Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Author Topic: VMG3925-B10B has higher sync but slow speed than HG612?  (Read 317 times)

dazmatic

  • Just arrived
  • *
  • Posts: 3
VMG3925-B10B has higher sync but slow speed than HG612?
« on: August 17, 2021, 04:19:00 PM »

Hi all,

I live out in the middle of the sticks at the end of a line.
That being said, I'm able to get sync speeds of VDSL2 at _around_ 38/9Mbps which I thought was quite good but the SNR ratio is poor, 3.8dB down and 6.3dB up.
That being said, I'm only getting about 30Mb down with the VMG3925 router and 33ish with a HG612. I believe I'm on a Broadcom cab too so I'm surprised to see that the VMG3925 to get a slower connection.

EE are being they're helpful selves by saying that there's no fault on the line but because I don't have their router plugged in, there isn't much more they can do.

Any ideas?

Thanks.
Logged

Alex Atkin UK

  • Kitizen
  • ****
  • Posts: 2885
    • Thinkbroadband Quality Monitors
Re: VMG3925-B10B has higher sync but slow speed than HG612?
« Reply #1 on: August 17, 2021, 04:53:37 PM »

Some variation between hardware is just to be expected, its why many of us on the forum have tried different hardware and use whatever works best.

I also wouldn't call 3.8dB SNRm "poor".  Anything that's within the tolerances of the dynamic line management by definition functioning as designed.
Logged
INTAKE (ECI) 2xHome Hub 5A (OpenWRT) on Zen/Plusnet, 1xHauwei B535-232 on Voxi 4G, 1xHauwei H122-373 on Three 5G Router: pfSense (i5-7200U) WiFi: nanoHD (OpenWRT) + Honor Router 3
My Broadband History & Ping Quality Monitors

meritez

  • Reg Member
  • ***
  • Posts: 682
Re: VMG3925-B10B has higher sync but slow speed than HG612?
« Reply #2 on: August 17, 2021, 07:06:55 PM »

@dazmatic welcome to kitz forums

What's stating you will get 38/9?
Logged

dazmatic

  • Just arrived
  • *
  • Posts: 3
Re: VMG3925-B10B has higher sync but slow speed than HG612?
« Reply #3 on: August 18, 2021, 09:00:35 AM »

I understand that there will be differences in hardware, just surprised that's it's backwards to what I've read.

The 38/9 is what's apparently attainable on my line according to the router, both the HG612 and the VMG3925 say similar things, just that the VMG actually throughputs less.

EE wanted me to plug in their router so they can pull some stats off it but I plugged it in, tried getting it to work with my existing network but it was a no go, their router doesn't allow bridge mode and there's no way I'm reconfiguring my network so that they can get stats for a couple of days.

Am I just clutching at straws here chasing a few Mb? I saw the 3.6dB SNR and was a bit concerned because that's quite low.
Logged

j0hn

  • Kitizen
  • ****
  • Posts: 3552
Re: VMG3925-B10B has higher sync but slow speed than HG612?
« Reply #4 on: August 18, 2021, 09:33:37 AM »


Am I just clutching at straws here chasing a few Mb? I saw the 3.6dB SNR and was a bit concerned because that's quite low.

The target SNRM starts at 6dB but if a line is stable the DLM will lower the SNRM as low as 3dB.

You would sync nearer 30Mb i6s the SNRM went back up to 6dB.
Logged
Talktalk FTTP 550/75 - Speedtest - BQM

dazmatic

  • Just arrived
  • *
  • Posts: 3
Re: VMG3925-B10B has higher sync but slow speed than HG612?
« Reply #5 on: August 18, 2021, 02:38:06 PM »

Thanks.

Am I reading this wrong then? I was under the impression that a low SNR = bad and high SNR = good?
Logged

hopkins35

  • Member
  • **
  • Posts: 32
Re: VMG3925-B10B has higher sync but slow speed than HG612?
« Reply #6 on: August 18, 2021, 03:47:25 PM »

Thanks.

Am I reading this wrong then? I was under the impression that a low SNR = bad and high SNR = good?

SNR is a balancing act between the target that DLM identifies for your line and your line's stability at that target. A lower target i.e. 3db will get you a higher sync rate than 6db but your line has less margin before it hits a point where errors overwhelm it and the connection drops entirely and a re-sync is needed. SNR fluctuates throughout the day and throughout the year due to changing environmental conditions and a problematic line is likely to suffer more than a more stable one which is why a higher target helps as your further away from the point of a possible re-sync which is what DLM attempts to achieve when your line hits a certain threshold of errors or disconnects.

So a low actual SNR could be considered bad in that there's less wiggle room before it hits the bad spot of errors and disconnects but a lower target SNR will allow for a greater sync speed
« Last Edit: August 18, 2021, 03:50:10 PM by hopkins35 »
Logged

tubaman

  • Addicted Kitizen
  • *****
  • Posts: 7987
Re: VMG3925-B10B has higher sync but slow speed than HG612?
« Reply #7 on: August 19, 2021, 08:12:13 AM »

I wouldn't pay too much attention to the 'attainable' numbers the routers are giving you as they often miscalculate them. If your downstream SNR is 3.8dB then you are most likely on a Huawei cabinet with G.INP doing its job to get you the best sync rate available.
As said there will be differences between devices, and if the HG612 is giving the best results on your line then I'd carry on using that.
 :)
Logged
BT FTTC 80/20 Huawei Cab - Zyxel VMG8924-B10A
 

anything