For a while, the terms OpenFlow and software-defined networking (SDN) were nearly interchangeable. The networking protocol enjoyed a lot of early hype, and network engineers saw it as the answer to SDN. But that attitude is changing, led in large part by networking vendors' efforts to differentiate their own SDN offerings -- and to maintain their market share. This guide provides an overview of opinions and approaches to OpenFlow SDN and how vendors are responding to the SDN protocol.
1OpenFlow SDN matters-
Why OpenFlow SDN matters
In a software-defined network, switches and routers take some form of direction from a centralized software management element. In the context of OpenFlow, the control plane is abstracted from the data forwarding plane. A centralized controller, which maintains a real-time, holistic view of the network, defines network paths as "flows" and distributes this flow data to individual switches and routers. With these flows, the controller coordinates the forwarding of data across all network devices.
OpenFlow has been well received by the networking community because it enables the automation and granularly managed dynamic provisioning necessary in virtualized environments and cloud networks.
OpenFlow directs network packet flows, but OpenFlow configuration protocols, OF-Config and OVSDB, form relationships between controllers and switches. Continue Reading
Georgia Tech's Nick Feamster talks creating a basic SDN controller inspired by routing, and using OpenFlow SDN for access-based control. Continue Reading
SDN is about network programmability, not necessarily OpenFlow
However, an OpenFlow network requires an OpenFlow controller and a network-switch vendor that supports the protocol. And some networking vendors are hesitant to jump on the bandwagon. Companies such as Cisco, VMware, Juniper, Brocade, Avaya, Embrane, Plexxi and PlumGrid posit that SDN is about network programmability, not necessarily OpenFlow.
It's worth noting that many of these companies are actively involved in the development of OpenFlow through the Open Networking Research Center and the Open Networking Foundation. So while each they want to promote and maintain their own approaches to SDN to differentiate their products, they're also keeping OpenFlow SDN in the mix.
Software-defined networking (SDN) and OpenFlow are no longer synonymous. Now vendors are taking individual approaches to SDN using other methods. What does this mean for OpenFlow? Continue Reading
The OpenFlow protocol isn't required for SDN, although the Open Network Foundation recommends it, which means networking vendors have options. Continue Reading
With Cisco ONE, Cisco moves beyond software-defined networking, introducing APIs and virtual network overlays that enable programmable networks. Continue Reading
OpenFlow is the earliest standard interface defined between the control and forwarding layers of SDN architecture, but issues exist with security, scalability and the need for specialized hardware. We found five SDN protocols other than OpenFlow. Continue Reading
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3Make OpenFlow SDN work-
Making OpenFlow SDN work on top of traditional hardware
Other SDN companies, like Big Switch Networks and HP, are making OpenFlow function on top of legacy hardware. The latter's Virtual Cloud Networking software functions is enhancement to OpenStack Neutron, as well as an SDN application that can run on HP's OpenFlow controller. HP has also integrated its controller and network management platform with VMware NSX, for joint management across physical and virtual networks.
Big Switch Networks is a big OpenFlow proponent, but the company also aims to make it possible for enterprises to build SDNs on top of any underlying physical infrastructure, whether or not they're OpenFlow-friendly. In doing so, Big Switch hopes to enable network virtualization that will easily rival VMware. Big Switch offers an OpenFlow controller, and it enables an OpenFlow network overlay technology as part of its Big Virtual Switch network virtualization application.
HP network virtualization software VCN enhances OpenStack Neutron and integrates with HP's OpenFlow controller. Continue Reading
Big Switch Networks introduced an OpenFlow network overlay that enables users to run a software-defined network with any physical infrastructure. Continue Reading
Cloud services require a more dynamic approach to networking like OpenFlow offers. Big Switch Networks' cloud networking play, Open SDN, appears to be a promising answer. Continue Reading
In this Q&A, Ixia's Mike Haugh explains why OpenFlow hardware support varies so much from vendor to vendor. Continue Reading
The future of OpenFlow
Despite some networking vendors' efforts to shift focus away from OpenFlow, the protocol continues to have passionate advocates among the networking community.
As vendors develop their own approaches to SDN in response to OpenFlow, the protocol continues to evolve and its capabilities continue to expand. With the "southbound" functionality of OpenFlow established, the Open Networking Foundation (ONF) is focusing on the protocol's "northbound" functionality.
In August 2012, the ONF acknowledged that developers of network-control applications wish to write "for the northbound edge of an OpenFlow controller." It also announced an initiative to catalog and characterize existing APIs in a first step toward assessing market requirements.
OpenFlow applications beat network management tools, offering a holistic view of the network's configuration and granular control even in a dynamic virtualized environment. Continue Reading
HP's marketplace for SDN apps is now open. Download apps from F5, Blue Cat, Kemp and others for HP's OpenFlow controller. Continue Reading
OpenFlow can be transformed into a network control protocol that pushes past Layer 2 to transform the WAN and optical transport layer of the network. Continue Reading
The Open Networking Foundation will move on northbound OpenFlow applications, but these northbound APIs could threaten Cisco's proprietary SDN plan. Continue Reading