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SDN basics: Five questions answered

Understanding SDN basics is key. We rounded up five reader questions answered by our experts that provide insight as to how SDN can and should be used.

Although SDN certifications and SDN education programs are beginning to take shape, engineers are seeking answers to questions about SDN basics. Our SearchSDN experts are open for business and ready to answer questions.

We rounded up five of our Ask the Expert questions and answers that explain a few SDN basics every network professional should know:

1. Why should I consider using SDN technology? According to SDN expert Lee Doyle, principal analyst at Doyle research, the most common issue SDN technology addresses is the inability of large data centers to support the requirements of server virtualization. Specifically, SDN enables automated provisioning of virtual networks and network services easily and quickly in order to support new virtual machines. But there are added benefits beyond networking for virtualization. SDN can mean programmability in any part of the network; it can also improve network visibility and reduce operational costs.

Read Doyle's explanation of the importance of SDN technology.

2. Do I need specialized switches for SDN? Not necessarily, explained Lee Doyle. Some vendors are developing SDN strategies that rely on OpenFlow controllers that will need to interact with OpenFlow-friendly switches; however, others will use virtual switches and network overlays to implement SDN and network virtualization architecture that in no way relies on SDN controllers.

Read more about the role of SDN switches.

3. Are SDN and network virtualization the same? No, wrote Lee Doyle. Network virtualization allows IT managers to consolidate multiple physical networks, divide a network into multiple segments, or create software-only networks betweenvirtual machines. The goal of virtualization, he added, is to improve automation and network management. Software-defined networking aims for separation of the control and data plane with the goal of overall programmability. SDN generally relies on a centralized controller to manage this programmability. Doyle concluded that it's clear SDN and network virtualization have similar concepts, and it's possible one is a subset of another.

Experts answering pressing SDN questions

Do we still need fabrics with SDN implementation?

Will SDN work with existing networks?

What's the difference between SDN and overlay networks?

To migrate to SDN, will I need a hybrid network?

What is the role of northbound APIs in an SDN environment?

Read more about the differences between SDN and network virtualization.

4. Do I need special controllers for SDN? A specialized controller isn't needed to implement SDN, Lee Doyle said. There are many approaches to SDN architecture -- some that depend on centralized controllers and others that use distributed software. In the OpenFlow community, however, a special controller is needed and is used by providers like Big Switch, IBM and NEC. On the other hand, Cisco's SDN architecture supports OpenFlow, but doesn't require an SDN controller. Cisco's strategy embeds intelligence in its Ethernet switches and network management software.

Read more about specialized controllers for SDN.

5. Do I need to use OpenFlow in software-defined networks? The OpenFlow protocol isn't required in SDN. SDN architectures will end up taking many approaches, and each vendor will have a different way of developing its SDN solution. However, the Open Network Foundation (ONF) has made great progress with the standard, and many vendors have already put OpenFlow into action. The ONF recommended using OpenFlow as the foundation technology for SDN implementation.

Read more about using OpenFlow and SDN.

Do you have a question regarding SDN? If so, email [email protected] to have it answered by one of our SDN experts.

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