DNS performance and the effectiveness of caching

This paper presents a detailed analysis of traces of DNS and associated TCP traffic collected on the Internet links of the MIT Laboratory for Computer Science and the Korea Advanced Institute of Science and Technology (KAIST). The first part of the analysis details how clients at these institutions interact with the wide-area DNS system, focusing on performance and prevalence of failures. The second part evaluates the effectiveness of DNS caching.In the most recent MIT trace, 23% of lookups receive no answer; these lookups account for more than half of all traced DNS packets since they are retransmitted multiple times. About 13% of all lookups result in an answer that indicates a failure. Many of these failures appear to be caused by missing inverse (IP-to-name) mappings or NS records that point to non-existent or inappropriate hosts. 27% of the queries sent to the root name servers result in such failures.The paper presents trace-driven simulations that explore the effect of varying TTLs and varying degrees of cache sharing on DNS cache hit rates. The results show that reducing the TTLs of address (A) records to as low as a few hundred seconds has little adverse effect on hit rates, and that little benefit is obtained from sharing a forwarding DNS cache among more than 10 or 20 clients. These results suggest that the performance of DNS is not as dependent on aggressive caching as is commonly believed, and that the widespread use of dynamic, low-TTL A-record bindings should not degrade DNS performance.

[1]  K. Frazer,et al.  Nsfnet: a partnership for high-speed networking , 1995 .

[2]  Ronald L. Rivest,et al.  The MD5 Message-Digest Algorithm , 1992, RFC.

[3]  Vern Paxson,et al.  End-to-end Internet packet dynamics , 1997, SIGCOMM '97.

[4]  Peter B. Danzig,et al.  An Analysis of Wide-Area Name Server Traffic: A Study of the Internet Domain Name System , 1992, SIGCOMM.

[5]  John Loughney,et al.  Roaming Support with DNS , 2000 .

[6]  Edith Cohen,et al.  Proactive caching of DNS records: addressing a performance bottleneck , 2001, Proceedings 2001 Symposium on Applications and the Internet.

[7]  CachingLee,et al.  On the Implications of Zipf ' s Law for Web , 1998 .

[8]  Craig E. Wills,et al.  The Contribution of DNS Lookup Costs to Web Object Retrieval , 2000 .

[9]  G. Voelker,et al.  On the scale and performance of cooperative Web proxy caching , 2000, OPSR.

[10]  Mark P. Andrews Negative Caching of DNS Queries (DNS NCACHE) , 1998, RFC.

[11]  Robert Tappan Morris,et al.  DNS performance and the effectiveness of caching , 2002, TNET.

[12]  Paul V. Mockapetris,et al.  Domain names - implementation and specification , 1987, RFC.

[13]  Peter B. Danzig,et al.  Common DNS Implementation Errors and Suggested Fixes , 1993, RFC.

[14]  Paul V. Mockapetris,et al.  Domain names: Concepts and facilities , 1983, RFC.

[15]  Azer Bestavros,et al.  Self-similarity in World Wide Web traffic: evidence and possible causes , 1996, SIGMETRICS '96.

[16]  Hari Balakrishnan,et al.  An end-to-end approach to host mobility , 2000, MobiCom '00.

[17]  Anees Shaikh,et al.  On the effectiveness of DNS-based server selection , 2001, Proceedings IEEE INFOCOM 2001. Conference on Computer Communications. Twentieth Annual Joint Conference of the IEEE Computer and Communications Society (Cat. No.01CH37213).

[18]  Hari Balakrishnan,et al.  Modeling TTL-based Internet caches , 2003, IEEE INFOCOM 2003. Twenty-second Annual Joint Conference of the IEEE Computer and Communications Societies (IEEE Cat. No.03CH37428).

[19]  Srinivasan Seshan,et al.  TCP behavior of a busy Internet server: analysis and improvements , 1997, Proceedings. IEEE INFOCOM '98, the Conference on Computer Communications. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies. Gateway to the 21st Century (Cat. No.98.

[20]  Alec Wolman,et al.  On the scale and performance of cooperative Web proxy caching , 1999, SOSP.

[21]  H. Grüneberg An Analysis of the , 1938 .

[22]  kc claffy,et al.  DNS Root/gTLD Performance Measurements , 2001 .

[23]  Azer Bestavros,et al.  Self-similarity in World Wide Web traffic: evidence and possible causes , 1997, TNET.

[24]  Evi Nemeth,et al.  DNS measurements at a root server , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[25]  Steven Glassman,et al.  A Caching Relay for the World Wide Web , 1994, Comput. Networks ISDN Syst..