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Latency spikes when downloading or streaming Netflix

FIXED
Newbie
Posts: 3
Fixes: 1
Registered: ‎27-01-2020

Latency spikes when downloading or streaming Netflix

I seem to be having quite large latency increases when I'm streaming Netfix. This causes my son who is an avid gamer to get very angry when my wife and I watch Netflix!

 

The line itself is working fine, I can get 50 Mbit/s down and 20 Mbit/s up which is what I've been able to get ever since it was installed (4 years ago?).

 

In order to narrow down the latency problem I rebooted everything, checked the connections etc but no changes. The Router is the only thing plugged into the master socket (we don't use a land line).

 

I did a 24h latency graph with think broadband which I've attached (couldn't figure out how to inline it!)  It shows large spikes in latency at times when the Internet is active, especially during Netflix streaming 8-10pm.

 

I did a more controlled test where I measured the latency when the line was idle.  These measurements are taken on the router itself, so don't traverse my home network.

 

 

$ ping -c10 pingbox1.thinkbroadband.com
PING pingbox1.thinkbroadband.com (80.249.99.164) 56(84) bytes of data.
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=1 ttl=57 time=7.53 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=2 ttl=57 time=7.69 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=3 ttl=57 time=7.73 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=4 ttl=57 time=7.54 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=5 ttl=57 time=7.60 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=6 ttl=57 time=7.49 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=7 ttl=57 time=7.52 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=8 ttl=57 time=7.50 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=9 ttl=57 time=7.97 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=10 ttl=57 time=7.76 ms

--- pingbox1.thinkbroadband.com ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 23ms
rtt min/avg/max/mdev = 7.486/7.630/7.965/0.178 ms

 

 

And then again while downloading one of the thinkbroadband files at 1Mbyte/s == 8 Mbit/s with 

 

 

rclone copyurl -P http://ipv4.download.thinkbroadband.com/1GB.zip 1GB.zip --bwlimit 1M

 

 

And this came up with

 

 

$ ping -c10 pingbox1.thinkbroadband.com
PING pingbox1.thinkbroadband.com (80.249.99.164) 56(84) bytes of data.
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=1 ttl=57 time=30.0 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=2 ttl=57 time=78.8 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=3 ttl=57 time=20.9 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=4 ttl=57 time=14.6 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=5 ttl=57 time=18.2 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=6 ttl=57 time=7.89 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=7 ttl=57 time=31.10 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=8 ttl=57 time=14.4 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=9 ttl=57 time=26.7 ms
64 bytes from pingbox1.thinkbroadband.com (80.249.99.164): icmp_seq=10 ttl=57 time=16.7 ms

--- pingbox1.thinkbroadband.com ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 21ms
rtt min/avg/max/mdev = 7.892/26.030/78.826/18.994 ms

 

 

So rather than a nice steady 7mS we get an average of 26mS and spikes up to 78mS.  This is only 8 Mbit/s of traffic on a 50 Mbit/s line so there really shouldn't be any noticeable latency.

 

I've noticed that when streaming Netfix in the evening the latency can easily go up to 500mS for a while. Needless to say this causes shouting from my Son!

 

Any help much appreciated - thanks.

 
3 REPLIES 3
Seasoned Hero
Posts: 5,750
Thanks: 2,548
Fixes: 168
Registered: ‎30-06-2016

Re: Latency spikes when downloading or streaming Netflix

@ncw  Welcome to the forum.

Are all your devices connected to your router via Ethernet cables or could wireless performane be a factor? If the latter then you need to eliminate the wireless element if only temporarily.

Newbie
Posts: 3
Fixes: 1
Registered: ‎27-01-2020

Re: Latency spikes when downloading or streaming Netflix

Yes, everything is connected via Ethernet.

Newbie
Posts: 3
Fixes: 1
Registered: ‎27-01-2020

Re: Latency spikes when downloading or streaming Netflix

Fix

I spent some time investigating the Ethernet and I found that the router and the switch were using flow control. I disabled that and the massive latency spikes while streaming Netfix disappeared 🙂

 

I still think there is more latency than there ought to be while downloading, but I'm going to mark this as solved as now we can watch Netflix without the son shouting at us.