Performance Comparison of ENUM Name Servers

ENUM is a protocol for mapping E.164 telephone numbers into Internet URIs. In this paper, we present a performance evaluation of ENUM name servers considering the new requirements and challenges imposed on traditional DNS servers with the incorporation of ENUM protocol. We defined three performance metrics for this performance evaluation: query throughput, response time, and CPU usage. Using a benchmarking testbed, we evaluated four name servers implementations (BIND, MyDNS-NG, NSD and PowerDNS) in different scenarios considering distinct size of database. Moreover, we improved the existing methodology for this kind of evaluation, since we identified the limitations of DNSPerf and proposed a new procedure for the evaluation. Results show that BIND and NSD servers achieved a high query throughput with great scalability features. On the other hand, PowerDNS server had a lower throughput and high sensibility to database size. MyDNS-NG server presented a quite low query throughput and poor scalability and, therefore, it is not suitable for ENUM purposes. These results bring to light a new reality for studies of ENUM servers, since they have not been evaluated in such a extended scenarios and size of the database.