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Slower upstream after switching modem

Newbie
Posts: 4
Registered: ‎13-08-2020

Slower upstream after switching modem

Hi guys!

 

I'd been using a Huawei HG612 for a few years as both modem and router and a couple of days ago I decided to replace it with a more advanced one as I need to connect to VPNs, etc. I opted for a Draytek 2762 as it seemed to provide the functionalities I need - and it doesn't have WiFi as I need to position an AP in a better spot.

 

I got it yesterday and as expected it was super easy to set up. Once it synced, though, I noticed the upstream rate is quite slower than it used to be as it went from 8Mbps to 5.5Mbps. No change at all to the downstream one.

 

Is there anything I should check - settings, stats, etc. - ? Or do you think it might just be due to the different hardware?

 

Thanks in advance for you help. Smiley

6 REPLIES 6
Superuser
Superuser
Posts: 9,135
Thanks: 2,218
Fixes: 160
Registered: ‎30-07-2007

Re: Slower upstream after switching modem

The 2762 uses a lantiq chipset whereas the hg612 is Broadcom. Depending on your dslam type (Huawei or eci) you might get differing speed with the different chipsets

Newbie
Posts: 4
Registered: ‎13-08-2020

Re: Slower upstream after switching modem

Makes sense. I'm wondering how come the downstream rate is not affected though.

 

Is it possible the different chipset makes it more susceptible to high attenuation levels?

 

  Downstream             Upstream                
Actual Rate 39998 Kbps 5762 Kbps
Attainable Rate 60158 Kbps 5762 Kbps
Path Mode Fast Fast
Interleave Depth 1 1
Actual PSD 4. 4 dB 13. 5 dB
 
 
  Near End                  Far End                   
Trellis ON ON
Bitswap ON ON
ReTx 0   1  
SNR Margin 9 dB 5 dB
Attenuation 20 dB 31 dB

 

Something like 20dB is decent so it makes no difference while 31dB is barely good enough and the new chipset doesn't like that. I can confirm the cabinet is Huawei.

Superuser
Superuser
Posts: 9,135
Thanks: 2,218
Fixes: 160
Registered: ‎30-07-2007

Re: Slower upstream after switching modem

Not sure why the upstream should be affected more than downstream. I think the huawei MAY be able to enable g.inp on the upstream with compatible modems ( the hg612) . Not sure what the effect of that being enabled would have when connecting a modem that's not capable

If you dont mind multiple boxes, You could always continue to use the hg612 in bridge mode and connect to the wan port on the 2762

Newbie
Posts: 4
Registered: ‎13-08-2020

Re: Slower upstream after switching modem

According to Draytek website ReTx refers to G.Inp so the stats seem to indicate that's active for upstream. I'm puzzled too.

 

I thought about using the HG612 as just a modem but I think I'd rather use a single box.

Newbie
Posts: 4
Registered: ‎13-08-2020

Re: Slower upstream after switching modem

Also, does it make sense that the HG612 gets a higher upstream rate AND a higher SNR margin? Does SNR depend on the chipset too? I thought it was just a physical property of the line.

 

Annotation 2020-08-13 100913.png

Superuser
Superuser
Posts: 9,135
Thanks: 2,218
Fixes: 160
Registered: ‎30-07-2007

Re: Slower upstream after switching modem

They're both on a target of 6db. I suspect it's just perhaps the time of day when the stats were taken or when the line synched. Once synched initially at 6db , the snr will move up or down by about 1db throughout the day as the background noise levels change.