An Adaptive Refresh Mechanism Based on DTTL Model for DNS

Most DNS system apply cache mechanism to improve the efficiency of domain name resolving. Setting up the TTL value of the cache item is the key issue of DNS performance optimization. This paper proposes a dynamic adjustment algorithm for DNS cache item. By using DTTL model, our algorithm dynamically changes the TTL value as the varying of resolving rate. With comparisons to modifying the zone file directly, our algorithm makes a tradeoff between the consistence and hit rate.