This paper provides analysis of:
- DNS performance (latency and failure)
- Effect of varying TTL and degree of caching affect
The analysis was performed on three traces that included DNS packets and TCP SYN, FIN and RST packet information. The authors found that over third of all DNS lookups were not answered successfully. 23% of the client lookups in the MIT trace failed to arrive at an answer while 13% lookups gave errors in the answer.
The authors show that name popularity distribution is zipf-like. Effectiveness of caching is determined by finding how useful is it to share DNS caches and the impact of choice of TTL value. Intuitively, I was under the assumption that reducing the TTL will severely affect the performance of DNS but the authors show that reducing TTLs of address(A) records to few hundred seconds has little effect on the hit rate. Also, sharing a forwarding DNS cache does not improve performance.
I found the paper very interesting to read. The analysis of performance of DNS is not dependent on aggressive caching is opposite to the general notion of DNS performance being tightly tied to caching. This observation is directly related to the relationship between TTL values and name popularity. Popular names will be cached effectively even with short TTL while unpopular names may not gain even with long TTL values.
It will be nice to discuss how would the results vary if analyzed with current time traces.
The authors show that name popularity distribution is zipf-like. Effectiveness of caching is determined by finding how useful is it to share DNS caches and the impact of choice of TTL value. Intuitively, I was under the assumption that reducing the TTL will severely affect the performance of DNS but the authors show that reducing TTLs of address(A) records to few hundred seconds has little effect on the hit rate. Also, sharing a forwarding DNS cache does not improve performance.
I found the paper very interesting to read. The analysis of performance of DNS is not dependent on aggressive caching is opposite to the general notion of DNS performance being tightly tied to caching. This observation is directly related to the relationship between TTL values and name popularity. Popular names will be cached effectively even with short TTL while unpopular names may not gain even with long TTL values.
It will be nice to discuss how would the results vary if analyzed with current time traces.
No comments:
Post a Comment