This paper evaluates the performance of DNS over several network traces, specifically looking at query failures (no response or response indicating nonexistent record) and latency perceived by Internet clients. Moreover, it takes the discussion of DNS caching in the previous paper one step further by questioning its impact on overall performance. The authors claim that DNS caching may inherently conflict with some applications that use the naming system, such as Content Delivery Networks (I'm still a bit confused about exactly why there's a conflict here). Looking at the trace analysis, they conclude that caching does not significantly improve performance for the clients but merely acts as a load-controlling mechanism for the name servers.
Even though the evaluation results were convincing, an intuitive explanation for the minimal impact of caching on client-perceived latency (for example) seemed missing. Yet again, several critical performance issues (negative responses, negative caching, etc.) were identified but a deeper insight into these problems was not necessarily offered. The paper provided a useful understanding of the practical issues surrounding the DNS, especially as it begins to interact with other protocols (e.g. TCP) and mechanisms such as CDNs.
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