Diversity in DNS performance Measures

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Diversity in DNS performance Measures

• R.Liston, S.Srinivasan, E.Zegura
• Presented by Baoning Wu

2
Motivation

• DNS performance in the wide-area is not well
  understood.
• Few studies of DNS from client locations.

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DNS behavior and terminology
4
Measurement methodology

• Collect 14,983 domain names
• Run their own tool independently on different
  sites ( 75 sites ) in the world (21 countries)
• Two primary periods Jan 2002 and Mar/Apr 2002.

5
Their Tool

• The key component is BIND named server.
• Modified to log each event with timestamp.
• A script to drive name lookups
• Post-process the logs.

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Results Complete vs successful
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Results Mean Response time
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Results MRTc vs MINc

• Connectivity Minimum response time of completed
  lookups (0.62)

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Results retries vs. MRTc

• Loss rate number of retries (0.50)

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Results MRTr vs. MRTc

• MRTr mean response time for root servers
• (0.86)

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Results MRTg vs. MRTc

• 0.94

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Results Percentages of different servers
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Results favored servers
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Results Aliases and CNAMEs
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• QUESTIONS?