1/0/20
port link-mode bridge
port link-type trunk
port trunk permit vlan 1 10 20 30 40
port link-aggregation group 1
interface GigabitEthernet1/0/21
port link-mode bridge
port link-type trunk
port trunk permit vlan 1 10 20 30 40
port link-aggregation group 1
实验结果图：
理清vlan与交换机之间的关系
中间层交换机建立相连pc的VLAN
上层交换机建立所有存在的VLAN（允许通过所有VLAN）
理清生成树实例
中间层和上层的交换机都要创建所有的VLAN对应的实例
注意上层交换机间的链路聚合
创建聚合组，放行所有VLAN