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SDN Introduction

  1. Software Defined Networking Concept Department of Computer Science and Information Engineering Chang Gung University Yoppy Yunhasnawa A Brief Introduction 9 April 2015
  2. Sections 1. Data Plane 2. Control Plane 3. The Drawbacks of Traditional Networking 4. The Needs of New Networking Strategy 5. Separation of Control Plane & Data Plane 6. Packet Forwarding 7. Network Controller
  3. 1. Data Plane
  4. Data Plane • Data plane or forwarding plane is a part in router architecture that defines what to do with every incoming packets. • Most commonly, it refers to a table used by router to: – Lookup the destination of the incoming packet. – Retrieves information about the path to the packet receiver. • Some policies or flags can also be incorporated in the table, so the router can determine whether the package should be delivered or discarded. • The table can be in the following forms: – Routing Information Base (RIB) – Forwarding Information Base (FIB)
  5. Data Plane An example of Routing Table
  6. 2. Control Plane
  7. Control Plane • Control Plane is a part of router architecture that executes the forwarding rules defined in the data plane while continuously updating the routing table according to the given protocol. • An imaginary map/topology of the network is exchanged from every one into another connected router to maintain the content of the data plane’s routing table. • Hence, it is the signaling of the network and it can be considered as the brain of a routing device.
  8. Control Plane ROUTING LOGIC INGRESS Ports EGRESS Ports Firewall MAC Filtering Encryption Decryption Etc…Etc… Routing Table Logic stacks X Packet X: DROP? CONTINUE to PORT X
  9. 3. The Drawbacks of Traditional Networking
  10. INTERNET The Drawbacks of Traditional Networking
  11. The Drawbacks of Traditional Networking • Complexity that lead to stasis – Complex network with a large number of switching device will require extra cautions when performing any change. This causes IT tends to let the network unchanged to minimize service disruption risks. • Inconsistent policies – Network administrators are unable to implement single policy because of the complexity problem. • Inability to scale – Numerous different user devices require different level of bandwidth. To update any configuration or to add new networking devices will be very difficult because reconfiguration must be done in device level. • Vendor dependence – Depending on the number of used networking hardware, the reconfiguration of the device will be more. Because hardware created by different factories, IT department must perform a lot of study from each vendor's manual book.
  12. 4. The Needs of New Networking Strategy
  13. The Needs of New Networking Strategy • Changing traffic patterns – In enterprise systems, users have different and unpredictable traffic pattern as a single user can access the systems through a numerous different devices and platform. Dynamic & flexible network service are needed. • The consumerization of IT – More and more users’ personal devices now access the corporate networks. All of them should be accommodated while protecting corporate data and intellectual property is also important. Therefore secure network is mandatory. • The rise of cloud service – Enterprises have high demand on cloud services, resulting in very high growth on this kind of services. Cloud service, requires elastic scaling of computing, storage, and network resources. And such capability often requires periodic changes in network infrastructure. • Big data. – Big data or mega datasets requires massive parallel processing on thousands of servers that are directly connected to each other. This constant demand for additional network capacity in the data center.
  14. 5. OpenFlow Protocol
  15. OpenFlow Protocol • OpenFlow is a communication protocol that opens access to every single routing device’s data plane over the entire network. • This access allows a remote controller to determine the path of network packets throughout the network switches. • That means, the work of all switches and routers can be monitored and controlled in a centralized manner. • Because OpenFlow is an open standard protocol, this centralized control can be done even the switches are from different manufacturers.
  16. OpenFlow Protocol Network Operating System Remote Controller Machine (Physical/Virtual) Switch’s Data Plane This API is also called Southbound API, can be inform of commands to forward, delete, or modify packets OpenFlow is this API or set of commands sent from network OS to switch and vice-versa
  17. OpenFlow Protocol • Each OpenFlow API is encapsulated in a set of bytes data frame called FLOW. • This Flow is sent from a controller to any switching devices over the entire network. • The purpose of this flow-sending is to modify certain routing tables so that all packets can be forwarded strictly based on the network administrator’s will. An example of FLOW
  19. 6. Separation of Control Plane & Data Plane
  20. Separation of Control Plane & Data Plane • Because of OpenFlow, the Data Plane and Control Plane can now be separated. • At first, typical switch is equipped with tons of tools consisting of millions of lines of source codes. • Those switches are expensive because their brains aka. Control Planes are installed with all of this features but not limited to: – Routing algorithm – Firewall – Security – Management Console, and MANY others • With the help of OpenFlow, all those features are enough to be installed in one or more centralized controller. • What next? All the switches can be simplified into a pure forwarding functions or Data Plane-centric switches that are: – Less resource consumption. – Easier to remove, add, replace or configure. – Less expensive aka. CHEAPER.
  21. Separation of Control Plane & Data Plane INTERNET
  22. Flow Table Forwarding Rules Flow Table Forwarding Rules Flow Table Forwarding Rules Flow Table Forwarding Rules Control Plane Data Plane Control Plane Data Plane Control Plane Data Plane Control Plane Data Plane Separation of Control Plane & Data Plane
  23. SDN Controller Separation of Control Plane & Data Plane
  24. 7. SDN Controller
  25. SDN Controller • An SDN Controller in a software-defined network (SDN) is the “brains” of the network. • It is the strategic control point in the SDN network. • It relays information to the switches/routers ‘below’ (via southbound APIs) and the applications and business logic ‘above’ (via northbound APIs). • An SDN Controller platform typically contains a collection of “pluggable” modules that can perform different network tasks. They are called network applications. • 2 most well-known protocols used by SDN Controllers: – OpenFlow – OVSDB.
  26. SDN Controller Distributed routing algorithm, difficult to change one switch without disturbing the others. Centralized management, enables easier maintenance. Allows programming the behavior of the network. • SDN Controller enables the global view of the network. • Because all of the knowledge from every single routing device are now stored in the central controller, the network topology can be simplified and encapsulated. • This encapsulation enables a much easier way for developer to write networking apps on top of the network OS because they no need to care about the specific location and properties of every router/switch.
  27. A schema of Congestion Avoidance using single SDN Controller SDN Controller Congestion Notifications No congestion! Heavy traffic Reduced traffic rate
  28. SDN Controller