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Hub 3 / Compal CH7465-LG (TG2492LG) and CGNV4 Latency Cause

Datalink
Up to speed

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]

4,478 REPLIES 4,478


@shanematthews wrote:

personally i'll just funnel the time i would spend complaining about something i have no control over in to doing other things, 

If you don't care fair enough. But maybe you should lead by example, and stop wasting *your* time trying to discourage people who care? 😉

 

 


@RidingTheFlow wrote:

@shanematthews wrote:

personally i'll just funnel the time i would spend complaining about something i have no control over in to doing other things, 

If you don't care fair enough. But maybe you should lead by example, and stop wasting *your* time trying to discourage people who care? 😉

 Well said, wasting his time telling us we're wasting our time.  Somewhat ironic.

 


 

These issues have stopped me signing up,so sorry to say you're wrong shane

wotusaw
Superfast

Indeed. Several of my friends have gone for SKY over Virgin due to this issue.

I think Virgin is totally underestimating Pumageddons damage to them.

If some dark boffin nerd does a massive DOSmageddon attack on Virgin customers then we'll see, erm, stuff happening big time.Smiley Mad

I would be interested to see Virgin advertise themselves out of DOSmageddon

 

I think the DoS issue will only get some legs if something happens. A major blow to an ISP's network is going to hit mainstream media and the current silence won't be acceptable at that point. Unfortunately/fortunately (double edged sword), knowing that the majority of large scale attacks are done for some kind of monetary/political gain, it seems a little a little bit high risk over little reward, so I'm doubtful such an attack will happen.

The latency however is bothering us all... every day. The problem is the majority of people just don't notice (unfortunately), but the fact remains it's still an issue. 

Anyway, we're 3 weeks or there abouts since the announcement of the trials starting 'soon' and not a sausage since (I'd even take quorn at this point), so can we get an update on this please? I suspect said update will not fix everything and will be our version of the 93v update, but the DNS fix alone would be a start.

--------------------------------------------------------
Look behind you, a three-headed monkey

Most likely attacks are already happening here and there - but people have no idea that they are attacked and just think its their modem or connection acting up, and customer services are asking them to use paperclip to reset their modem 😉

 

At this point - I don't see any fix being deployed that will "solve" the problem. My only hope is that I get a letter or e-mail advising me of the price rise that allows me to get out of the contract. I've been with Virgin 10 years and the ever increasing price rises and lack of response on this issue has tipped me into looking elsewhere.

mannakin, prices rises are happening on the 1st Nov so use that as the reason for terminating your service.


@GMAN73 wrote:

mannakin, prices rises are happening on the 1st Nov so use that as the reason for terminating your service.



I spoke to customer support and they told me that I’m not affected by the price increase till the end of my contract (next year April). Unless they aren’t informed I’m more inclined to believe that customers who are in contract won’t be affected but if not then great news as I’m ready to go. I’d rather use my 4G connection and tether off that as it’s just as fast and the latency is STABLE.


@bambamboyo wrote:
I have also written to watchdog via the online link.
Suggest everyone does the same!

https://ssl.bbc.co.uk/programmes/b006mg74/contact

I’ve written to watchdog, thanks for the link, I advise others to do the same too.

I’ve be had by the Usain Bolt and Richard Branson lie-vert.