1. 配置各接口所属VLAN
[LSW1]vlan batch 10 20
[LSW1-GigabitEthernet0/0/2]port link-type trunk
[LSW1-GigabitEthernet0/0/2]port trunk allow-pass vlan 10
[LSW1-GigabitEthernet0/0/3]port link-type trunk
[LSW1-GigabitEthernet0/0/3]port trunk allow-pass vlan 20
[LSW2]vlan batch 10 30
[LSW2-GigabitEthernet0/0/1]port link-type trunk
[LSW2-GigabitEthernet0/0/1]port trunk allow-pass vlan 10
[LSW2-GigabitEthernet0/0/4]port link-type trunk
[LSW2-GigabitEthernet0/0/4]port trunk allow-pass vlan 30
[LSW3]vlan batch 20 40
[LSW3-GigabitEthernet0/0/1]port link-type trunk
[LSW3-GigabitEthernet0/0/1]port trunk allow-pass vlan 20
[LSW3-GigabitEthernet0/0/4]port link-type trunk
[LSW3-GigabitEthernet0/0/4]port trunk allow-pass vlan 40
[LSW4]vlan batch 30 40 50
[LSW4-GigabitEthernet0/0/2]port link-type trunk
[LSW4-GigabitEthernet0/0/2]port trunk allow-pass vlan 30
[LSW4-GigabitEthernet0/0/3]port link-type trunk
[LSW4-GigabitEthernet0/0/3]port trunk allow-pass vlan 40
[LSW4-GigabitEthernet0/0/5]port link-type trunk
[LSW4-GigabitEthernet0/0/5]port trunk allow-pass vlan 50
2. 配置各VLANIF接口的IP地址
[LSW1-Vlanif10]ip add 10.1.1.1 24
[LSW1-Vlanif20]ip add 10.1.2.1 24
[LSW2-Vlanif10]ip add 10.1.1.2 24
[LSW2-Vlanif30]ip add 10.1.3.2 24
[LSW3-Vlanif20]ip add 10.1.2.3 24
[LSW3-Vlanif40]ip add 10.1.4.3 24
[LSW4-Vlanif30]ip add 10.1.3.4 24
[LSW4-Vlanif40]ip add 10.1.4.4 24
[LSW4-Vlanif50]ip add 192.168.1.4 24
[LSW1]stp disable
[LSW2]stp disable
[LSW3]stp disable
[LSW4]stp disable
3. 配置BGP连接
[LSW1]bgp 100
[LSW1-bgp]router-id 1.1.1.1
[LSW1-bgp]peer 10.1.1.2 as-number 300
[LSW1-bgp]peer 10.1.2.3 as-number 300
[LSW2]bgp 300
[LSW2-bgp]router-id 2.2.2.2
[LSW2-bgp]peer 10.1.1.1 as-number 100
[LSW2-bgp]peer 10.1.3.4 as-number 200
[LSW3]bgp 300
[LSW3-bgp]router-id 3.3.3.3
[LSW3-bgp]peer 10.1.2.1 as-number 100
[LSW3-bgp]peer 10.1.4.4 as-number 200
[LSW4]bgp 200
[LSW4-bgp]router-id 4.4.4.4
[LSW4-bgp]peer 10.1.3.2 as-number 300
[LSW4-bgp]peer 10.1.4.3 as-number 300
[LSW4-bgp]ipv4-family unicast
[LSW4-bgp-af-ipv4]network 192.168.1.0 24
从路由表中可以看出，LSW1到目的地址192.168.1.0/24有两条有效路由，其中下一跳为10.1.1.2的路由是最优路由（因为LSW2的Router ID要小一些）
4. 配置负载分担
[LSW1]bgp 100
[LSW1-bgp]ipv4-family unicast
[LSW1-bgp-af-ipv4]maximum load-balancing 2
5. 检查配置结果
从路由表中可以看到，BGP路由192.168.1.0/24存在两个下一跳，分别是10.1.1.2和10.1.2.3，且都被优选