RYU控制器的學習筆記（一）

參考鏈接：https://www.cnblogs.com/goldsunshine/p/11720310.html

1.默認的流表

當你啓動任何一個ryu app之後，交換機的流表就被設置爲默認的下面的內容

root@user-NF8480M5:/home/user/qyq/dragonflow/main# ovs-ofctl dump-flows ckltest-br
NXST_FLOW reply (xid=0x4):
 cookie=0x0, duration=1.737s, table=0, n_packets=0, n_bytes=0, idle_age=1, priority=1,arp actions=CONTROLLER:65535
 cookie=0x0, duration=1.737s, table=0, n_packets=0, n_bytes=0, idle_age=1, priority=1,ip actions=drop
 cookie=0x0, duration=1.737s, table=0, n_packets=0, n_bytes=0, idle_age=1, priority=0 actions=NORMAL

2.默認流表下的流量轉發

以同一個ovs上的主機Aping主機B爲例，默認的話是ping不通的，僅僅增加arp表項的處理包個數

例如，下面的是192.168.1.2 ping 192.168.0.3,會首先尋找默認網關的mac地址

root@user-NF8480M5:/home/user# tcpdump -i tapq
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tapq, link-type EN10MB (Ethernet), capture size 262144 bytes
16:29:36.922760 ARP, Request who-has 192.168.1.1 tell 192.168.1.2, length 28
16:29:37.939530 ARP, Request who-has 192.168.1.1 tell 192.168.1.2, length 28
16:29:38.963532 ARP, Request who-has 192.168.1.1 tell 192.168.1.2, length 28
16:29:39.987755 ARP, Request who-has 192.168.1.1 tell 192.168.1.2, length 28
16:29:41.011541 ARP, Request who-has 192.168.1.1 tell 192.168.1.2, length 28
16:29:42.035539 ARP, Request who-has 192.168.1.1 tell 192.168.1.2, length 28

剛好被流表接受到6個流量包

NXST_FLOW reply (xid=0x4):
 cookie=0x0, duration=574.422s, table=0, n_packets=6, n_bytes=252, idle_age=560, priority=1,arp actions=CONTROLLER:65535
 cookie=0x0, duration=574.422s, table=0, n_packets=0, n_bytes=0, idle_age=574, priority=1,ip actions=drop
 cookie=0x0, duration=574.422s, table=0, n_packets=0, n_bytes=0, idle_age=574, priority=0 actions=NORMAL

3.CONTROLLER:65535是什麼意思？

是指將流量包轉發給控制器的意思

4.啓動