Transport, Radio and Cloud Orchestration with SDN

SDN was the main keyword when it came to optical networks and their control at the OFC 2015. Orchestrating resources across multiple layers and domains—as an important next step in introducing SDN to the networks—is specifically worth highlighting. In other words, multi-layer/multi-domain orchestration seems to have emerged as a major added value of SDN to the networks.

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At the conference, we presented details behind our SDN-based multi-domain orchestration demonstrator as a Post-deadline paper.

The outstanding OFC Conference and Exhibition is the largest annual event in the area of optical networking and communications. In the post-deadline achievements session, I had the honor to present some details of our work on the SDN-based multi-domain orchestration demonstrator we have developed in Ericsson Research. In our work we demonstrate — through a proof-of-concept — advantages of the multi-domain orchestration across transport, wireless access network and cloud domains.

Before going a bit more in-depth on our work and the demo, I’d like to share some highlights and personal reflections from the OFC as a whole.

The conference excitement started early, for the flight from London to LA was packed with familiar faces, all heading to OFC, enthusiastically chatting about their work.

8 areas were identified as hot topics for this year, including 100G/400G network design and optimization, silicon photonics, as well as virtualization and software defined networks (SDN). SDN was, undoubtedly, the main keyword when it came to optical networks and their control.

Among the several interesting lectures, demonstrations and panel discussions on applications of the SDN technology in the optical domain and relevant use-cases were: Approaches to abstracting various optical network elements and integrating their control into the SDN controller; Ideas for adopting SDN for automation of transport network control/management tasks; and Experimental results on virtualization of optical networking resources with SDN.

The highlight of this part of the event was presentations and discussions—both from academics, networking vendors and operators—on an important next step in introducing SDN to the (optical) networks, specifically, on employing various flavors of SDN control architecture for orchestrating resources across multiple layers and domains. It seems that the multi-layer/multi-domain orchestration has emerged as a major added value of SDN to the networks. In particular, the presentations and demonstrations included solutions both for multi-layer/multi-domain transport networks orchestration (including for the classical problem of packet-optical integration), as well as for resource orchestration across domains with heterogeneous sets of resources, i.e., cloud and networking resources.

Post-deadline paper

My talk “First experimental demonstration of orchestration of optical transport, RAN and cloud based on SDN” highlighted the importance of an additional dimension in the multi-domain orchestration: the resources of wireless networks. We at Ericsson Research believe that the full potential of multi-domain orchestration can be reached only when wireless network resources are factored in, even though coordinating multiple domains of networking and cloud resources is a crucial step towards agile service creation and management.

Why do we think that? In the networked society, the majority of traffic will originate and/or terminate at wireless devices and endpoints. Moreover, 5G wireless access networks are expected to support new types of services and to utilize advanced technologies, which collectively necessitate orchestration across all domains: from the wireless access networks to the backhaul/fronthaul network to the core network and data centers.

Our proof-of-concept demonstrator

This is the 5G transport demo that we partially introduced in an earlier blog post.

As shown in the figure below, our proof-of-concept is composed of a dense wavelength division multiplexing (DWDM)-centric optical network providing programmable transport services at the wavelength level, an LTE-based mobile broadband domain with Centralized RAN (CRAN) architecture providing broadband services to mobile users, and a cloud domain with two emulated data centers providing processing/storage services. The platform further includes a hierarchical SDN-based control plane, where each of the three domains is controlled through a corresponding domain controller.

The Orchestrator is realized on top of the domain controllers, and acts as the convergence layer for unified resource coordination across the three domains. Specifically, the Orchestrator creates a global view of heterogeneous resources/capabilities and exposes it to higher layer applications over its northbound application-programming interface (API). The API enables the applications/service controllers (Network Apps) to request desired services from the infrastructure, and the Orchestrator then translates the requests — according to the configured orchestration policy — to existing resources and accordingly programs the data plane through the corresponding controllers.

In our experiments we have created two use-cases: an elastic mobile broadband service, where the service capacity is adjusted depending on the actual demand, and a distributed file system across the two data centers, where the copies of large files are synched across data centers once any of them is changed. The common point of the two services is the dynamic use of the optical network resources, which are shared between the services according to the orchestration policy. We demonstrate how the orchestration enables agile and resource-efficient creation of diverse services across the three domains (optical, mobile and cloud).

OFC2015 took place in Los Angeles March 22-26 in the international year of light and light-based technologies. The 2015 event attracted more than 12000 scientists, engineers, exhibitors and students from across the world to present and discuss their latest achievements on various aspects of optical communications and networking; ranging from the physical layer to the network and application layers.

I am sure many have already started planning their contributions for next year’s event. I for one am looking forward to seeing more on SDN and transport networks at OFC 2016 in Anaheim.

Ahmad Rostami – Ericsson Research


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