Hub 3 / Compal CH7465-LG (TG2492LG) and CGNV4 Latency Cause

[Datalink]

Good Day Ladies and Gentlemen,

Greetings from the other side of the pond, so to speak.  Over the last few weeks I've been perusing various user forums across North America and Europe for issues related to Intel Puma 6 modem latency.  Of those forums, your Hub 3 stands out as yet another Puma 6 based modem where users see continuous latency no matter what site is used or what online game is played. Considering all of the problems that are on the go, the following information should be of interest to all Hub 3, Compal CH7465-LG and Hitron CGNV4 modem users.  There is much more to post regarding this, so this is a start, to alert VM users as to the real cause of the latency and hopefully engage the VM engineering staff, via the forum staff, with Arris.  I am surprised to see that there has been no mention on this board of users from other ISPs who are suffering the exact same issues with their modems, so, this may come as a surprise to some, and possibly old news to others.

So, the short story ........

The Hub 3 / Compal CH7465-LG (TG2492LG) & Hiton CGNV4 modems are Intel Puma 6 / 6 Media Gateway (MG) based modems.  These modems exhibit high latency to the modem and high latency thru the modem.  The latency affects all IPV4 and IPV6 protocols, so it will be seen on every internet application and game.  The basic cause is the processing of the data packets thru a CPU software based process instead of thru the hardware processor / accelerator.  It appears that a higher priority task runs periodically, causing the packet processing to halt, and then resume.  This is observed as latency in applications and in ping tests to the modem and beyond.  For the last several weeks, Hitron, along with Intel and Rogers Communications in Canada have been addressing the latency issue within the Hitron CGNxxx series modems.  To date, only the IPV4 ICMP latency has been resolved.  Although this is only one protocol, it does show that a Puma 6MG modem is capable of using the hardware processor / accelerator with good results.  Currently Rogers is waiting for further firmware updates from Hitron which should include an expanded list of resolved protocol latency issues.  For Arris modems, "Netdog" an Arris engineer indicated last week that Arris was onboard to address the issue for the Arris SB6190 modem.  That should be considered as good news for any Arris modem (read Hub 3) user as Arris should be able to port those changes over to other Puma 6/6MG modems fairly quickly.  This is not a trivial exercise and will probably take several weeks to accomplish.  Note that there is no guarantee at this point that it is possible to shift all packet processing to the hardware processor / accelerator without suffering from any packet loss side effects.  Time will tell if all of the technical issues can be resolved with the current hardware included in the Puma 6/6MG chipset.  Last night, Netdog loaded beta firmware on selected test modems on the Comcast Communications network.  As this was only done last night, it's too soon to tell what this version resolves and if it was successful or not.  Netdog has contacts with staff at Comcast, Rogers, Charter and Cox Communications to fan out beta versions and modifications for testing.  I'd say its time to add Virgin Media and/or Liberty Global to that group as well.

Recent activity:

Approx three weeks ago a DSLReports user, xymox1 started a thread where he reported high latency to an Arris SB6190 and illustrated that with numerous MultiPing plots.  This is the same latency that I and other users with Rogers communications have been dealing with for months so it came as no surprise.  As well as reporting via that thread, xymox1 took it upon himself to email several staff members at Arris, Intel, Cablelabs and others.  The result of that campaign was Netdog's announcement, last week, that Arris was fully engaged at resolving the issue.  That has led to last nights release of beta firmware, although as I indicated its too early to determine what the beta firmware resolves, if anything.

The original thread that xymox1 started is here:

https://www.dslreports.com/forum/r31079834-ALL-SB6190-is-a-terrible-modem-Intel-Puma-6-MaxLinear-mis...

Yesterday, DSLReports issued a news story covering the thread:

https://www.dslreports.com/shownews/The-Arris-SB6190-Modem-Puma-6-Chipset-Have-Some-Major-Issues-138...

Today, Arris responded:

https://www.dslreports.com/shownews/Arris-Tells-us-Its-Working-With-Intel-on-SB6190-Puma6-Problems-1...

That response was also picked by Multichannel.com

http://www.multichannel.com/news/distribution/intel-arris-working-firmware-fix-sb6190-modem/409379

This is more news likely to appear in the next few days as additional tech and news staff pick up on this issue.

Hub 3 observations:

Like many others using a Puma 6/6MG modem, Hub 3 users are experiencing latency when they ping the modem, or ping a target outside of the home, game online or use low latency applications.  The common misconception is that this is Buffer Bloat. It's not. Its most likely a case of the packet processing stopping while the CPU processes a higher priority task.  The packet processing is done via the CPU no matter what mode the modem is operating in, modem mode or router mode and no matter what IPV4 or IPV6 protocol is used.  Normally, the latency is just that, latency.  The exception are UDP packets. In this case there is latency and packet loss.  The result of that is delayed and failed DNS lookups, and poor game performance for games that use UDP for player/server comms or player/player comms.

Can this be fixed?

So far, it appears that the answer is yes.  Rogers Communications issued beta firmware to a small group of test modems in October.  This version shifted the IPV4 ICMP processing from the CPU to the hardware processor / accelerator, resulting in greatly improved performance in ping latency.  At the present time we are waiting for the next version firmware which should shift other protocols over to the hardware processor / accelerator.  That can be seen in the following post:

http://communityforums.rogers.com/t5/forums/forumtopicpage/board-id/Getting_connected/message-id/369...

The details and results of last nights beta release to the Comcast group have yet to be seen.

At this point there is enough reading to keep most staff and users busy.  My intention is to post some of the history leading up to this point and instructions on how to detect the latency and packet loss.  This is not thru the use of a BQM.  I had hoped to post this all at once but events are moving much faster than I had thought they would.  For now this should suffice to get the ball rolling.

Below is a link to a post with a couple of HrPing plots from my 32 channel modem to the connected CMTS.  This shows the latency that is observed and reflects what others have posted in this forum using Pingplotter and HrPing.

https://www.dslreports.com/forum/r31106550-

HrPing is one of the freebie applications that can be used to monitor the latency to and thru the modem. 

Pingplots with Pingplotter which show the latency from my modem to the CMTS can be found in the first two to three rows of my online image library at Rogers Communications, located below.  They are essentially what the BQM would look like if you were able to zoom into the plot to the point where you could see the individual ping spikes.  Those ping spikes are common to Puma 6 and Puma 6MG modems.

http://communityforums.rogers.com/t5/media/gallerypage/user-id/829158

 [MOD EDIT: Subject heading changed to assist community]

[RidingTheFlow]

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@DarkBahamut wrote:

How many people complain and moan about utilisation issues? Plenty. The SH3 goes some way to helping that particular issue (over the SH1/2 models) so there are many benefits to VM trying to get people on them.

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I see people keep saying that, but I've never actually seen on this forum anyone who got any measured "benefit" to peak time congestion after they've upgraded to SH3. If it does help over SH2, its all miniscule and completely drown by hugely increased max latency - so not visible on monitoring.

VM only pushing them because they don't have anything else and want to decommission old equipment.

[horseman]

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RidingTheFlow wrote:

....I see people keep saying that, but I've never actually seen on this forum anyone who got any measured "benefit" to peak time congestion after they've upgraded to SH3. If it does help over SH2, its all miniscule and completely drown by hugely increased max latency - so not visible on monitoring.

You're right to be sceptical but "absence of proof is not proof of absence"

This evidence is available...   but..... "limited" and also   in order to even (easily) illustrate this then you will need, eg:

1. SH2(legacy 8x4) Hub in Router Mode on same cable segment monitored by SamKnows 24x7 "whitebox" on at least V200 Tier

2. SH3(24x8) in Router Mode on same cable segment monitored by separate SKWB 24x7 on (ideally) same Tier as 1. above.

Unfortunately "easily" thus effectively means that very few here will be either SU's AND Trialists (including SK Performance Trialists) and have the ability to run the above configuration scenario!  😞 

That's without covering  a multitude of other DOCSIS3 regional infrastructure(topology) variations over and above Arris E6k/Cisco CBR8 IOS firmware levels and Dynamic Loading configuration variations that may well "muddy-the-waters" further.

So (IMO) - two main obstacles:

1. Providing the comparison you/we seek between 8x2/4 Tier and 24x2/4 Tier (utilisation/loading - I'd rather avoid "congestion" as my data doesn't reflect any cable segment "congestion" yet.... simply differences in "load balancing"...),  is not sufficient based on just 1 individual sample!  

2. Unfortunately many of us SU/Trialists et al are limited in what we can disclose as part of agreement  in participating in these trials.  That by definition is a "Catch 22" because "all-of-us" are caught between recognising that without "understanding the overall AND COMPLETE context" then some premature  disclosures simply provoke further questions because of (I hate to say "time-wasting"  because it's derogatory) general" lack of knowledge in community (and us!) versus the objectives of this website/fora to both assist diagnosis(and progress towards resolution of customers individual and common problems) and to encourage AND promote disseminate knowledge of  DOCSIS and understanding  aspects of peripheral WiFi/technology.

So one of our "respected and valued brethren" has already been "demoted" for attempting to assist the community by publishing details of SH3 firmware almost exactly a year ago(that was already in the public domain anyway!).  

So given all the above, exactly (in detail) what "comparison" between SK monitors on items 1 & 2 would assist your understanding? Before I stick my neck on the "martyrs" Dr Guillotine - do you want any requested "SK Reports"  via PM or on forum?  Think carefully - thats a "loaded question" and you'll obviously understand the ethics involved and consequent "conundrum" in your choice?.  

Good luck with that uneviable choice because many of us have been wrestling with those mutually exclusive principles for last 8 years of this website and upto a further 10 years via Usenet preceeding that!  😛

EDIT: forgot the very pertinent last point of your post:

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RidingTheFlow wrote:  ....  VM only pushing them because they don't have anything else and want to decommission old equipment. 

Absolutely agree and as the wife's a shareholder then I recognise any efficiency on BB utilisation and/or converged networks) will ultimately provide some fiscal/value add to both shareholders and residential/business customers!  Of course without elaborating on the whole infrastructure context then this just results in same recursive "VM fanboy" v "VM Septic Sceptic" timewasting ardument/discussion! 😞 

[donniem]

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@DS4130 wrote:

After a series of detailed letters to VM I was rather taken back by the most recent reply, the second paragraph of the exert below especially:

Also note my scanner does not have any fault, it appears they are experiencing print quality issues at the complaints department. Also on this third letter they manged to get my postcode incorrect hmmm

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That's quite incredible

[dcookster]

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@DS4130 wrote:

After a series of detailed letters to VM I was rather taken back by the most recent reply, the second paragraph of the exert below especially:

Also note my scanner does not have any fault, it appears they are experiencing print quality issues at the complaints department. Also on this third letter they manged to get my postcode incorrect hmmm

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"We do not appear to have any other reports regarding this issue" either complete lies or just plain old incompetence.

Maybe next time include a link to this thread, The Register, ISPreview etc.

[wotusaw]

That's truly amazing. 186 pages of people whinging about this issue and...what!!!!!! Never mind DSL etc.

Wow. Oh my. Mmm, they cannot communicate between themselves. Maybe that's it.

This whole thing is NOT doing Virgin any favours at all. This just makes everyone even more angry and ***** **. I mean...WHAT!!

Going off to kick something. I am so put out.

Ridiculous state of affairs for any business to just ignore/ cover up/whistle dixie....WHAT!!

[GMAN73]

I wrote a letter to the CEO office asking for a SH2ac. A week later I had a missed call on my mobile turns out it was an Indian drone who left a voice message asking me to call back regarding the complaint about my slow broadband. My complaint was regarding an SH2ac I never **bleep** mentioned slow broadband in the letter.

VM are **bleep** hopeless. There is more chance of me having a meeting with Kelly Brook and Gal Gadot than me getting a SH2ac.

[MOD EDIT: Inappropriate Content removed, please review the Forum Guidelines]

[AlteranAncient]

Agreed there - I've had a complaint escalated to retention and one of their "network specialists". Either they're clueless, or they're being deceitful.

They won't find an issue with any one person's super-hub, though, because if they're all broken, then clearly none of them are!

Liberty Global hasn't been doing Virgin Media (or its' customers) any favours.

[Stythinator]

They know there is an Issue but they are failing to resolve it. We know something is in the pipe line however this has gone on for far too long and it needs to be sorted. Up to date firmware for the SH3 won't go a miss ... Seem's everyone is in the dark and the Forum Team are not answering anything recently like they all are a sleep. 

[mbulliva]

Yes, especially since the Virgin Business Broadband modem, the Hitron CGNV4, is getting firmware updates which do make the broadband testing charts look better but still has some of the latency issues I suspect.

The other issues with the Hub 3.0 such as the port forwarding issue need to be set up in ascending order could also get fixed at the same time.

[shanematthews]

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@Stythinator wrote:

They know there is an Issue but they are failing to resolve it. We know something is in the pipe line however this has gone on for far too long and it needs to be sorted. Up to date firmware for the SH3 won't go a miss ... Seem's everyone is in the dark and the Forum Team are not answering anything recently like they all are a sleep. 

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Problem is that as far as the hub3 goes it would seem that a firmware fix isn't actually possible as its the hardware configuration causing the issues, there isn't a solution for that, the "thing in the pipeline" will be a new revision of the hub which is likely to not be a puma based device given that the puma 7 modem is shown to have similar issues, this however takes time