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]

[Anonymous]

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@RidingTheFlowwrote:

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@cje85wrote:

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@RidingTheFlowwrote:

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They have already upgraded most of their network to DOCSIS 3.1 compatiable CMTS, Arris E6000 or Cisco cBR-8 depending on area.

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I know they've upgraded some. "most of their network" - not sure so much. Great if this true.

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If there are more than 12 downstream channels there it's upgraded to an E6k or cBR-8.

The older Motorola BSR was an I-CMTS and supported 12 downstream channels only. The older Cisco 10k supported 10 channels as an I-CMTS and even that with a line card change. May have been the very odd instance where they moved to more on the 10k via other line cards but those should all have been replaced by now: going above 8 downstream channels on the 10k was strictly a 'tactical' and temporary solution. VM replaced the 10k when they moved to CCAP. The major obstacle to getting rid of the 64k and 10k was physical issues - power, space, cooling. The last of those should've been removed through a literal lift and shift process. Warn customers of downtime or carry out work during maintenance window, disconnect and unrack the old CMTS, replace with a preconfigured new one. This was doable as the newer CMTS were far higher density, the only real obstacle being the extra space, etc, for the CCAP kit, however much of this was in place anyway as part of the VoD / DTV platform.

EDIT: For punctuation.

[RidingTheFlow]

Actually one thing to note that these CMTS didn't provide DOCSIS 3.1 OFDM "by default" (they are just "capable") - at the very least, all endpoints will need line card upgrades. This still will cost money & time - so not clear how eager VM will be on them (probably more in very congested areas then the others).

[Anonymous]

They don't provide 3.0 by default either, still need line cards.

Liberty Global decide when DOCSIS 3.1 is being released and they are not in a hurry. The big cost will be the modems and the CEO is already on record as saying he's no interest in deploying 'indiscriminately' but only where they can get extra cash and in the most economical way possible.

http://www.broadbandworldnews.com/author.asp?section_id=472&doc_id=740713

[supernovi]

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@beanieboy182wrote:

If you love Virgin broadband speeds but hate the Puma 6 issue and have tried the old /ping 192.168.0.1 and get responses like 156m/s which should be closer to 0.1m/s (that is the puma 6 intel chip issue)

ring virgin and speak to a chap called tristen (i think he is from the doncaster branch) and he has a special way to get u a super hub 2AC which does not have this issue

U have to ask for a call back from tristen himself which could take 2 weeks and is appointment only.

this has solved my lag in games + it is a known issue by everyone they just refuse to accept it.

I have not been back on this forum since i got my superhub 2AC so take that as proof this works.

thanks ❤️

x

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Really? Seems unlikely.

Anyone else had any success doing this?

[Boygroucho]

The only way to get a sh2ac is to go through to retentions and ask to give 30 days notice to cancel your service (and be happy if they say OK).

Only then do they seem motivated to send you one.  This will involve transferring you to the BB "specialists" there are a few of them who will arrange it.

But not before they have messed you around with promises of call backs etc.

Its a slow and frustrating process...it actually feels like they are taking the proverbial and having a laugh at your expense.

While the SH2ac has greatly improved my gaming experience I think I will leave anyway just for the appalling CS.

[RidingTheFlow]

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@supernoviwrote:

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@beanieboy182

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Really? Seems unlikely.

Anyone else had any success doing this?

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Several people on this thread did, me included (though I was referred to him as "broadband specialist" by CEO office complaint department). 

The tricky part is actually reaching the proper guy.

[dossdes]

Yes, I had success too. Got through to a really nice guy called Steve at the Newcastle office. Explained the issues, mentioned puma 6 and he sent me a 2ac. Admittedly getting through to,him took me 3 months of complaining but glad I did.

[WhyLieToUs]

What bugs me most is that they lie so much

"No, we cannot even connect a SH2AC to the network now..... "

"No, we cannot now offer your current package so you have to upgrade...."

"No, if you DO upgrade you must take SH3..."

and yet they admit they know SH3 is faulty

[Springer1]

VM lie, not having that......................I have had a VIRGIN ENGINEER standing in my house telling me that the Hub 3 is a great piece of kit never had a problem with one.He must know his stuff I thought, been well trained by VM in all avenues of dealing with customers and fixing things, but i don't why this thread has 3500 posts and over 40,000 views. Can only think that we are a moaning lot about nothing. Not to mention all the other threads and posts about the same issue, just moaners, that’s the answer, never satisfied.

I started moaning nearly two weeks ago, best offer I have was when a forum girl  offered to get my hub2 reinstated, great she must know that their ENGINEER takes them away and sadly they do not have any to offer me either. MUST BE A BIG PILE OF THEM SOMEWHERE. LOL

A disgrace the whole thing, customers treated like...............nice words fail me !

[SonarUK]

had an inbox message from the trials team on 31-01-2018 14:46 I completed the survey back then. I was then told ide receive another message telling me how to get into the trial firmware.

Ive heard nothing back yet.