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]

[patch22]

We probably should have done the same but we kept it, it has other benefits-ish and can be taken advantage of even more if this issue ever gets fixed

It's inconsistent here which in a weird way is worse, sometimes it's fine then it completely falls out of out of nowhere, only noticable in game

To be honest a jitter issue is different from handling the 350vivid and docsis3 but i know what you're saying, they told us the same about their old cables getting replaced. Whatever they have to say to keep the customer temporarily calm in that moment. Disgraceful

Only downgrading to a SH2ac will fix it from what i've heard

[zarf2007]

I'm wondering now that hub3s are being delivered with the new firmware already installed, its worth logging a 'fault' with mine which is still on old firmware (technically I wouldn't be lying) to get a replacement with the new firmware on. might be quicker than waiting for it to be deployed.

[Darkman]

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@patch22 wrote:

Only downgrading to a SH2ac will fix it from what i've heard

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Well it'll probably be better (example from a busy last Sunday above), but you're still reliant on the underlying network infrastructure and utilisation in your area; SH 2ac might not suffer as much as the Hub 3.0 does with this particular latency problem but there's not much it can do to make up for any other problems you may be having with your local network and good luck trying to get a straight answer out of anyone at VM about that.

[patch22]

@Darkman , it's literally only the latency issue that's the problem for us. It's unbearable for online gaming, speeds are great. Barely ever disconnect, just the latency fluctuations

[gav114]

Yeah. Speed is fine. Just the horrible jitter and latency.

[RedGooner]

Do a search for Puma 6 Test.

The more red you get is bad. I am lucky as i mostly get Green on SH3 in modem mode.

[gav114]

True.

Unfortunately i have to make do with a crappy signal and all the other usual guff that comes with it. I also use a cheap wifi extender to get the cctv system on my network to work.

Thats a beast of a router BTW. Wish i had the money to get that. Id imagine the signal would go through the roof.

Literally ^^

[RedGooner]

Signal is good. I mainly got it for the raw computing speed for my own network.

If only the SH3 has more raw computing power, there would be no need for a external router.

[patch22]

Did the test i get some red. I don't know what's going on but the latency issue is worse than ever right now and i'm using a Netgear R7800

NAT type open via DMZ for console etc, it's just unplayable. Fiddled with so many settings even though it was "okay" a while ago. For me, since we ever had the SH3, it's been utterly impossible to have smooth online gaming experience consistently. Doesn't matter what i do.

Edit: Finally got round to setting up a BQM, will check the results in 24hrs

[patch22]

From what i understand this looks pretty healthy? No packet loss, ping stable enough

This has led me to checking out other things, such as my XB1 console itself. I gave it a reset but still have the same issues, i'm running out of ideas here. It's been DMZ'd so every port is open, when i keep it turnt off for a while (say a few days mininum to a week) then initially it runs fine (in game, e.g. fifa)

But after a good session it will slowly return back to it's old ways of being unplayable again. I was convinced this was to do with the latency issue but it doesn't seem to be. I game'd today and the results would've shown up here if it was the renowned latency issue causing it - because it was unplayable pretty much as usual