The Performance Argument for Blockchain-based Edge DNS Caching

The Domain Name System (DNS,) a standard way of looking up IP addresses of Internet services, has served the Internet ecosystem well. However with the advent of edge computing, it falls short of many desirable properties. These include accurate fine-grained geographic localization of edge services, fast look-ups, and ensuring record freshness and cache integrity for end users. To satisfy these properties we consider blockchain-based solutions, a counter-intuitive approach as blockchain is not often associated with performance or the latency requirements of the edge. Despite this, we argue blockchain can address the shortcomings we've identified in DNS specifically in the edge context. We've found blockchain-based solutions are not sufficient as is, thus we present GeoENS - a prototype based on the Ethereum blockchain suitable for, and enabled by, the edge. It achieves these goals via novel record organization for smart contract, push-based record invalidation, and a look through cache. Given the skepticism of blockchain to out-perform DNS, we provide preliminary results which show GeoENS achieves its goals of fine-grained geo-localization accurate to ±20 meters, fast query latency for non-cached records under 50 ms, and cache freshness at edge scale of 10 minutes (vs. 3 hour DNS TTLs.) GeoENS does this with negligible bandwidth and CPU load overhead and reasonable storage requirements in the proposed deployment scenario.