OpenFlow

OpenFlow
Name	OpenFlow
Developer	Open Networking Foundation
Initial release	2008
Programming language	C, Python
Operating system	Linux, FreeBSD
License	Various (proprietary and open-source)

OpenFlow OpenFlow is a networking protocol for programmable packet forwarding that separates the control plane from the data plane. Initially specified by the Open Networking Foundation, it influenced software-defined networking developments across vendors such as Cisco Systems, Juniper Networks, Arista Networks, HP Inc., and Huawei. It is associated with research at institutions including Stanford University, University of California, Berkeley, ETH Zurich, Carnegie Mellon University, and Massachusetts Institute of Technology.

Overview

OpenFlow emerged from academic work at Stanford University and standardization efforts by the Open Networking Foundation during the late 2000s, alongside initiatives by Google and Facebook to scale datacenter networks. It defines a set of flow-table operations for switches from vendors like Broadcom and Intel Corporation, and influenced projects at IETF, IEEE, ONF Technical Advisory Group, and industry consortia including OpenStack Foundation and Cloud Native Computing Foundation. Major adopters and contributors include Microsoft, Amazon Web Services, IBM, HP Enterprise, Dell Technologies, and Fujitsu.

Architecture and Components

The architecture separates controllers such as NOX, POX Project, Ryu (software) and commercial controllers like OpenDaylight, ONOS (Open Network Operating System), Floodlight from forwarding elements produced by Arista Networks, Cisco Systems, Juniper Networks, Huawei Technologies Co., Ltd., and Netronome. Data plane devices use silicon from Broadcom, Marvell Technology Group, and Intel Corporation. Management and orchestration tools integrate with Kubernetes, OpenStack, VMware, and Ansible (software). Related research and testbeds include GENI (testbed), PlanetLab, Emulab, and Mininet.

Protocol Operations and Messages

OpenFlow specifies control messages exchanged between controllers such as OpenDaylight and switches produced by Cumulus Networks using TCP/TLS sessions derived from practices at IETF and cryptographic libraries like OpenSSL. Message classes include Hello, Echo, Feature Request, Flow Mod, Packet-In, and Packet-Out, echoing patterns in protocols used by BGP routers from Juniper Networks and Cisco Systems. Flow table entries reference match fields corresponding to headers defined by IETF RFCs and are installed, modified, and removed via messages similar to interactions in SNMP and NETCONF management paradigms. Controllers implement routing and policy logic comparable to systems developed at Carnegie Mellon University and MIT Computer Science and Artificial Intelligence Laboratory.

Implementations and Platforms

Open-source implementations include Open vSwitch, Quagga, and vendor SDKs from Broadcom and Intel Corporation. Commercial platforms built around OpenFlow include offerings by Cisco Systems, Juniper Networks, HP Enterprise, Dell Technologies, and Huawei Technologies Co., Ltd.. Research implementations appeared in projects at Stanford University, UC Berkeley, ETH Zurich, and Princeton University. Virtualization and network function integration involves KVM, Xen Project, VMware ESXi, Docker, and orchestration with OpenStack Foundation and Kubernetes.

Use Cases and Applications

OpenFlow has been used in datacenter fabrics for companies like Google and Facebook, wide-area network experiments by Internet2 and GEANT, campus networks at Stanford University and University of Cambridge, and carrier-grade trials by Telefonica, AT&T, Verizon Communications, and NTT Communications. It enabled rapid prototyping in research labs including Microsoft Research, IBM Research, Bell Labs, and PARC (Palo Alto Research Center). Integration with security and monitoring tools included solutions from Palo Alto Networks, Cisco Systems, and Splunk Inc., while academic projects evaluated traffic engineering and QoS with work by CMU, MIT, and ETH Zurich.

Security and Limitations

Security concerns noted by organizations such as CERT Coordination Center and research teams at MIT and Stanford University include controller availability, TLS session vulnerabilities, and malicious flow rules. Limitations include dependence on switch hardware capabilities from vendors like Broadcom and Intel Corporation, scalability constraints studied by IETF and ONF, and interoperability challenges addressed by Open Networking Foundation and Institute of Electrical and Electronics Engineers. Subsequent paradigms and standards by IETF and initiatives from OpenStack Foundation and Cloud Native Computing Foundation evolved to complement and, in some domains, supplant early OpenFlow deployments.

Category:Networking protocols Category:Software-defined networking