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]

[Darkman]

As expected I received another Hub 3.0 yesterday. After over an hour of fruitless back and forth between Customer Retentions and Technical Support I can only conclude that the chance of getting a SH2(ac) replacement is remote at best and it's now time to seriously consider switching to Infinity2, which has finally arrived at my local exchange.

After sending the TiVos back a few months ago it now looks increasingly likely that my collection of Hubs will be next.

After the fiasco of the original SuperHub I wondered if Virgin Media would ever learn from their mistakes and eventually realise that sourcing and supplying a premium product would save them money in the long run with increased customer satisfaction and dramatically reduced callouts. It seems we have our answer.

[Sky_Lord]

Virgin is no different to any other company. Always go for the cheapest option, even if it's **bleep**e.

[dcookster]

Stock response from VM

A Virgin Media Spokesperson told ISPreview.co.uk:

“We take the security and the reliability of our service very seriously and have tools and systems in place on our network to protect our customers. We are currently speaking to our suppliers regarding reports of Puma 6 issues.”

[Guybrush85]

Typical response really. I've personally read threads with people suffering from DDOS type issues whereby a game they are playing has allowed someone to get details of their IP. Usually this goes on for months, or the person is forced to go into modem mode (or back to router mode), to force a new IP until a time the DHCP reservation of the old IP drops off and they hopefull can go back.

If they haven't been able to magically fix the issue with large volumes of traffic at a network level (which the message implies), then I'm sat here with a notepad and ears at the ready to hear just how they plan to do it when it's a tiny amount of traffic.

[shanematthews]

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@RockerSBM wrote:
HI NALLAR

I too wanting to use My own modem I'm wanting to import a netgear CM1000 to use on the vm network.

I'm going to Be emailing one of the ceo about to to try and get them to do it.

Cheers
Shaun

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You're going to need more than luck, they won't allow non-VM certified kit on the network

[JJC1138]

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@shanematthews wrote:

You're going to need more than luck, they won't allow non-VM certified kit on the network

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I agree that they wouldn't let uncertified modems on the network, but I wonder if given the current circumstances they might decide to pick some existing modem and certify it for VM as a way of placating people who complain about the SH3 problems? I'd guess that they could do that a lot quicker than getting a whole new SH4 designed and built?

[shanematthews]

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@JJC1138 wrote:

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@shanematthews wrote:

You're going to need more than luck, they won't allow non-VM certified kit on the network

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I agree that they wouldn't let uncertified modems on the network, but I wonder if given the current circumstances they might decide to pick some existing modem and certify it for VM as a way of placating people who complain about the SH3 problems? I'd guess that they could do that a lot quicker than getting a whole new SH4 designed and built?

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Well it might take less time, depends how the system is setup, its still extremely unlikely as they would open themselves up to all sorts of issues, they might certify a specific model that you then end up flashing with an uncertified firmware which causes issues on the network, i mean its a cool idea but the likelihood of this happening is about the same as me getting in to bed with a superstar 😛

[boltedenergy]

tested my SH3 modem for the DOS issue...

nailed it! 😛

[Guybrush85]

Yeah, doesn't take much to do, which is rather scary. Wouldn't be so much of an issue if it wasn't something that could be done remotely just as easily

[cje85]

Someone has posted on the dslreports.com forum that UPC in Poland (a Liberty Global company like VM) will send out a firmware update at the start of May. I think this will be the latency improvement update, but if true hopefully it won't be long until VM users get it.

https://www.dslreports.com/forum/r31382894-