Date: Fri, 1 Oct 1999 15:48:19 -0400 (EDT) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: net@freebsd.org Subject: Announcing alpha release of latd, a continuous latency monitor Message-ID: <199910011948.PAA23943@khavrinen.lcs.mit.edu>
next in thread | raw e-mail | index | archive | help
latd 0.0 is now available for download at <ftp://ftp.lcs.mit.edu/pub/wollman/latd-0.0.tar.gz>. From the README file: ------------------------------------ $Id: README,v 1.3 1999/10/01 19:41:41 wollman Exp $ This is latd, version 0.0. latd is a program which continuously samples network latencies between a management station (the machine running latd) and a list of machines elsewhere on the network. Currently, latd supports the ICMP and UDP ECHO protocols, but adding other protocols (such as HTTP) is a Small Matter of Programming. The significant advantage of latd, as compared to simply periodically pinging every end station, is that it attempts to sample the data in a statistically-useful way. Rather than taking a measurement every fixed interval, latd randomizes its measurement periods uniformly over the range [i/2, 3*i/2], where `i' is the desired average measurement period. (By default, `i' is 20 seconds, which is chosen to give 15 measurements over a 5-minute interval.) By spreading out measurements in this way, the probability of `missing' a network disturbance which takes place between two measurements is lessened. (Suggestions from statisticians as to more appropriate distribution functions are gladly accepted.) By taking measurements over a fairly long average period, it is possible to measure the latency to a large number of destinations without placing an undue burden on the network. Future versions of latd will provide support for configurable periodic statistics generation. Currently, latd will open a couple of log files into which statistics might be written, but the code to actually compute those statistics does not yet exist -- indeed, I have not yet figured out which statistics are worth implementing. In the mean time, latd is still useful using the `-p' option, which specifies a log file to which every observation is written. External scripts, such as the provided `make-plot' and `make-stats', can then post-process this log file to extract interesting information. Future versions of latd will also provide support for configurable alarms, based on the generated statistics or on individual observations. [deletia] ------------------------------------ -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199910011948.PAA23943>