1. 实验拓扑
（1）创建test2.py文档
代码如下：
from mininet.topo import Topo
class Topo2( Topo ):
def __init__( self ):
# Initialize topology
Topo.__init__( self )
# add switches and hosts
sw1 = self.addSwitch('s1')
sw2 = self.addSwitch('s2')
h1 = self.addHost('h1')
h2 = self.addHost('h2')
h3 = self.addHost('h3')
h4 = self.addHost('h4')
h5 = self.addHost('h5')
h6 = self.addHost('h6')
# add links
self.addLink(h1,sw1,1,1)
self.addLink(h2,sw1,1,2)
self.addLink(h3,sw1,1,3)
self.addLink(sw1,sw2,4,4)
self.addLink(h4,sw2,1,1)
self.addLink(h5,sw2,1,2)
self.addLink(h6,sw2,1,3)
topos = { 'mytopo': ( lambda: Topo2() ) }（2）输入具体命令如下，创建拓扑
sudo mn --custom ./test2.py --topo mytopo --controller=remote,ip=127.0.0.1,port=6653 --switch ovsk,protocols=OpenFlow13（3）使用net命令查看拓扑并使用pingall命令测试所有节点连通性
2.使用Ryu的REST API下发流表实现和第2次实验同样的VLAN
（1）这里贴出s1和s2的脚本完整代码
#s1
#端口号1发来数据
curl -X POST -d '{
"dpid": 1,
"priority":1,
"match":{
"in_port":1
},
"actions":[
{
"type": "PUSH_VLAN", # s1将从主机发来的数据包打上vlan_tag
"ethertype": 33024 # 帧类型0x8100(=33024): 表示IEEE 802.1Q的VLAN数据帧
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # 设置VLAN ID
"value": 4096 # 设置vlan_id的值
},
{
"type": "OUTPUT",
"port": 4
}
]
}' http://127.0.0.1:8080/stats/flowentry/add
#端口号2发来数据
curl -X POST -d '{
"dpid": 1,
"priority":1,
"match":{
"in_port":2
},
"actions":[
{
"type": "PUSH_VLAN", # s1将从主机发来的数据包打上vlan_tag
"ethertype": 33024 # 帧类型0x8100(=33024): 表示IEEE 802.1Q的VLAN数据帧
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # 设置VLAN ID
"value": 4097 # 设置vlan_id的值
},
{
"type": "OUTPUT",
"port": 4
}
]
}' http://127.0.0.1:8080/stats/flowentry/add
#端口号3发来数据
curl -X POST -d '{
"dpid": 1,
"priority":1,
"match":{
"in_port":3
},
"actions":[
{
"type": "PUSH_VLAN", # s1将从主机发来的数据包打上vlan_tag
"ethertype": 33024 # 帧类型0x8100(=33024): 表示IEEE 802.1Q的VLAN数据帧
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # 设置VLAN ID
"value": 4098 # 设置vlan_id的值
},
{
"type": "OUTPUT",
"port": 4
}
]
}' http://127.0.0.1:8080/stats/flowentry/add
#向端口1转发
curl -X POST -d '{
"dpid": 1,
"priority":1,
"match":{
"dl_vlan": "0"
},
"actions":[
{
"type": "POP_VLAN", # 给进入交换机的包去除 vlan_tag
},
{
"type": "OUTPUT",
"port": 1
}
]
}' http://localhost:8080/stats/flowentry/add
#向端口2转发
curl -X POST -d '{
"dpid": 1,
"priority":1,
"match":{
"dl_vlan": "1"
},
"actions":[
{
"type": "POP_VLAN", # 给进入交换机的包去除 vlan_tag
},
{
"type": "OUTPUT",
"port": 2
}
]
}' http://localhost:8080/stats/flowentry/add
#向端口3转发
curl -X POST -d '{
"dpid": 1,
"priority":1,
"match":{
"dl_vlan": "2"
},
"actions":[
{
"type": "POP_VLAN", # 给进入交换机的包去除 vlan_tag
},
{
"type": "OUTPUT",
"port": 3
}
]
}' http://localhost:8080/stats/flowentry/add
#s2
#端口号1发来数据
curl -X POST -d '{
"dpid": 2,
"priority":1,
"match":{
"in_port":1
},
"actions":[
{
"type": "PUSH_VLAN", # s1将从主机发来的数据包打上vlan_tag
"ethertype": 33024 # 帧类型0x8100(=33024): 表示IEEE 802.1Q的VLAN数据帧
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # 设置VLAN ID
"value": 4096 # 设置vlan_id的值
},
{
"type": "OUTPUT",
"port": 4
}
]
}' http://127.0.0.1:8080/stats/flowentry/add
#端口号2发来数据
curl -X POST -d '{
"dpid": 2,
"priority":1,
"match":{
"in_port":2
},
"actions":[
{
"type": "PUSH_VLAN", # s1将从主机发来的数据包打上vlan_tag
"ethertype": 33024 # 帧类型0x8100(=33024): 表示IEEE 802.1Q的VLAN数据帧
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # 设置VLAN ID
"value": 4097 # 设置vlan_id的值
},
{
"type": "OUTPUT",
"port": 4
}
]
}' http://127.0.0.1:8080/stats/flowentry/add
#端口号3发来数据
curl -X POST -d '{
"dpid": 2,
"priority":1,
"match":{
"in_port":3
},
"actions":[
{
"type": "PUSH_VLAN", # s1将从主机发来的数据包打上vlan_tag
"ethertype": 33024 # 帧类型0x8100(=33024): 表示IEEE 802.1Q的VLAN数据帧
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # 设置VLAN ID
"value": 4098 # 设置vlan_id的值
},
{
"type": "OUTPUT",
"port": 4
}
]
}' http://127.0.0.1:8080/stats/flowentry/add
#向端口1转发
curl -X POST -d '{
"dpid": 2,
"priority":1,
"match":{
"dl_vlan": "0"
},
"actions":[
{
"type": "POP_VLAN", # 给进入交换机的包去除 vlan_tag
},
{
"type": "OUTPUT",
"port": 1
}
]
}' http://localhost:8080/stats/flowentry/add
#向端口2转发
curl -X POST -d '{
"dpid": 2,
"priority":1,
"match":{
"dl_vlan": "1"
},
"actions":[
{
"type": "POP_VLAN", # 给进入交换机的包去除 vlan_tag
},
{
"type": "OUTPUT",
"port": 2
}
]
}' http://localhost:8080/stats/flowentry/add
#向端口3转发
curl -X POST -d '{
"dpid": 2,
"priority":1,
"match":{
"dl_vlan": "2"
},
"actions":[
{
"type": "POP_VLAN", # 给进入交换机的包去除 vlan_tag
},
{
"type": "OUTPUT",
"port": 3
}
]
}' http://localhost:8080/stats/flowentry/add实际上s2就是基于s1换个dpid就ok
（2）直接在命令行中执行
（3）查看下发流表结果
（4）查看s1和s2流表
sudo ovs-ofctl -O OpenFlow13 dump-flows s1
sudo ovs-ofctl -O OpenFlow13 dump-flows s2（5）最后对比一下前后pingall的结果
3.对比两种方法，写出你的实验体会
我们目前学习到的都是比较基础的基于实验去做一些操作，这两种方法都体现了流表的灵活性，这是SDN网络的优势之一。据我了解，利用这两种方法查看流表，验证网络功能，开发APP都具有非常重要的作用。
对于上一次实验二使用的ovs方法，会比较简单，可以直接在 Open vSwitch 下发流表，但是在使用RYU的过程中，有时需要使用web拓扑，有时也需要通过API去下发流表等操作。这些操作在RYU中都会使用到RESTAPI。