Error: The VLAN has a L3 interface. Please delete it first .

在化为S3700的使用中删除vlan时出现Error: The VLAN has a L3 interface. Please delete it first提示，无法undo；

原因为为要删除的vlan配置了ip地址导致，如vlan编号为604：

[Quidway-vlan604]dis this                  
#
vlan 604
 traffic-policy 1M inbound
#
return

发现里边没有IP地址，于是退出此vlan使用display cu命令来查看发现如下信息：

interface Vlanif604                       
 ip address 10.0.154.246 255.255.255.0

OK，找到原因，那么就好办了：

[Quidway]inter vlanif604
[Quidway-Vlanif604]dis this
#
interface Vlanif604
 ip address 10.0.154.246 255.255.255.0
#
return
[Quidway-Vlanif604]undo ip address
[Quidway-Vlanif604]dis this
#
interface Vlanif604
#
return

[Quidway-Vlanif604]undo vlan 604
Error: The VLAN has a L3 interface. Please delete it first.

还是报这个错误！

还需要删除这个Vlanif604啊，操作如下：

[Quidway]undo interface Vlanif604
Info: This operation may take a few seconds. Please wait for a moment...succeeded.

OK，搞定，然后就undo vlan 604即可搞定