OIF defines carrier requirements for SDN

The Optical Internetworking Forum (OIF) has achieved its first milestone in defining the carrier requirements for software-defined networking (SDN).

The orchestration layer will coordinate the data centre and transport network activities and give easy access to new applications

Hans-Martin Foisel, OIF

The OIF's Carrier Working Group has begun the next stage, a framework document, to identify missing functionalities required to fulfill the carriers' SDN requirements. "The framework document should define the gaps we have to bridge with new specifications," says Hans-Martin Foisel of Deutsche Telekom, and chair of the OIF working group.

There are three main reasons why operators are interested in SDN, says Foisel. SDN offers a way for carriers to optimise their networks more comprehensively than before; not just the network but also processing and storage within the data centre.

"IP-based services and networks are making intensive use of applications and functionalities residing in the data centre - they are determining our traffic matrix," says Foisel. The data centre and transport network need to be coordinated and SDN can determine how best to distribute processing, storage and networking functionality, he says.  

SDN also promises to simplify operators' operational support systems (OSS) software, and separate the network's management, control and data planes to achieve new efficiencies.  

SDN architecture

The OIF's focus is on Transport SDN, involving the management, control and data plane layers of the network. Also included is an orchestration layer that will sit above the data centre and transport network, overseeing the two domains. Applications then reside on top of the orchestration layer, communicating with it and the underlying infrastructure via a programmable interface. 

"Aligning the thinking among different people is quite an educational exercise, and we will have to get to a new understanding"

"The orchestration layer will coordinate the data centre and transport network activities and give, northbound, easy access to new applications," says Foisel. 

A key SDN concept is programmability and application awareness, he says. The orchestration layer will require specified interfaces to ease the adding of applications independent of whether they impact the data centre, transport network or both.

Foisel says the OIF work has already highlighted the breadth of vision within the industry regarding how SDN should look. "Aligning the thinking among different people is quite an educational exercise, and we will have to get to a new understanding," he says.

Having equipment prototypes is also helping in understanding SDN. "Implementations that show part of this big picture - it is doable, it is working and how it is working - is quite helpful," says Foisel.

The OIF Carrier Working Group is working closely with the Open Networking Foundation's (ONF) Optical Transport Working Group to ensure that the two group are aligned. The ONF's Optical Transport Group is developing optical extensions to the OpenFlow standard.