Service Provider Networks are complex and multi-layer in nature. Each of these layers, including packet and optical, is provisioned and managed independently. Sometimes, the provisioning and adding of capacity or new services requires order of days if not months. A converged SDN control plane for packet and optical networks can help address all of these inefficiencies. Service providers can optimize across packet and optical layers in real-time for availability and economics, thereby reducing over-provisioning. They can add capacity based on traffic and other considerations in minutes instead of days or months.
Typical optical transport networks are made up of ROADMs (Reconfigurable Optical Add Drop Multiplexers) that switch wavelengths and sub-wavelength circuits (OTN), while multiple IP layer connections are carried over the same wavelength. Provisioning of these optical wavelengths or lambdas is a labor-intensive and manual task that requires physically fibering of tunable lasers to the correct port. Adding on-demand connections or shifting capacity must be planned well in advance, and at significant operational expenses, ultimately creating an optical layer which is static and inflexible.
Additionally, due to this inflexible nature of current transport networks, a great deal of spare packet and optical capacity is deployed to cover all possible failure points. This is combined with the need to support busy hour scenarios with overcapacity to minimize packet loss. Capacity planning and traffic engineering must consider all possible traffic load and failure scenarios because the optical network cannot be reconfigured at will. Furthermore, optical impairments are complex and require careful planning and traffic optimization practices. For example, optical reach must be carefully considered when paths are set up by the path computation elements/Engines.
Our goal is to build an open source solution that allows effective multi-layer network programmability using novel abstractions such as intent-based networking and converged topology graphs.
- Tom Tofigh (AT&T), Marc De Leenheer (ON.Lab)
Converged Packet-Optical Software Defined Networking
IEEE Computer Society Chapter of Santa Clara Valley, Sep 15, 2015.
- Marc De Leenheer (ON.Lab), Guru Parulkar (Stanford University & ON.Lab), Tom Tofigh (AT&T)
Control of Packet-over-Optical Networks
Optical Fiber Communication Conference and Exhibition (OFC), March 24, 2015.
- SDN Control of Packet-Optical Networks