openflow readme added

knetsolutions · Mar 16, 2018 · 9f40805 · 9f40805
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diff --git a/openflow_overview.md b/openflow_overview.md
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+# How Traditional L2 Switch Works (Technical details) :
+
+
+1. Traditional Switch have built in Control Plane + Data Plane.
+2. Mac Table( a.k.a Forwarding table) is Empty when the switch starts.
+3. Control Plane updates the Mac Table with the MAC and the PORT Number. This information is extracted from incoming Packet.
+4. Control Plane keeps on building/updating the Mac Table.
+5. When the packet arrives, Switch Data plane looks the Mac table, if the destination MAC matches in the Mac table, it forwards the packet to the respective Port.
+
+
+# How SDN Switch(Openflow Switch) Works:
+
+
+1. RYU L3 Application
+
+```
+ryu-manager ryu.app.simple_switch_13
+```
+
+
+2. Run the Linear Mininet Topology, 
+
+```
+sudo mn --controller=remote,ip=127.0.0.1 --mac -i 10.1.1.0/24 --switch=ovsk,protocols=OpenFlow13 --topo=linear,4
+```
+
+
+3. Start Wireshark Capture
+
+
+## overview
+
+1. Switch is configured with SDN Controller IP and Openflow protocol version.
+2. Switch will establish the communication with SDN Controller.
+3. Initialy the Switch flow table will be empty, When the Packet arrives Switch will send the packets to the Controller.
+4. Controller build the Switch Logic with the packets.
+5. Controller adds the Flow table to the switch.
+6. Now, Switch data path is built with flows. So when the Packet arrive it will look the Flow table and forward the packet to respective port.
+
+
+
+# Openflow Messages in Detail:
+
+
+## 1.Hello Message:
+
+   a.  Switch sends Openflow Hello Message(includes version number) to the Controller (port number 6653)
+
+   b.  Controller responds with the Hello Message if version is supported.
+
+  Failure Case(Version MisMatch):
+
+   If different Openflow Version is user between the Controller and Switch, Hello Message will fail.
+
+   You will see similar error msg in the controller.
+
+  	Error:
+  	unsupported version 0x1. If possible, set the switch to use one of the versions [3]
+
+
+## 2.Features Request/Reply Message:
+
+	1.Controller will send the Feature Request Message to the Switch and asking for the Switch supported features.
+
+ 	2. Switch will reply with
+ 	        datapath ID, buffers, tables size,
+ 	        stats reporting : flow stats, port stats, table stats etc.
+
+
+## 3.Port Desc/Status Message:
+
+	1. Controller will ask for the port description/ status message.
+
+    2. Switch will send the Port details of each port.
+
+
+## 4. Packet In/Packet Out Message:
+
+	1. If Switch want to send a data packet to the Controller, it uses the PACKET IN message
+
+	2.Controller process the Packet in message, and decides what to do(which port to forward/ or drop etc) with this packet.
+
+	3. Controller respond with Packet Out Message with actions (FLOOD etc.)
+
+
+
+## 5. Flow Modification(add,delete) Message:
+
+	1. To add, remove, modify the flow in the switch, controller using this message.
+	2. Controller Sends the Flow Modification message to the switch with this important params.
+		a. Command,
+		b. Match
+		c. Instruction, action.
+
+
+	At the time of switch starts(initial negotiatian), Controller adds TABLE MISS entry in to the switch.
+
+
+	### Table Miss Entry:
+
+	The flow entry that wildcards all fields (all fields omitted) and has priority equal to 0 is called the table-miss flow entry
+
+	RYU installs the table miss entry to forward the packets to the controller port(action = output:Controller port).
+
+
+## 6. Echo Request/Reply Message: 
+
+   To identify the liveliness of the Controller, Switch will send periodic health Check message to the Controller and expects the response. (default: 5sec interval)
+
+	A. Switch sends Echo Request to the Controller.
+
+	B. Controller responds back with Echo Reply.
+
+
+## Statistics Message:
+
+   1. flow(individual,aggregate),table,port,queue stats message will send by the controller.
+
+   2. Switch will respond with the relavent statistics.
+
+   This is used for monitoring the switches (with variour counter packets/sec, errors, etc)
+
+
+
+# Important Openvswitch Commands
+
+sudo ovs-vsctl show
+sudo ovs-ofctl -O <openflow-version> show <switch-name>
+sudo ovs-ofctl -O OpenFlow13 show s1
+sudo ovs-ofctl -O Openflow13 dump-flows s1
+
+
+
+# Take aways:
+
+1) Controller must use same Openflow version which switch uses.
+
+2) Our Controller Application(our RYU project/exercise) should process Packet IN (Message), to build the Switching/Routing logic.
+
+3) Our Controller Application(our RYU project/exercise) should use Flow Modifcation message to add/modify/delete the flows in the switch.
+
+4) Our Controller Application(our RYU project/exercise) should use Flow Stats, Port Stats request message to get the statistics(Packets Sent/Received , etc) of the flows, Ports .
+
+
+
+# References
+
+https://www.opennetworking.org/software-defined-standards/specifications/
+https://osrg.github.io/ryu/resources.html
diff --git a/ryu-exercises/ex8_rest_api_integreation.py b/ryu-exercises/ex8_rest_api_integreation.py
diff --git a/ryu-exercises/ex9_project1.py b/ryu-exercises/ex9_project1.py
diff --git a/ryu_part1.md b/ryu_part1.md
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+RYU Basic Commands:
+=========================
+
+
+## 1. How to start the ryu controller
+
+
+```
+ryu-manager  <filename/application name>
+
+```
+
+
+RYU Manager starts the application. 
+Check the running process details.
+
+ps -ef | grep ryu-manager
+
+RYU Manager listens on openflow ports(6653,6633) are in listening state.
+
+Check the port statistics
+
+netstat -ap | grep <pid>
+
+
+
+
+
+
+## 2. How to stop the ryu controller
+
+```
+CTRL + C (Kill the Process)
+
+( or )
+pkill -9 ryu-manager
+
+```
+
+
+
+## 3. RYU Controller command line options
+
+
+```
+ryu-manager --help
+
+```
+
+```
+ryu-manager --verbose  <application>
+
+```
+
+
+## 4. How to run the Application
+
+Example Application is installed in ryu/app folder.
+
+Specify the filename as ryu.app.<filename>
+
+Example:
+
+
+```
+ryu-manager --verbose  ryu.app.simple_switch_13
+
+```
+
+Download the file  and run it.
+
+
+```
+ryu-manager --verbose  simple_switch_13.py
+
+```
+
+
+
+# References
+
+https://en.wikipedia.org/wiki/OpenFlow
+
+http://ryu.readthedocs.io/en/latest/
+
+https://osrg.github.io/ryu/resources.html
+
+https://github.com/osrg/ryu/tree/master/ryu
+
diff --git a/ryu_part10.md b/ryu_part10.md
diff --git a/ryu_part2.md b/ryu_part2.md
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+RYU Part2:
+=========
+
+In this part , we are going to start writing the sample RYU applications step by step.
+
+I will be explaining the openflow protocol and openvswitch commands whereever required.
+
+
+
+Base Rule for beginners:
+Please copy the example application file and modify as per your needs.
+
+In this ryu exercises, i am going to use Openflow 1.3 Version, and use simple_switch_13.py as example program to start with.
+
+
+I copied the simple_switch_13.py file in ryu-projects folder.
+
+
+
+# RYU Programming Structure Overview :
+
+
+
+
+
+
+# How to Implement Openflow L2 Switch in RYU :
+
+
+
+
+
+
+
+
+
+
+
+# Execute the Openflow L2 Switch :
+
+
+
+
+
+# References
+
+https://en.wikipedia.org/wiki/OpenFlow
+
+http://ryu.readthedocs.io/en/latest/
+
+https://osrg.github.io/ryu/resources.html
+
+https://github.com/osrg/ryu/tree/master/ryu
diff --git a/ryu_part3.md b/ryu_part3.md
diff --git a/ryu_part4.md b/ryu_part4.md
diff --git a/ryu_part5.md b/ryu_part5.md
diff --git a/ryu_part6.md b/ryu_part6.md
diff --git a/ryu_part7.md b/ryu_part7.md
diff --git a/ryu_part8.md b/ryu_part8.md
diff --git a/ryu_part9.md b/ryu_part9.md
diff --git a/wireshark_traces/Openflow13_GoodMsg.pcapng b/wireshark_traces/Openflow13_GoodMsg.pcapng