A TCP Instrumentation and Its Use in Evaluating Roundtrip-Time Estimators

Abstract

We describe an instrumentation of TCP/IP that monitors TCP connections and provides values of internal variables of the implementation. We define interface events for a TCP/IP connection, describes how traces are obtained, and how application processes initiate trace collection. The instrumentation has been implemented in 4.3BSD UNIX. The instrumented TCP/IP provides a flexible environment for experimental studies. Using the instrumentation, we have studied the performance of different roundtrip-time estimators in the Internet environment. One conclusion of our study is that clock resolution is an important parameter, and the resolution currently used in UNIX implementations of TCP is woefully inadequate. Another conclusion is that, with an adequate clock resolution, a recently proposed estimator performs substantially better than the estimator suggested in the TCP specifications. Keywords: TCP(Transmission Control Protocol), Information transfer, Computer networks.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1990
Accession Number
ADA221290

Entities

People

  • A. U. Shankar
  • Dheeraj Sanghi
  • M. C. Subramaniam
  • Olafur Gudmundsson
  • Pankaj Jalote

Organizations

  • University of Maryland

Tags

Communities of Interest

  • C4I
  • Materials and Manufacturing Processes
  • Space

DTIC Thesaurus Topics

  • Classification
  • Communication Channels
  • Computer Communications
  • Computer Networks
  • Computer Science
  • Computers
  • Estimators
  • Information Transfer
  • Instrumentation
  • Internet
  • Network Protocols
  • Network Science
  • Networks
  • Operating Systems
  • Packet Loss
  • Specifications
  • Transport Protocols

Fields of Study

  • Computer science

Readers

  • Computer Networking
  • Database Systems and Applications
  • Systems Analysis and Design