Carrier Ethernet services have seen significant growth over the last decade, most recently being driven by the uptake in cloud services. Now SDN will bring greater performance and cost efficiency to optical transport networks and carrier Ethernet services, further driving this growth.
What SDN will do for carrier Ethernet
SDN will change carrier Ethernet and its services in three significant ways:
Cost: A key objective for both SDN and carrier Ethernet is to reduce overall costs. SDN has the potential to lower operational expenditures through increased network automation and network optimization. This will also reduce capital expenditures. Carrier Ethernet is proven to significantly reduce network costs and in many cases reduce solution complexity. Coupling SDN with carrier Ethernet to reduce costs just makes sense.
Control: SDN leverages a logically centralized control model to enable deterministic, dynamic, on-demand services that comply with strong service-level agreements. Carrier Ethernet, when coupled with SDN, provides an agile and flexible network for network virtualization and dynamic bandwidth services.
Ubiquity: Ethernet has become a ubiquitous networking technology. It dominates the marketplace as the interface for IP networking, whether in its wired forms or as Wi-Fi. It does not rely on Layer 1 or optical technologies to carry it over fiber, but can be used over any of today's optical technologies to gain enhanced distance, even trans-Pacific submarine links. SDN's tight coupling with Ethernet strongly positions carrier Ethernet coupled with SDN to be critical in next-generation service and content provider networks. Currently, the Optical Transport working group of the Open Networking Foundation (ONF) is working on standards that will allow SDN controllers to manage or direct optical networks.
As this partnership between Ethernet and SDN evolves, the Ethernet industry will naturally focus on improving switch capacity, as well as rapid configurability, packet-forwarding, statistics, diagnostics and packet handling. Meanwhile, it will extricate itself from Spanning Tree, Transparent Interconnection of Lots of Links (TRILL) and other control capabilities that will be interworked with and later replaced by the SDN control layer.
How Metro Ethernet will contribute to SDN
There is also the opportunity to further expand the partnership between SDN and carrier Ethernet. For example, SDN may benefit from the service definitions the Metro Ethernet Forum (MEF) has delivered. SDN architectures include the northbound interface (NBI) which is a RESTful interface. The MEF has delivered a strong set of carrier Ethernet service specifications with clear Ethernet service types, Ethernet service attributes and Ethernet service attribute parameters. REST constructs could easily carry Type Length Value (TLV) fields with these service types, attributes and parameters from the application layer to the controller layer, defining a full end-to-end carrier Ethernet service to be provisioned with on-demand service attributes. Toward this end, the MEF and the ONF have been liaising to discuss how MEF carrier Ethernet services map into the SDN architecture.
As optical networks become SDN-enabled, SDN and carrier Ethernet over photonics and optical transport networking will achieve greater service distances coupled with a highly agile network at all layers. By coupling this with multi-layer networking, we will be able to build networks that deliver a wide variety of services using the minimum resources required among all layers.
About the author:
Rob Tomkins is senior advisor for portfolio strategy in the office of the CTO at Ciena.
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