Analysis of point-to-point packet delay in an operational network

Baek Young Choi, Sue Moon, Zhi Li Zhang, Konstantina Papagiannaki, Christophe Diot

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


In this paper, we perform a detailed analysis of point-to-point packet delay in an operational tier-1 network. The point-to-point delay is the time experienced by a packet from an ingress to an egress point in an ISP, and it provides the most basic information regarding the delay performance of the ISP's network. Using packet traces captured in the operational network, we obtain precise point-to-point packet delay measurements and analyze the various factors affecting them. Through a simple, step-by-step, systematic methodology and careful data analysis, we identify the major network factors that contribute to point-to-point packet delay and characterize their effect on the network delay performance. Our findings are: (1) delay distributions vary greatly in shape, depending on the path and link utilization; (2) after constant factors dependent only on the path and packet size are removed, the 99th percentile variable delay remains under 1 ms over several hops and under link utilization below 90% on a bottleneck; (3) a very small number of packets experience very large delay in short bursts.

Original languageEnglish (US)
Pages (from-to)3812-3827
Number of pages16
JournalComputer Networks
Issue number13
StatePublished - Sep 12 2007

Bibliographical note

Funding Information:
Zhi-Li Zhang received a B.S. degree in computer science from Nanjing University, China, in 1986 and his M.S. and Ph.D. degrees in computer science from the University of Massachusetts in 1992 and 1997. In 1997 he joined the Computer Science and Engineering faculty at the University of Minnesota, where he is currently a professor. From 1987 to 1990, he conducted research in Computer Science Department at Århus University, Denmark, under a fellowship from the Chinese National Committee for Education. He has held visiting positions at Sprint Advanced Technology Labs; IBM T.J. Watson Research Center; Fujitsu Labs of America, Microsoft Research China, and INRIA, Sophia-Antipolis, France.


  • Delay
  • ECMP
  • Operational network

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