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]

[shanematthews]

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@Enigmo wrote:
don't ofcom regulate these guys?

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The modem is made by intel, only they can update it, ofcom doesn't regulate intel as they are not a provider of telecoms services, VM cannot "fix" an issue that exists on something they did NOT make, ofcom will regulate the network and the network itself is working fine, so screaming at ofcom doesn't get you anything

[ILuvNips]

Isn't that a bit like BMW blaming the OEM supplier and then not fixing the issue?

Virgin need to go after Intel, if need be via the courts for compensation and a way forward, Intel putting out a fix which makes the problem look a bit better isn't really a fix in my eyes.

[shanematthews]

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@ILuvNips wrote:

Isn't that a bit like BMW blaming the OEM supplier and then not fixing the issue?

Virgin need to go after Intel, if need be via the courts for compensation and a way forward, Intel putting out a fix which makes the problem look a bit better isn't really a fix in my eyes.

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All depends really, latency was never part of the deal, hence its unlikely that intel have actually breeched any part of their agreement, VM literally cannot "fix" the issue they are entirely reliant on intel for a fix and unless intel actually breeches their end of the contract, VM can't get rid of them without incurring massive fees, i mean if you want to finance the ETF for a contract on that scale then i'm sure VM will change suppliers, but considering latency wasn't part of the deal and isn't even covered in the VM contract with customers either....

[lyonc]

I've got a possible fix for this, the fix only lasts a few hours but it's better than nothing. Turn off and unplug the power cable from your SH3 for a few minutes (Power cycle) then turn it all back on, you can leave the cable that runs into the street plugged in. Unbelievably the spikes actually stop for me for about 4 to 7 hours before starting again.

Does anyone have any idea about the high priority task that's behind all this bs? And is there anyway to disable it or lower it's affinity on the router so it doesn't cause as much disruption? Could an engineer do that?

[Static]

@lyonc
Unfortunately it’s down to the firmware and hardware, an engineer can’t change when the task runs, etc.
Using the Hub 3 in modem mode with a 3rd party router will give you the best experience.

[gav114]

Im waiting for asus's new ax mesh routers to comeout. Seems like decent 3rd party hardware is the only viable fix for us.

As it stands all my ip cctv cameras are extremely unreliable too. They can see sky signals from all over the place but the signal from my hub cant reach thorough a single brick wall!

[PhilHornby]

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@lyonc wrote:

Does anyone have any idea about the high priority task that's behind all this bs? And is there anyway to disable it or lower it's affinity on the router so it doesn't cause as much disruption? Could an engineer do that?

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No, it's entirely heresay and supposition! No tangible evidence has ever been put forward for this 'fact'.

The only people who could possibly know if this was the underlying cause will have signed 'non-disclosure agreements' and thus are in no position to supply this evidence.

[Enigmo]

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@shanematthews wrote:

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@Enigmo wrote:
don't ofcom regulate these guys?

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The modem is made by intel, only they can update it, ofcom doesn't regulate intel as they are not a provider of telecoms services, VM cannot "fix" an issue that exists on something they did NOT make, ofcom will regulate the network and the network itself is working fine, so screaming at ofcom doesn't get you anything

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That is still not a worthy defense. It's Virgin's responsibility to ammend the quality of faulty products/services as soon as they realise it. Ofcom's job is simply to ensure consumer welfare and it's pretty obvious Virgin are hurting consumers to an unbelievable degree by not fixing this issue.

Agiain, for "fixing the issue", don't say it's up to Intel to fix it. No, it's up to Virgin to find somewhere else to go to for the chip. Since they're choosing not to do that, all this trouble is on them.

It's like me building a PC at home and knowingly purchasing a motherboard that isn't compatible with the CPU I have, but then instead of buying a compatible motherboard I complain that this mobo should be "fixed". No, what I'm meant to do is accept that I've wasted money on an incompatible motherboard, and spend money on another that this time works. The money I spent on a faulty motherboard is the price I'm paying for making a dumb mistake.

switching from Intel would be costly for them, but that's the price they pay for making this mistake of getting faulty chips. To take faulty goods and supply them to customers (who are paying a lot for their subscriptions) is entirely Virgin's own mistake so they really should start paying for that mistake by switching from Intel. No matter how you try to twist it, Virgin are the problem here.

[Guybrush85]

Why are people talking like this isn't sorted (or as near to as it will ever be) in .608? 

[CursedLemon]

Because a lot of people still haven't got the .608 firmware and have no idea when they will?