eBooks

FierceTelecom.com 8 7 M ay 2 0 13 M ay 2 0 13 FierceTelecom SDN revolutionized data centers and now telecom providers are hoping it will do the same for wide area networks. Public network operators may not want to admit it, but they occasionally take their technology cues from other networking sectors. Ethernet is a prime example. Long before becoming carrier-grade, it was a huge enterprise success story. Now, the same thing may be set to happen with software- defined networking. SDN has been all the rage in the data center market for a couple of years now, being used as a method for separating the control plane from the data plane of data center hardware elements so that switching, routing and other control processes can be virtualized and centralized to better deal with the demands of various applications and dynamically changing traffic flows. One of the ways in which this is done is by creating an abstraction layer using OpenFlow technology as a common SDN controller interface to the different elements. Companies that work with SDN in the data center say that it is spurring a revolution in how data centers are designed, inducing operational cost savings, upgrading application performance and improving traffic shaping and management. All of those benefits sound like things carriers would be interested having in the wide area networks, so a number of them have started to look at how they might be able to use SDN for WAN optimization between data centers, as well as other applications. However, like Ethernet before it, the version of SDN used to great success inside data centers is not necessarily carrier-grade, at least not yet. "OpenFlow and other technologies used inside the data center aren't yet adequate for service providers' needs," said Prayson Pate, chief technologist at Overture Networks. One of the perceived shortcomings of OpenFlow is that it has not been deployed on a wide scale yet— just within the scope of individual data centers. If carriers are to use SDN to create their own WAN-size abstraction layers, they need to be able to trust it at that scale. OpenFlow also was not designed sDn Takes a Transport Trip By dA N O 'shE A to interface with transport network platforms, said Mike Capuano, vice president of corporate marketing at Infinera. "If you look at OpenFlow and transport routers and switches, it's like they speak different languages," he said. "To enable OpenFlow to talk to these transport platforms, we need to develop a new piece of software called an open transport switch (OTS)." The OTS, basically a transport network version of a virtual switch, could work with an SDN controller to be implemented alongside many individual switches and routers throughout the network, or could be used to create APIs or an overlay to program how services are provisioned or traffic and applications are handled at various locations. The OTS is one part of how data center-variety SDN is being evolved into a concept several vendors, including Infinera, Adva Optical Networking, Overture, Cyan and others, are calling transport SDN. "Today, service provisioning is still pretty manual, complicated and tedious," Capuano said. "With a northbound interface from the SDN controller, circuits can be set up for a specific amount of time at a specific latency and then easily torn down. Also, application performance can be improved because the application will see a flat network, not a heterogeneous and complex one. SDN can help the application find the best and easiest path." Overture's Pate agreed, saying, "The drivers for expanding the use of SDN beyond the data center are focused on two major service provider objectives: Maximizing service provider operational efficiencies, and enabling new revenue-generating services. By creating an open automation and orchestration environment for the multi-vendor metro edge, service providers can eliminate time and expense normally associated with service activation and assurance." In addition to OTS developments and related solutions from vendors, industry standards bodies from both the WAN and LAN environments are working on so-called OpenFlow extensions. The IETF has a Forwarding and Control Element Separation (ForCES) Working Group looking at how OpenFlow layer separation and abstraction qualities could be applied to the transport network, while another IETF group, the Network Virtualization Overlays group, is sizing specifically how SDN overlays can be created between data centers. Meanwhile, the Open Networking Foundation (ONF) also is studying and developing transport SDN documents via a newly-created Optical Transport Working Group. Several vendors reported that both the IETF and ONF have several different proposals before them regarding how to proceed with transport SDN standards. Aside from the IETF and ONF, several major service providers also have aligned their SDN interests in the Networks Virtualization initiative. While many carriers are likely to wait for the various transport SDN projects at the IETF and ONF to sort themselves' out, others may opt to work with their vendors to create partial transport SDN environment with whatever SDN capabilities and features they feel comfortable using in their networks now. In carrier networks, MPLS and GMPLS already perform some of the control-related functions that SDN is designed for, but transport SDN should complement these existing technologies, said Jim Theodoras, director of technical marketing at Adva Optical Networking. "You can use "Traditional carriers right now are slow- rolling transport sDn." Jim theoDoras, Directorof technical marketing, avDa optical networking

• Cover