OpenFlow and sFlow

OpenFlow is gaining considerable attention as the technology moves from research labs into mainstream products. The recently formed Open Networking Foundation's first priority is to "develop and use the OpenFlow protocol" and it is well placed to have an impact on the networking industry with major network operators and manufacturers as members: Deutsche Telekom, Facebook, Google, Microsoft, Verizon, Yahoo!, Big Switch Networks, Broadcom, Brocade, Ciena, Cisco, Citrix, Comcast, Dell, Ericsson, Extreme Networks, Force10 Networks, HP, IBM, IP Infusion, Juniper Networks, Marvell, Metaswitch Networks, NEC, Netgear, Netronome, Nicira Networks, Nokia, Siemens Networks, NTT, Plexxi Inc., Riverbed Technology, Vello Systems and VMware.

Many of the same network equipment manufacturers are also members of the sFlow.org industry consortium and the sFlow standard is widely supported in Ethernet switches; including many of the recently announced OpenFlow switches.

The diagram shows how sFlow and OpenFlow provide complementary functions that together offer exciting opportunities for delivering breakthrough data center and cloud networking performance. The OpenFlow protocol allows controller software running on a server to configure the hardware forwarding tables in a network of switches. The sFlow standard specifies instrumentation in the forwarding table hardware that provides real-time, network-wide visibility into traffic flowing across the network. In addition, sFlow also provides real-time visibility into the performance of servers. Combined, sFlow and OpenFlow can be used to construct feedback control systems that optimize performance, automatically adapting the network to meet changing demands.

The paper, DevoFlow: Cost-Effective Flow Management for High Performance Enterprise Networks, Ninth ACM Workshop on Hot Topics in Networks (HotNets-IX), describes research at HP Labs to create exactly this type hybrid sFlow/OpenFlow controller, combining the strengths of sFlow as a measurement technology with the strengths of OpenFlow as a control technology in order to create a scalable traffic control system.

Software controlled networking is evolving rapidly and much of the innovation in this space is being driven by smaller companies: Big Switch Networks and Nicira Networks, both developing OpenFlow controllers and InMon Corp. a leading provider of sFlow analysis software that already includes basic traffic control capabilities.