The Agendas Surrounding SDNs May Be as Complex as the Technology

Carl Weinschenk

One of the hot topics in networking circles is software-defined networks (SDNs). In essence, this approach allows network management systems from different companies to work together more easily and for that control to be applied in a more consolidated and precise manner.


The big initiative to SDNs is OpenFlow, which is a specification being developed by the Open Networking Foundation. Experts say that the evolution of SDNs still is in its early days. Indeed, new benefits still are emerging. At WAN Speak, David Greenfield describes a conversation between Network World's John Dix and Google Principal Engineer Amin Vahdat. Vahdat explained that the traffic prioritization and shaping capabilities in an SDN can reduce the wiggle room necessary to project mission-critical data. In short, a higher percentage of a given network's capacity can be used - and less kept in reserve - if it is an SDN.


The challenge is that technical changes and evolution upset the apple cart and create winners and losers. It figures that if the network is opened up - if company X and company Y suddenly can sell hardware and software to an enterprise or carrier, though the infrastructure formerly was managed solely by gear from company C - company C would lose market share. The "C" in this representation conveniently stands, in most cases, for Cisco.


For this reason, moves like this always deeply impact the agendas of each player. This week, C - I mean Cisco - detailed its vision at Cisco Live. InformationWeek's Art Wittmann offers a very clear view on what he thinks Cisco is up to. In essence, its focus is on defining what people want through the prism of what its equipment is capable of providing - not new things that proponents claim SDNs can bring to the table, and which may bring new players into the market:

Cisco's core proposition is that while the industry is abuzz with OpenFlow and SDN, what customers really want is programmability of the network. So, while OpenFlow and SDN are important developments, the real thing that will get customers excited, according to Cisco, is exposing all that intelligence that's already in the network and letting users program it. Rather than dealing with BGP and VLAN setups, just tell the network you want a connection between point A and point B, and describe your SLA. The underlying network will do the rest.

CIOs, CTOs and, eventually, the markets will decide how deeply to deploy SDNs - and pass judgment on Cisco's stance. Clearly, it is not presented by the company in the context of its impact on the company's bottom line. The intellectual and conceptual ideas behind its approach to SDNs was, according to The Register, best described by David Ward, chief architect of Cisco's Service Provider Group. The bottom line is that he doesn't think SDNs are a very good idea:

During a Q&A session following the press conference, Ward explained that software-defined networks violate the very tenets of routing and switching, where they state of the network is stored in a config file inside of the gear and also, equally importantly, provides a centralized view of the network topology surrounding any piece of gear. By definition, any SDN approach means making all of this malleable, changing topologies on the fly and having networks react to applications instead of the other way around, when networks simply and silently don't give applications the resources they need if they don't have them allocated.

It is the beginning of a long path for SDNs. It will be interesting to see how the technology evolves and how the various players hedge their bets.

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