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]

[dcookster]

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@shanematthews wrote:

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@qpop wrote:

I have also flagged this thread with Money Saving Expert via Twitter. Who else can we point this issue out to try and get things moving?

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Nobody can speed up the fix, it will take intel as long as it takes them to resolve it, assuming they can even fully resolve it with a firmware update, its entirely possible that its just bad design and cannot be completely fixed, publicity can't fix a bad design, as the hub2's have been phased out they are likely either out of stock or at a very low stock level, getting one would be a lottery in itself, i'm dreading the day my hub2 kicks the bucket because i'll be stuck with a hub3 which won't be fun, my only hope is the hub 4 is out before that happens because at this point thats likely to be our best bet

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Acknowledgement by VM of the problem would be a start.  People reaching out to other media outlets is better than doing nothing than wait for the SH4!

[dcookster]

The Register now published the DOS issue.

https://www.theregister.co.uk/2017/04/27/intel_puma6_chipset_trivial_to_dos/

[cje85]

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@dcookster wrote:

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@shanematthews wrote:

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@qpop wrote:

I have also flagged this thread with Money Saving Expert via Twitter. Who else can we point this issue out to try and get things moving?

---

Nobody can speed up the fix, it will take intel as long as it takes them to resolve it, assuming they can even fully resolve it with a firmware update, its entirely possible that its just bad design and cannot be completely fixed, publicity can't fix a bad design, as the hub2's have been phased out they are likely either out of stock or at a very low stock level, getting one would be a lottery in itself, i'm dreading the day my hub2 kicks the bucket because i'll be stuck with a hub3 which won't be fun, my only hope is the hub 4 is out before that happens because at this point thats likely to be our best bet

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Acknowledgement by VM of the problem would be a start.  People reaching out to other media outlets is better than doing nothing than wait for the SH4!

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VM acknowledged the problem last month and say that a firmware update is being worked on:

http://www.ispreview.co.uk/index.php/2017/03/virgin-media-prep-firmware-fix-superhub-3-latency-packe...

[qpop]

We should still apply as much pressure as possible, as there is not currently a reasonable resolution. Evidently, insufficient resources are being used on fixing their flagship broadband router/modem, and no alternatives are available.

[Guybrush85]

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cje85 wrote: VM acknowledged the problem last month and say that a firmware update is being worked on:

http://www.ispreview.co.uk/index.php/2017/03/virgin-media-prep-firmware-fix-superhub-3-latency-packe...

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I would really call that an acknowledgement. If it was announced on the forums, or any other virgin media publication, then you could say that it's an acknowledgement.

[dcookster]

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@cje85 wrote:

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@dcookster wrote:

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@shanematthews wrote:

---

@qpop wrote:

I have also flagged this thread with Money Saving Expert via Twitter. Who else can we point this issue out to try and get things moving?

---

Nobody can speed up the fix, it will take intel as long as it takes them to resolve it, assuming they can even fully resolve it with a firmware update, its entirely possible that its just bad design and cannot be completely fixed, publicity can't fix a bad design, as the hub2's have been phased out they are likely either out of stock or at a very low stock level, getting one would be a lottery in itself, i'm dreading the day my hub2 kicks the bucket because i'll be stuck with a hub3 which won't be fun, my only hope is the hub 4 is out before that happens because at this point thats likely to be our best bet

---

Acknowledgement by VM of the problem would be a start.  People reaching out to other media outlets is better than doing nothing than wait for the SH4!

---

VM acknowledged the problem last month and say that a firmware update is being worked on:

http://www.ispreview.co.uk/index.php/2017/03/virgin-media-prep-firmware-fix-superhub-3-latency-packe...

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Well the staff didn't get the memo or Tech support!  Try giving them a call.

Also nothing posted on here to their Customers.

More outlets now picking up the Dos attack vulnerability.

http://www.ispreview.co.uk/index.php/2017/04/claims-low-bandwidth-dos-attack-can-hammer-virgin-media...

[Anonymous]

People need to start contacting their elected MP's over this to try and force VM into putting more resources into resolving this, and who knows - they might decide legislation might be needed to force companies to act more promptly as some companies are supplying hardware to their customer which they have no choice but to use - that is underperforming, not to mention - could in essence be a 'national security issue' because who knows who is using this faulty hardware? Many 'organisations' as well as private consumers? Unfortunately, I cannot go back to a 2AC because of the DHCP bug with it which completely resets the DOCSIS lock when it encounters a DHCP misconfiguration so I am stuck with this SH3. At the end of the day, I would rather have a stable (ish) modem (SH3) then one that cuts out every couple of days (2AC). I am a gamer/streamer too and demand the highest performance so I know how everyone feels about this but I feel totally helpless now, apart from having to contact my MP - who has helped me before with dealing with VM, yet again over the never ending issues with this service.

[cje85]

Intel are ultimately responsible for fixing their faulty processors, VM can only wait for Intel to release new firmware and then roll it out to the hubs. A couple of US cable users on the DSLreports forum have received a partial fix which seems to improve performance but definitely doesn't fully resolve the problem. I'm not sure if that update been widely released yet or is just a beta for selected users.

With Docsis 3.1 on the way VM will need a new modem/router for that anyway so I would expect a new hub later this year....hopefully with no Intel involvement!!

[shanematthews]

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@qpop wrote:

We should still apply as much pressure as possible, as there is not currently a reasonable resolution. Evidently, insufficient resources are being used on fixing their flagship broadband router/modem, and no alternatives are available.

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You're trying to apply pressure in the wrong place though, VM can't do anything to speed this up outside of designing a hub4 with another supplier, and this takes a great deal of time, there isn't a fix they can just deploy and be done with, by all means put pressure on the company that can actually fix it, intel, i'm sure they will care a great deal 😛

[shanematthews]

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@Anonymous wrote:

People need to start contacting their elected MP's over this to try and force VM into putting more resources into resolving this, and who knows - they might decide legislation might be needed to force companies to act more promptly as some companies are supplying hardware to their customer which they have no choice but to use - that is underperforming, not to mention - could in essence be a 'national security issue' because who knows who is using this faulty hardware? Many 'organisations' as well as private consumers? Unfortunately, I cannot go back to a 2AC because of the DHCP bug with it which completely resets the DOCSIS lock when it encounters a DHCP misconfiguration so I am stuck with this SH3. At the end of the day, I would rather have a stable (ish) modem (SH3) then one that cuts out every couple of days (2AC). I am a gamer/streamer too and demand the highest performance so I know how everyone feels about this but I feel totally helpless now, apart from having to contact my MP - who has helped me before with dealing with VM, yet again over the never ending issues with this service.

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No amount of resources from VM can fix this as the issue is caused by Intel not VM, so putting pressure on VM won't actually do anything at all as they cannot fix the issue, as i've mentioned above the likely fix is going to be a hub4 without the puma6 chipset, but thats going to take time to develop and roll out to customers, i wouldn't expect a fix anytime soon unless intel somehow have a breakthrough and find a fix for what is likely a hardware design flaw that cannot be entirely fixed by a firmware update, so by all means waste your MP's time on an issue that cannot actually be fixed by VM at this point