Traffic Engineering the Web Using A Light System Called Arrow

Researchers at the Massachusetts Institute of Technology (MIT) have created a reconfigurable fibre optic network to maintain high throughput even when physical network links break. This is software technology comes out of the MIT Computer Science and Artificial Intelligence Laboratory, known as CSAIL, and is designed to preserve wide-area connectivity using redirected optical light running through fibre optic cables.

Called ARROW, the technology is an algorithm (the term that computer scientists bandy about all the time that means software instructions) to look for surrogate healthy fibre optic cables nearby when network traffic gets interrupted. In simulation tests, ARROW shows it can carry up to 2.4 times more traffic volume without deploying new fibre optic cable.

Zhizhen Zhong, the MIT post-doctoral lead author of the paper that describes ARROW in an MIT News release issued August 30, 2021. He states, “ARROW can be used to improve service availability…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…With ARROW, some failures can be eliminated or partially restored, and this changes the way we think about network management and traffic engineering.”

My background in telecommunications networks involved developing and monitoring the physical infrastructure that underlies today’s Internet and World Wide Web. What Zhong describes solves what was, during my working life, a problem that required network engineers to built levels of redundancy and overcapacity into the network infrastructure to keep data and voice connectivity flowing and reduce latency (the lagging of data and voice during transmission) and downtime (breaks in connectivity). But what his MIT colleagues and he have produced using optical waves that can be redirected by small mirrors to find healthy fibre nearby means no rewiring is required.

With ARROW the physical infrastructure of the Internet becomes dynamic and malleable and far more reliable with continuous interconnectedness meeting or exceeding the standard that telecommunications companies have always attempted to attain, five 9s, that is 99.999% uptime or down no more than 2 minutes in any given year.

The instant reconfigurability that ARROW provides means even that the best performance guarantee of 2 minutes downtime can be surpassed and without building overcapacity and multiple redundancies that are featured in today’s Internet. Considering the last year-and-a-half for all of us on the planet, the Internet has been an essential lifeline throughout the COVID-19 global pandemic.

The work at MIT has been done with the collaboration of Facebook with plans for the social network to deploy ARROW at some point in the future. Additional funding has come from the Advanced Research Projects Agency (ARPA)-Energy, the Defense Advanced Research Projects Agency (DARPA), and the U.S. National Science Foundation.