Last week we attended the NetEvents EMEA Press and Analyst Summit. Part of the 2-day program was a debate session on Software Defined Networks (SDN) with panellists from Gartner, IDC, IBM, Dell, HP, Extreme Networks, Enterasys and yours truly. The debate centred on the question who is first to ride the SDN revolution, the Enterprise, the Cloud Data Centre, or the Service Provider (and where is it taking them)?
What is SDN?
SDN is about separating the network router and switch data plane (hardware that does packet forwarding) from the control plane (logic that controls packet forwarding). In SDN the control path decisions are taken out of the switch and managed by software on a centralised server. In other words, SDN is about providing a programmable interface into the infrastructure to modify the network infrastructure behaviour and delegate the capability of modifying that to other IT systems. The OpenFlow protocol, which the Open Networking Foundation (ONF) is standardizing, is part of SDN and is used to communicate between an external OpenFlow controller and OpenFlow enabled switches (see Figure below).
Why is SDN important?
The disruptive aspect of SDN is that it potentially opens up today’s vertically integrated distributed control networking gear and allows standard switch hardware to be controlled centrally via OpenFlow through an SDN controller. Of course, the other side of the coin is that vendors can and will develop their own proprietary versions of SDN and OpenFlow, delivering hybrid and centralized control in a vertically integrated fashion. Already Cisco, HP, IBM and Dell are selling so-called converged infrastructure solutions that package servers, storage, networks, and orchestration software in a single rack.
The SDN and OpenFlow development also ties into OpenStack, an open source cloud operating system with the mission to enable any organization to create and offer cloud computing services running on standard hardware. Open source cloud management platforms (CMP) like OpenStack can automatically provision network resources through linking into an SDN controller that is controlling OpenFlow enabled switches. CMPs like VMware vCloud are looking to do the same. VMware recently acquired Nicira, a network virtualisation software vendor as part of their move to create the software defined datacenter. A fully automated datacenter, where all infrastructure is virtualized and delivered as a service. Network virtualisation is not new – virtual LANs have been around for ages – but creating virtual networks is currently time consuming, involves command line interfacing rather than mouse point and click, and is tough to implement across vendors and geographies.
Automated datacenters are an important prerequisite for our happy cloud scenario. With 47% of the $299B datacenter market pie attributable to internal staff – source ITCandor – the potential cost savings of automation are also significant.
Who is selling SDN?
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