Kitz Forum

Broadband Related => FTTC and FTTP Issues => Topic started by: timerider on September 14, 2020, 03:04:38 PM

Title: Difference between Sync and PPP Session
Post by: timerider on September 14, 2020, 03:04:38 PM
Hi.

I have using AA for the last few months without any issues. One of the great things of AA it gives information so you can obsess on other details.

 ;D

I been swapping modems try to get the best sync rate. I just got a VMG8324-B10A that seems to be a preferred modem for the forum. My line is just on the limit to able to get the full 80Mbps. And I tried. a few Lantiq modems (Vigor, Netgear, BTHH5) and I wasn't able to get a better sync rate that I had from my old HG612. I saw the DLM putting down a few times the sync rate and I can see the change in the AA panel.

Now I been running the  VMG8324-B10A for about 15 days and I was able to gain back the full sync speed.

Current stats:

VDSL Training Status:   Showtime
                    Mode:   VDSL2 Annex B
            VDSL Profile:   Profile 17a
                G.Vector:   Disable
            Traffic Type:   PTM Mode
             Link Uptime:   10 days: 4 hours: 50 minutes
====================================================================================
       VDSL Port Details       Upstream         Downstream
               Line Rate:     20.063 Mbps       79.998 Mbps
    Actual Net Data Rate:     19.999 Mbps       79.999 Mbps
          Trellis Coding:         ON                ON
              SNR Margin:       15.4 dB            4.4 dB
            Actual Delay:          0 ms              0 ms
          Transmit Power:        0.7 dBm          13.2 dBm
           Receive Power:      -15.6 dBm           0.5 dBm
              Actual INP:        0.0 symbols      52.0 symbols
       Total Attenuation:        0.0 dB          12.4 dB
Attainable Net Data Rate:     24.337 Mbps       81.409 Mbps
====================================================================================
  VDSL Band Status        U0      U1      U2      U3      U4      D1      D2      D3
  Line Attenuation(dB):    3.4    14.2    21.6     N/A     N/A    7.7    17.0    27.0   
Signal Attenuation(dB):    3.4    13.5    21.1     N/A     N/A    9.8    16.8    27.0   
        SNR Margin(dB):    15.4    15.4    15.5     N/A     N/A    4.4    4.4    4.4   
         TX Power(dBm):   -14.0   -29.5    0.5     N/A     N/A    9.8    7.9    7.0   
====================================================================================


However on my AA panel still shows 76.5MBps.

Tx rate (adjusted) 72120349 to 75151746 (rx 19999000) and it got stuck in there for at least 15 days or so.

So my question comes I see there is a difference between the physical sync rate and what the provider (AA for this case) observes.

Running a speed test will give a 74Mbps result. So it confirms that I get close what the AA Panel says, but is not the real sync speed.

So I am not sure where the difference is between the sync rate and the AA panel rate. Also, if I am syncing at 80Mbps, My speedtest should be close to 80Mbps and not around 74Mbps ish.

Thanks!

Title: Re: Difference between Sync and PPP Session
Post by: jelv on September 14, 2020, 03:25:07 PM
What do you have the rate set at in Line Options?

(https://forum.kitz.co.uk/index.php?action=dlattach;topic=25164.0;attach=29136;image)
Title: Re: Difference between Sync and PPP Session
Post by: jelv on September 14, 2020, 03:28:40 PM
Also, sync rate is the speed you get with all the packet headers. Speed tests report the speeds of the data only within the packets and will be lower. 74Mbps is pretty good!
Title: Re: Difference between Sync and PPP Session
Post by: timerider on September 14, 2020, 03:33:58 PM
Thanks jelv.

My panel is set at 100%

After my post I found another post about the BRAS profile and probably is related.

My detailed stats are:

INP:      52.00      0.00
INPRein:   1.00      0.00
delay:      0      0
PER:      0.00      3.98
OR:      0.01      64.22
AgR:      80244.76   20063.54

         Bearer 1
INP:      4.00      0.00
INPRein:   4.00      0.00
delay:      3      0
PER:      16.06      0.01
OR:      95.62      0.01
AgR:      95.62   0.01

So I have INPRein on my line (no surprised as is borderline). And I am reading a long post on downgrading the line rate for a few days to trick the DLM. This probably is related, right?
Title: Re: Difference between Sync and PPP Session
Post by: jelv on September 14, 2020, 03:44:49 PM
Extracts from my stats:
Max:    Upstream rate = 24585 Kbps, Downstream rate = 86454 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79999 Kbps

                        Bearer 0
INP:            48.00           0.00
INPRein:        0.00            0.00
delay:          0               0
PER:            0.00            3.98
OR:             0.01            64.22
AgR:            80614.82        20063.54

                        Bearer 1
INP:            4.00            0.00
INPRein:        4.00            0.00
delay:          3               0
PER:            16.06           0.01
OR:             95.62           0.01
AgR:            95.62   0.01


My panel shows Line rate: Down: 79.6M

ETA Tip: Wrap the stats in pre tags (the (https://forum.kitz.co.uk/Themes/KitzBlue/images/bbc/pre.gif) button) to fix the layout.
Title: Re: Difference between Sync and PPP Session
Post by: timerider on September 14, 2020, 04:12:14 PM
Thanks! I think your post confirm my suspicion

You INPRein is = 0

INPRein:        0.00            0.00


Mine is = 1

INPRein:   1.00      0.00



I think this post is relevant as is the same case as me.

https://forum.kitz.co.uk/index.php/topic,22086.0.html


Anyone can provide some other perspective on why this speed difference?

Thanks!!
Title: Re: Difference between Sync and PPP Session
Post by: j0hn on September 15, 2020, 01:56:27 PM
You are on Retx High (retransmission high).
This gives an IP profile (and throughput) around 91-92% of the sync speed.

Retx Low gives exactly 96.69% of the sync speed.

The line can be capped temporarily to "nudge" DLM in to putting it on Retx Low if you really want the extra throughput.
Title: Re: Difference between Sync and PPP Session
Post by: timerider on September 15, 2020, 09:51:33 PM
Thanks J0hn!!

That is confirms what I was reading in some other posts and thanks for confirming this!  ;D

I had capped my line to 60/15 now for a few days.

VDSL Training Status:   Showtime
                    Mode:   VDSL2 Annex B
            VDSL Profile:   Profile 17a
                G.Vector:   Disable
            Traffic Type:   PTM Mode
             Link Uptime:   1 day: 4 hours: 27 minutes
====================================================================================
       VDSL Port Details       Upstream         Downstream
               Line Rate:     15.056 Mbps       59.999 Mbps
    Actual Net Data Rate:     14.999 Mbps       60.000 Mbps
          Trellis Coding:         ON                ON
              SNR Margin:       18.8 dB           10.0 dB
            Actual Delay:          0 ms              0 ms
          Transmit Power:        0.7 dBm          13.2 dBm
           Receive Power:      -15.5 dBm           0.2 dBm
              Actual INP:        0.0 symbols      52.0 symbols
       Total Attenuation:        0.0 dB          12.7 dB
Attainable Net Data Rate:     24.210 Mbps       83.465 Mbps


Will report back in about 4 days...(?)