2019 SDN上机第6次作业

1.实验拓扑

Python脚本

from mininet.topo import Topo
 
class MyTopo( Topo ):
    "Simple topology example."
 
    def __init__( self ):
        "Create custom topo."
 
        # Initialize topology
        Topo.__init__( self )
        L1 = 2
        L2 = L1 * 3
        s = []
        h = []
          
        for i in range( L1 ):
                sw = self.addSwitch( 's{}'.format( i + 1 ) )
                s.append( sw )
    
        self.addLink(s[0],s[1],4,4)
    
        count = 1
        for sw1 in s:
                for i in range(3):
                    host = self.addHost( 'h{}'.format( count ) )
                    self.addLink( sw1, host,i+1,1 )
                    count += 1
topos = { 'mytopo': ( lambda: MyTopo() ) }

运行以下代码创建拓扑

sudo mn --custom ./fattree.py --topo mytopo --controller=remote,ip=127.0.0.1,port=6653 --switch ovsk,protocols=OpenFlow13

使用net命令查看拓扑

pingall测试主机连通性

运行以下命令：

ryu-manager gui_topology.py

2.使用Ryu的REST API下发流表实现和第2次实验同样的VLAN

向交换机1发来消息：

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

交换机1向端口1转发消息：

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

运行脚本

pingall：

图形界面查看交换机：

ovs命令查看流表：

sudo ovs-ofctl -O OpenFlow13 dump-flows s1
sudo ovs-ofctl -O OpenFlow13 dump-flows s2

3.对比两种方法，写出你的实验体会

与ovs命令直接下发流表相比，通过ryu的脚本可以实现自动化地下发流表