Line quality and jitter
 

So I've now had the service for about a week. I'd think that's a reasonable timeframe for the circuit to 'sync'...?

Been running a couple of tests as below. My only concern are the jitter values - can anyone comment and suggest if that's something I should try and improve on? and if so, which action should be taken?

Many thanks!

NC

Re: Line quality and jitter
 

VM usually has jitter
Some areas where are not many VM users are lucky to have low jitter or some after area upgrade also are lucky to have low jitter too
Set up a thinkbroadband to watch your line quality such maybe packet drops,or jitter/high latency
That will help you see if is any congestion as well
Keep an eye in this thread for some VM monitor graphs to compare with your connection
http://www.cableforum.co.uk/board/12...-page-137.html

The only you can do is to contact VM if you are in congested area (thinkbroadband monitor will show and VM is accepting it as evidence)and if is congestion ask if will take any future action (and if ...will be usually after long time)
OR
try reset the Superhub (at my case had to reset it over 20 times) if will lock after the reset to a less congested channel
http://www.cableforum.co.uk/board/35464997-post9.html
Note the blue around 12-6pm jitter was around 15ms after reset jitter was 0-1ms

Re: Line quality and jitter
 

Babs has advised you well.

During peak times I average 9ms via the same JDast test as you, and maybe 3 or 4ms at other times. I've seen the odd 15ms jitter. So it dpends on the loads in your area.

BTW my BT Infinity service usually shows 0ms jitter and maimum 1ms, although the minimum latency is always 25ms. It's better for my son's gaming.

Dunno what else to say; VM's jitter record isn't what I would call good and they are silent on the subject.

Re: Line quality and jitter
 

Doesn't the way cable upstream work with the need to request a broadcast timeslot make jitter inevitable unless the utilisation is kept at very low levels indeed?

Do you have numbers for the jitter levels US cable providers have?

---------- Post added at 10:31 ---------- Previous post was at 10:29 ----------

A couple of minutes max is a reasonable timeframe for it to boot and sync. There is no DLM on cable.

Re: Line quality and jitter
 

Kwikkie

http://www.dslreports.com/forum/rema...?hilite=jitter

Looks to me like Comcast has exactly the same profile. I selected this post at random, but look how aposite it is mentioning the DSL Qwest in the same breath.

Good technical call on the upstream mini-slot, BTW.

Re: Line quality and jitter
 

Ofcom results for packet lost and latency
http://www.ispreview.co.uk/index.php...band-isps.html

Re: Line quality and jitter
 

The annoying thing about both those graphs -

https://www.cableforum.co.uk/images/...2012/09/18.gif

and

https://www.cableforum.co.uk/images/...2012/09/19.gif

They suggest that VMs services change between packages, that upgrading from 30mb to 60mb will give you lower ping/jitter, and 100mb will lower that further, so based on that research, people may upgrade to 100mb for better gaming performace when actually performance is going to be exactly the same, using the same d/s and u/s channels

of course, without opening up a can bucket silo of worms it may be because a lot of 100mb users have kept the VMNG300

Re: Line quality and jitter
 

Here are some updated stats.I'm yet to see jitter dropping lower, and have rebooted the superhub a few times already. I'm using it in modem mode, btw, with the asus RTN66U router.

Not sure what can be learned from these stats about the line state and capability.

Cheers,

NC

Re: Line quality and jitter
 

Another week's gone, jitter and ping times continue to rise...

See attached for quality monitor and JD test results.

Any suggestions? At which point should I contact VM and what number/method is the best way to get a good response?

Thx,

NC

Re: Line quality and jitter
 

ASAP, and on the forum is probably your best bet, phone support may mess you around whereas the forum team will probably be able to raise it as high utilisation

Re: Line quality and jitter
 

Thanks, have just posted on the VM forum. Any idea of the likely action which can be taken?

Re: Line quality and jitter
 

will take a few days for a reply, then a VM bod will give a reply as to the problem

Re: Line quality and jitter
 

Which, in all likellihood will be a crock of the proverbial. Don't hold your breath for a timely resolution, you will (in all probability) turn a strange blue colour.

Re: Line quality and jitter
 

That suggests to me VM perhaps put higher paying customers on lower populated channels or bump their priority, its interesting to say the least.

Re: Line quality and jitter
 

Not for me
Originally i was with 30mb and upgraded to 100mb
i have the same 2 upstream channels and exactly same downstream channels
To me seems we getting what ever is available in the area not matter what package is (even the business one)

Re: Line quality and jitter
 

I thought I'd explained this already, it's probably nothing to do with channels or priority.

TCP tries to send faster and faster until it hits packet loss. When this eventually exceeds the speed someone is paying for, VM's network starts bufferbloating and then dropping packets.

People on lower speeds are more likely to hit their speed cap and therefore more likely to get their data dropped, simply from normal use.

Re: Line quality and jitter
 

except jitter measurements are not TCP.

I know how TCP works thank you.

Re: Line quality and jitter
 

Well then you'll know that TCP and ICMP packets go down the same line and when one fills it up the other will also start getting dropped.

Re: Line quality and jitter
 

Your explanation is assuming the results are affected by people pegging their connections hitting speed caps and getting affected results.

The samknows test only runs when the connection is idle, if its busy then the test is skipped.

Re: Line quality and jitter
 

No, I'm saying in any random selection of people doing a random selection of things at random times of day the ones with lower speed caps are more likely to hit speed caps.

The latency and jitter tests run continuously, it's only the speedtests that get "skipped" when the line is busy.

Re: Line quality and jitter
 

on my test device they all skipped if line is busy.

Re: Line quality and jitter
 

Is that right, Qasi? The 30/60/100 cap points are respectively 7/10/20 GB My spreadsheet says that (during the day):

30 meg hits the cap after 31 minutes
60 meg hits the cap after 22 minutes
100 meg hits the cap after 27 minutes

During the evening period, the cap points are halved and those times are:

L30 hits the cap after 16 minutes
XL30 hits the cap after 16 minutes
XL60 hits the cap after 11 minutes
XXL100 hits the cap after 13 minutes

Re: Line quality and jitter
 

wat do u mean by that? by the cap and the mins? i am lost

Re: Line quality and jitter
 

downloading at full speed on each package would trigger STM downloading for those lengths of time

Re: Line quality and jitter
 

The 30/60/100 cap points are respective 33Mbit/sec, 66Mbit/sec and 111MBit/sec.

I'm talking about the connection speed, this discussion has nothing to do with STM.

Re: Line quality and jitter
 

No they're not the cap points. The cap points are the data thresholds that I posted which trigger the caps.

Re: Line quality and jitter
 

I think you're misunderstanding the term speed cap. What you're talking about is completely unrelated.