Hi everyone, I did a fair amount of experimenting and research while looking for a monitoring solution for jitter/delay/loss and what I found in relation to Smokeping created a couple of questions.
1. Some of the results produced seem to be inconsistent with the state of the network and parallel probes disagree with each other. I set up monitoring with a probe configured like ++ FPingAF packetsize = 84 hostinterval = 0.02 mininterval = 0.001 pings = 500 offset = 0% with iptables -t mangle -A POSTROUTING -s x.x.x.x -p icmp -m length --length 112 -j TOS --set-tos 0x90 on the smokeping server to provide QoS marking (one way at least) This produced a flat graph with hardly any delay/jitter. When I added same probe to two more hosts, jitter and delay appeared (3-4ms) on all hosts for the 20ms probe. Thinking that it is an issue where FPing handles the load badly, I added one more graph to a fourth host and expected an increase in jitter, but it went away completely and returned to the original state for all four hosts. I am able to reproduce that. At the same time I had a parallel probe running which only differed in the offset - it was completely unaffected and flat at all times. 2. Separate scaling issue follows from FPing being limited to sending pings at 1ms interval as its highest speed. For the purposes of VoIP, jitter needs to be measured on packets sent at 20ms intervals, which limits the number of hosts we can monitor to 20 at a particular offset and to 200 if we only monitor 10% of the time and split the hosts in 10 groups. Those numbers are the theoretical maximum and are likely to actually be lower. I am new to the list and not sure if I can attach the config files and images to the email - I will of course email them to anyone who might be interested. cheers Nik _______________________________________________ smokeping-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/smokeping-users
