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]

[Xymox]

Also on a separate note.. Just a reminder to all who are technical of the danger that the silicon might be the issue. https://www.dslreports.com/forum/r31122204-SB6190-Puma6-TCP-UDP-Network-Latency-Issue-Discussion~sta...

[JohnE4U]

I too am suffering the same problems described in this (and other) threads.

The thing that angers me the most is that I did not ask for my SH 2 to be replaced, it was done in an attempt by Virgin, to fix an issue that clearly was not an issue within my house, but one in the main "box" that feed my house.  When they fixed the "box", the main issue was resolved, and I was left with the issue you all describe here.

I simply do not understand why Virgin persist in distributing this know faulty router.  It is disgraceful that their first line support simply do not know (or will not acknowledge) this SH 3 issue; instead wasting my time taking me through diagnostics, or telling me "there is no problem in your area", forcing me to be available for half a day for an engineer visit, which results in nothing (apart from wasting my time).  All the time continuing to take my money from my account; forcing me to go through their ridiculous customer support phone system in an attempt to get any form of recompense for the not "fit for purpose" service.

Last month (July 2017) there was a BBC Watchdog article criticising Virgin, for their mis-selling of broadband (based on quoted speeds); indeed Tom Mockridge, Virgin Media CEO, came on the show to apologise.  This specific issue was not discussed, and yet, he sat their telling the audience how sorry he was "I, along with everybody at Virgin Media, am disappointed that, in these cases, we fell short of the high standards we set for ourselves and which our customers rightly expect of us." 

Why don't we all try complaining to BBC watchdog?  Looking at the number of replies on here (and other) threads, there is clearly enough people who have and continue to experience this appalling service.

[RidingTheFlow]

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@JohnE4U wrote:

I too am suffering the same problems described in this (and other) threads.

The thing that angers me the most is that I did not ask for my SH 2 to be replaced, it was done in an attempt by Virgin, to fix an issue that clearly was not an issue within my house, but one in the main "box" that feed my house.  When they fixed the "box", the main issue was resolved, and I was left with the issue you all describe here.

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To me it was even worse - I was (deliberately or out of ignorance) misinformed by visiting engineer who told me that "hub 3 is better, so lets upgrade it", and took away my perfectly working hub 2. After I've noticed latency problems next week, Virgin could not be less helpful and outright refused to fix things claiming "our system does not allow to order hub 2 if you already had hub 3", "we have no idea where is your old hub is, NE London is a big department", everybody just shrugging their proverbial shoulders "well, its not my fault", and nobody's responsible.

[JohnE4U]

Oh, and please share my Facebook post.  Let's start making some noise about this.  Virgin are happy for you to keep complaining within their forum, it keeps it contained.

https://www.facebook.com/john.ocallaghan.7967/posts/1656510004373837

Share, please.

[JohnE4U]

Hi Riding; I too was given the same spin (SU 3 better than SU 2). Why are they doing this? It makes no sense.

[RidingTheFlow]

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@JohnE4U wrote:
Hi Riding; I too was given the same spin (SU 3 better than SU 2). Why are they doing this? It makes no sense.

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I think its:

- Part ignorance. Low level staff and engineers *told* that SH3 is better, that SH2 *must* be upgraded (or it will stop working), etc. They genuinely believe it.

- Part deliberate misinformation. Certain staff levels actively encourage SH2=>SH3 migration, "because their boss told so" or "my checklist says so" or because "its how system programmed".

- Part denial. I believe certain staff actually developed rather childish contrarian attitudes - more they hear people complaints about how bad SH3 is, more they try to deny it and try to push it on people.

I've also encountered famous shrug-off meme in relation to people complaining - "vocal minority".

And the real underlying reason I believe it is - they simply have no choice, SH2 is not being manufactured anymore, if they let people have them, they will quickly run out of stock, so they think that its better to keep denying since SH3 is the only way to go, whether you like it or not. If they let cat out of the bag, this will show up how massive screw up adoption of SH3 was, and nobody is eager to own up to it. 

[JohnE4U]

...and here is the BBC Watchdog thread related to their previous "apology"....... share my post, and this (even comment), the more public noise we make about it, the greater chance we will be acknowledged, and perhaps, given clear commitments as to what they are going to do about it.

[RidingTheFlow]

That apology means nothing to me... They also apologised to me that they can not fix my internet to the way it was - do I care? Not a bit, because it does not change anything.

[shanematthews]

"I simply do not understand why Virgin persist in distributing this know faulty router."

Because thats all they have in stock, they no longer maintain an active stock of hub 2's and a hub replacement is the first step in troubleshooting any issues, which means people will be given a hub 3 as a replacement

"Why don't we all try complaining to BBC watchdog?"

Because they won't care and it won't change anything, VM does not have any other kit they can offer you, VM are also unable to fix the issue themselves, they need intel to create a fix and then for arris and netgear to create a firmware update that contains those fixes that can then be passed to VM for testing and distribution, yes i know it says VM on the box but VM don't actually make any of it

"All the time continuing to take my money from my account; forcing me to go through their ridiculous customer support phone system in an attempt to get any form of recompense for the not "fit for purpose" service."

Your contract doesn't cover latency, are you getting the advertised speeds, remember all speeds are also quoted as "up to" so there is no guaranteed speed either, if such you are getting what you paid for and any "goodwill" credit is down to VM to offer only IF they feel like it there is no regulation that states they have to

At the end of the day its intel and arris you need to really yell at, VM isn't the one able to do anything about this issue themselves

[nallar]

VM are capable of fixing this without relying on arris. There are non-puma 6 modems available which they could buy for moaning users and authorise on their network. VM also choose not to authorise user-supplied modems. It's common for cable providers in the US to allow this, from an approved list of hardware.

Why do you continue to pretend that VM have no options here? This has already been discussed many pages earlier.