Namecast: A Reliable, Flexible, Scalable DNS Hosting System
We design and implement a new DNS hosting system called Namecast that is especially reliable, flexible, and scalable compared to existing DNS hosting systems. Namecast operates at multiple geographically distributed locations, called nodes, that are accessible over IP anycast. The system uses a distributed storage layer, so it can automatically adjust as nodes fail and scale as new ones come online, without any disruption in service or loss of data. Security is maintained through the use of the Digital Signature Algorithm (DSA); each account is associated with a DSA key that is used to authenticate users' interactions with the system. Therefore, no registration is required to establish a new account with Namecast: a new account is automatically established the first time each new DSA key is seen.
Developing this system also brought to light some interesting questions regarding the failover performance of IP anycast--that is, how quickly BGP can redirect traffic away from a failed node--under various configurations. In order to evaluate and optimize the performance of the Namecast system, we perform microbenchmarks on some of its components and experimental simulations to test the failover behavior of IP anycast and BGP and determine the configuration that produces the fastest failover.