Sponsored Links

Poor latency when downloading?

Parzival

Casual Member
I've been using 4G as our main source of internet at home for about 3/4 months now and this has been largely trouble free and a nice improvement over the poor rural internet we had before.

One thing I have noticed since the beginning was as soon as you start downloading and using the majority of the available bandwidth the latency shoots up (400ms-to-seconds). This poor ping makes gaming while anyone else is downloading near enough impossible and slows down any pages loading while browsing. This doesn't occur when less bandwidth is used, so Netflix and YouTube (even multiple 1080p streams) does not have this effect. It's been an inconvenience since switching to 4G but better than the alternative, but I was wondering if this is typical of 4G broadband?

If it helps I am using the following setup:

Voxi unlimited sim
TP-Link MR600 using the internal antenna

Thanks folks!
 
I've always had this issue on Three.

If the Xbox starts auto-updating, watching a you-tube video starts buffering or the kids playing a game on their phone get kicked out of it.

Its like the router is incapable of sharing the load across all devices effectively.

Another thing I've noticed is how utterly useless the B535 becomes once you exceed around 120 UDP connections. It just bogs down and completely becomes incapable of downloading anywhere near maximum bandwidth, so you literally have to cut back on simultaneous downloads until below that number, then bang, the bandwidth returns to full download speeds. As the amount of download bandwidth increases the latency increases too.

I just don't think the B535 is up to the task. Its a cheap CAT 6 device, which is "adequate at best" (so it goes with three's quality of service pretty well in that regard.)
 
I'd never actually looked into it, but it does appear that utilising bandwidth does impact latency times.
While I think it feels logical that this would occur regardless of the type of connection (copper/fibre/mobile network), I don't know if the hardwired types of connection would be as affected in the way mobile is, or to the same extent.

In my one-off test of [ping google.com -t] while performing a speedtest using nperf.com the increased latency is particularly apparent during the upload phase, with one request even timing out.

Download = red, Upload = yellow

1598525350804.webp
 
Sponsored Links
Apparently this is down to something called "bufferbloat" which is rather complex but to do with Smart Queue Management algorithms within routers. I don't think the B535 even has them.


You are correct with regard to the upload Gavin, you can do a 4g test (click the yellow "more" and 4g appears) here:


It appears Three's upload bandwidth is seriously buffer-bloat impacted.
 
I can't even get the bufferbloat to work with the speedtest, it keeps disabling due to high latency (to US/Netherlands).

However, from this page
it does feel like bufferbloat is a feature of mobile networks - all the US '4G' networks are featured in the bottom table for "ISPs with most bufferbloat" and there are no 4G networks in the 'least' table.
 
Yeah I noticed that Dave. I'll stick with lobbying the UK Government to implement proper infrastructure projects instead, its far cheaper.
 
Sponsored Links
Interesting read here: Tackling Bufferbloat in 3G/4G Networks


Of note:

The reasons behind such performance degradation are two-fold.

First, most of the widely deployed TCP implementations use loss-based congestion control where the sender will not slow down its sending rate until it sees packet loss. Second, most cellular networks are overbuffered to accommodate traffic burstiness and channel variability. The exceptionally large buffer along with link layer re-transmission conceals packet losses from TCP senders. The combination of these two facts leads to the following phenomenon: theTCP sender continues to increase its sending rate even if it has already exceeded the bottleneck link capacity since all of the overshot packets are absorbed by the buffers. This results in up to several seconds of round trip delay.
 
Top
Cheap BIG ISPs for 100Mbps+
Community Fibre UK ISP Logo
150Mbps
Gift: None
Virgin Media UK ISP Logo
Virgin Media £22.99
132Mbps
Gift: None
Vodafone UK ISP Logo
Vodafone £24.00 - 26.00
150Mbps
Gift: None
NOW UK ISP Logo
NOW £24.00
100Mbps
Gift: None
Plusnet UK ISP Logo
Plusnet £25.99
145Mbps
Gift: £50 Reward Card
Large Availability | View All
Cheapest ISPs for 100Mbps+
Gigaclear UK ISP Logo
Gigaclear £17.00
200Mbps
Gift: None
Community Fibre UK ISP Logo
150Mbps
Gift: None
Virgin Media UK ISP Logo
Virgin Media £22.99
132Mbps
Gift: None
Hey! Broadband UK ISP Logo
150Mbps
Gift: None
Youfibre UK ISP Logo
Youfibre £23.99
150Mbps
Gift: None
Large Availability | View All
Sponsored Links
The Top 15 Category Tags
  1. FTTP (6026)
  2. BT (3639)
  3. Politics (2721)
  4. Business (2439)
  5. Openreach (2405)
  6. Building Digital UK (2330)
  7. Mobile Broadband (2146)
  8. FTTC (2083)
  9. Statistics (1901)
  10. 4G (1816)
  11. Virgin Media (1764)
  12. Ofcom Regulation (1582)
  13. Fibre Optic (1467)
  14. Wireless Internet (1462)
  15. 5G (1407)
Sponsored

Copyright © 1999 to Present - ISPreview.co.uk - All Rights Reserved - Terms  ,  Privacy and Cookie Policy  ,  Links  ,  Website Rules