Kitz Forum

Broadband Related => Broadband Hardware => Topic started by: Weaver on June 28, 2018, 03:52:43 AM

Title: ZyXEL VMG 1312-B10A stats check
Post by: Weaver on June 28, 2018, 03:52:43 AM
Could someone give me a stats check on this lot, any opinions, comments?
Code: [Select]
VMG1312-B10A
Login: admin
Password:
 > adsl info --show
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    8000
Last initialization procedure status:   0
Max:    Upstream rate = 448 Kbps, Downstream rate = 3344 Kbps
Bearer: 0, Upstream rate = 505 Kbps, Downstream rate = 3041 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):        1.6             6.2
Attn(dB):        69.0            41.7
Pwr(dBm):        18.4            12.4

                        ADSL2 framing
                        Bearer 0
MSGc:           53              11
B:              34              62
M:              4               1
T:              3               1
R:              10              12
S:              1.4493          3.9216
L:              828             153
D:              2               8

                        Counters
                        Bearer 0
SF:             1850949         786235
SFErr:          0               19
RS:             81904520                411903
RSCorr:         48862           4029
RSUnCorr:       0               0

ReXmt:          1062            0
ReXmtCorr:      745             0
ReXmtUnCorr:    0               0

                        Bearer 0
HEC:            0               37
OCD:            0               0
LCD:            0               0
Total Cells:    214291050               35642587
Data Cells:     32016647                5249963
Drop Cells:     0
Bit Errors:     0               1458

ES:             0               23
SES:            0               0
UAS:            111             111
AS:             29880

                        Bearer 0
INP:            26.00           2.50
INPRein:        0.00            0.00
delay:          8               8
PER:            16.03           16.66
OR:             29.44           8.16
AgR:            3057.17 512.07

Bitswap:        8185/8272               36/36
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: johnson on June 28, 2018, 04:56:19 AM
Code: [Select]
xdslctl info --stats

May be slightly more illuminating in terms of actual corrupted vs recovered packets in terms of the things you mentioned in the other thread. It will only give you FEC & CRC errors, and from the looks of your ES being 0 on the downstream you are probably not experiencing any unrecoverable errors. Will also show link uptime which is fairly necessary to have when making any judgements about error rates.
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: Weaver on June 28, 2018, 05:20:21 AM
As requested:
Code: [Select]
VMG1312-B10A
Login: admin
Password:
 > xdslctl info --stats
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    8000
Last initialization procedure status:   0
Max:    Upstream rate = 448 Kbps, Downstream rate = 3384 Kbps
Bearer: 0, Upstream rate = 505 Kbps, Downstream rate = 3041 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):        2.0             6.1
Attn(dB):        69.0            41.7
Pwr(dBm):        18.4            12.4

                        ADSL2 framing
                        Bearer 0
MSGc:           53              11
B:              34              62
M:              4               1
T:              3               1
R:              10              12
S:              1.4493          3.9216
L:              828             153
D:              2               8

                        Counters
                        Bearer 0
SF:             2371971         284161
SFErr:          0               19
RS:             104959762               400798
RSCorr:         56942           4904
RSUnCorr:       0               0

ReXmt:          1470            0
ReXmtCorr:      1086            0
ReXmtUnCorr:    0               0

                        Bearer 0
HEC:            0               37
OCD:            0               0
LCD:            0               0
Total Cells:    274611677               45675966
Data Cells:     91380752                12592860
Drop Cells:     0
Bit Errors:     0               1458

ES:             0               23
SES:            0               0
UAS:            111             111
AS:             38290

                        Bearer 0
INP:            26.00           2.50
INPRein:        0.00            0.00
delay:          8               8
PER:            16.03           16.66
OR:             29.44           8.16
AgR:            3057.17 512.07

Bitswap:        10119/10226             36/36

Total time = 12 hours 29 min 0 sec
FEC:            56985           7591
CRC:            0               29
ES:             0               23
SES:            0               0
UAS:            111             111
LOS:            0               0
LOF:            0               0
LOM:            0               0
Latest 15 minutes time = 14 min 0 sec
FEC:            292             92
CRC:            0               0
ES:             0               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Previous 15 minutes time = 15 min 0 sec
FEC:            299             79
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 = 12 hours 29 min 0 sec
FEC:            56985           7591
CRC:            0               29
ES:             0               23
SES:            0               0
UAS:            111             111
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 = 10 hours 38 min 9 sec
FEC:            56942           4904
CRC:            0               19
ES:             0               14
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: johnson on June 28, 2018, 05:47:47 AM
Been a while since I had adsl so its hard to remember what made for good or bad stats, but I'd say error rates are really low for the line length.

~ 50 FECs per minute on the downstream, 0 CRCs. ~30 upstream CRCs in 12 hours is I assume well within DLM limits even on ADSL.

1.6db downstream margin, if you believe the previous modems were maybe cutting it even closer you could drop this down to say 1db to test. Graphs of downstream SNR margin over a the course of a few days would really help to see if you had any room there. It might be rock solid 1.6db all day and night, it might vary considerably, knowing where it bottoms out would tell you if could get away with lowering it slightly.

Similarly knowing when you had the highest margin would allow you to pick the best time for a resync, but thats pretty much equivalent to changing the margin yourself with the method discussed elsewhere.

16ms of extra delay due to interleaving might annoy someone who plays games, but given your line length seems a small price to pay given the low error rates.

Is it well documented that broadcom's phyre works on ADSL2? I have no memory of it from my line. Good that it seems to enabled and doing its job though.
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: Weaver on June 28, 2018, 07:01:27 AM
The MSAN in the exchange at NSBFD is fairly recent, installed in november 2015 and it is confirmed as Broadcom from the vendor string or whatever it is called, so that is the reason we have a chance of getting retx going with a Broadcom-Broadcom setup in ADLS2.
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: Weaver on June 30, 2018, 11:00:17 AM
We have established that I could profitably try going down a bit further. This seems like a reasonable idea as the previous modems would drop from an initial ~1.6dB down to a later 0.6-0.8dB sometimes but still hang on in there for days.

The pattern with the DLink modems was that they always started off with downstream SNRM much lower than the supposed target. I set 3.0 dB downstream target SNRM, by using an option in the ISP, Andrews and Arnold’s clueless.aa.net.uk control server. But the modems never observed this on the downstream. Upstream was as it should be though. It is as if the Dlinks feature built-in tweaking to boost performance. Is that kind of design trick a bit naughty?

I can also cope with lower reliability in the sense of tolerating the occasional resync fine, because I have three modems and the others will cary on and take over the load, so I never even inside an outage. However, I cannot be doing with packet loss due to packet corruption though. It is a bit difficult to quantify these thought and turn them into something more concrete.

Of course since I now have Broadcom low-level L2 retransmissions (‘PhyR’) so then I should effectively not ever be getting any packets dropped due to corruption ? Because the retx covers that up.


But in general terms, do those numbers look reasonably good otherwise ?
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: PhilipD on July 02, 2018, 03:46:44 PM
Hi

Of course since I now have Broadcom low-level L2 retransmissions (‘PhyR’) so then I should effectively not ever be getting any packets dropped due to corruption ? Because the retx covers that up.

But also reduces your data-throughput as packets are sent again using up "slots" new data could travel in, and latency increases for those re-transmitted packets, and PhyR can only deal with a very limited amount of errors as buffers are small.

Whatever you tweak seemingly for the better in one aspect, leads to worsening performance elsewhere. 

Regards

Phil

Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: tubaman on July 02, 2018, 04:42:28 PM
Hi

But also reduces your data-throughput as packets are sent again using up "slots" new data could travel in, and latency increases for those re-transmitted packets, and PhyR can only deal with a very limited amount of errors as buffers are small.

Whatever you tweak seemingly for the better in one aspect, leads to worsening performance elsewhere. 

Regards

Phil

But it is far faster to re-transmit those packets from the buffer than to request that they are resent from the source.
The alternative is likely to be interleaving which puts an overhead and delay on every packet irrespective of whether it is corrupted or not.

On my FTTC line G.INP and 3dB SNR together have been a revelation. My sync rate has increased from 35Mb/s to 46Mb/s with actual download up by about 8Mb/s. Ping can be down as low as 11ms.
I know which I'd rather have.
 :)
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: j0hn on July 02, 2018, 04:43:39 PM
Are you able to post the --stats from all 3 lines?

I assume you have the 3 ZyXEL's numbered something like...
192.168.1.1
192.168.1.2
192.168.1.3
so you are able to log in to each individually at any time.

I see you are using ADSL2+.
Are you using this on all 3 lines?
How does ADSL2 compare and is PhyR still active on ADSL2?

Sorry for all the questions.
Title: Re: ZyXEL VMG 1312-B10A stats check
Post by: Weaver on July 02, 2018, 05:03:15 PM
Yes, I can post stats for all three modems up. I have arranged distinct IP addresses, 192.18.1.1 and 2.1 and 3.1 for the admin i/fs.

The lines are 7300m.

I am using ADSL2 not ADSL2+, on all three lines. The difference turns out to be practically nothing, it is in the noise. PhyR is still active on ADSL2.