The case for software-defined networking (SDN) in a cloud context is nicely summarized by Hewlett-Packard Co. HP points out that if a cloud provider has, for example, 500 servers in a data center, each running 20 virtual machines (VMs), the result is a possible 10,000 workloads that need connections. If each connection has five attributes, 50,000 network attributes may need to be configured. If each attribute requires five CLI commands, then even if a cloud provider manages to reduce its configuration error rate to one in a thousand, that's a significant number of problems to troubleshoot.

And in the dynamic environment of the cloud, providers can't just nail up connections once and forget about them. As workloads move across physical servers and data centers, new switches and network appliances continually need to be configured to support them – and at a speed that matches the velocity of VM creation/migration.

As one cloud provider puts it, most of the failures it sees in the data center are network-related, due to the complexity and un-automated nature of network provisioning. And as operators start to link MPLS IP/VPNs with data center LANs to give customers virtual private "carrier" clouds, they add another dimension to the problem of network configuration. They also create a further driver for SDN, where SDN means the abstraction of the entire network rather than simply the abstraction of the data center switching layer.

The cloud is focusing operator attention on the need to accelerate, automate and converge network management processes (provisioning and assurance) that are traditionally highly fragmented and manual. In this respect, network management is following the path of IT management, where the growing discontinuity between the tools used to manage traditional, bare metal IT infrastructure and those emerging for the management of "cloudified" infrastructure has been apparent for some time. VMWare, for example, is a strong challenger to traditional IT management tool suite vendors in the data center.

As SDN and emerging Network Function Virtualization (NFV) approaches create an increasingly abstracted, virtualized and programmable network, traditional operation support system (OSS) vendors similarly face potential disintermediation by a new breed of SDN controller and real-time OSS player. Such vendors are designing new network abstraction and orchestration systems to cope with the dynamic environment of the carrier cloud. Some vendors' "real-time OSS" sits on top of, and orchestrates, legacy OSS/IT management systems for now, but intend to drive network equipment/virtualized network resources directly in the future.

Heavy Reading Service Provider IT Insider, "Real-Time OSS for SDN & the Cloud," investigates whether existing OSS can be repurposed to handle SDN in a cloud context and looks at up-and-coming OSS vendors and approaches that are winning favor with leading telco cloud providers. It points out that OSS vendors have to support much higher levels of automation, integration and proactivity in the cloud infrastructure than has been needed in the telco's existing, physical network environment. It finds that network equipment vendors have reacted more quickly than many IT vendors to the OSS needs of cloud and SDN – the former have been acquiring, partnering and innovating in the OSS domain over the past 18 months to try and establish a market lead.

The report also suggests that the largest threat to vendors is cloud service providers that can't wait for the market to provide what they want and that are integrating SDN-inspired abstraction and orchestration layers for themselves. Such cloud providers understand that real-time OSS will enable them to manage cloud infrastructure cost-effectively and at the scale they need to deliver competitive cloud services.

— Caroline Chappell, Analyst, Heavy Reading Service Provider IT Insider

Real-Time OSS for SDN & the Cloud, a 27-page report in PDF format, is available as part of an annual subscription (6 bimonthly issues) to Heavy Reading Service Provider IT Insider, priced at $1,595. Individual reports are available for $900.