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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

Been having huge latency issues with my 2ac and had an engineer come today, replaced the 2ac with the 3 and it's insane how consistent the latency spikes are now compared to how it was when I called to get the engineer. It's honestly like pulling teeth to get an engineer to come out, being told that latency is not something they support issues for; What a joke that is. Luckily I kept on and I've got another coming, hopefully I'll also get the engineer to activate a spare 2ac I have.

Apparently there's a Hub 4 on it's way to release soon, not sure how soon but looking at the Hub 3 it can't come soon enough.

Same issue here. There were issues on my line with high latency and dropped packets. Engineer came out and swapped the hub 3 which (sort of) fixed the dropped packets but the latency is all over the place (45ms - 500 ms and sometimes even higher) and there are still some dropped packets every now and then. 

Really wish there was some competition with cable broadband providers.

If you have a spare 2ac which was previously reigstered to your account then it can be activiated over the phone, provided you account is below 200Mbps

And the same with me - some connectivity problems, engineer swapped out a SH2 for a Superhub 3 that's made things worse.  Incidentally, in response to my earlier open question about whether it was possible to use our own modem, I was PM'd by another user who'd asked VM if they could use their own cable modem and been told no.  They escalated the matter to the Chief Executive's office, but because Virginmedia don't care about the poor standard of service they provide with these awful modems, they actually responded that the only devices that could be connected were the VM superhubs, and if the customer didn't like that they should take their business elsewhere.  Given the appalling performance of the SH3, I really think that "couldn't care less" attitude is unacceptable, although since the CEO is paid £3 million a year, its hardly surprising he's completely out of touch with customers.

However, there is a tiny way to keep up the pressure.  Virginmedia have missed their new customer sign up targets (under Project Lightning) by some considerable measure, and investors aren't happy.  Make sure that if anybody asks you about cable, if Virginmedia or broadband comes up in conversation with family or colleagues that you give a firm and frank view of Virginmedia.  I can't see many people taking up VM cable based on the review that I'd give them.  If Virginmedia want to be more successful, then here's a few things they need to do:

1) Be better value.  VM is rip off at the full tariff prices. 

2) Fix the SH3 properly! Not some botch that makes it 30% less rubbish.  I'm personally not expecting anything other than a botch, so in that case they need to either release a new VM cable modem that doesn't have "Intel inside" or allow customers to use third party modems. 

3) Bring back all customer contact and phone tech support to the UK.  The offshore customer "service" is appalling.  If VM's executives can't organise that, resign and let somebody competent do it. 


@lobster123 wrote:

How long do Virgin media typically trial new router firmware?


You'll discover that you can't generalise on VM scheduling even by specific product....... it's not consistent (from an end user perspective) as far too many variables! The only crude determinations/approximations you can make are:

  1. Trial firmware has already been released internally to various VM company alpha/beta testers which may be (initially) months prior to "limited public trials" -
  2. "Limited public trials" may be offered to SU group initially (but not always include solely SuperUsers ) but increasingly even the delta between SU's and subsequent limited "public pilot's" since SH1/VMDG480, SH2/VMDG485,SH2AC/VMDG490 and SH3/VMDG505 has reduced from months to weeks.
  3. The number of firmware versions that are "Trialed" sequentially/serially can be specific to (various) Internal VM testing group and not ALL reflected in subsequent SU Trials and consequently only final or penultimate release candidate eventually "piloted" to regional user group.
  4. Unfortunately "commercial sensitivity" means the heirarchial grouping structure implies that "employment contracts", NDA's and even T&C's for SU's mean that a lot of "Trial information" cannot be forwarded down the "food chain" without the risk of punitive reprisals against individuals if any forum/Trial T&C's are inadvertently compromised (ambiguity/ignorance of T&C's is not an acceptable excuse).
  5.  End result is that many "firmware" issues already fedback to CPE firmware group/Lab may not be prioritised/resolved (or even acknowledged) at Internal, SU, Limited Forum Trial, Early Pilot Release stages,,,, . That (often) cause's frustration, confusion and wasted (duplicated effort) at any/all stages....
Regards Tony
"Life is a Binary Inspired Turing Computed Hologram"(don't PM or @Mention me - in case ignoring you offends)
DEFROCKED

cje85
Trouble shooter

@Andrew-G wrote:

 

2) Fix the SH3 properly! Not some botch that makes it 30% less rubbish.  I'm personally not expecting anything other than a botch, so in that case they need to either release a new VM cable modem that doesn't have "Intel inside" or allow customers to use third party modems. 

I totally understand people's frustration, but there's not much Virgin Media alone can do about the Intel Puma issues. They can only put pressure on Arris, who in turn can put pressure on Intel to try and produce a firmware based fix. This has affected cable companies worldwide and other modem manufacturers such as Netgear who seemingly all released modems/routers powered by this chip without noticing the problems. From what experts on other forums have said, a firmware fix will never fully resolve the issue as it's a problem with the Puma chip architecture.

Stoddy27
On our wavelength

Whilst this is true virgin could eliminate all these issues and allow customers who care about networking equipment to attach their own modems to the line. There is no reason not too most of the other comparable tech companies do this. They could still supply the SH3 to customers and then it is their choice if this is changed or kept. 

Virgin decided to stop manufacturing their own modems and allow other companies to produce them a couple of years back meaning they now have no control over what is put inside them and what technology is used. This decision was a cost-saving exercise that has now backfired.

4 weeks into the trial firmware and once again it's improved but still has the issues which is so frustrating when you sit down to start gaming to relax and end up being more stressed!

 

ShadowOfDeth69
Dialled in
My BQM a few days in.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/e49106ac9007327dc2e33cf515bfc92c1a...

Not AS bad as some I've seen but still pretty gross right?


@ShadowOfDeth69 wrote:
My BQM a few days in.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/e49106ac9007327dc2e33cf515bfc92c1a...

Not AS bad as some I've seen but still pretty gross right?

Pretty much the same as mine

 

27ad6d7729a19bdf57009abde59955dff4b63d8d

How did you get the trial firmware?