从本节开始我们举例来分析详细的流表实现，首先我们分析L2 Switch功能实现。

1. Tenants Topology

图1 TenantsTopology

此图为netvirtdemo生成的拓扑，包括两个租户Tenant1与Tenant2，Tenant1中的VM分别部署在control节点与compute节点，其信息如下：

Devicetype	tenant	host	ip	mac	ofport	vxlan
T1-VM1	Tenant1	control	2.0.0.2	fa:16:3e:37:be:fa	3	1001(0x3e9)
T1-VM2	Tenant1	compute	2.0.0.3	fa:16:3e:46:db:d5	2	1001(0x3e9)
T1-DHCP	Tenant1	control	2.0.0.1	fa:16:3e:46:64:2b	1	1001(0x3e9)
	vxlan tunnel	control	192.168.50.20	1e:ac:ec:85:4b:a1	2	1001(0x3e9)

启动netvirt，并对控制节点与计算节点手工创建br-int，配置OVS manager与controller配置后，节点ovs配置如下：

控制节点：

vagrant@devstack-control:~/devstack$ sudo ovs-vsctl show
39745b5b-2ff9-416b-ab3e-f1b81fd29fd7
    Manager "tcp:192.168.50.20:6640"
        is_connected: true
Bridge br-int
        Controller "tcp:192.168.50.20:6633"
            is_connected: true
fail_mode: secure
        Port br-int
            Interface br-int
type: internal
    ovs_version: "2.3.2"

vagrant@devstack-control:~/devstack$ sudo ovs-vsctl show

39745b5b-2ff9-416b-ab3e-f1b81fd29fd7

Manager "tcp:192.168.50.20:6640"

is_connected: true

Bridge br-int

Controller "tcp:192.168.50.20:6633"

is_connected: true

fail_mode: secure

Port br-int

Interface br-int

type: internal

ovs_version: "2.3.2"

计算节点：

vagrant@devstack-compute-1:~/devstack$ sudo ovs-vsctl show
6a894e1d-05d8-49be-8359-a09978281b36
    Manager "tcp:192.168.50.20:6640"
        is_connected: true
Bridge br-int
        Controller "tcp:192.168.50.20:6633"
            is_connected: true
fail_mode: secure
        Port br-int
            Interface br-int
    ovs_version: "2.3.2"

vagrant@devstack-compute-1:~/devstack$ sudo ovs-vsctl show

6a894e1d-05d8-49be-8359-a09978281b36

Manager "tcp:192.168.50.20:6640"

is_connected: true

Bridge br-int

Controller "tcp:192.168.50.20:6633"

is_connected: true

fail_mode: secure

Port br-int

Interface br-int

ovs_version: "2.3.2"

2. Pipeline

控制节点：

vagrant@devstack-control:~/devstack$ sudo ovs-ofctl -O OpenFlow13 dump-flows br-intOFPST_FLOW reply (OF1.3) (xid=0x2):

# match rule from t1_dhcp, add tunnel and set reg0=1
cookie=0x0, duration=15406.148s, table=0, n_packets=266, n_bytes=34723, in_port=1,dl_src=fa:16:3e:46:64:2b actions=set_field:0x3e9->tun_id,load:0x1->NXM_NX_REG0[],goto_table:20 

#match rule from t1_vm1, config tunnel and set reg0=1
cookie=0x0, duration=15395.780s, table=0, n_packets=193, n_bytes=23952, 
in_port=3,dl_src=fa:16:3e:37:be:fa actions=set_field:0x3e9->tun_id,load:0x1->NXM_NX_REG0[],goto_table:20 

#default drop from t1_vm1
cookie=0x0, duration=30844.578s, table=0, n_packets=2, n_bytes=180, priority=0 actions=goto_table:20 cookie=0x0, duration=15395.275s, table=0, n_packets=0, n_bytes=0, priority=8192,in_port=3 actions=drop 

#default drop from t1_dhcp
cookie=0x0, duration=15405.654s, table=0, n_packets=0, n_bytes=0, priority=8192,in_port=1 actions=drop

#input to t1_vm1 by tun_id and in_port, set reg0=2
cookie=0x0, duration=15402.453s, table=0, n_packets=35, n_bytes=2966, tun_id=0x3e9,in_port=2 actions=load:0x2->NXM_NX_REG0[],goto_table:20

#match lldp to control
cookie=0x0, duration=30845.251s, table=0, n_packets=3082, n_bytes=342102, dl_type=0x88cc actions=CONTROLLER:65535

#pipeline process
cookie=0x0, duration=30844.074s, table=20, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:30
cookie=0x0, duration=30843.566s, table=30, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:40
cookie=0x0, duration=30843.065s, table=40, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:50
cookie=0x0, duration=30842.560s, table=50, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:60
cookie=0x0, duration=30842.052s, table=60, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:70
cookie=0x0, duration=30841.545s, table=70, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:80
cookie=0x0, duration=30841.040s, table=80, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:90
cookie=0x0, duration=30840.530s, table=90, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:100
cookie=0x0, duration=30839.531s, table=100, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:110

#broadcast from t1_vm1,  output to vxlan tunnel, t1_dhcp and t1_vm1(to bedetermined)
cookie=0x0, duration=15404.003s, table=110, n_packets=23, n_bytes=1812, priority=16384,reg0=0x1,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:1,output:2,output:3 

#broadcast from tunnel, flood to t1_vm1 and t1_dhcp, not tunnel.
cookie=0x0, duration=15404.507s, table=110, n_packets=18, n_bytes=1546, priority=16384,reg0=0x2,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:1,output:3

#vxlan table, where delete tunnel id ?
cookie=0x0, duration=15405.140s, table=110, n_packets=180, n_bytes=22986, tun_id=0x3e9,dl_dst=fa:16:3e:46:64:2b actions=output:1
cookie=0x0, duration=15394.764s, table=110, n_packets=250, n_bytes=32821, tun_id=0x3e9,dl_dst=fa:16:3e:37:be:fa actions=output:3
cookie=0x0, duration=15380.960s, table=110, n_packets=19, n_bytes=2148, tun_id=0x3e9,dl_dst=fa:16:3e:46:db:d5 actions=output:2

#default drop for other pkts
cookie=0x0, duration=15402.964s, table=110, n_packets=0, n_bytes=0, priority=8192,tun_id=0x3e9 actions=drop
cookie=0x0, duration=30839.028s, table=110, n_packets=6, n_bytes=508, priority=0 actions=drop

vagrant@devstack-control:~/devstack$ sudo ovs-ofctl -O OpenFlow13 dump-flows br-intOFPST_FLOW reply (OF1.3) (xid=0x2):

# match rule from t1_dhcp, add tunnel and set reg0=1

cookie=0x0, duration=15406.148s, table=0, n_packets=266, n_bytes=34723, in_port=1,dl_src=fa:16:3e:46:64:2b actions=set_field:0x3e9->tun_id,load:0x1->NXM_NX_REG0[],goto_table:20

#match rule from t1_vm1, config tunnel and set reg0=1

cookie=0x0, duration=15395.780s, table=0, n_packets=193, n_bytes=23952,

in_port=3,dl_src=fa:16:3e:37:be:fa actions=set_field:0x3e9->tun_id,load:0x1->NXM_NX_REG0[],goto_table:20

#default drop from t1_vm1

cookie=0x0, duration=30844.578s, table=0, n_packets=2, n_bytes=180, priority=0 actions=goto_table:20 cookie=0x0, duration=15395.275s, table=0, n_packets=0, n_bytes=0, priority=8192,in_port=3 actions=drop

#default drop from t1_dhcp

cookie=0x0, duration=15405.654s, table=0, n_packets=0, n_bytes=0, priority=8192,in_port=1 actions=drop

#input to t1_vm1 by tun_id and in_port, set reg0=2

cookie=0x0, duration=15402.453s, table=0, n_packets=35, n_bytes=2966, tun_id=0x3e9,in_port=2 actions=load:0x2->NXM_NX_REG0[],goto_table:20

#match lldp to control

cookie=0x0, duration=30845.251s, table=0, n_packets=3082, n_bytes=342102, dl_type=0x88cc actions=CONTROLLER:65535

#pipeline process

cookie=0x0, duration=30844.074s, table=20, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:30

cookie=0x0, duration=30843.566s, table=30, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:40

cookie=0x0, duration=30843.065s, table=40, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:50

cookie=0x0, duration=30842.560s, table=50, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:60

cookie=0x0, duration=30842.052s, table=60, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:70

cookie=0x0, duration=30841.545s, table=70, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:80

cookie=0x0, duration=30841.040s, table=80, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:90

cookie=0x0, duration=30840.530s, table=90, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:100

cookie=0x0, duration=30839.531s, table=100, n_packets=496, n_bytes=61821, priority=0 actions=goto_table:110

#broadcast from t1_vm1, output to vxlan tunnel, t1_dhcp and t1_vm1(to bedetermined)

cookie=0x0, duration=15404.003s, table=110, n_packets=23, n_bytes=1812, priority=16384,reg0=0x1,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:1,output:2,output:3

#broadcast from tunnel, flood to t1_vm1 and t1_dhcp, not tunnel.

cookie=0x0, duration=15404.507s, table=110, n_packets=18, n_bytes=1546, priority=16384,reg0=0x2,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:1,output:3

#vxlan table, where delete tunnel id ?

cookie=0x0, duration=15405.140s, table=110, n_packets=180, n_bytes=22986, tun_id=0x3e9,dl_dst=fa:16:3e:46:64:2b actions=output:1

cookie=0x0, duration=15394.764s, table=110, n_packets=250, n_bytes=32821, tun_id=0x3e9,dl_dst=fa:16:3e:37:be:fa actions=output:3

cookie=0x0, duration=15380.960s, table=110, n_packets=19, n_bytes=2148, tun_id=0x3e9,dl_dst=fa:16:3e:46:db:d5 actions=output:2

#default drop for other pkts

cookie=0x0, duration=15402.964s, table=110, n_packets=0, n_bytes=0, priority=8192,tun_id=0x3e9 actions=drop

cookie=0x0, duration=30839.028s, table=110, n_packets=6, n_bytes=508, priority=0 actions=drop

计算节点：

vagrant@devstack-compute-1:~/devstack$ sudo ovs-ofctl -O OpenFlow13 dump-flows br-int
OFPST_FLOW reply (OF1.3) (xid=0x2):

#from t1_vm2, add tun_id and set reg0=1
cookie=0x0, duration=15739.120s, table=0, n_packets=35, n_bytes=2966, in_port=2,dl_src=fa:16:3e:46:db:d5 actions=set_field:0x3e9->tun_id,load:0x1->NXM_NX_REG0[],goto_table:20

#other pkt goto 20
cookie=0x0, duration=29264.258s, table=0, n_packets=10, n_bytes=1238, priority=0 actions=goto_table:20

#default drop from t1_vm2
cookie=0x0, duration=15738.584s, table=0, n_packets=0, n_bytes=0, priority=8192,in_port=2 actions=drop

#from tunnel, set reg0=2
cookie=0x0, duration=15735.532s, table=0, n_packets=32, n_bytes=2722, tun_id=0x3e9,in_port=1 actions=load:0x2->NXM_NX_REG0[],goto_table:20

#lldp packetin to controller
cookie=0x0, duration=29265.209s, table=0, n_packets=3153, n_bytes=356289, dl_type=0x88cc actions=CONTROLLER:65535

#pipeline process
cookie=0x0, duration=29263.763s, table=20, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:30
cookie=0x0, duration=29263.238s, table=30, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:40
cookie=0x0, duration=29262.723s, table=40, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:50
cookie=0x0, duration=29262.220s, table=50, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:60
cookie=0x0, duration=29261.719s, table=60, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:70
cookie=0x0, duration=29261.201s, table=70, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:80
cookie=0x0, duration=29260.698s, table=80, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:90
cookie=0x0, duration=29260.194s, table=90, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:100
cookie=0x0, duration=29259.692s, table=100, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:110

#broadcast from t1_vm2, output all port include t1_vm2 and tunnel
cookie=0x0, duration=15737.047s, table=110, n_packets=18, n_bytes=1546, priority=16384,reg0=0x1,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:2,output:1

#broadcast from tunnel, flood to all port, only t1_vm2
cookie=0x0, duration=15737.567s, table=110, n_packets=13, n_bytes=574, priority=16384,reg0=0x2,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:2

#vxlan table for tenant1, include dhcp, vm1 and vm2
cookie=0x0, duration=15755.001s, table=110, n_packets=12, n_bytes=1042, tun_id=0x3e9,dl_dst=fa:16:3e:46:64:2b actions=output:1
cookie=0x0, duration=15744.709s, table=110, n_packets=5, n_bytes=378, tun_id=0x3e9,dl_dst=fa:16:3e:37:be:fa actions=output:1
cookie=0x0, duration=15738.080s, table=110, n_packets=19, n_bytes=2148, tun_id=0x3e9,dl_dst=fa:16:3e:46:db:d5 actions=output:2

#default drop
cookie=0x0, duration=15736.031s, table=110, n_packets=0, n_bytes=0, priority=8192,tun_id=0x3e9 actions=drop
cookie=0x0, duration=29259.185s, table=110, n_packets=10, n_bytes=1238, priority=0 actions=drop

vagrant@devstack-compute-1:~/devstack$ sudo ovs-ofctl -O OpenFlow13 dump-flows br-int

OFPST_FLOW reply (OF1.3) (xid=0x2):

#from t1_vm2, add tun_id and set reg0=1

cookie=0x0, duration=15739.120s, table=0, n_packets=35, n_bytes=2966, in_port=2,dl_src=fa:16:3e:46:db:d5 actions=set_field:0x3e9->tun_id,load:0x1->NXM_NX_REG0[],goto_table:20

#other pkt goto 20

cookie=0x0, duration=29264.258s, table=0, n_packets=10, n_bytes=1238, priority=0 actions=goto_table:20

#default drop from t1_vm2

cookie=0x0, duration=15738.584s, table=0, n_packets=0, n_bytes=0, priority=8192,in_port=2 actions=drop

#from tunnel, set reg0=2

cookie=0x0, duration=15735.532s, table=0, n_packets=32, n_bytes=2722, tun_id=0x3e9,in_port=1 actions=load:0x2->NXM_NX_REG0[],goto_table:20

#lldp packetin to controller

cookie=0x0, duration=29265.209s, table=0, n_packets=3153, n_bytes=356289, dl_type=0x88cc actions=CONTROLLER:65535

#pipeline process

cookie=0x0, duration=29263.763s, table=20, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:30

cookie=0x0, duration=29263.238s, table=30, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:40

cookie=0x0, duration=29262.723s, table=40, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:50

cookie=0x0, duration=29262.220s, table=50, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:60

cookie=0x0, duration=29261.719s, table=60, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:70

cookie=0x0, duration=29261.201s, table=70, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:80

cookie=0x0, duration=29260.698s, table=80, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:90

cookie=0x0, duration=29260.194s, table=90, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:100

cookie=0x0, duration=29259.692s, table=100, n_packets=77, n_bytes=6926, priority=0 actions=goto_table:110

#broadcast from t1_vm2, output all port include t1_vm2 and tunnel

cookie=0x0, duration=15737.047s, table=110, n_packets=18, n_bytes=1546, priority=16384,reg0=0x1,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:2,output:1

#broadcast from tunnel, flood to all port, only t1_vm2

cookie=0x0, duration=15737.567s, table=110, n_packets=13, n_bytes=574, priority=16384,reg0=0x2,tun_id=0x3e9,dl_dst=01:00:00:00:00:00/01:00:00:00:00:00 actions=output:2

#vxlan table for tenant1, include dhcp, vm1 and vm2

cookie=0x0, duration=15755.001s, table=110, n_packets=12, n_bytes=1042, tun_id=0x3e9,dl_dst=fa:16:3e:46:64:2b actions=output:1

cookie=0x0, duration=15744.709s, table=110, n_packets=5, n_bytes=378, tun_id=0x3e9,dl_dst=fa:16:3e:37:be:fa actions=output:1

cookie=0x0, duration=15738.080s, table=110, n_packets=19, n_bytes=2148, tun_id=0x3e9,dl_dst=fa:16:3e:46:db:d5 actions=output:2

#default drop

cookie=0x0, duration=15736.031s, table=110, n_packets=0, n_bytes=0, priority=8192,tun_id=0x3e9 actions=drop

cookie=0x0, duration=29259.185s, table=110, n_packets=10, n_bytes=1238, priority=0 actions=drop

3 关注表项

Table 110

作者简介：胡西宁，搞过neutron，对SDN/NFV有浓厚兴趣，一直从事相关工作，现在某通信公司工作

1. Tenants Topology

图1 TenantsTopology

2. Pipeline

3 关注表项

SDNLAB