Mobile Network Tracing (RFC2041)
Original Publication Date: 1996-Oct-01
Included in the Prior Art Database: 2019-Feb-16
Internet Society Requests For Comment (RFCs)
B. Noble: AUTHOR [+3]
This RFC argues that mobile network tracing provides both tools to improve our understanding of wireless channels, as well as to build realistic, repeatable testbeds for mobile software and systems. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.
Network Working Group B. Noble Request for Comments: 2041 Carnegie Mellon University Category: Informational G. Nguyen University of California, Berkeley M. Satyanarayanan Carnegie Mellon University R. Katz University of California, Berkeley October 1996
Mobile Network Tracing
Status of this Memo
This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
Mobile networks are both poorly understood and difficult to experiment with. This RFC argues that mobile network tracing provides both tools to improve our understanding of wireless channels, as well as to build realistic, repeatable testbeds for mobile software and systems. The RFC is a status report on our work tracing mobile networks. Our goal is to begin discussion on a standard format for mobile network tracing as well as a testbed for mobile systems research. We present our format for collecting mobile network traces, and tools to produce from such traces analytical models of mobile network behavior.
We also describe a set of tools to provide network modulation based on collected traces. Modulation allows the emulation of wireless channel latency, bandwidth, loss, and error rates on private, wired networks. This allows system designers to test systems in a realistic yet repeatable manner.
Noble, et. al. Informational [Page 1]
RFC 2041 Mobile Network Tracing October 1996
How does one accurately capture and reproduce the observed behavior of a network? This is an especially challenging problem in mobile computing because the network quality experienced by a mobile host can vary dramatically over time and space. Neither long-term average measures nor simple analytical models can capture the variations in bandwidth, latency, and signal degradation observed by such a host. In this RFC, we describe a solution based on network tracing. Our solution consists of two phases: trace recording and trace modulation.
In the trace recording phase, an experimenter with an instrumented mobile host physically traverses a path of interest to him. During the traversal, packets from a known workload are generated from a static host. The mobile host records observations of both packets received from the known workload as well as the device characteristics during the workload. At the end of the traversal, the list of observations represents an accurate trace of the observed network behavior for this traversal. By performing multiple traversals of the same path, and by using different workloads, one can obtain a trace family that collectively characterizes network quality on that path.
In the trace modulation phase, mobile system and application software is subjected to the network behavior observed in a recorded trace. The mobile software is run on a LAN-attached host whose kernel is modified to read a file containing the trace (possibly postprocessed for efficiency,) and to delay, drop...