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Internals of the alarm system.

Who should read this?

This page contains details about the alarm setup and is primarily intended for the test-box operators at the NCC.

Which programs run on the test-box?

Two processes are run by the cron deamon at regular intervals. Each process consists of a perl-script to set up links and such, and piece of C-code that does the actual work. Output is written to the GENE-file of the test-box. The perl-scripts are called lta.pl and sta.pl, the corresponding C-programs lta and sta.

LTA.PL

lta.pl is run once a day at 5 minutes past midnight. It should be run once a day, the 5 minutes is just to avoid conflicts with other things that might happen at the turn of the day.

Lta.pl calls lta. Lta first reads a 2-dimensional histogram from the lta_history file, with along 1 axis the delay in ms-bins and along the other the day data was taken. Lta then reads all RCDP files on the system, checks which one have been produced since the last time the program was run, and adds that data to the histogram. Bins with data older than 30 days are discarded. The histogram is then written back to the lta_history file.

STA.PL

sta.pl is run every 15 minutes, at 7, 22, 37 and 52 minutes past the hour. There is no fundamental reason for this, it should just not be run exactly on the hour or when lta.pl is run, to avoid conflits with those programs.

Sta.pl is used to set up sym-links and such. It then calls the C-code.

Sta reads the lta_history file and creates a histogram with the delay distribution for each connection with data from corresponding period (0-6 hours, 6-12, etc), for the last 30 days. It determines median and percentiles. Sta then reads the 2 most recent RCPD files and creates short term histograms for each connection with the data taken during the last 30 minutes. Again, percentiles are determined.

The program then reads the alarm status from the last time the program was run. It calculates the alarm code for the current status and, if this differs from the last time the program was run, it prints a message. Finally, the current alarm status is written back to the sta_history file.

Control is then passed back to sta.pl. Sta.pl takes the output of sta and sends emails to ttXX@ripe.net, where ttXX@ripe.net is defined in /etc/aliases as an alias for the host of ttXX. At the moment, this file is created by hand from Fotis' notes.


Page created by Henk Uijterwaal, Last Update: $Date: 2000/01/21 14:26:11 $