WACCO and LOKO: Strong Consistency at Global Scale

Motivated by a vision for future global-scale services supporting frequent updates and widespread concurrent reads, we propose a scalable object-sharing system called WACCO offering strong consistency semantics. WACCO propagates read responses on a tree-based topology to satisfy broad demand and migrates objects dynamically to place them close to that demand. To demonstrate WACCO, we use it to develop a service called LOKO that could roughly encompass the current duties of the DNS and simultaneously support granular status updates (e.g., currently preferred routes) in a future Internet. We evaluate LOKO, including the performance impact of updates, migration, and fault tolerance, using both traces of DNS queries served by Akamai and traces of NFS traffic on the UNC campus. WACCO uses a novel consistency model that is both stronger than sequential consistency and more scalable than linearizability. Our results show that this model performs better in the DNS case than the NFS case because the former represents a global, shared-object system which better fits the design goals of WACCO. We evaluate two different migration techniques, one of which considers not just client-visible latency but also the budget for the network (e.g., for public and hybrid clouds) among other factors.Doctor of Philosoph

A Replicated Architecture for the Domain Name System

We propose a new design for the Domain Name System (DNS) that takes advantage of recent advances in disk storage and multicast distribution technology. In essence, our design consists of geographically distributed servers, called replicated servers, each of which having a complete and up-to-date copy of the entire DNS database. To keep the replicated servers up-to-date, they distribute new resource records over a satellite channel or over terrestrial multicast. The design allows Web sites to dynamically wander and replicate themselves without having to change their URLs. The design can also significantly improve the Web surfing experience since it significantly reduces the DNS lookup delay