Software defined networks and openflow protocol
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Software Defined Networks (SDN) separate the control plane from the data plane in network nodes, allowing for centralized control and programmability. The Open Flow protocol allows an external controller to communicate with SDN-enabled switches to program their flow tables and direct traffic. This provides benefits like increased flexibility, automation, and innovation compared to traditional networks where control and forwarding are coupled in closed hardware devices.
Software defined networks and openflow protocol
- 1. Software Defined Networks and Open flow Protocol Mahesh M 11/27/2015Software Defined Networks and Open Flow Protocol 1
- 2. Introduction to SDN An innovative approach to network architecture that provides the ability to create a whole new class of functionality Experimental Separates the data plane and the control plane of nodes Nodes will only be forwarding the information 11/27/2015Software Defined Networks and Open Flow Protocol 2
- 3. Why SDN? Network – Core element of an organization’s technology service Current Scenario Several discrete network devices require manual configuration and management These devices will be closed, proprietary units that limit innovation Hence extensibility close to zero Need for a New network? Change in traffic patterns The “consumerisation of IT” Rise of cloud services Big Data => requirement of more bandwidth 11/27/2015Software Defined Networks and Open Flow Protocol 3
- 4. Transition to SDN… 11/27/2015Software Defined Networks and Open Flow Protocol 4 Features Features Operating System Specialized packet forwarding hardware Features Features Operating System Specialized packet forwarding hardware Features Features Operating System Specialized packet forwarding hardware
- 5. Transition to SDN… 11/27/2015Software Defined Networks and Open Flow Protocol 5 packet forwarding Features Features Network Operating System Control Plane Data Plane Open Flow Protocol packet forwarding packet forwarding
- 6. What is SDN? A flexible network architecture Control plane and Data plane – core components of a network switch Current devices have both control and data plane residing on the physical switch SDN - Control plane separated from the data plane and placed on a server Software application – provides direction to data plane Interaction between controller and data plane – using Open Flow protocol 11/27/2015Software Defined Networks and Open Flow Protocol 6
- 7. Open Flow Protocol TCP based Maintained by the open networking foundation Provides numerous functions and commands for Communication of data Status and management of the devices 11/27/2015Software Defined Networks and Open Flow Protocol 7
- 8. Open Flow Protocol Basic idea – use of flow tables as in Ethernet switches Flow Tables – vendor specific OFP : provides an open protocol to program the flow table in different switches and routers In a OFP : data path consists of flow table An action will be associated with a flow entry Set of actions supported by the open flow is extensible 11/27/2015Software Defined Networks and Open Flow Protocol 8
- 9. The Open Flow Switch Consists of at least 3 parts A flow table – an action associated with each flow entry A secure channel – connects the switch to a remote control process(controller) Open Flow Protocol – Open and standard way for a controller to communicate with a switch Types Dedicated OF switches Open Flow Enabled switches 11/27/2015Software Defined Networks and Open Flow Protocol 9
- 10. OFP – How it works? 11/27/2015Software Defined Networks and Open Flow Protocol 10 Controller Node 4 Node 2 Node 3 Flow Table If matchfield : forward message to node 4 If matchfield : change header and forward to node 2
- 11. Flow Table Consists of flow entries Each flow entry has Match fields Counters – update the number of matching packets Set of instructions to apply to matching packets Matching starts from 1st flow table and may continue to other flow tables Matching done in priority order – first match is used If no match – may continue to next flow table or may be forwarded to the controller via OFP or packet can be dropped – depends on the switch configuration 11/27/2015Software Defined Networks and Open Flow Protocol 11
- 12. 11/27/2015Software Defined Networks and Open Flow Protocol 12 Flowchart detailing packet flow through an Open Flow switch
- 13. Instructions Each flow entry include set of instructions that are executed when a packet matches the entry Supported instructions Apply-Actions action Clear-Action Write-Action actions 11/27/2015Software Defined Networks and Open Flow Protocol 13
- 14. Open Flow Channel Connects each open flow switch to the controller Usually encrypted using TLS, but may be run directly over TCP PROTOCOL OVERVIEW Support 3 messages Controller to switch Asynchronous symmetric 11/27/2015Software Defined Networks and Open Flow Protocol 14
- 15. Controller to Switch Initiated by the controller Message types Features : Controller may request for the features of the switch – expects a features reply with available capabilities of the switch Configuration : controller set/query conffig parameters Modify State : manages state on the switches – mainly to add/delete/modify flow entries Read State : to collect sttistics from the switch Packet-out : used to send packets out of a specied port on the switch, and to forward packets received via Packet-in messages Barrier : to ensure message dependencies have been met or to receive notications for completed operations 11/27/2015Software Defined Networks and Open Flow Protocol 15
- 16. Asynchronous Switches send these to indicate packet arrival, switch state change or error Message types: Packet In : For all packets that do not have a matching row entry, a packet-in event may be sent to the controller Flow removed Port status Error 11/27/2015Software Defined Networks and Open Flow Protocol 16
- 17. Synchronous sent without solicitation, in either direction Hello: Hello messages are exchanged between the switch and controller upon connection startup Echo : used to measure the latency or bandwidth of a controller-switch connection, as well as verify its liveness 11/27/2015Software Defined Networks and Open Flow Protocol 17
- 18. Open Flow Channel Connection setup Switch must be able to connect to a known IP via a user specified port If IP is known – switch initiates a TLS or TCP connection to the controller After connection is established each side should send a OFTP_Hello message with the version number If version supported connection proceeds Else – reply OFPT_Error with with a type field of OFPET_HELLO_FAILED, a code field of OFPHFC_COMPATIBLE, and optionally an ASCII string explaining the situation in data, And terminate the connection 11/27/2015Software Defined Networks and Open Flow Protocol 18
- 19. Connection Interruption Switch may lose connection due to Echo request timeout TLS session timeout Or other disconnections Switch should contact one or more backup controllers – not specified in the protocol Two modes Fail Secure – packets and messages destined to current controller is dropped Fail standalone – Switch act as a legacy Ethernet switch or router – processes all the packets by itself 11/27/2015Software Defined Networks and Open Flow Protocol 19
- 20. Encryption and Message Handling Encryption Communication through TLS connection TLS initiated by switch during the startup Controller and switch mutually authenticate using certificates Controller Certificate Switch Certificate Message Handling OFP provide reliable message delivery and processing Does not provide automatic acknowledgements 11/27/2015Software Defined Networks and Open Flow Protocol 20
- 21. Benefits of Open flow SDN Centralized control of multi-vendor environments Reduced complexity through automation Higher rate of innovation Increased network reliability and security More granular network control Better user experience 11/27/2015Software Defined Networks and Open Flow Protocol 21
- 22. Summary Current networks - less extensible Solution - Software Defined Networking and Open Flow protocol SDN – Emerging technology Separates data and control planes Makes the network control centralized Network devices are only packet forwarding objects 11/27/2015Software Defined Networks and Open Flow Protocol 22
- 23. References OpenFlow Switch Specication, Version 1.1.0 Implemented (Wire Protocol 0x02 ), February 28, 2011 – The Open Networking Foundation Software-Defined Networking: The New Norm for Networks, ONF White Paper, April 13, 2012 Zanna, P.; Hosseini, S.; Radcliffe, P.; O'Neill, B., "The challenges of deploying a software defined network," in Telecommunication Networks and Applications Conference (ATNAC), 2014 Australasian , vol., no., pp.111-116, 26-28 Nov. 2014 doi: 10.1109/ATNAC.2014.7020883 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7020883&isnumber=7 020854 Jian-Quan Wang; Haijing Fu; Chang Cao, "Software defined networking for telecom operators: Architecture and applications," in Communications and Networking in China (CHINACOM), 2013 8th International ICST Conference on , vol., no., pp.828-833, 14-16 Aug. 2013 doi: 10.1109/ChinaCom.2013.6694710 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6694710&isnumber=6 694549 11/27/2015Software Defined Networks and Open Flow Protocol 23
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Editor's Notes
- #4: Difficult to manage a large network 2.1 * 2.2 vendor dependence 2.3 inability to scale 3.1 client server apps – communication between one client and one server only – now – commn. With many servers while fetching a data 3.2 increase in use of mobile devices – these need to be iincorporated into the network while securing the corporate data – eg; amritanet 3.3 everythning in cloud now – both public and private clouds – access from anywhere – elastic scaling, storage n/w resoources etc. 3.4 need to maintain any to any connection without broke
- #5: Other features may be routing, Traffic Engineering, bandwidth allocation
- #7: Data plane on physical switch
- #9: * * Network admin can partition the trffic into research and production => researchers can control their own flows => try mew protocols etc.
- #10: 1. 2. 3. OFP – using this can add, delete and/or update the flow entries both reactively(in response to the packets) and proactively
- #14: Action Set AA Action - Applies the specic action(s) immediately, without any change to the Action Set. This instruction may be used to modify the packet between two tables or to execute multiple actions of the same type. WA Action - Merges the specied action(s) into the current action set (see 4.7). If an action of the given type exists in the current set, overwrite it, otherwise add it.
- #21: Message handling Message delivery Message processing – if connection fail send error Message ordering done through barrier message – if barrier absent randomly reorder for maximum performance Message before a barrier should be processed completely including sending replies or errors Barrier then processed and a barrier reply sent Process message after the barrier