A key promise of SDN/NFV is to enable service providers to offer innovative, on-demand enterprise services with unprecedented flexibility. Building a network capable of delivering flexible, dynamic, customer-tailored services, is however a challenge for service providers. As a matter of fact, end-to-end service orchestration within the virtualized infrastructure and across complex multi-vendor network domains outside the NFVI is anything but a walk in the park.
Standardization bodies, the acceptance of open source solutions and service provider led programs such as AT&T Domain 2.0, Orange SDN for Business or Deutsche Telekom Terastream have driven interoperability in the NFVI and MANO spheres. One major roadblock to capture the full potential of network virtualization is the orchestration of network elements beyond the NFVI boundary, in order to provide full service delivery automation across the network. Yet one key question is how can orchestrators work with networking elements outside the NFVI? As service providers look to transform their networks, the answer to this question is crucial in order to deliver end-to-end enterprise managed services.
The challenge for the orchestrator is to configure all the nodes in the service delivery chain from the customer premises to the NFVI and steer the traffic to the virtual service platform. This integration work across multi-vendor network domains can be substantial as many network devices have to be configured and managed, often with specific proprietary interfaces. Nevertheless, the development of vendor equipment adapters in the orchestration platform to cope with proprietary CLI and varying administration protocols is a prospective cost that industry players want to avoid and is based on a short term view of the problem.
Verizon’s white paper on its SDN/NFV strategy confirms that cross-domain and cross-vendor programmability is key to meet the dynamicity promised by SDN/NFV services. In order to replace a myriad of element management systems (EMS) tied to network elements with proprietary protocols and interfaces, Verizon recommends in the near term to use domain-specific SDN controllers to manage vendor-specific network elements.
Looking at the longer-term perspective, there is an opportunity to unify a diverse set of provisioning and configuration chains under a common NETCONF/YANG umbrella to simplify integration, operation and maintenance. NETCONF/YANG provides a perfect programmatic interface to prolong the orchestration domain and configure end-to-end service chains on-demand by spawning VNFs in the NFVI and steering traffic according to service requirements across the network.
The significant traction of NETCONF/YANG in the multi-vendor orchestration space makes it a good fit to streamline the integration of end-to-end automated SDN/NFV services. The support of NETCONF/YANG by a number of commercial orchestration platforms (Ciena Blue Planet, WebNMS, Cisco NSO,...) and the standardization of YANG modules by the MEF (Metro Ethernet Forum) for the orchestration of Carrier Ethernet 2.0 services add momentum to an already fast moving trend toward a NETCONF/YANG end-to-end orchestrated network model.