关键词: 域名系统, AR(1), 时间序列预测, 服务器选择算法, 迭代查询, Unbound

Abstract: Server selection algorithm is the key algorithm for Domain Name System (DNS) while handling iterative queries. Among all queries sent to DNS, the proportion of iterative query is larger than 30%, so the performance of server selection algorithm directly affects the performance of a DNS server. The existing server selection algorithms were briefly reviewed and both advantages and disadvantages of these algorithms were described. Then, an improved AR(1) auto-regressive model was proposed. Through this new model, the response time of DNS server could be dynamically predicted by using previous response time series. This new model can efficiently avoid performance fluctuation and loss due to network congestion and short-time system failure. At the same time, the application scope of AR(1) model is broadened by the new model and it is suitable for all DNS.

Key words: DNS（Domain Name System）, AR(1), time series prediction, server selection algorithm, iterative query, Unbound