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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

@CraigC90

"I mainly play Battlefield 1 on the PS4 Pro, are the lag spikes really that bad?"

In all honesty, you'd put it down to general internet "noise" giving a slightly whiffy link to the gaming server if you didn't know better.  But you will regularly see the effect - jumped frames, players jumping or disappearing, missed shots etc because if the latency spikes to 150-200 ms, then in an action game that tenth to a fifth of a second is a very long time that you are frozen.  In some cases you may get kicked from the server for poor latency.  If you do a broadband quality monitor, you'll be horrified by the latency performance, and then you won't be able to avoid being angry that Virginmedia have foisted this POS on you. Personally, I would only recommend a gamer join Virginmedia if they've got an Openreach line so slow that it is causing serious problems in non-gaming use.  That's because the actual speed of your connection in Mbps is almost irrelevant for gaming, it is the latency and dropped packets that count.  So a slow Openreach connection but with a good quality connection would be fine for gaming, but might not suit heavy downloaders, busy households, or 4k movie streamers.  Consider your needs against your Openreach alternatives, and maybe run a Thinkbroadband quality test on Sky Fibre, and compare to the charts regularly posted in this thread.

"Would putting the Hub 3 in modem mode and using my own router decrease the lag spikes?"

In short, no.  All the problems with the Superhub 3 are on the cable modem processor, the infamous Puma chipset. The router side of the SH3 is basic but usually adequate for undemanding use, and uses its own processor, so using your own, better quality router should get you a better wifi connection, but sadly won't have a material impact on the SH3 problems.  If it did, we'd all be doing it.

"Have those testing new firmware actually had the issue fixed or is the Hub 3 unfixable? "

There's been some promising results posted by at least one tester in this thread, but Virginmedia won't say what they are doing, what's likely to be fixed, what isn't, and how long this charade will go on for.  

Sorry if those aren't the answers you wanted.  

 

CraigC90
On our wavelength

I have posted this twice and can't see it, third time lucky.

Thank you for your replies. The speed Virgin offer would benefit us greatly however my only concern is with the lag spikes and from what I have come across online this seems to affect some users more than others. Part of me wants to go for Virgin and hope for the best and end up regretting it later and wait eagerly for Virgin to issue a fix... Something in my head keeps saying MORE SPEEED! 

Anyway, if I go ahead I put at risk my near perfect Sky fibre/Openreach connection which I can't fault in terms of latency, it has been excellent! I have not noticed any issues when I play Battlefield 1 as my ping is usually around 20-30. Out of interest I have set up a think broadband quality monitor to see what the results are. For those interested: 

Sky Fibre Max - Broadband Quality Monitor

Broadband Link

Downstream

Upstream

Connection Speed

80000 kbps

19999 kbps

Line Attenuation

8.9 dB

0.0 dB

Noise Margin

6.3 dB

15.15 dB

 

You'll probably see me back here in a few weeks cursing and regretting my decision. Fingers crossed this issue gets fixed for you all soon and thank you for the latest info!

 

@ CraigC90

No problem - your link worked for me in all three posts!  

Looking at your BQM data, I think you don't have a perfect Openreach connection (other people have posted much, much smoother charts for OR connections in this thread), but even so your Sky Fibre is still noticeably better than a SH3.  If you need the download speed, I'd say go ahead with Virginmedia, but condition your expectations - you probably won't find the VM connection on an SH3 that much worse.

Compare my chart below to yours, and you'll see that my SH3 latency spikes more frequently, but on balance I think you'll get on fine compared to current latency.  Of course, that assumes your VM connection is the same as mine - some people have far worse problems with SH3 connections.  You'll see there's no material packet loss on my chart - some users do appear to have a real problem, and when gaming, packet loss would have near enough the same symptoms as latency spikes.

Good luck! 

 

My Broadband Ping - VM Home broadand


@CraigC90 wrote:

I have posted this twice and can't see it, third time lucky.

Thank you for your replies. The speed Virgin offer would benefit us greatly however my only concern is with the lag spikes and from what I have come across online this seems to affect some users more than others. Part of me wants to go for Virgin and hope for the best and end up regretting it later and wait eagerly for Virgin to issue a fix... Something in my head keeps saying MORE SPEEED! 

Anyway, if I go ahead I put at risk my near perfect Sky fibre/Openreach connection which I can't fault in terms of latency, it has been excellent! I have not noticed any issues when I play Battlefield 1 as my ping is usually around 20-30. Out of interest I have set up a think broadband quality monitor to see what the results are. For those interested: 

Sky Fibre Max - Broadband Quality Monitor

Broadband Link

Downstream

Upstream

Connection Speed

80000 kbps

19999 kbps

Line Attenuation

8.9 dB

0.0 dB

Noise Margin

6.3 dB

15.15 dB

 

You'll probably see me back here in a few weeks cursing and regretting my decision. Fingers crossed this issue gets fixed for you all soon and thank you for the latest info!

 


Deffo looks like your line has a fault... you should not have those spikes.

Here is my SH3 Vivid 350 graph27ad6d7729a19bdf57009abde59955dff4b63d8d

 

Even mine looks better than your Fibre one.It should look more like this:
3bda517a7b7e4cc316333145ae5894251b6169cd

 

CraigC90
On our wavelength

I apologise for the multiple posts! My reply didn't show up so I tried again but I guess this was down to some sort of delay or post approval process. 

I retract the word perfect from my Openreach connection, I am quite surprised by the results of the BQM as I hadn't come across any noticeable issues with it. I think on that basis I am going to go ahead and have Virgin installed. Out of interest I will be comparing the BQM data from Sky and my new Virgin connection  once installed as there will be a few days overlap between Virgin installing and the Sky Fibre disconnection.

Thank's again everyone for your help. 


@CraigC90 wrote:

I apologise for the multiple posts! My reply didn't show up so I tried again but I guess this was down to some sort of delay or post approval process. 

I retract the word perfect from my Openreach connection, I am quite surprised by the results of the BQM as I hadn't come across any noticeable issues with it. I think on that basis I am going to go ahead and have Virgin installed. Out of interest I will be comparing the BQM data from Sky and my new Virgin connection  once installed as there will be a few days overlap between Virgin installing and the Sky Fibre disconnection.

Thank's again everyone for your help. 


Why not keep SKY for at least a month so you can make a better decision?

dasBOT
On our wavelength

quick question, i switched my sh3 to modem mode and now the indicator on the front panel is red ... is it normal?

CraigC90
On our wavelength

@tommey wrote:

@CraigC90 wrote:

I apologise for the multiple posts! My reply didn't show up so I tried again but I guess this was down to some sort of delay or post approval process. 

I retract the word perfect from my Openreach connection, I am quite surprised by the results of the BQM as I hadn't come across any noticeable issues with it. I think on that basis I am going to go ahead and have Virgin installed. Out of interest I will be comparing the BQM data from Sky and my new Virgin connection  once installed as there will be a few days overlap between Virgin installing and the Sky Fibre disconnection.

Thank's again everyone for your help. 


Why not keep SKY for at least a month so you can make a better decision?


Unfortunately I don't have the option, I recently moved from another provider to Sky so I am cancelling within the cooling off period with 14 days notice otherwise I would be tied into a contract. 

コナー
Dialled in

Just got off the phone with Virgin complaints, they're not willing give me more than £5 off for this issue but it was confirmed there's an internal test of Hub 3s without the Puma chipset for only Virgin staff members. Annoying how I have to fight to even have communication.





Forever waiting for the Hub 4

My understanding is that the Hub 4 is in Trial stage with some customers now.