One of the most controversial components of an SDN is the northbound API. To better understand what is happening with that API, I interviewed Dave Hawley, who is one of HP’s global product line managers.
I started my interview with Dave by asking him why there seems to be so much discussion about protocols such as OpenFlow and yet relatively little discussion of the northbound API. Dave said that OpenFlow has justifiably received a lot of attention because it is the key standards based enabler for SDN. He added that while there hasn’t been much of a conversation in the industry to date about the northbound API but that we can expect that situation to change very quickly.
I then asked Dave if he subscribed to the notion that as a result of implementing SDN, an application would be able to dynamically signal the network for the resources it needed — and if he did subscribe to that notion, does that mean that application developers will need to have a deep knowledge of the network? Dave stated that application developers won’t need to have a deep knowledge of networks, because the goal of the northbound API is to get to a point where the network elements can translate high-level requirements into an end-to-end configuration that satisfies the business requirements.
I made the comment to Dave that I didn’t see organizations such as the ONF or the Open Daylight consortium getting involved in developing a standards-based northbound API. I asked Dave if he agreed with that statement and if he did, why he thought that was the case. Dave said that the OpenDaylight consortium isn’t a standards body but a code-producing body, and it is unlikely that in the short term the consortium will deviate from their charter. He added that the ONF has been driving a discussion on the northbound API and that while they haven’t yet taken any steps towards creating a standard for this API, HP would like to see them take on this role.
In closing the interview, I asked Dave if having an open northbound API was sufficient, or if he felt that API needs to be standards-based. Dave stated that having the northbound API be open was good, but not good enough. His concern was that this approach may well lead to a situation in which there are as many open APIs as there are vendors and that this lack of consistency hurts customers, as it tends to create vendor lock-in. Dave said that the best way to avoid this type of lock-in is to have the northbound API be standards-based.
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