Stanford Distributed Systems Seminar

12:45 PM, May 10, 2000
Room 150, McCullough Building

Proactive DNS Caching: Addressing a Performance Bottleneck

Edith Cohen
AT&T Labs-Research

About the talk:

The resolution of a host name to an IP-address is a necessary predecessor to connection establishment and HTTP exchanges. The Domain Name System, responsible for translating between hostnames and IP-addresses, is a large distributedly-maintained database. While DNS design accomodated the explosive Web growth, DNS lookups inherently involve communication with one or more remote name-servers, which causes prolonged response times. As the overall quality of service rises, lookup times are becoming a dominant cause of pathological delays and hinder consistency and quality of service. Caching of DNS records at name servers and Web browsers alleviates the problem but is limited by cache content. Current popular name-server software incorporate passive cache management where records are brought into the cache only as a result of clients' requests and are used for the TTL duration (a TTL value is provided with each record). We propose and evaluate enhancements to passive caching aimed at reducing the fraction of HTTP connection establishments that are affected by long resolutions times. Our proposed approaches operate on top and consistently with DNS, and require only local deployment.

This is joint work with Haim Kaplan.

About the speaker:

Edith Cohen is a researcher at AT&T Labs-Research. She did her undergraduate and Masters studies at Tel-Aviv University, and received her Ph.D. in Computer Science from Stanford University in 1991. She joined Bell Laboratories in 1991. During 1997, she was in UC Berkeley as a visiting professor. Her research interests include design and analysis of algorithms, combinatorial optimization, Web performance, networking, and data mining.