[VoiceOps] Maximum latency

[Anthony Orlando]

Cool. Didn't realize u were running voice traffic while doing that?  What was the sound quality like?  

Sent from my iPhone

> On Mar 22, 2017, at 5:49 PM, Alex Balashov <abalashov at evaristesys.com> wrote:
> 
> What is it that makes people think you need a special application or
> tool to do these things?
> 
> Here's my default gateway on my home LAN:
> 
> sasha at mouse ~> ping -c 5 172.30.105.1
> PING 172.30.105.1 (172.30.105.1) 56(84) bytes of data.
> 64 bytes from 172.30.105.1: icmp_seq=1 ttl=64 time=0.238 ms
> 64 bytes from 172.30.105.1: icmp_seq=2 ttl=64 time=0.618 ms
> 64 bytes from 172.30.105.1: icmp_seq=3 ttl=64 time=0.457 ms
> 64 bytes from 172.30.105.1: icmp_seq=4 ttl=64 time=0.474 ms
> 64 bytes from 172.30.105.1: icmp_seq=5 ttl=64 time=0.382 ms
> 
> --- 172.30.105.1 ping statistics ---
> 5 packets transmitted, 5 received, 0% packet loss, time 4052ms
> rtt min/avg/max/mdev = 0.238/0.433/0.618/0.126 ms
> 
> And here's my default gateway on my home LAN with 300 ms of latency
> "injected":
> 
> sasha at mouse ~> sudo tc qdisc add dev enp1s0 root netem delay 300ms
> 
> sasha at mouse ~> ping -c 5 172.30.105.1
> PING 172.30.105.1 (172.30.105.1) 56(84) bytes of data.
> 64 bytes from 172.30.105.1: icmp_seq=1 ttl=64 time=300 ms
> 64 bytes from 172.30.105.1: icmp_seq=2 ttl=64 time=300 ms
> 64 bytes from 172.30.105.1: icmp_seq=3 ttl=64 time=300 ms
> 64 bytes from 172.30.105.1: icmp_seq=4 ttl=64 time=301 ms
> 64 bytes from 172.30.105.1: icmp_seq=5 ttl=64 time=300 ms
> 
> --- 172.30.105.1 ping statistics ---
> 5 packets transmitted, 5 received, 0% packet loss, time 4005ms
> rtt min/avg/max/mdev = 300.841/300.902/301.038/0.605 ms
> 
> And here's 300ms latency +/- variability of 40ms:
> 
> sasha at mouse ~> sudo tc qdisc add dev enp1s0 root netem delay 300ms 40ms
> sasha at mouse ~> ping -c 5 172.30.105.1
> PING 172.30.105.1 (172.30.105.1) 56(84) bytes of data.
> 64 bytes from 172.30.105.1: icmp_seq=1 ttl=64 time=299 ms
> 64 bytes from 172.30.105.1: icmp_seq=2 ttl=64 time=316 ms
> 64 bytes from 172.30.105.1: icmp_seq=3 ttl=64 time=324 ms
> 64 bytes from 172.30.105.1: icmp_seq=4 ttl=64 time=321 ms
> 64 bytes from 172.30.105.1: icmp_seq=5 ttl=64 time=326 ms
> 
> --- 172.30.105.1 ping statistics ---
> 5 packets transmitted, 5 received, 0% packet loss, time 4002ms
> rtt min/avg/max/mdev = 299.411/317.749/326.472/9.706 ms
> 
> And here's back to normal:
> 
> [root at mouse ~]# tc qdisc del dev enp1s0 root netem
> [root at mouse ~]# ping 172.30.105.1
> PING 172.30.105.1 (172.30.105.1) 56(84) bytes of data.
> 64 bytes from 172.30.105.1: icmp_seq=1 ttl=64 time=0.342 ms
> ^C
> --- 172.30.105.1 ping statistics ---
> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
> rtt min/avg/max/mdev = 0.342/0.342/0.342/0.000 ms
> 
> And here's "loss insertion" of 5%:
> 
> sasha at mouse ~> sudo tc qdisc add dev enp1s0 root netem loss 5%
> sasha at mouse ~> ping -c 5 172.30.105.1
> PING 172.30.105.1 (172.30.105.1) 56(84) bytes of data.
> 64 bytes from 172.30.105.1: icmp_seq=2 ttl=64 time=0.514 ms
> 64 bytes from 172.30.105.1: icmp_seq=3 ttl=64 time=0.501 ms
> 64 bytes from 172.30.105.1: icmp_seq=4 ttl=64 time=0.546 ms
> 64 bytes from 172.30.105.1: icmp_seq=5 ttl=64 time=0.279 ms
> 
> --- 172.30.105.1 ping statistics ---
> 5 packets transmitted, 4 received, 20% packet loss, time 4056ms
> rtt min/avg/max/mdev = 0.279/0.460/0.546/0.105 ms
> 
> sasha at mouse ~> ping -c 5 172.30.105.1
> PING 172.30.105.1 (172.30.105.1) 56(84) bytes of data.
> 64 bytes from 172.30.105.1: icmp_seq=1 ttl=64 time=0.732 ms
> 64 bytes from 172.30.105.1: icmp_seq=2 ttl=64 time=0.471 ms
> 64 bytes from 172.30.105.1: icmp_seq=3 ttl=64 time=0.474 ms
> 64 bytes from 172.30.105.1: icmp_seq=4 ttl=64 time=0.334 ms
> 64 bytes from 172.30.105.1: icmp_seq=5 ttl=64 time=0.367 ms
> 
> --- 172.30.105.1 ping statistics ---
> 5 packets transmitted, 5 received, 0% packet loss, time 4020ms
> rtt min/avg/max/mdev = 0.334/0.475/0.732/0.141 ms
> 
> No, I'm not that brilliant. I Googled it:
> 
> http://stackoverflow.com/questions/614795/simulate-delayed-and-dropped-packets-on-linux
> 
> App to inject latency? You people kill me sometimes.
> 
> -- Alex
> 
> -- 
> Alex Balashov | Principal | Evariste Systems LLC
> 
> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) 
> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
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