The models sub-package

This has an implementation of an emulator to emulate wide-area traffic (latency/losses) on a set of machines -- possibly all in the same LAN. The emulator setup is shown in the picture below.



The files in this sub-package are:

The outage distribution files

In addition, the sub-directory udp-distributions and ping-distributions have the distributions of outage periods on wide-area Internet paths -- based on UDP measurements, and ping measurements respectively. The "*.density" files are the PDFs, and the "*.density.cdf" files are the CDFs of the same distribution -- the result of running pdf2cdf.pl on the "*.density" files. Each PDF file has three columns:

  1. The outage period in ms
  2. The absolute count of the outages in this range, during the experiment, and
  3. The relative frequency of the outages in this range.

Introducing deterministic failures: det-fail.cfg

Deterministic failures in the overlay links can be introduced by configuring the fwdRaw program. When the fwdRaw program gets a Ctrl-C, it looks for a "det-fail.cfg" file, to read the deterministic outages it is supposed to emulate. NOTE: if the fwdRaw program cannot find a det-fail.cfg file, and receives Ctrl-C, it exits. A nice way to do this would be have a soft-link named det-fail.cfg to the actual config files in the det-fail-cfgs sub-directory. The soft-link can exist when you hit Ctrl-C, and you can remove it before hitting another Ctrl-C to terminate the fwdRaw program. The format of "det-fail.cfg" is that it has a set of lines, each specifying a deterministic outage of an overlay link. Each line has 4 columns:

  1. The destination service-cluster ID (SCID) of the overlay link to be failed.
  2. The origin SCID of the overlay link to be failed.
  3. The start time, in ms, of the failure. The failure is started after this duration, after a Ctrl-C has been hit, on the fwdRaw program.
  4. The duration of the failure, in ms.

Compile-time configurations

Here are the compile-time options, and hardcoded values:

Command-line arguments


Bhaskaran Raman, bhaskar@cs.berkeley.edu
Last modified: Tue Jan 22 15:38:52 PST 2002