An algorithm developed by Frank Kelly has led to improvements in mobile phone and network performance worldwide.
At a time when demands on the internet were growing, Frank Kelly’s mathematical research explained why the internet worked as well as it did, providing confidence in its reliability and robustness under rapid growth, rendering re-design unnecessary.
He then developed a novel algorithm to route traffic via multiple paths, which increases reliability and performance, without compromising stability.
Kelly’s algorithm is a routing extension to the Transmission Control Protocol (TCP). All traffic on the internet (downloads, videos, etc) is broken down into, and transferred as, packets. These packets contain information about the source and the destination. TCP is the main system of rules for transferring these packets across the internet.
His work demonstrated that TCP effectively solves a very large-scale resource allocation problem, and that it is both stable and fair. The model he constructed describes which path should be used, and how much traffic should be sent.
A group of computer science researchers then translated Kelly’s theoretical work on routing traffic via multiple paths into a practical implementation, known as Multipath TCP (MPTCP). MPTCP has since been deployed in iPhones and other mobile phones, increased internet speed in six countries and was recently adopted as part of 5G developments.
Key impacts include the deployment of MPTCP on over 1.38 billion Apple iPhones worldwide, representing sales of over $951 billion. Since July 2020, MPTCP has become a standard feature of 5G.
In 2015, a new company was founded, Tessares, which uses MPTCP to provide faster internet services, particularly in rural areas, in Belgium, Croatia, Finland, Lithuania, Netherlands and Malta.
“[MPTCP] leverages Kelly’s theoretical results and makes them usable… on the Internet… Five different countries [Belgium, Croatia, Finland, Lithuania, Netherlands – and, since the letter, Malta] benefit from this technology and there are ongoing discussions with network operators in Asia Pacific and America.”– Tessares’ Managing Director