ip netns {list | add delete | exec | identify | pids | monitor等}
ip [{-s | -v 等等}] link [ {add | delete | set | show} ] type [{bridge| bond | can | vcan | veth | vlan 等}]

• 创建 namespace： ip netns add [name]

• 在namespace中执行： ip netns exec [name] command

• 查看namespace：ip netns list

• 创建虚拟网卡：ip link add XXX type veth peer name XXX

• 网卡加入namespace：ip link set [XXX] netns [name]

1)ip netns exec ns1 ip link show|list
2)ip netns exec ns1 ip link set dev tap1 down 
3)ip netns exec ns1 ip address add 192.68.102.40/24 broadcast + dev tap1
4)ip netns exec ns1 ip link set dev tap1 up