Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[jan8p]

Hi all,

I migrated from PlusNet to Zen a couple of days ago...all went smoothly apart from I am now syncing at 72Mb, where as PN was rock solid 80Mb for 2 years.

Is this normal?  Looking at my stats my SNR is steady at 6.4.....I thought 3dB was the normal target SNR?  Here's my stats, any insight as to why this has happened is appreciated!

   Downstream   Upstream
Line Coding (Trellis)   On   On
SNR Margin (dB)   6.4   15.2
Attenuation (dB)   12.2   0.0
Output Power (dBm)   12.9   -1.2
Attainable Rate (Kbps)   73306   26901
Rate (Kbps)   72225   19999
B (# of bytes in Mux Data Frame)   243   237
M (# of Mux Data Frames in an RS codeword)   1   1
T (# of Mux Data Frames in an OH sub-frame)   0   42
R (# of redundancy bytes in the RS codeword)   10   16
S (# of data symbols over which the RS code word spans)   0.1076   0.3781
L (# of bits transmitted in each data symbol)   18889   5374
D (interleaver depth)   8   1
I (interleaver block size in bytes)   254   127
N (RS codeword size)   254   254
Delay (msec)   0   0
INP (DMT symbol)   48.00   0.00
OH Frames   0   0
OH Frame Errors   0   3
RS Words   32556744   710496
RS Correctable Errors   16   4
RS Uncorrectable Errors   0   0
HEC Errors   0   0
OCD Errors   0   0
LCD Errors   0   0
Total Cells   122226417   0
Data Cells   3830401   0
Bit Errors   0   0
Total ES   0   4
Total SES   0   0
Total UAS   32   32

[Alex Atkin UK]

When you change ISPs the line profile is reset so may take a while to return to where it was before, especially if you had less than 6dB SNRm (6dB is still the standard target).

[tubaman]

Assuming you are on a Huawei cabinet and the line has low errors then DLM should drop you back to 3dB (in 1dB steps), and hopefully 80Mbs, in the coming days.
Just need to be patient.
 

[jan8p]

Ah ok!  Didn't know it reset on a migration

I've been resyncing it every day at around lunchtime to see if there's any movement....presumably that won't have a negative effect?

Thanks for the replies!

[tubaman]

Ah ok!  Didn't know it reset on a migration

I've been resyncing it every day at around lunchtime to see if there's any movement....presumably that won't have a negative effect?

Thanks for the replies!

Best to just leave it be - it'll resync on its own, usually overnight, as it needs to.
 

[Alex Atkin UK]

Ah ok!  Didn't know it reset on a migration

I've been resyncing it every day at around lunchtime to see if there's any movement....presumably that won't have a negative effect?

Any adjustments are automatic, usually around 3am and any manual resyncs you do can be interpreted as instability and delay or prevent it returning to the same profile as it was before.

[jan8p]

Great, thanks both!

[tiffy]

@jan8p:
Congratulations on your escape from Plusnet, from my experience a wise move.
I hope the exit process from PN goes to plan and you don't experience any final billing issues.

I completed the same migration, Plusnet to Zen, in December and documented the events here:
https://forum.kitz.co.uk/index.php/topic,25387.msg425966.html#msg425966
You may find this of interest.

As the very knowledgable forum patrons have already advised, best to leave everything up to DLM certainly until the line has returned to 3dB DS SNRM, assuming you are served by a Huawei cabinet, manual modem re-synching won't speed up the process but can extend the post DLM reset recovery time.

The only manual intervention I had to carry out (after achieving 3dB DS SNRM) was assistance to recover DS G.Inp Re-Tx low profile by application of graduated modem DS speed limiting as outlined in my post.

Experience with Zen so far, very good, only minor criticism is lack of response to an e-mail enquiring about a FTTP upgrade which has just become available at my address.

[jan8p]

Thanks, will keep an eye on the bill!

To be honest I've had zero issues with PN over the past few years, I'd happily recommend them. Only reason I'm going to Zen is for native IPV6!

Also, my target SNR seems to have dropped to 5 overnight and now syncing at 75MB, hopefully another few days and it'll be down to 3!

[tubaman]

...

Also, my target SNR seems to have dropped to 5 overnight and now syncing at 75MB, hopefully another few days and it'll be down to 3!

Good news - sounds like your journey back to 3dB has begun.
 

[tiffy]

To be honest I've had zero issues with PN over the past few years, I'd happily recommend them. Only reason I'm going to Zen is for native IPV6!

You were one of the lucky ones an awful lot were not!
I would have agreed with you for the first 9 years of my 11 year patronage with PN, however with the introduction of their new admin & billing system late 2018 it became a constant hassle every month, had to bite the bullet and leave as no resolution was in sight and I grew weary of the never ending monthly dialogue.

Also, my target SNR seems to have dropped to 5 overnight and now syncing at 75MB, hopefully another few days and it'll be down to 3!

Good old DLM seems to be doing the business at it's own rate.
When you do get to DS 3dB SNRM remember to keep an eye on your DS G.Inp re-tx profile, if it remains "high" (which appears to be the default after a DLM reset) then the line BRAS IP profile will be approx 93% of the DS synch speed as opposed to approx 97% with re-tx low profile, ie., your DS data throughput rate with respect to DS synch speed will be proportionately lower. 

[jan8p]

How do I tell if that's the case? My modem is a Billion 8800NL and I get stats as per my first post. Can you tell from that?

[tubaman]

I think the stat that tells you is having Bearer 0 INPRein=1, but that doesn't show on your list. Can you telnet into the router and get stats via 'xdslctl info --stats' as that should show you?
 

[tiffy]

As "tubaman" has said the parameter to check is Bearer 0 INPRein, =1 is re-tx high profile, =0 is re-tx low profile.
Does not show on the stat's listing you have provided, however, noted that your "DS INP" is 48 and from my experience on 3 VDSL lines I have long term monitored, DS IMP <50 indicates re-tx low profile and DS INP 50 or greater indicates high re-tx profile.
I have only ever found one exception to this indication, however, Bearer 0 INPRein 0/1 state is still the best indication of re-tx profile state.

Again as "tubaman" has said, a Telnet full stat listing should display Bearer 0 parameters.
I remotely monitor a Billion 8800NL r2 on my daughters VDSL-2 line using DSLStats, will attach some snapshots from this to illustrate a line running with re-tx high profile, always been too noisy to maintain low re-tx profile.
Stat's monitoring and recording has always been so much easier with DSLStats, thanks to "Roseway" (Eric), I have run this with both r1 & r2 versions of the Billion 8800NL, works perfectly.

Another more direct way of checking is to obtain your line BRAS IP profile from here:
https://speedtest.btwholesale.com/
Run "Additional Diagnostics" after speed test and enter telephone number. (NB. speed test is not very accurate, ignore)
or here:
https://windows.mouselike.org/be/index.asp?DoAction=BrasChecker
Again enter telephone number.

BRAS DS IP Profile/DS Synch Speed X 100 = DS synch/data ratio, for example, my line with low G.Inp re-tx profile:
38.67/40.00*100 = 96.67%

There have been a few forum patrons recently that have recorded approx 88% DS synch/data ratio on their VDSL-2 lines but this would appear to be associated with the very, very few that have Vectoring enabled on Huawei cabinets. 
 

[jan8p]

Interesting!  Checker shows this:

The current Downstream IP profile rate is: 69.13
The current Upstream IP profile rate is: 20

With a 75MB sync rate.

I will telnet to the router at some point and check, but it I use it in modem only mode so need to plug a laptop directly into it to get the stats!