Hello I'll start with the problem. I'm using RRDtool to monitor 2T1 lines on two different networks, and it consistently reports average aggregate bandwidth values exceeding 1.54 Mbps, which is supposed to be impossible.
(by the way, if this message is inappropriate for this list, please point me somewhere; this issue is rather frustrating.) Here are some more details. One on place I have a router with two T1s, and I collect data in a sloppy way (note I don't administer these routers so I don't have much say in how I get to collect data). Basically, I have an expect script run from cron, which, every 5 minutes, telnets into the router and gets its 5 minute throughput averages for s1 and s2, and puts them on some graphs. It constantly passes 1.54 .. even more oddly, it seems that output peaks at 1.54, whereas input and go uninhibited (albeit below 1.54) during this time frame. example images: old one: http://ultrasoul.com/~matusa/graphs2.png slightly newer; this one uses gprint to show averages: http://ultrasoul.com/~matusa/damnit.png now: I have ntop listening to this network on a hub (not a switch that calls itself a hub; a real, stupid hub). It reports similar values (this is a network with minimum local traffic). I have also run tests, and the throughput I generated was reflected accurately on the graphs. Next. I have another setup which is much more cleanly done. There are two routers each with a T1 (again, I didn't set that up), and I talk to them through SNMP. I collect ifInOctets and ifOutOctets from both of them, and do all necessary computation. In this case I use a COUNTER data source type, whereas the last was a GAUGE. I guess that is obvious. Anyway, that network isn't as overloaded, but it gets the same oddities. I check the counter every minute, so there is no way that a weird abnormal burst could mess this up; if it spikes past 1.54 aggregate, then that is an average for one minute. Ntop listens on this network too. it matches my data. Also, someone fired up some crap windows program (I'm doing all this on linux, of course) that talks SNMP and does graphs real-time: It ran for only a moment, so it didn't catch values past 1.54, but while it was running, my data matched it. Just in case any one is wondering, the difference is not slight, as the graphs indicate--sometimes we hit 2.5 on one T1. Also, the data I collect from the routers is from the serial device of course, not the eth device (just in case someone thought I made a dumb error). oh yeah, i telnetted into the routers a few times and added up the 5 minute average throughput values by hand. They were past 1.54 (by a lot.. 1.87 for instance). If anyone can explain what the hell is going on, and why these T1s are retartedly fat (not like I'm complaining), I would be much obliged. Oh yeah. Tobi, if you read this far, RRDtool is a tool of great value to me; I use it to monitor many aspects of my linux boxes (collected via /proc). You RULE!!!! -mateusz- By the way, I wrote this email a week ago, and since I wasn't on the list, it bounced. I'm on the list now, a week later, and the issue is about the same. I haven't dealt with it much, having had other things to do. oh.. one new development, MRTG agrees with me on another network (though I haven't seen if it passes the 1.54 boundary when mine does, though you'd expect it to) tobi, once again, thank you for making this excellent piece of software -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://www.ee.ethz.ch/~slist/rrd-users WebAdmin http://www.ee.ethz.ch/~slist/lsg2.cgi
