Open Flow Protocol

Describes about the basic terminologies and operations of OpenFlow Protocol

1. OpenFlow Networks

2. Computer Network : set of computers connected together for the purpose of sharing resources Software-defined networking (SDN) : Approach to allow network administrators to programmatically initialize, control, change, and manage network behavior dynamically Network Switch : connects devices together using packet switching Hub : common connection point for devices in a network,used to connect segments of a LAN Router : forwards data packets between computer networks

3. Current Internet Closed to Innovations in the Infrastructure n App App App Operating System n Specialized Packet Forwarding Hardware n App App App Operating System Specialized Packet Forwarding Hardware

4. “Software Defined Networking” approac h to open it Network Operating System App App App n App App App Operating System n Specialized Packet Forwarding Hardware n App App App Operating System Specialized Packet Forwarding Hardware

5. The “Software-defined Network” Network Operating System App App App 3.Well Defined Open API 2. At least one good operating system Extensible, possibly open-source Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware 1. Open interface to hardware

6. OpenFlow - Defintion enabler of SDN first standard communication interface defined between the control and forwarding layers of SDN Architecture needed to move network control out of proprietary network switches into control software that's open source mainly used between switch and controller as a secure channel layered on top of the Transmission Control Protocol(TCP) controllers listen on TCP port 6653 for the switches to connect

7. How does OpenFlow work? Data Path (Hardware) Control Path OpenFlow OpenFlow Controller OpenFlow Protocol (SSL/TCP)

8. Components of OpenFlow Network

9. OpenFlow Controller Manages one or more switch via OpenFlow channels Uses OpenFlow protocol to communicate with a OpenFlow aware switch OpenFlow Channel Used to exchange OpenFlow message between switch and controller OpenFlow Switch Consists of one or more flow tables,group table and meter table Single switch can be manages by one or more controllers Flow tables and group tables are used during the lookup or forwading phase Meter table is used to perform simple QOS operations

10. OpenFlow Basics Switch Port MAC src MAC dst Eth type VLAN ID IP Src IP Dst IP Prot L4 sport L4 dport Rule Action Stats Forward packet to zero or more ports Encapsulate and forward to controller Send to normal processing pipeline Modify Fields Any extensions you add! + mask what fields to match Packet + byte counters VLAN pcp IP ToS Flow entries : instructions that tell an openflow switch what to do with an incoming stream of packets and the are stored in the flow table

11. Operating Modes Reactive First packet of flow triggers controller to insert flow entries Efficient use of flow table Every flow incurs small additional flow setup time If control connection lost, switch has limited utility Proactive Controller pre-populates flow table in switch Essentially requires aggregated (wildcard) rules Zero additional flow setup time Loss of control connection does not disrupt traffic Reactive vs. Proactive (pre-populated) Both models are possible with OpenFlow

12. Centralized Control OpenFlow Switch OpenFlow Switch OpenFlow Switch Controller Distributed Control OpenFlow Switch OpenFlow Switch OpenFlow Switch Controller Controller Controller Centralized vs Distributed Control Both models are possible with OpenFlow Control Modes

13. Flow Routing vs. Aggregation Both models are possible with OpenFlow Flow-Based Every flow is individually set up by controller Exact-match flow entries Flow table contains one entry per flow Good for fine grain control, e.g. campus networks Aggregated One flow entry covers large groups of flows Wildcard flow entries Flow table contains one entry per category of flows Good for large number of flows, e.g. backbone

14. Simple Packet Forwarding Hardware Network Operating System 1 Open interface to hardware Virtualization or “Slicing” Layer Network Operating System 2 Network Operating System 3 Network Operating System 4 App App App App App App App App Many operating systems, or Many versions Open interface to hardware Isolated “slices” Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Virtualizing OpenFlow

15. Summary OpenFlow /SDN is evolving to facilitate an ecosystem for innovation OpenFlow is being deployed in over 100 organizations world-wide GEC9 in Nov, 2010 showcased nation-wide OF Internet 2 and NLR starting to serve as the GENI Backbone OpenFlow is essential for Service Providers Custom control for Traffic Engineering Combined Packet/Circuit switched networks

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