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]

[Emma_E]

Hi JohnGW75, 

Thanks for getting back to me so quickly. I am sorry you have also had connection issues. 

I have taken a look and it seems your upstream power levels are too high. 

I will pop you a Pm to get an engineer out for you. Keep an eye out for the Purple Envelope, top right hand corner. 

Speak to you soon. 

Emma

[JohnGW75]

Info sent thanks

[Pro4TLZZ]

My ping sucks and affects gaming 

https://www.thinkbroadband.com/broadband/monitoring/quality/share/e3d84393f0cbb89be833ef5150648538b4b88d7b-14-06-2018Ping

[ILuvNips]

Super Emma to the rescue, nice to see some actions being taken 🙂

[SonarUK]

Emma feel free to check out my thread.

I don't have a huge problem but would like a quick line check.

https://community.virginmedia.com/t5/Networking-and-WiFi/Dropped-packets/m-p/3753702

[nad223]

I am seeing packet loss since updating to 9.1.116.608

@Emma_E 

Cable Modem StatusItem Status Comments

Acquired Downstream Channel (Hz)	299000000	Locked
Ranged Upstream Channel (Hz)	46200000	Locked
Provisioning State	Online

[MS8]

With regards to packet loss, I can see 1%-2% packet loss every few hours. I done testing on my Xbox one to measure packet loss on the console side. I done tests for one hour straight and every test it showed 0% packet loss. 🤷‍♂️

[Sephiroth]

The packet loss on the ping side can occur because the low priority packets can be discarded at any point in the flow.

Any traffic that uses the TCP will be delivered without loss and the BQM cannot reflect that.

[panoSs1]

Well I managed to dodge hub 3 thanks to this thread so thank you all. I have seriously low wi fi speeds (40 max) on hub1 while ethernet is fine (110). The tech guy checked power levels and all replaced cable and all but obviously couldn't fix the wi fi speed. Imo the router wi fi is faulty or something and needed replacement, but he had only hub 3 which I declined. Hope new firmware works fine and is upgraded fast for all speeds and I pray is the last time I deal with virgin. Btw if anyone has any clue why my wi fi speed is underperforming please pm me. I am on 2.4ghz network btw.

[ScottJT]

Hi folks, had an interesting conversation with a fellow on customer support today, was wondering if anyone else has had the same response.

We're on 200mb Fibre and my Superhub 2AC was having issues, so I called customer support. They sent me out a Superhub 3 (joy). After connecting it up the usual SH3 issues greatly affected gaming performance in the house, so I purchased a Nighthawk in the hope it might alleviate the issue. It didn't, so I ended up calling support again and asked to be switched back to the 2AC. This was no issue and the 2AC was back in minutes and combined with the Nighthawk the issue I was having with the 2AC stopped.

Some time has passed since this and we've ended up back on the Superhub 3 in the hopes the new firmware update will help resolve some of the issues. Support has been very coy in regards to when we will actually receive this update so after intense pressure from the kids, miffed that their gaming performance is being affected again caused me to call customer support again to go back to the 2AC. I figured i'd just wait for more information upon this firmware's release and hang on using the 2AC as long as possible. Despite it being on it's last legs, it's easily better for gaming.

Upon calling today I was met by a fellow who immediately blamed the problem on an area fault and said it was nothing to do with the Superhub. I enquired about the firmware update to be told it was 'company policy' not to reveal any information about the update but that it has been pushed out already to our SH3. I told him that the firmware version our SH3 is using is 9.1.116V and there is no sign of this mystical update on the device information page or in the router logs. His response was again that company policy is not to reveal any information about the firmware update (including version number, though that information is widely available here and he seemed quite surprised that I could read out the correct version number to him), and that the company does not promote (or particularly like) users going through their own router logs. In his view, we have the update and both the router and I are wrong. He also point blank refused to switch the hub back.

Anyone else had this experience?