AWS rolls the dice for faster, more efficient networking

Honey, I flattened the datacenter network Thomas Claburn Thomas Claburn Senior reporter Published sat // UTC Amazon has developed a new networking topology that's up to a third faster and up to 40 percent more energy efficient than traditional hierarchical network designs. The novel architecture, called Resilient Network Graphs (RNG), is based on random graph theory. "Traditional networks have always been hierarchical," explained Matt Rehder, VP of global network engineering at AWS, in a recent interview. "They're sort of like an org chart where one network device will talk to the boss network device which will talk to the next boss network device and you gotta go up the chain of command in order to talk to someone else in another department." There are reasons for that, Rehder said. Hierarchy creates structure and makes data routing rules simpler. "You don't have to know how to talk to everyone in the organization, you just talk to the person above you," he said. The tree-like structure creates points of contention where data flow bottlenecks can occur. At the same time, other parts of the network may be underutilized.  Rehder said that academics in 2012 proposed a random graph topology for networks.  But that design, as detailed [PDF] , had issues. The reimagined network structure, dubbed Jellyfish, relied on truly random graphs and called for removing routers from server racks and locating them centrally to simplify cabling. But that approach ended up increasing latency between servers within a rack. Rehder said no one has been able to put that design into production.  "It requires much more complicated routing rules to figure out how to program every device – you can't just program every device to know who everyone is, they have limited memory space," he said. "And then the other [issue] is that the cabling actually is very complicated. Part of that hierarchy is about simplifying how you build the network in the datacenter and with a random graph it's literally random and you can't just have cable spaghetti all over a datacenter. So you could build it in a lab but you could never really do it at scale." Nonetheless, said Rehder, AWS has been solving these problems over the past few years. "The only reason we were able to even think about tackling them is that 15-year history of iteratively improving our hardware development and software ownership of our network," he said.  Less random Inspired , AWS managed to succeed with random network topology .