Scientists at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) recently devised a method to protect the network and cut costs when the fibre goes down. Their “ARROW” technology reconfigures optical light from a broken fibre to healthy fibres while utilizing an online algorithm to proactively plan for future fibre cuts ahead of time depending on real-time Internet traffic demands.
ARROW is based on two distinct approaches: “failure-aware traffic engineering (TE),” which directs traffic to where the bandwidth resources are after fibre breaks, and “wavelength reconfiguration,” which recovers failed bandwidth resources by reconfiguring the light.
Despite its strength, this combination is theoretically difficult to solve due to its NP-hardness in computational complexity theory.
The team devised a unique method that can generate “LotteryTickets” as an abstraction for the “wavelength reconfiguration problem” on optical fibres while only feeding relevant information into the “traffic engineering problem.” This works in tandem with their “optical restoration approach,” which transfers light from the cut fibre to “surrogate” healthy fibres to restore network connectivity. The system also considers real-time traffic while optimizing for optimal network throughput.
“ARROW can be used to improve service availability and enhance the resiliency of the Internet infrastructure against fiber cuts. It renovates the way we think about the relationship between failures and network management—previously failures were deterministic events, where failure meant failure, and there was no way around it except over-provisioning the network,” says MIT postdoc Zhizhen Zhong, the lead author on a new paper about ARROW. “With ARROW, some failures can be eliminated or partially restored, and this changes the way we think about network management and traffic engineering, opening up opportunities for rethinking traffic engineering systems, risk assessment systems, and emerging applications too.”
“We are excited that there would be many practical challenges ahead to bring ARROW from research lab ideas to real world systems that serve billions of people, and possibly reduce the number of service interruptions that we experience today, such as less news reports on how fiber cuts affect Internet connectivity,” says Zhong. “We hope that ARROW could make our Internet more resilient to failures with less cost.”