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:

Pages: 1 [2] 3

Author Topic: ADSL2 vs ADSL2+ tests  (Read 1584 times)

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6053
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: ADSL2 vs ADSL2+ tests
« Reply #15 on: May 01, 2018, 11:44:30 PM »

For some reason though I have had a very good experience with a huge pile of MediaTek / Trendchip modems in my DLinks. I'm using these as modems only, not as routers so maybe I am not seeing some of the software nasties, my line is long and slow but I think ultra-clean, and also no VDSL2 so those could be reasons why my experience might be different.
Logged

burakkucat

  • Global Moderator
  • Senior Kitizen
  • *
  • Posts: 23581
  • Over the Rainbow Bridge
    • The ELRepo Project
Re: ADSL2 vs ADSL2+ tests
« Reply #16 on: May 01, 2018, 11:54:48 PM »

[off topic]

My thoughts exactly. Probably comparable to MediaTek. ;D Can't say I've used either the v5 or a MediaTek-based modem, but Infineon chipsets that were used in some of the TalkTalk modem-router combos (D-Link, AFAIK) back in the ADSL days were certainly bad enough (at least on my line).

Conexant, Infineon and Lantiq are all on a "To Avoid" list that is maintained in "The Cattery".  :-X

[/off topic]
Logged
:cat:  100% Linux and, previously, Unix. Co-founder of the ELRepo Project.

Please consider making a donation to support the running of this site.

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6053
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: ADSL2 vs ADSL2+ tests
« Reply #17 on: May 17, 2018, 12:06:20 PM »

I did some tests now on line cwcc@a.1 with a ZyXEL VMG 1312-B10A modem -

Settings were:
  • PhyR down = on, up = on (suspect it is really on too, for downstream; poss not on for upstream)
  • SRA = on (supposedly; 'allowed' at least)
  • bitswap = on

Sync rates (kbps):
G.992.5   G.992.3
downup   downup
3034?   3134519
3103515   3066515
3085519   3081515
3085519   3060512
   3085515
   3081519
   3081519

So very little in it, but a paltry amount of data for decent statistics I am ashamed to say.
« Last Edit: May 17, 2018, 12:20:13 PM by Weaver »
Logged

Chrysalis

  • Content Team
  • Addicted Kitizen
  • *
  • Posts: 5416
Re: ADSL2 vs ADSL2+ tests
« Reply #18 on: May 17, 2018, 12:11:21 PM »

Interesting results, thanks Weaver.
Logged
Sky Fiber Pro - Billion 8800NL bridge & PFSense BOX running PFSense 2.4 - ECI Cab - LINE STATISTICS CLICK HERE

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6053
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: ADSL2 vs ADSL2+ tests
« Reply #19 on: May 17, 2018, 12:49:18 PM »

Btw these are all with downstream target SNRM set by AA to 3dB and actual downstream SNRM is about that too. Upstream target SNRM is 6dB and actual value matches that.

A few other points. The data doesn't point this out but it is clear that with this modem the sync rates (even the downstream) doesn't just go up and down for the hell of it, because of DLM mucking about or something. If you just reboot the modem and don't change any parameters at all then it tends to come up with the same sync rate it had before, so it's very consistent and this has not always been the case.

In the past there has been a lot of statistical ‘noise’ in these kind of sync rate stats, for reasons unknown. It could have been somehow linked to the downstream sync rate drooping, starting well below the downstream target SNRM and then sometimes going down further then yo-yoing. That doesn't happen any more either. Even on a 3dB downstream target SNRM the number seem a lot more consistent and healthy. The instantaneous downstream sync rates quoted for the DLink DSL-320B-Z1 modems in the past were at anything from ~0.6dB - 2.5 dB and rarely as high as an actual 3dB.

Coming back to the present, there does not seem to be much variation between sync rate achieved after a resynch performed at night time vs in the day time.

The bits per bin spectrum of the ZyXEL has some of the holes missing compared with the measurements taken with DLinks on two lines (although the line used in the ZyXel measurement is neither of those lines used with the DLinks, so not quite a completely fair comparison). It has a much longer tail at the top end, with a lot of values being 1 bit higher and there are a lot of 1-bit bins at the very top whereas there are no 1-bit bins with the DLinks almost as if they were not doing them 1-bit to a lack of such capabilities, or else a policy, almost like it thinks it is G.992.1. But who knows it could just be something to do with noise levels on those bins and bitswap decisions especially if the DLinks do not have monitored tones? Anyway, some of this might be related to why the thing seems to differ less between daytime and nighttime. I seem to remember reading something or other that mentioned an (analog?) filter, at the front end, maybe a higher-quality more expensive AFE on the B10A compared to some of the other competitor devices. Maybe better noise filtering means more resilience to RF ingress and that could help at night?
Logged

re0

  • Reg Member
  • ***
  • Posts: 290
Re: ADSL2 vs ADSL2+ tests
« Reply #20 on: May 18, 2018, 12:39:55 AM »

PhyR down = on, up = on (suspect it is really on too, for downstream; poss not on for upstream)
PhyR (AKA G.INP) is not enabled on ADSL connections for any direction on any wholesale platform in the UK AFAIK.

SRA = on (supposedly; 'allowed' at least)
Seamless Rate Adaption is also not enabled for ADSL connections.

Essentially, the settings above won't do anything - but regardless of whether they're on or off it should not have any performance impact as they will not be utilised when the connection is negotiated.
Logged

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6053
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: ADSL2 vs ADSL2+ tests
« Reply #21 on: May 18, 2018, 08:53:44 AM »

The reason I thought PhyR was working is that there was a sizeable PhyR event count value for downstream.
Logged

re0

  • Reg Member
  • ***
  • Posts: 290
Re: ADSL2 vs ADSL2+ tests
« Reply #22 on: May 18, 2018, 10:32:06 AM »

Then all I can say is "pass". I am not aware of any major ISP offering ADSL with LLU presence having PhyR enabled. That doesn't mean that it doesn't exist, but I am not aware and cannot find any significant information to prove or disprove this. I am almost certain that connections on BTW do not have it.

Would be interesting to see your statistics, if you are able to provide the information from the CLI using:
Code: [Select]
adsl info --statsIf I am not mistaken, you should have two bearers (0 and 1, though the latter will be 0 kbps for both directions). You should also have an INP figure.
Logged

j0hn

  • Kitizen
  • ****
  • Posts: 1786
Re: ADSL2 vs ADSL2+ tests
« Reply #23 on: May 18, 2018, 12:36:20 PM »

Quote
PhyR (AKA G.INP) is not enabled on ADSL connections for any direction on any wholesale platform in the UK AFAIK.

It is.
It is also not aka G.INP
PhyR is Broadcoms own proprietary invention. It was then standardised by the ITU as G.998.4/G.INP

You can only have PhyR with Broadcom modem to Broadcom DSLAM.

Quote
I am almost certain that connections on BTW do not have it.

The opposite. Only fairly new BT 21CN equipment seems to use this.

Sky also have G.INP on ADSL, but that's actual G.INP, not PhyR.

Weaver, have you checked the stats and double checked PhyR is on and working on both ADSL2 and ADSL2+?

Quote
Would be interesting to see your statistics, if you are able to provide the information from the CLI using

You can see his PhyR here

https://forum.kitz.co.uk/index.php/topic,21513.msg372354.html#msg372354
« Last Edit: May 18, 2018, 12:41:27 PM by j0hn »
Logged
BT FTTC 55/10 ECI now Huawei cab
Zyxel VMG1312-B10A bridge mode with 1508 MTU + Asus RT-AC68U running Asuswrt-Merlin

re0

  • Reg Member
  • ***
  • Posts: 290
Re: ADSL2 vs ADSL2+ tests
« Reply #24 on: May 18, 2018, 04:20:06 PM »

I was not intending on spreading misinformation. So I am glad you pointed out errors in my post, j0hn.

We think this is now Broadcom talking to Broadcom at the NSBFD exchange.
I do not know if you have checked or mentioned the vendor before, buit perhaps you could confirm with:
Code: [Select]
adsl info --vendorPerhaps a pointless experiment, since there is no reason why it won't return BDCM.
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31553
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: ADSL2 vs ADSL2+ tests
« Reply #25 on: May 18, 2018, 06:08:33 PM »

Quote
Only fairly new BT 21CN equipment seems to use this.

Sky also have G.INP on ADSL, but that's actual G.INP, not PhyR.

G.INP works with G.992.3, G992.5, G993.2 & G.993.5 and iirc only works on the downstream direction for adsl2/adsl2+


Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6053
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: ADSL2 vs ADSL2+ tests
« Reply #26 on: May 18, 2018, 06:20:32 PM »

Fyi - do we think that indicates the presence of Broadcom PhyR active? It is a relatively new MSAN installed 2015-12 at NSBFD
Code: [Select]
VMG1312-B10A
Login: admin
Password:
 > adsl info --stats
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    8000
Last initialization procedure status:   0
Max:    Upstream rate = 430 Kbps, Downstream rate = 3360 Kbps
Bearer: 0, Upstream rate = 515 Kbps, Downstream rate = 3052 Kbps

Link Power State:       L0
Mode:                   ADSL2 Annex A
TPS-TC:                 ATM Mode(0x0)
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):        3.0             5.8
Attn(dB):        65.0            41.0
Pwr(dBm):        18.4            12.4

                        ADSL2 framing
                        Bearer 0
MSGc:           52              11
B:              35              62
M:              4               1
T:              3               1
R:              10              12
S:              1.4861          3.8462
L:              829             156
D:              2               8

                        Counters
                        Bearer 0
SF:             4572161         445221
SFErr:          6               59
RS:             198889038               51454
RSCorr:         1004            6954
RSUnCorr:       26              0

ReXmt:          920             0
ReXmtCorr:      851             0
ReXmtUnCorr:    27              0

                        Bearer 0
HEC:            31              107
OCD:            0               0
LCD:            0               0
Total Cells:    535374229               90480196
Data Cells:     4314082         1084725
Drop Cells:     0
Bit Errors:     978             13038

ES:             3               39
SES:            0               0
UAS:            48              48
AS:             74387

                        Bearer 0
INP:            26.00           2.00
INPRein:        0.00            0.00
delay:          8               8
PER:            16.16           16.34
OR:             28.70           8.32
AgR:            3067.16 522.12

Bitswap:        13620/13748             37/37

Total time = 20 hours 40 min 35 sec
FEC:            1004            6954
CRC:            6               59
ES:             3               39
SES:            0               0
UAS:            48              48
LOS:            0               0
LOF:            0               0
LOM:            0               0
Latest 15 minutes time = 10 min 35 sec
FEC:            33              140
CRC:            0               2
ES:             0               1
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Previous 15 minutes time = 15 min 0 sec
FEC:            20              35
CRC:            0               0
ES:             0               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Latest 1 day time = 20 hours 40 min 35 sec
FEC:            1004            6954
CRC:            6               59
ES:             3               39
SES:            0               0
UAS:            48              48
LOS:            0               0
LOF:            0               0
LOM:            0               0
Previous 1 day time = 0 sec
FEC:            0               0
CRC:            0               0
ES:             0               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Since Link time = 20 hours 39 min 45 sec
FEC:            1004            6954
CRC:            6               59
ES:             3               39
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0

and

Code: [Select]
> adsl info --vendor
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    8000
Last initialization procedure status:   0
Max:    Upstream rate = 430 Kbps, Downstream rate = 3372 Kbps
Bearer: 0, Upstream rate = 515 Kbps, Downstream rate = 3052 Kbps

ChipSet Vendor Id:      BDCM:0xa3a7
ChipSet VersionNumber:  0xa3a7
ChipSet SerialNumber:   
« Last Edit: May 18, 2018, 06:23:45 PM by Weaver »
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 31553
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: ADSL2 vs ADSL2+ tests
« Reply #27 on: May 18, 2018, 06:23:24 PM »

I've been a long term advocate that adsl2 may work better on long lines rather than adsl2+ and I believe I may have been one of the first to start suggesting this dating to when BTw first started using adsl2+.   

I recall having a telephone conversation many years ago with Azzaka from Zen about a problematic line which definitely worked better on adsl2 than adsl2+ and adsl and giving him my theory why this was.  If Leo was still around he would be able to confirm that after our conversation Zen started recommending adsl2 to EU's on long lines. 

Theres a post about this subject here, which also mentions the 2700HGV negotiating adsl2 mode
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

Weaver

  • Addicted Kitizen
  • *****
  • Posts: 6053
  • Retd sw dev; A&A; 4 × 7km ADSL2; IPv6; Firebrick
Re: ADSL2 vs ADSL2+ tests
« Reply #28 on: May 18, 2018, 06:26:42 PM »

Is it possible that the experiment would benefit from PhyR being disabled? Don't know why I suggest that.
Logged

ejs

  • Kitizen
  • ****
  • Posts: 1747
Re: ADSL2 vs ADSL2+ tests
« Reply #29 on: May 18, 2018, 06:49:57 PM »

I think any apparent difference between ADSL2 and ADSL2+ is not due to any difference between the ADSL2 and ADSL2+ standards, it's entirely due to the type of equipment. The oldest type of ADSL2+ equipment (TSTC) isn't good at ADSL2+, on any length of line, but long lines have a sort of get out by being able to sensibly switch to ADSL2 or even ADSL1.

Long line behaviour:
TSTC: does ADSL2+ badly
IFTN: automatically switches to ADSL2
BDCM: ADSL2 / ADSL2+ makes no difference

You don't often get to clearly see the difference the equipment makes unless someone has two lines to the same place on difference equipment, or has some sort of protracted fault and manages to get their line switched from one type of equipment to another.
Logged
Pages: 1 [2] 3