RYU basic architecture

1. RYU shanyu@sdnds-tw

2. Outline
❖ Introduction to RYU
❖ Environment Setup
❖ Basic RYU Operation
❖ RYU Application Development
❖ RYU Restful API

3. Outline
❖ Introduction to RYU
❖ Environment Setup
❖ Basic RYU Operation
❖ RYU Application Development
❖ RYU Restful API

4. RYU
❖ Ryu is a component-based software defined
networking framework
❖ Fully written in Python
❖ Ryu supports various protocols for managing network
devices
 OpenFlow 1.0, 1.2, 1.3, 1.4, Netconf, OF-config, SNMP etc.
Official site:
• http://osrg.github.io/ryu/
Mailing list:
• https://lists.sourceforge.net/lists/listinfo/ryu-devel
API Documentation:
• http://ryu.readthedocs.org/en/latest/
RyuBook Tutorial (Chinese):
• http://osrg.github.io/ryu-book/zh_tw/html/

5. Controller and Switch OpenFlow Message
CONFIG_DISPATCHER
HANDSHAKE_DISPATCHER
MAIN_DISPATCHER
DEAD_DISPATCHER
RYU four status

6. RYU OpenFlow Message
Type Message Name Ryu OpenFlow Message
Controller-to-Switch
Features OFPFeaturesRequest / OFPSwitchFeatures
Configuration OFPSetConfig
Packet-out OFPPacketOut
Modify-State OFPFlowMod
Read-State OFPFlowStatsRequest/OFPFlowStatsReply
OFPPortStatsRequest/OFPPortStatsReply
Barrier OFPBarrierRequest/OFPBarrierReply
Asynchronous
(switch->controller)
Packet-In OFPPacketIn
Flow Removed OFPFlowRemoved
Port Status OFPPortStatus
Error OFPErrorMsg
Symmetric
(switch<->controller)
Hello OFPHello
Echo Request / Reply OFPEchoRequest/OFPEchoReply
Vender OFPExperimenter

7. RYU Application Programming Model
❖ Data path thread 接收所有來自 OpenFlow switch events
❖ Asynchronous messages
❖ Switch reply messages
❖ Data path thread 收到 event 後即分配給所有有註冊這
event 的 application
❖ 每個 Application 維護
自己的 Event queue
❖ decorator (@) 接收事件
❖ Programmer 定義 Event Handler
(Event Dispatcher)

8. Outline
❖ Introduction to RYU
❖ Environment Setup
❖ Basic RYU Operation
❖ RYU Application Development
❖ RYU Restful API

9. Environment Setup
❖ All-in-one tutorial VM contains:
❖ SDN Controllers: OpenDaylight, ONOS, RYU, Floodlight, Floodlight-
OF1.3, POX, and Trema
❖ Open vSwitch 2.3.0 with support for Openflow 1.2, 1.3 and 1.4, and
LINC switch
❖ Mininet to create and run example topologies
❖ Pyretic
❖ Wireshark 1.12.1 with native support for OpenFlow parsing
❖ JDK 1.8, Eclipse Luna, and Maven 3.3.3
❖ Update newest RYU version
$ cd ~/ryu
$ git fetch
$ git merge origin
$ python ./setup.py install http://sdnhub.org/tutorials/sdn-tutorial-vm/

10. Outline
❖ Introduction to RYU
❖ Environment Setup
❖ Basic RYU Operation
❖ RYU Application Development
❖ RYU Restful API

11. Basic RYU operation - CLI
❖ ryu-manager, ryu run
❖ 啟動ryu
❖ --h
❖ Show help message
❖ --verbose
❖ Show debug output
❖ --version
❖ Show program’s version
❖ --observe-links
❖ 定期發送 LLDP 封包
❖ Example:
$ cd ~/ryu/
$ ./bin/ryu-manager --observe-links ryu/app/simple_switch.py
ryu.app.simple_switch

12. Basic RYU operation - GUI
$ ./bin/ryu-manager --observe-links ryu.app.gui_topology.gui_topology
ryu.app.simple_switch
$ sudo mn --topo=single,3 --controller=remote --mac

13. Outline
❖ Introduction to RYU
❖ Environment Setup
❖ Basic RYU Operation
❖ RYU Application Development
❖ Simple Switch
❖ Traffic Monitor
❖ Lab
❖ RYU Restful API

14. RYU application – Simple Switch
• mac_to_port
目前所學習到連接埠與 host 之 MAC 對應關係
• Receive pkt_in
dst_mac存在於 mac_to_port
-> 轉送該封包到相對應的連接埠
dst_mac不存在於 mac_to_port
-> Flood

15. Simple Switch – Example (1/4)
❖ Initial status

16. Simple Switch – Example (2/4)
❖ Host A -> Host B
❖ Host A triggers Packet-In message
❖ Record Host A MAC
❖ Host B has not been found, the packets are flooded
❖ Host B and host C received

17. Simple Switch – Example (3/4)
❖ Host B -> Host A
❖ When the packets are returned from host B to host A
❖ Host B triggers Packet-In message
❖ Record Host B MAC
❖ Controller installs an entry to the flow table and also the
packets are transferred to port 1.

18. Simple Switch – Example (4/4)
❖ Host A -> Host B
❖ Controller installs an entry to the flow table

19. RYU application – Traffic Monitor
Controller
OpenFlow
Switch
Stats_reqeust Stats_reply
https://github.com/osrg/ryu-book/blob/master/en/source/sources/simple_monitor.py

20. Outline
❖ Introduction to RYU
❖ Environment Setup
❖ Basic RYU Operation
❖ RYU Application Development
❖ RYU Restful API

21. RYU Restful API
OpenFlow
Switch
SDN App SDN App
RYU APP RYU APP
OpenFlow
Switch
Network
Device
Event
Dispatcher
Libraries
RYU provided restful API:
/ryu/app/rest*.py
/ryu/app/ofctl_rest.py
Open Protocol
(OpenFlow, OF-config, NetConf..)
Control layer
Well-defined API
(REST, RPC)
Application layer

22. Reference
❖ SDNDS-TW
❖ http://sdnds.tw/
❖ RYU Contributor
❖ John-Lin
❖ http://linton.tw/
❖ http://www.slideshare.net/ireri339/sdndstw-ryu-developing
❖ Tseng Yi
❖ http://blog.takeshi.tw/about.html

23. Thank you

24. 補充 – OpenFlow

25. OpenFlow - Controller-to-Switch (1/6)
❖ Controller sends a Feature request message to the switch to get
the capabilities of a switch
❖ Switch must reply with a Feature reply that specifies the
capabilities supported by the switch
 max packets buffered at once
 capabilities supported by switch
 flow statis, table statis, port statis, reassemble IP fragments,...
 actions supported by the switch
 SET_VLAN_VID, SET_DL_SRC, SET_DL_DST, ENQUEUE,...
 describe all the physical ports (which support OpenFlow)
 port no, hw addr, state,...

26. OpenFlow - Controller-to-Switch (2/6)
❖ SET_CONFIG
 Controller send a SET_CONFIG message to set configuration parameters in
the switch
 max bytes of new flow that switch should send to the controller
 handling of IP fragments (normal, drop, reassemble,...)
❖ GET_CONFIG
 Controller send a GET_CONFIG Request message to query configuration
parameters in the switch
 Switch responds to a configuration request with an GET_CONFIG Reply
message

27. OpenFlow - Controller-to-Switch (3/6)
❖ Controller sends Packet_out of a specified port on the switch
 buffer_id
 in_port
 port = TABLE
 actions

28. OpenFlow - Controller-to-Switch (4/6)
❖ Controller send Flow_mod message to switch to
add/delete/modify flows in the flow tables
❖ match fields
❖ idle/hard timeout
❖ buffer_id
❖ actions

29. OpenFlow - Controller-to-Switch (5/6)
❖ Stats request is used by the controller to collect statistics
❖ Switches flow-tables, ports and the individual flow entries
❖ switch responds with one or more Stats reply messages

30. OpenFlow - Controller-to-Switch (6/6)
❖ Controller to ensure message dependencies have been met
or to receive notifications for completed operations
❖ Switch must finish processing all previously-received
messages before executing any messages beyond the Barrier
request
❖ switch must send an Barrier reply message when such
processing is complete

31. OpenFlow - Asynchronous
❖ Packet_in
❖ Packet_in message (event) is sent to the controller when
❖ a packet do not have a matching flow entry
❖ a packet matches an entry with a "send to controller" action
❖ Flow_removed
❖ Switch sends a Flow_removed message to controller when
❖ flow time out
❖ delete flow using Flow_removed message by controller
❖ Port_status
❖ As physical ports are added, modified, and removed from the switch

32. OpenFlow - Symmetric
❖ Hello
❖ Hello messages are exchanged between the switch and
controller upon connection startup
❖ version negotiation
❖ Echo
❖ indicate liveness of a controller-switch connection
❖ Vendor
❖ Offer additional functionality within the OpenFlow message type space