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Software-defined infrastructure is gaining a lot of momentum as the core architecture for the modern data center. The aim is to deliver much more flexibility and control to clouds and clusters, while reducing costs and increasing performance.
The networking segment, software-defined networking (SDN), is leading the software-defined infrastructure effort and is already well-defined. Here, the control software for switching is separated from the switch hardware itself and runs on virtual instances in the server farm. This leads to inexpensive switches using merchant silicon, which allows low-priced vendors access to the larger market, just one of the benefits of SDN.
SDN coexists with network function virtualization (NFV), with the latter essentially being a use-case of SDN. This is important, since NFV has gained quite a bit of momentum in its own right. SDN is the virtual network viewed from the administration side, while NFV is the view from the data or switch node side. It's more complex than that, but the result is that we need a mashup of both to achieve fully virtualized networking with centralized control.
Another one of the benefits of SDN is the automated orchestration of services in the data center. We already have that for servers, and extending the method to both networking and storage is seen as an essential step in scaling data center operations. Automation will move operations from its current manual setup process to a script-based system using template libraries.
The software-defined future
The function of the next-generation network administrator will be creating these templates in line with governance and security policies. If this is done well, the use of the templates can be delegated to departmental computing in larger companies, with the assurance that proper controls are in place.
This is a major step up in deployment quality for networking in virtualized environments. It will reduce the administrative workload at all levels, especially at the network administration level, and also speed up configuring virtual local area networks. Crucially, errors in setup should drop dramatically, reducing support call workloads.
Because the network is presented as a single switch to users, SDN has to mask the addition and removal of new switch gear. This effectively decouples the hardware buys from the virtual network, allowing a company's networking to evolve over time in a way that would be much more difficult with the traditional networking approach.
The moving of data services to the virtualized server farm opens up the opportunity to easily mix and match services and to tailor data flows to specific needs. Services such as boundary security and deep packet inspection should be available on demand, with the ability to expand service bandwidth readily by adding more instances.
Standardization vs. lock-in
There is a good deal of effort aimed at standardization of inter-service interfaces. The aim is to achieve plug-and-play for both services and hardware switches. As in all of these efforts, there are competing standards, driven by vendor agendas. Some software-defined platforms still exhibit vendor lock-in, which will be expensive compared to approaches that have open application program interfaces (APIs).
The open approach should create a highly innovative and competitive environment, where the common APIs will help keep licensing costs in check. This, of course, adds a new dimension to the benefits of SDN software sourcing, since the vendor base will be much larger. Admins will see more rapid evolution and competition, leading to a continuous evaluation model, rather than the quasistatic approach common in the traditional network.
The software-defined approach is being extended to the wide area network, as SD-WAN. Still embryonic, this should tackle the difficulties of operating hybrid clouds using automated orchestration.
While there are many benefits of SDN, it still faces challenges. Automation tends to mask security issues, which results in a need for automated services to prevent or detect attacks. Resilience and automated path redundancy is also a work in progress. As SDN installations evolve, many will become heterogeneous, with generations of services and switches from a variety of vendors. Ensuring that the necessary security tools cover all of this is a further challenge, though well-crafted APIs should ease the burden as SDN evolves.
Overall, SDN is going to be the way of life in the virtualized data center within a few years. IT staff will have to adapt to its processes and the higher class of skills needed to cope with a more complex and rapidly changing environment.
Taking advantage of software-defined infrastructure
Software-defined networking adoption
Implement SDN architecture