Enabling Router-Assisted Congestion Control on the Internet

Enabling communication between routers and endpoints has long been sought after as an approach to congestion control in the Internet. However, the narrow-waist of TCP/IP has complicated the deployment of such communication. In this paper, we present Kick-Ass, a congestion control mechanism that enables explicit rate congestion control protocols to be deployed within the TCP/IP stack. The key idea is to utilize packet lengths as a vehicle to communicate fine-grained explicit rate and other information from routers to endpoints and vice versa. Given that our approach (i) requires no explicit coordination among KickAss routers, (ii) no explicit coordination among Kick-Ass routers and endpoints, and (iii) is effective on paths that include legacy routers, it provides a practical road towards a faster Internet, today.

Using large-scale simulations, testbed experiments, and widearea Internet evaluations, we demonstrate that (i) a basic explicit-rate protocol using the Kick-Ass mechanism improves flow completion times by up to an order of magnitude and outperforms endpoint-based approaches, including CUBIC and PCC. (ii) Kick-Ass is incrementally deployable on the Internet. (iii) Deploying Kick-Ass at end-hosts and edge routers can enable the above performance benefits, without waiting for universal adoption. (iv) Our packet-fragmentation mechanism is well behaved on the Internet.