Will SDN finally enable the IP and optical convergence in the WAN that has eluded the industry for a long time?
After all, for how much longer can operators continue to suffer?
The two networks are built independently, are expanded independently and are maintained by two operations teams that work in complete silos.
And the result? Each layer is over-provisioned to cope with uncertain network demands and overprotected by using resources on each layer.
This is really painful.
We are talking about additional capex because of transponders and router ports -- the most expensive part of the core of the network.
And we're talking about huge opex, because of multiple teams handling the provisioning of a single service. Then there's the loss of time because multiple processes and teams are being deployed.
This raises a question: Can SDN come to our rescue?
An SDN controller that can decide on optimizing resources across layers, intelligently route traffic on the low-cost layer and enable an operator to provision services, whether IP or optical, from a single management system would indeed be a welcome addition to the network of an operator.
That's why the SDN use-case for multilayer IP/optical optimization in the WAN has received a lot of industry attention.
But for such IP/optical integration to happen, the industry must collaborate. That means the broader participation of all stakeholders, including the IP/MPLS vendors, the optical vendors and the operators.
Anything less would be a silo or less effective initiative and would result in a strategy that represents the voice of one segment of the industry.
Like the one from the Transport SDN group of Open Networking Foundation (ONF): That represents the voice of the optical transport segment of the industry, minus IP. And understandably so, because this group is chartered to bring SDN to Layers 0, 1 and 2 (transport), and not Layer 3 (IP).
So even though there is a clear use case of IP/optical integration in the ONF white paper on Optical Transport Use Cases, the efforts to bring such optimization would only be effective if either mainstream IP/MPLS vendors join the group or close collaboration happens with them.
But ONF is not alone. A close look at the initiatives in the industry reveal the dispersed and disintegrated status of the IP/optical convergence initiatives (see the table below).
Table 1: IP/Optical Convergence Initiatives
|Initiative||Lead members||Goal||Why this is a silo|
|IP/optical initiative of ONOS||AT&T, NTT, Ciena||IP/optical Integration||Seems a very good initiative with a clear strategy. However, it is missing broader industry participation, especially IP/MPLS vendors. AT&T is the most active member.|
|IP/optical initiative of the Telecom Infra Project (TIP)||Facebook, DT, Juniper, ADVA, Coriant||IP/optical integration||Unclear strategy as still new. Needs broader industry participation.|
|Optical Transport Group of ONF||All traditional optical (Huawei, Ciena, Nokia etc.)||Transport SDN. It has a use case for IP/optical integration.||Optical vendors' silo.|
|NSP from Nokia*||Nokia proprietary||IP/optical integration||Single vendor silo.|
|nlight System from Cisco*||Cisco proprietary||IP/optical integration||Single vendor silo.|
|* Nokia and Cisco included owing to a clear IP/optical strategy and available commercial products.|
'Broader industry participation' in this instance means significant participation of all three main groups: traditionally optical (for example Huawei, Ciena, ZTE, Nokia, etc), traditionally IP/MPLS (such as Cisco, Juniper) and operators.
The same goal but six independent initiatives!
Wouldn't it make sense to have more focused efforts on IP/optical integration? Wouldn't it auger well if there are just a few open interfaces for SDN rather than many?
Even though some vendors would boast of open interfaces on their SDN platforms, this is not enough. Firstly, not everyone supports multiple open interfaces. Secondly, open interfaces do not always mean plug-and-play systems: There will always be a need for some scale of interoperability tests between the vendors.
Therefore, buying a solution of one silo would mean the risk of interoperability issues with a solution from another silo.
If that happens, the operator would again be stuck in a silo. This time, it would not be a silo between an IP and optical network, but a silo of a certain group or a vendor, and that even be worse!
The industry needs collaboration and integration. Too many initiatives may de-focus the industry from achieving the ultimate goal of IP/optical integration. Therefore I ask for you, the industry, to share your opinions here (using the message board below) on how this collaboration can be enabled for such an important issue.
— Faisal Khan has 15 years' experience working with a range of network operators across the Middle East and Africa region, including one where he is working now: The views expressed here are his own and do not reflect those of his employer.