Infinera has announced a first customer for its Open Transport Switch, meaning that the world now has its first commercial implementation of SDN control for the optical layer.
Asian operator Pacnet has 15 datacentres across Asia and is a provider of managed connectivity across 46,000 km of fibre. It is using Infinera’s Open Transport Switch (OTS) to offer dynamic control of its optical transport layer, which is built as a meshed network on Infinera DTN-X optical gear.
The SDN deployment, which Infinera is positioning as virtualisation of the optical layer, means that customers can turn on connectivity in 10G (and soon 100G) increments at their own initiative through a self-service portal/web GUI, and the SDN controller takes care of fulfilment and provisioning across the network. One extra enabler here is Infinera’s deployment of optical wavelengths on one line card within the same platform, meaning wavelengths can be licensed and turned on dynamically.
Geoff Bennett, Director of Solutions and Technology, Infinera, told TMN, “A key property of the DTN-X is that it is very programmable. All the wavelengths are sitting there waiting to be used. Previously if a customer wanted to turn up another 100G it required engineers to install and bring it up. With the wavelength already there, that makes it very fluid. And with the OTS sitting as an underlay integrated with OTN switching you can have a deterministic use of capacity, making the OTN manageable by an SDN controller.”
So what is going on? Well, the OTS is an “underlay” software layer that sits on the Optical switch, between the SDN controller and the physical transport layer. Using Web2.0 REST APIs the software can talk northbound to any SDN controller in the orchestration layer (not just a vendor-specific controller), and southbound to the elements themselves. That enables operators to control the optical transport layer using the same controllers they might use for routers and Ethernet switches, and also to control virtualised network (NFV) elements. The advantage of the “underlay” approach, rather than tunneling SDN control over the top of the existing network from end point (data centre) to endpoint, is that operators can gain visibility and control of all the elements in the network, including the virtualisation infrastructure layer in the data centre. That makes it a better fit for service provider networks, argues Infinera.
“An underlay gives visibility inside the transport network cloud and opens that to the hypervisors in the data centre or to the customer portal,” Bennett said.
Additionally acting as a mediatory layer between the network and the controller, the OTS can also mitigate hundreds of commands to and from the controller to the network down to just tens.
Why is this of interest to mobile operators? Well the answer is obvious. Operators are increasingly requiring to shift large amounts of traffic around between their own nodes in the network. Not only that, but as they move to virtualised instances of their core network and service architecture, the ability to have integrated control of the optical and router layer will be a big cost saving. Finally, there is the customer-facing element, where operators can open up a self-service capability for large corporate customers and to wholesale partners.
Optical SDN use cases
The OTS technology that Pacnet has deployed is the same technology that Telefonica trialled a year ago in a multi-layer NaaS trial. That was a proof of concept trial which put optical transport and L3 routers under the same controllers.
Bennett said that muli-layer control is one use case for OTS, with another being multi-domain end-to-end provisioning, across metro and national domains, or even for carrier to carrier interconnect.
Pacnet’s deployment shows the ability to use SDN to open up true-self ordering for carrier and large enterprise customers, whilst keeping a hybrid control layer (OTS plus GMPLS).