A Low-Latency Transport Layer

For interactive networked applications like web browsing, every one round-trip time (RTT) matters. We introduce ASAP, a new naming and transport protocol that reduces latency by

• shortcutting DNS requests, and

• eliminating TCP's three-way handshake (3WH), while

• ensuring the key security property of verifiable provenance of client requests.

ASAP eliminates between one and two RTTs, cutting the delay of small requests by up to 2/3.

ASAP: A Low-Latency Transport Layer [slides] [code]
Wenxuan Zhou, Qingxi Li, Matthew Caesar, P. Brighten Godfrey
ACM CoNEXT 2011

Verifying provenance without a handshake: Simply eliminating the 3WH would enable dangerous reflection-and-amplification DoS attacks. ASAP leverages usable cryptographic proof to verify the provenance of client requests without requiring an RTT delay on every connection.

ASAP requires changes to some parts of the Internet, but only to devices under the client's and server's control: authoritative DNS servers, end host clients and servers. This simplifies deployability. It provides improved latency, at the cost of additional, yet negligible processing overhead, as shown below. Results were collected from a PlanetLab deployment, and please check out our paper and code for details.