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]

[Luke_113]

Is the answer we have all be looking for!

[Luke_113]

As a business user I get advanced notification of downtime, and I got an email on friday last week to say that there is downtime planned at the end of the month (lasting about 15mins) by between midnight and 6am, they described in the downtime notes about fixing speed issues in the area affecting several customers, so whether thats this patch for the Hitrons or whether they're increasing capacity in the area wasn't clear.

My main concern is the gaming performance being fixed.....which from all accounts it doesn't appear to be.

[Andrew-G]

StopItRawr: If repeated, would mean that your area probably has low level utilisation issues. Nothing enough to make VM do much about it, but enough to make gaming and other latency sensitive applications a borderline experience.

DasBot:  thx, any suggestion how to force VM to actually fix it?

Your only options are the usual complaints routes, and if those don't work escalating to the arbitration service CISAS.  Realistically, there's people with far worse connections and much longer standing problems, even if VM want to do something in your area (for this reason) there's other areas demanding more urgent attention.  You might get lucky with a CMTS upgrade or some other network enhancement that is already in the pipeline for other reasons, but as StopItRawr says, they probably wouldn't act on the peak time latency issue alone, looking at your BQM post firmware update.

Even if you take it to CISAS, they might decide there's no valid complaint, or that a VM defence that the problem isn't severe and doesn't merit investment is a valid one.  Or they might look at your before and after BQM and say "they've made it sooo much better, stop complainigng, You might get a few quid knocked off your bill if you complain to the retentions team, but I think that the two options you've really got are unfortunately:

(1) Tolerate it, 

(2) Find another ISP.

[wotusaw]

This is just shocking. The results for some reason have deteriorated since the engineer came Saturday?

I've rung Virgin and the chap said it would be fixed in 2 hours. That was at 12 midday and it's now 4.20pm and still not fixed.

Do you think he was just trying to get rid of me?

Anyway, I'm posting my results to warn others of the glorious HUB3. I used to have 1ms on the CMD test and the occasional 100/150/200 every minute or so, but nothing like the pic below.

Personally think mines dying and I'm after getting a replacement.

Think number 2. Been looking at BT and SKY. Don't want to change but what with the engineer lecturing me on Saturday and this guy today just stringing me along I'm starting to get really p***** off. I actually spoke to 4 people before I got to him, btw. Repeating my name and address etc 5 times including him.

[tommey]

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@cje85wrote:

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@tommeywrote:

Well I am still stuck on 9.1.116V tried a reboot earlier to force it to update but nothing  always seem to be the last to get anything from Virgin Media including waiting over 3yrs for a Utilisation issue that's STILL NOT FIXED....

The graph in your signature (if it's your connection) doesn't appear to show any significant utilisation now. The blue average latency level is constantly stable with no signs of any increase at peak times.

utilisation should show like this:

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I can assure you my connection slows down to a crawl between 4pm - Midnight daily and even earlier on weekends, if that's not utilisation then what is it?

[Anonymous]

I think my Hub 3 is trying to download new firmware, last 2 days its restarted at exactly 1:17am when i'm playing a bloody game too!

[WildWayz]

Mine has been at around 2am... can see a red line on my BQM. Even factory reset the router to see if a config i had was stopping it... nope

[ShadowOfDeth69]

https://www.thinkbroadband.com/broadband/monitoring/quality/share/6a115fd02598180be0435242919679cc7a...

What's up with all that noise in my BQM? Couldn't use my connection at all yesterday when I got home at 18:00. Checked the router settings webpage but was greeted with "access denied".

I'm the only one using my connection and there's nothing at home using it when I'm not there. I did find out a few weeks ago that I'm connected to VM via a splitter shared with a neighbour. Could their internet use be messing with mine?https://imgur.com/2DsVkyC

[RidingTheFlow]

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@Badvokwrote:

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@RidingTheFlowwrote:

So in a nutshell:

- does problem exist? yes

- does it affect games & applications? yes, because lag spikes are here

- does it affect them do detrimental extent? this entirely up to specific user expectation and needs

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You forgot to include a: "My BQM graph looks bad, I really need it fixed. What are VM playing at?" category.

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Well, BQM graph is not just some random picture but a well-known diagnostic tool. And when it show(ed) high ping ceiling all the time (high for what you'd expect from modern internet), I don't think there is anything wrong with not wanting to have it. Even if it does not affect anything for them at the moment, it still could in the future. Also, not everyone have alternate connection/alternate hub model to obtain 100% proof that game of their choice actually could work better with less ping spikes so they have to trust just the diagnostic they have.

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@boltedenergywrote:

One thing I would like raise from your points is that the firmware released now to general VM users is not the same version as the beta release so there may have been further improvements since you last ran all your checks?

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That is true. I don't claim I have 100% up-to-date information, especially since there are appear to be several new betas with confusion to what they are, who has them and what they actually do. It would be nice for people having them doing proper TCP/UDP pingplotter graphs at the very least.

Though I have some (maybe wrong) assumptions that:

- these modems/Puma 6 chipset are not exclusive to UK/VM, they are actually much widespread in US, which have much bigger cable internet community, scrutiny and deregulation

- US crowd keeps close eye on Puma 6 lag spike issues. Especially because there is class action lawsuit over whole debacle going on right now.

- They appear not to have any firmware yet which actually fixed the lag spikes on traffic that matters (TCP/UDP). There were couple of promises from big names, but they were missed all the time. Intel (who actually makes chip and firmware) stayed completely silent I think over almost at least half a year (since lawsuit happened)

- Up to this point VM always got firmware with features that US modems had for several months. They never had something faster.

That's why I assume that proper fix still does not exist and VM firmwares are just variation of same firmwares that US MSOs already rolled out. Best with ICMP lag fixes and UDP packet drop fixes, but not UDP/TCP lag spikes. I may be wrong.

[xanthic]

This firmware seems to fix the BQM graphs and Puma6 checker, making it appear as though the issue is resolved when it is not. It smacks of deliberate deceit, much like the Volkswagen diesel defeat device.