According to the Open Networking Foundation (ONF), SDN as an architecture decouples the network control and forwarding functions, enabling the network control to become directly programmable and the underlying infrastructure to be abstracted for applications and network services.
The ONF is a user-driven organization dedicated to the promotion and adoption of SDN through open standards development.
According to Liu, SDN can help protect customer investment. "When the forwarding plane is programmable, organizations can customize their campus networks through software and application development rather than buying new hardware from vendors," he said.
As SDN encourages a transition from ASIC to programmability on the forwarding plane, networks and switches will become more agile in meeting changing traffic demand, he added.
When and where SDNs make sense
But SDN isn't for everybody, said US-based networking consultant and analyst Kurt Marko.
"It's unclear right now how valuable SDN will be to the typical enterprise datacenter," he said. "What's more clear is the technology's value for service providers and big cloud providers because their network traffic can be much more variable and unpredictable depending on what kinds of data are running over them, what types of applications are used and what types of end-user profiles they see," Marko pointed out.
"In an enterprise datacenter, however, the network traffic tends to be more uniform and stable. There's not so much of a high variability in the load, and they're already built to handle any big traffic spikes and react to those automatically," he said.
Where SDN has more potential in the enterprise is to replace network application hardware like load balancers, firewalls and other hardware that handles higher-level networking issues instead of individual packets of traffic, said Marko.
Five key considerations
In addition, organizations must assess themselves in deciding whether or not the benefits of SDN are worth their effort or investment. There are five considerations for IT shops evaluating SDNs, according to IT management software company SolarWinds:
1) The organization's access to personnel and capital resources
If an IT shop doesn't have network engineering expertise, or personnel is stretched thin, SDN is not the project to undertake, Castelino said.
SDN deployments are done in parallel with the production environment, test, evaluated, validated and tested again before they are cut over to the production network. It takes time, people and money.
2) The size of an organization's network
While there is not a distinct bare metal server or virtual machine threshold for implementing an SDN or not, the rule of thumb is hundreds of IP addresses. "For 50 IP addresses, it's not worth the change," he said. "For hundreds of IP addresses, you might need the automation."
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