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]

[Andrew-G]

"Same here - HUB 3 user... no issues with lag in game."

Fair comment, and I accept that many people don't see the effects - but I still struggle to see why they're involved in this thread.  If you're happy, be happy, rather than implying that because you can't see it, there isn't any problem.  You are subject to the same problem, as a simple matter of fact and physics, inherent from the Puma 6 chipset.  Under some (reproduce-able) circumstances I can even see texture tearing at exactly the two second interrupt frequency associated with the Puma 6 process problem, and that's because my computer has lost about ten frames, and when repainted according to the latest server information it creates a texture rip.  For many people they'll either not notice, ascribe it to poor graphics, to their GPU, to the wider internet.  But it is still there.  In actual game play it results in a momentary freeze in your input and your display, the actual pauses are too short to readily perceive other than as a momentary jerk in fast moving elements of the image, whilst the game continues on the server.  You'll miss shots, and other people will still be able to hit you.  Any competent gamer can still game, but it's like a 10% discount on your performance.  

The Thinkbroadband BQM shows the latency spikes clearly enough, but bear in mind that the BQM is only sample packets, so the spikes only show when the packet arrives as the Puma 6 puts its slippers on and sits in its armchair to suck on a Werthers for a while.  If you look at (for example) the more detailed testing shown on some Youtube videos with near continuous monitoring, you'll see that the Puma 6 CPU does this regularly every two seconds.  Imagine a target shooter being very gently nudged every two seconds - sometimes that will convert a potential miss to a hit, far more often than not it converts a potential hit to a miss.

For those happy with the Hub 3, I am delighted for your satisfaction, but if you honestly believe that you are not subject to the problem when playing fast action games, then you must have some magic version that the rest of us have been denied.  I suspect that it really depends what you want, and what you expect.  For the high price VM charge, on a network advertised as suitable for FPS gaming, and in 2018, I personally expect better than being forced to use a faulty cable modem that actively interferes with my gaming experience, and which VM could and should have avoided through better testing and competent procurement.  And as soon as the problems were known they should have sorted out alternative equipment that works properly, instead, VM replaced my SH2 with a Hub 3, so they actively made my connection worse.

[WildWayz]

And this is the flip-side arguement... just because YOU have the issue, doesn't mean everyone has it. As I said, so many factors go into what impacts a broadband line that it could be something else factoring in. Sure, BQMs are **bleep**e but end of the day ICMP ping/trace is often low/no priority on a network - so the response isn't ask quick as another provider. I know the company I work for blackholes ICMP ping/trace - so BQMs will show as dead.

I follow this thread out of curiosity and as someone who routinely product tests firmwares/routers for an ISP. And I also think the SH3 is crap anyway.

[WildWayz]

Oh and also, working for another ISP, we at one stage prioritised ThinkBroadband traffic so stats got reported as much better than they really were.

I play FPS games all the time... Overwatch, Destiny 1/2, Fortnight, PUBG to name a few

[wotusaw]

WildWayz@

"Oh and also, working for another ISP, we at one stage prioritised ThinkBroadband traffic so stats got reported as much better than they really were."

Wow...everyone seems to use all these tricks and treats to fool us munchkins.

I like to see the other side of the coin and think 'WildWayz' has made some very interesting and informative comments. Most certainly would miss him if he went.....

My adoration of him of course would not stop me fragging his **** if I ever saw him on 'Overwatch'.

I'm just hoping Virgin is'nt going to go cheap with the HUB4. Don't think they will and in 6 months we will all be happy bunnies....What's that?,,,Yes, I have just got out of the clinic...how'd you guess?

[WildWayz]

git gud scrub. 😛

[Andrew-G]

@WildWayz: "And this is the flip-side arguement... just because YOU have the issue, doesn't mean everyone has it."

No, not everyone has it because the Hub 3 is not yet universal.  But everyone with a Hub 3 has the issue - it's baked into the firmware and hardware.  The question is only whether they notice or care.  I'd agree with you that most customers don't know, don't notice, or don't care, and you're telling me that you're in that group.  But at least we agree the Hub 3 is a pile of steaming ordure.

[RidingTheFlow]

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@WildWayz wrote:

git gud scrub. 😛

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Oh, that's *really* helpful advice to affected people /s 

Say, some sorcery makes Hub 3 work well for some customers, ok.  Why VM then does not find out what exactly it is, and resolve problems for people who are suffering from latency? Surely that should score *some* "good customer care" points and eliminate their massive support headaches? I don't think that "duh, works for me/someone" is the particularly good solution.

[boltedenergy]

for people on the trial, how is the ping spiking & latency these days?

[Adduxi]

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@boltedenergy wrote:

for people on the trial, how is the ping spiking & latency these days?

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People on the trials are asked not to disclose any information on these forums.  Sorry ,,,,,

[jlippa]

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@Adduxi wrote:

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@boltedenergy wrote:

for people on the trial, how is the ping spiking & latency these days?

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People on the trials are asked not to disclose any information on these forums.  Sorry ,,,,,

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How about disclosing the information elsewhere i.e. pastebin and then leaking it's location to someone else so this info finds it's way back into here..posted by someone not actually on the trial.

I'm aware that having to do this would be the height of patheticness to disclose the details of something that shouldn't be getting handled like a national secret.