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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

Just double checked definitely 9.1.116V so no idea when this area is getting the new software....Just odd to see my ping have gone down without any new software Smiley Very Happy maybe they upgrade there Arris CMTS (what im on) then push the new software to hub 3's?

Hub 3.0, VIVID200 Package only

  wrote:

Just double checked definitely 9.1.116V so no idea when this area is getting the new software....Just odd to see my ping have gone down without any new software Smiley Very Happy maybe they upgrade there Arris CMTS (what im on) then push the new software to hub 3's?


 On the 200 as well, ping went from average of 27 down to 11.  Not sure the significance but fingers crossed firmware is on the way.

horseman
Alessandro Volta

@robblij wrote:

   On the 200 as well, ping went from average of 27 down to 11.  Not sure the significance but fingers crossed firmware is on the way.


fwiw and curiously (or coincidentally?) my ICMP latency reduced with 603 at beginning of Feb:Screen Shot 2018-05-16 at 07.06.34.png

 

as did the UDP latency which also has reduced partially again with 608 at end of April:

 

 

Screen Shot 2018-05-16 at 07.01.39.png

 

 

 

That also appeared coincident with Upstream doubling from 2 x64QAM  to 4 x 64QAM on same V200x12 provisioning.  I suspect that was due to upstream capacity uplift to support 350 Tier on my Arris cable segment and current stabilising of dynamic upstream load balancing since 26thApril?

That said I can't comment further on specific Trials detail but it might indicate why there is a community perception that you can get the firmware in some areas when upgrading to 350 Tier service?

It could be a plausible hypothesis if users have the ability/incentive to regularly monitor ICMP,(AND) UDP and Hub stats consistently (and regularly) and determine if/when 350 is available on their own cable segment?  Conveniently explains why VM can't release an accurate  firmware schedule (or even 350 availability).

Until then good luck with yours.....

Regards Tony
"Life is a Binary Inspired Turing Computed Hologram"(don't PM or @Mention me - in case ignoring you offends)
DEFROCKED

608 dropped for me last night as well, I was on 603.  Sheffield S12.

Software version: 9.1.116.608

 

untitled.pnguntitled1.png


@nickking wrote:

608 dropped for me last night as well, I was on 603.  Sheffield S12.

Software version: 9.1.116.608

 

untitled.pnguntitled1.png


Did you do a reboot to get it or it just installed?


@mitch84 wrote:

@nickking wrote:

608 dropped for me last night as well, I was on 603.  Sheffield S12.

Software version: 9.1.116.608

 

untitled.pnguntitled1.png


Did you do a reboot to get it or it just installed?


I didn't reboot, it was automatically installed.


@nickking wrote:

@mitch84 wrote:

@nickking wrote:

608 dropped for me last night as well, I was on 603.  Sheffield S12.

Software version: 9.1.116.608

 

untitled.pnguntitled1.png


Did you do a reboot to get it or it just installed?


I didn't reboot, it was automatically installed.


I have had two attempts of software being pushed to my hub 3, one on the 9th and one on the 14th, first said something about file corruption and the one pushed the other day said "upgrade failed before download server not present"

Strange, im on .603, but looks like VM are trying to push .608 to my hub.

Whenever I've seen a failed update and multiple failed attempts a restart of the router is normally enough to get the update down and installed.

________________________________________________________________

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No update here - getting a bit miffed to say the least (although I'm only on 100Mb and not a hardcore gamer by any means).

The situation here is: Amazon Echo works when playing radio or streaming audio for about an hour then 'clicks' repeatedly making it unbearable.

Netflix/Amazon Prime works for the mostpart, but the TV screen periodically goes black, audio drops and signal skips a couple of seconds. 

I have my old Superhub 2.0 and want to switch back, so I phoned Virgin last night and the very nice chap on the phone said there was NO way I could 'downgrade' to the hub 2.0.  I pushed him, he said absolutely not possible. He advised that the fix would be to split the 2.4 and 5 Ghz signals. It's made no difference. 

How the hell do I switch back to Hub 2.0?  To be honest I now don''t even want to wait for the new Hub 3 firmware, I just want what I had before the 'free upgrade'!

 I'm not saying it's not the Hub 3, but those issues don't sound like they'll be sorted by a new firmware anyway. More likely a line issue, power level problem or something else with the hub.

On VIVID 200 and have no issues with streaming radio or 4K Amazon Prime with Hub 3.0.