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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

350mbs package My hub 3 on 603 firmware

Standard specification compliant: DOCSIS 3.0
Hardware version: 10
Software version: 9.1.116.603

 

3ef6c26e5afcb58d27096b723365dbbf1e666fc0-25-04-2018.png

 

 

I was a big complainer but to be honest the latest trial firmware looks pretty rosy compared to before! Smiley Happy

 iperf1.PNGiperf2.PNG

pingplotter1.PNGpuma6test.PNG

Wow - that's a big difference, numbers wise!

As others have said, the proof of the pudding is in the eating. Smiley Indifferent So does it *FEEL* any different, though?

Numbers are one thing but I have noticed more lag when browsing compared to the SH2AC so I'd be interested to know if your online experience, be that gaming, VoIP or whatever - is actually any better . . . .


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HUB 3 & ASUS RT-AC87U in MODEM Mode M500 Package
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My Broadband Ping - HDD23 500mbps VM


@CJS23 wrote:

Numbers are one thing but I have noticed more lag when browsing compared to the SH2AC so I'd be interested to know if your online experience, be that gaming, VoIP or whatever - is actually any better . . . .


 I work from home a couple of days a week, and have at least one videoconference meeting each day, and I've definitely noticed a difference. We use Cisco Jabber and it seems to be *very* jitter sensitive. Before, I'd have the video and audio stuttering, and then dropping a load of frames of both to catch up so I'd miss important parts every 30s or so.

Since the firmware upgrade that's gone - everything is buttery smooth.

I also use Sipgate for the phone as VM couldn't offer a phone service when I signed up, and to be honest, that was always fine, and still is.

I think the problems some people see with DNS is that the SH doesn't have a caching DNS resolver on it, so you rely on your computer doing it, or reaching out every time to VM's (probably overloaded) DNS servers. I've got the hub in modem mode and running Unbound on my router with a large cache (65k entries IIRC) so only ever have to reach out to Cloudflare DNS (1.1.1.1, 1.0.0.1) when the TTL on a record is expired, or for a new lookup.


@philjohn wrote:

@CJS23 wrote:

Numbers are one thing but I have noticed more lag when browsing compared to the SH2AC so I'd be interested to know if your online experience, be that gaming, VoIP or whatever - is actually any better . . . .


 I work from home a couple of days a week, and have at least one videoconference meeting each day, and I've definitely noticed a difference. We use Cisco Jabber and it seems to be *very* jitter sensitive. Before, I'd have the video and audio stuttering, and then dropping a load of frames of both to catch up so I'd miss important parts every 30s or so.

Since the firmware upgrade that's gone - everything is buttery smooth.

I also use Sipgate for the phone as VM couldn't offer a phone service when I signed up, and to be honest, that was always fine, and still is.

I think the problems some people see with DNS is that the SH doesn't have a caching DNS resolver on it, so you rely on your computer doing it, or reaching out every time to VM's (probably overloaded) DNS servers. I've got the hub in modem mode and running Unbound on my router with a large cache (65k entries IIRC) so only ever have to reach out to Cloudflare DNS (1.1.1.1, 1.0.0.1) when the TTL on a record is expired, or for a new lookup.


Off topic, but at this point it's a FFA on things anyway 😛 Did you find 1.0.0.1 quicker than 1.1.1.1? I have it in that order (although I've lost DNScrypt to test it).

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


@Guybrush85 wrote:

Off topic, but at this point it's a FFA on things anyway 😛 Did you find 1.0.0.1 quicker than 1.1.1.1? I have it in that order (although I've lost DNScrypt to test it).


They're pretty much equal for me - I've got unbound running (instead of using Dnsmasq on OpenWRT) so that it's using TLS.


@philjohn wrote:

@CJS23 wrote:

Numbers are one thing but I have noticed more lag when browsing compared to the SH2AC so I'd be interested to know if your online experience, be that gaming, VoIP or whatever - is actually any better . . . .


 I work from home a couple of days a week, and have at least one videoconference meeting each day, and I've definitely noticed a difference. We use Cisco Jabber and it seems to be *very* jitter sensitive. Before, I'd have the video and audio stuttering, and then dropping a load of frames of both to catch up so I'd miss important parts every 30s or so.

Since the firmware upgrade that's gone - everything is buttery smooth.

I also use Sipgate for the phone as VM couldn't offer a phone service when I signed up, and to be honest, that was always fine, and still is.

I think the problems some people see with DNS is that the SH doesn't have a caching DNS resolver on it, so you rely on your computer doing it, or reaching out every time to VM's (probably overloaded) DNS servers. I've got the hub in modem mode and running Unbound on my router with a large cache (65k entries IIRC) so only ever have to reach out to Cloudflare DNS (1.1.1.1, 1.0.0.1) when the TTL on a record is expired, or for a new lookup.


@Wow! Really pleased to hear that. As @Sephiroth and others have said, it's easy to become obsessed with jitter, ping, latency, bufferbloat etc etc but all we really want at the end of the day is a stable connection that we pay damn good money for!

I am so proud to be part of a VM Community on here that strives to highlight issues and get a resolution! This is a MASSIVE long-running saga. I believe that we will prevail and that this is only possible by concerted and continuous effort.


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HUB 3 & ASUS RT-AC87U in MODEM Mode M500 Package
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My Broadband Ping - HDD23 500mbps VM

By the way, you can view the entire US Class-Action Lawsuit here

https://www.courtlistener.com/docket/6232601/carlos-reyna-v-arris-international-plc/

It's fascinating! A battle between Carlos Reyna v. Arris International plc (5:17-cv-01834) which at the moment is ploughing through "do we Seal or not Seal" various bits and bobs. Intel / Arris claiming intellectual property rights. The other side claiming disclosure is needed to show how this debacle with Puma 6.

Ruling on those points here - https://www.courtlistener.com/recap/gov.uscourts.cand.309618/gov.uscourts.cand.309618.70.0.pdf

This reminds me of Sarah Langelaan vs Nvidia which essentially went on to prove that electron bombardment against the anode in the newer variants of eutectic solder caused electromigration. In layman's terms, lots of nVidia chips went bad and caused artefacts on the screen etc.

The result? "A settlement has been approved by the court in the NVIDIA Graphics Processing Units Class Action with NVIDIA (the "Settlement Agreement"). Under the Settlement Agreement, NVIDIA will pay CAD$1,900,000.00 for the benefit of the Settlement Class in exchange for a full release of claims against it in the NVIDIA Graphics Processing Units Class Action." - http://www.canadiannvidiasettlement.com/

In this Virgin Media Puma 6 problem, you may find it interesting to note that . . . . 

"4. Intel argues that “[i]f Intel’s internal improvement efforts
were to become public, third-party competitors would be able to use Intel’s own internal analysis,
which they ordinarily would not be able to access, to disparage Intel’s Puma 6 chipset and spread
fear, uncertainty, and doubt in the marketplace relating to the Puma 6 chipset and latency issues
that Intel identified and already resolved.

Now then Virgin Media, that's a sworn statement to a US Judge in a live Class-Action Lawsuit. It thus logically follows that the only delays to fixing the global issue is actually customising the firmware and then deploying.

This still does not excuse your denial and subsequently obfuscatory behaviour, Virgin Media. As a business, you made the classic mistake of not listening to your loyal customer base. Within this base lie users far more experienced and knowledgeable than I as regards these issues, yet to chose to bury your heads in the sand.

This court case and this thread are about so much more than a fault with the Hub 3.0. It's about forgetting the loyal customers who made you what you are as a corporation. It's about short-sighted greed getting ahead of your core values as an entity.

You foolishly poked the collective geeky bear. I hope the decision makers learn lessons from this.

This entire debacle could have been prevented by using a collaborative approach.

"Give light, and the darkness will disappear of itself" - Desiderius Erasmus


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HUB 3 & ASUS RT-AC87U in MODEM Mode M500 Package
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My Broadband Ping - HDD23 500mbps VM

Sure, as usual, ODM claims "trade secrets" and "IP rights" to prevent disclosure of royal mess of their development practices (chasing cost-cutting, underpowered hardware, sloppy firmware team) which lead to undeserving marks customers strung around and having to fight protracted court battle just to have semblance of admittance of failure.

Nothing new here, come along...

Good to see they are still getting noses bloodied over this though - they always grow complacent if "life is good" for too long.

 

 

"I was a big complainer but to be honest the latest trial firmware looks pretty rosy compared to before!"

 

Its interesting that as expectations lower, how much easier it is to celebrate mediocrity.

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