Home News Forum Articles
  Welcome back Join CF
You are here You are here: Home | Forum | Think Broadband Ping Monitor Results (POST YOURS)

You are currently viewing our boards as a guest which gives you limited access to view most of the discussions, articles and other free features. By joining our Virgin Media community you will have full access to all discussions, be able to view and post threads, communicate privately with other members (PM), respond to polls, upload your own images/photos, and access many other special features. Registration is fast, simple and absolutely free so please join our community today.


Welcome to Cable Forum
Go Back   Cable Forum > Virgin Media Services > Virgin Media Internet Service

Think Broadband Ping Monitor Results (POST YOURS)
Reply
 
Thread Tools
Old 25-01-2015, 16:17   #4906
Tonydtiger
cf.member
 
Join Date: Oct 2009
Location: Warwickshire
Services: XL TV, Tivo, 152Mb, Phone
Posts: 41
Tonydtiger is an unknown quantity at this point
Re: Think Broadband Ping Monitor Results (POST YOURS)

Tonydtiger is offline   Reply With Quote
Advertisement
Old 28-01-2015, 22:54   #4907
japitts
cf.addict
 
Join Date: Apr 2008
Services: TiVo 1Tb with TV-XL Sports & Movies, 100Mb broadband, Talk Weekends. EE 3G mobile
Posts: 369
japitts has a spectacular aura about themjapitts has a spectacular aura about themjapitts has a spectacular aura about themjapitts has a spectacular aura about them
Re: Think Broadband Ping Monitor Results (POST YOURS)

What sort of speeds are you getting in the evening peak then Tony? My 50Mb is currently only getting anything between 5-12Mb/s at peak times since a few weeks, but the graph is nowhere near that bad.
japitts is offline   Reply With Quote
Old 02-02-2015, 16:54   #4908
horseman
cf.geek
 
horseman's Avatar
 
Join Date: Dec 2003
Location: Hove East sussex
Age: 66
Posts: 572
horseman has reached the bronze age
horseman has reached the bronze agehorseman has reached the bronze age
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by japitts View Post
What sort of speeds are you getting in the evening peak then Tony? My 50Mb is currently only getting anything between 5-12Mb/s at peak times since a few weeks, but the graph is nowhere near that bad.
From what I've experienced then TBB is skewed more towards showing upstream utilisation and mine doesn't indicate downstream utilisation to anything like the same extent.
(Since I have Samknows then I have a relatively accurate and consistent benchmark to compare against)
__________________
Rgds - TW
17+yrs customer currently on Vivid 200/12Mbps service tier via SH2AC(VMDG490) or <cough> others, provisioned from brig19 Arris E6k (BN3 7Nx node).
horseman is offline   Reply With Quote
Old 03-02-2015, 00:24   #4909
qasdfdsaq
cf. mega noob
 
Join Date: Aug 2004
Posts: 11,207
qasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronze
qasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronze
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by horseman View Post
From what I've experienced then TBB is skewed more towards showing upstream utilisation and mine doesn't indicate downstream utilisation to anything like the same extent.
That's less about the TBB graphs than it is about latency on DOCSIS simply being affected more by upstream utilisation than down.
qasdfdsaq is offline   Reply With Quote
Old 03-02-2015, 08:20   #4910
Ignitionnet
Pragmatist
 
Ignitionnet's Avatar
 
Join Date: Jun 2008
Location: Leeds, West Yorkshire
Age: 39
Services: Pulse8 52/19 business VDSL, SD-WAN, phone line. Freeview TV. Lots of streaming services.
Posts: 13,707
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by horseman View Post
From what I've experienced then TBB is skewed more towards showing upstream utilisation and mine doesn't indicate downstream utilisation to anything like the same extent.
(Since I have Samknows then I have a relatively accurate and consistent benchmark to compare against)
Two issues at play here.

1) DOCSIS upstream is TDMA which is more prone to latency caused by utilisation - there are 2 contention points at play, contending to send your request for a grant and then waiting for the grant time to actually transmit the data.
2) DOCSIS allows large traffic bursts to request more bandwidth as part of a data burst so favours continuous large amounts of upstream traffic over small bursts such as a response to a TBB ping.

Downstream uses a scheduler at the CMTS. The pipe has to max out, with interest, in order to increase latency substantially.
Ignitionnet is offline   Reply With Quote
Old 03-02-2015, 11:03   #4911
Eeeps
cf.addict
 
Join Date: May 2012
Posts: 153
Eeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the rough
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by Ignitionnet View Post
Two issues at play here.

1) DOCSIS upstream is TDMA which is more prone to latency caused by utilisation - there are 2 contention points at play, contending to send your request for a grant and then waiting for the grant time to actually transmit the data.
2) DOCSIS allows large traffic bursts to request more bandwidth as part of a data burst so favours continuous large amounts of upstream traffic over small bursts such as a response to a TBB ping.

Downstream uses a scheduler at the CMTS. The pipe has to max out, with interest, in order to increase latency substantially.
Which makes sense but what about the relationship between download speed and latency.

At peak times my download drops to 50% (50Mb/s from 100Ms/s) but the peak latency on the graph does not increase significantly (outside of the test window).

If my download packets cannot be scheduled at the required rate to achieve 100Mb/s and are buffered in the CMTS then surely ICMP packet would be delayed too?

Also, the TBB speed test during peak hours shows a big drop in the x1 speed even before the x6 rate gets reduced. This x1 rate always starts high (close to 100Mb/s) and drops back to 20M/s or so.
To my mind this suggest some packet priority scheme on the downstream based on how close together packets are received by the CMTS for a particular CPE.
So if you're gaming with infrequent bursts these get scheduled immediately but if you are downloading the packets get delayed.

This is my speed test at ~11am



Ian
Eeeps is offline   Reply With Quote
Old 03-02-2015, 12:33   #4912
qasdfdsaq
cf. mega noob
 
Join Date: Aug 2004
Posts: 11,207
qasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronze
qasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronze
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by Eeeps View Post
If my download packets cannot be scheduled at the required rate to achieve 100Mb/s and are buffered in the CMTS then surely ICMP packet would be delayed too?
ICMP does not require 100Mb/s. There may not be enough capacity left to schedule an additional 100Mb/s while still having 0.01Mb/s required for ICMP.

---------- Post added at 12:33 ---------- Previous post was at 12:28 ----------

Quote:
Originally Posted by Eeeps View Post
To my mind this suggest some packet priority scheme on the downstream based on how close together packets are received by the CMTS for a particular CPE.
Oh how I wish VM were actually that competent.
qasdfdsaq is offline   Reply With Quote
Old 03-02-2015, 13:07   #4913
Ignitionnet
Pragmatist
 
Ignitionnet's Avatar
 
Join Date: Jun 2008
Location: Leeds, West Yorkshire
Age: 39
Services: Pulse8 52/19 business VDSL, SD-WAN, phone line. Freeview TV. Lots of streaming services.
Posts: 13,707
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by Eeeps View Post
Which makes sense but what about the relationship between download speed and latency.
Easy - the DOCSIS scheduler uses something similar to Weighted Fair Queuing.
Ignitionnet is offline   Reply With Quote
Old 03-02-2015, 15:29   #4914
Eeeps
cf.addict
 
Join Date: May 2012
Posts: 153
Eeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the rough
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by Ignitionnet View Post
Easy - the DOCSIS scheduler uses something similar to Weighted Fair Queuing.
Had to look that up but from Wiki...

'...an ill-behaved flow (who has sent larger packets or more packets per second than the others since it became active) will only punish itself and not other sessions' which is kind of what I described (in a less technical way).

Do the Virgin CMTS really implement that? On the upstream too?

Ian
Eeeps is offline   Reply With Quote
Old 03-02-2015, 22:22   #4915
Ignitionnet
Pragmatist
 
Ignitionnet's Avatar
 
Join Date: Jun 2008
Location: Leeds, West Yorkshire
Age: 39
Services: Pulse8 52/19 business VDSL, SD-WAN, phone line. Freeview TV. Lots of streaming services.
Posts: 13,707
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Re: Think Broadband Ping Monitor Results (POST YOURS)

Downstream it works that way, upstream doesn't use the DOCSIS scheduler it uses TDMA.

See my earlier post - http://www.cableforum.co.uk/board/35...-post4910.html
Ignitionnet is offline   Reply With Quote
Old 04-02-2015, 12:52   #4916
Eeeps
cf.addict
 
Join Date: May 2012
Posts: 153
Eeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the roughEeeps is a jewel in the rough
Re: Think Broadband Ping Monitor Results (POST YOURS)

Quote:
Originally Posted by Ignitionnet View Post
Downstream it works that way, upstream doesn't use the DOCSIS scheduler it uses TDMA.

See my earlier post - http://www.cableforum.co.uk/board/35...-post4910.html
I guess something similar could be implemented on upstream by limiting the rate of the 'grants' for 'ill-behaved' streams.

Thinking about the downstream, this definitely seems to explains why the TBB graph can look quite good even though download speeds have dropped significantly due to congestion; infrequent ICMPs being scheduled in advance of download packets for other CPEs.

I would have thought this constitutes a form of traffic management / priority scheme?

Ian
Eeeps is offline   Reply With Quote
Old 04-02-2015, 13:32   #4917
Ignitionnet
Pragmatist
 
Ignitionnet's Avatar
 
Join Date: Jun 2008
Location: Leeds, West Yorkshire
Age: 39
Services: Pulse8 52/19 business VDSL, SD-WAN, phone line. Freeview TV. Lots of streaming services.
Posts: 13,707
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Ignitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny starsIgnitionnet has a pair of shiny stars
Re: Think Broadband Ping Monitor Results (POST YOURS)

The scheduler isn't a traffic management scheme, it doesn't really have any intelligence to speak of.

I was, perhaps, overly kind when I described the scheduler as being WFQ. It doesn't have the smarts to 'selectively' slow heavy bandwidth flows, it's more that it shares bandwidth between flows and the way it empties buffers.

Essentially smaller packets, such as pings, get through more quickly than larger ones, such as a standard download.

On the upstream you can, certainly, prefer certain traffic, indeed it's needed as part of voice services, however it's of questionable value and is more inefficient in terms of usage of the resource to prefer pings or whatever over normal traffic.

This will be useful in DOCSIS 3.1 though and will I suspect present way more of a benefit than playing with upstream schedulers.
Ignitionnet is offline   Reply With Quote
Old 04-02-2015, 13:59   #4918
qasdfdsaq
cf. mega noob
 
Join Date: Aug 2004
Posts: 11,207
qasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronze
qasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronzeqasdfdsaq is cast in bronze
Re: Think Broadband Ping Monitor Results (POST YOURS)



Well that's a very up-to-date game...

---------- Post added at 13:59 ---------- Previous post was at 13:55 ----------

[Edit]

So basically they've implemented random early detection, a standard, widespread queue management mechanism that's been around since 1993...

... And what about ECN? Why aren't more people using it?
qasdfdsaq is offline   Reply With Quote
Old 05-02-2015, 19:13   #4919
craigj2k12
Sell me this pen....
Snake Champion
 
craigj2k12's Avatar
 
Join Date: Nov 2010
Location: Stafford
Posts: 4,220
craigj2k12 has a bronzed appealcraigj2k12 has a bronzed appeal
craigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appealcraigj2k12 has a bronzed appeal
Re: Think Broadband Ping Monitor Results (POST YOURS)

I seem to be getting awful jitter at the moment!

craigj2k12 is offline   Reply With Quote
Old 05-02-2015, 20:39   #4920
Kushan
FORMER Virgin Media Staff
 
Kushan's Avatar
 
Join Date: Dec 2010
Location: Warrington
Posts: 4,274
Kushan has a bronzed appealKushan has a bronzed appeal
Kushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appealKushan has a bronzed appeal
Re: Think Broadband Ping Monitor Results (POST YOURS)

Well as you can see, there's absolutely nothing wrong with my area at the moment.

__________________
My views are my own and in no way reflect those of Virgin Media.
Kushan is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 11:21.


Server: calcium.zmnt.net
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2017, vBulletin Solutions Inc.