As the next generation of packet-optical integration permeates multi-layer Internet architecture as well as telecom equipment designs, valuable lessons can be drawn from hybrid network concepts championed and operationalized by research and education (R&E) networks. In fact, the ESnet4 hybrid architecture, conceived in 2006 and made operational in 2008, consists of separate physical wavelengths for IP-routed and dynamic virtual-circuit services. We are pleased to have an impact on the research and development of these hybrid networking concepts. IEEE Communications Magazine‘s special issue on hybrid networking published in May includes three ESnet co-authored articles:

1.  Hybrid Networks: Lessons Learned and Future Challenges from the ESnet4 Experience, shares lessons learned from operating a hybrid infrastructure consisting of separate IP-routed and dynamic circuit services. As service requirements are driven by increasingly rigorous application needs as well as impetus to reduce operating costs through automation, working out optimal frameworks will be important as the Internet evolves.
2. Multilayer Networks: An Architecture Framework, presents an architecture framework for control and management of multi-layer, multi-domain hybrid networks and associated network services.
3. Advance Reservation Frameworks for Wavelength-Routed WDM Networks introduces different networks and frameworks that support advance bandwidth reservation.

As industry moves towards circuit and packet technology integration, characterizing and abstracting the interactions between the multiple layers will be important to ensure a stable operating environment. Virtual circuit services provided by a network services agent (NSA), such as the OSCARS/ARCHSTONE project funded by DOE, will be able to make complex topology reservations across a multi-layer environment using network capabilities provided by multi-protocol label switching (MPLS), carrier Ethernet, and wavelength/optical switching. The tricky part is to determine the optimal level of co-ordination and management feedback between the packet- and circuit-switched technologies. This matters greatly not just for Internet and telecommunication service providers, but also for future development of data center interconnects, cloud computing systems and green networks. We would like to thank the guest editors for championing this important topic. We are honored to participate in this special issue of IEEE Communications Magazine, and look forward to your feedback.

–Inder Monga and Chin Guok on behalf of ESnet’s network and research engineers.