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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

Thanks for chipping in Mud_Wizard.

I had an engineer over on Monday due to the same fault last week. Their remote tests found no fault, and neither did the engineer when he came.

No idea how the single/multiple IP thing works, but the agent said specifically that "static with a single IP doesn't work, but the block of 5 is fine". We'll see when it gets installed. It's not too important, so don't mind dropping down to a dynamic if needs be.

I figured at the end of the day, the Hitron isn't going to get rid of the Puma 6 issues, but I'm more likely to be able to apply pressure from a business perspective when a replacement without the Puma chipset starts rolling out. Also I save twenty quid a month.


@BlackDwarf wrote:
Thanks for chipping in Mud_Wizard.

I had an engineer over on Monday due to the same fault last week. Their remote tests found no fault, and neither did the engineer when he came.
Yeah but the remote end is only going to show your upstream. The downstream is coming your way and VM have no sensors in the field so rely on what the hub sends back. The regular tech's don't have equipment for finding SNR faults, only the network tech's do that. So depends which you had. Essentially VM are blind on downstream without a network tech in the field and/or accurate updates from the hubs.

No idea how the single/multiple IP thing works, but the agent said specifically that "static with a single IP doesn't work, but the block of 5 is fine". We'll see when it gets installed. It's not too important, so don't mind dropping down to a dynamic if needs be.
I edited my post above to explain how it works.

I figured at the end of the day, the Hitron isn't going to get rid of the Puma 6 issues, but I'm more likely to be able to apply pressure from a business perspective when a replacement without the Puma chipset starts rolling out. Also I save twenty quid a month.

Yeah that's fair enough and you have the SLA and tech support which are easy to talk to about tech matters, unlike residential.

On the DSLreports.com forum, a member of Intel staff has posted a few messages (I believe he's been verified as genuine). Apparently they are working on firmware which further improves the latency, along with trying to resolve the DOS attack issue.

VM users haven't even got the first latency firmware update yet so it could be a long time before we see the second one.

https://www.dslreports.com/forum/r31415995-SB6190-Puma6-TCP-UDP-Network-Latency-Issue-Discussion
https://www.dslreports.com/forum/r31413390-SB6190-Puma6-TCP-UDP-Network-Latency-Issue-Discussion

wotusaw
Superfast

Thankyou so much 'cje85' for that info.

Been looking for anything positive on this problem.

I hope the **** Virgin send down an update quickly.

I've had no end of adverts through the post etc for BT Infinity.

I don't intend to change so this is'nt a sulky threat, but think BT may have sussed out the anger of Virgin HUB 3 users and are going for a 'grab customers while they can' campaign drive. Robot LOL

Had a real rage quit moment last night playing Titanfall 2 using the HUB 3 with it's shocking latency...so bad I frightened my son playing Minecraft on the other gaming pc.Smiley Mad


@wotusaw wrote:

Thankyou so much 'cje85' for that info.

Been looking for anything positive on this problem.

I hope the **** Virgin send down an update quickly.

I've had no end of adverts through the post etc for BT Infinity.

I don't intend to change so this is'nt a sulky threat, but think BT may have sussed out the anger of Virgin HUB 3 users and are going for a 'grab customers while they can' campaign drive. Robot LOL

Had a real rage quit moment last night playing Titanfall 2 using the HUB 3 with it's shocking latency...so bad I frightened my son playing Minecraft on the other gaming pc.Smiley Mad


We haven't had the first fix yet, expect several months for this second fix to arrive and thats if it even does completely fix the issue

You'd think Virgin would have some level of damage control out for this.


@Tengenstein wrote:

You'd think Virgin would have some level of damage control out for this.


Virgin media representative: "Volcano? What Volcano? I see no lava flow.." as he gets swept away..

I fixed mine. Hooked up the old sh2ac ๐Ÿ˜‚

Ping is now better but speed is the same as it's been for years i.e absolute shat.
7Mb of pure hyper download speed ๐Ÿ˜‚ Virgin are brilliant - that new advert makes me laugh so much with all that content running down their cable and the reality is I can't stream a single YouTube video at decent quality without buffering.

The final post in this thread, seems to suggest that a firmware update for the SH3 could be out this month to fix the Puma6 chipset issue that causes latency issues:

http://www.ispreview.co.uk/index.ph...e-fix-superhub-3-latency-packet-loss-bug.html

Apparently Intel have been trialling a fix for a while and have rolled it out to manufacturers a few months ago for deployment testing. There has been no news on whether the patch is successful though.

 

wotusaw
Superfast

Theyv'e had the Virgin truck thing in my local town shopping centre on Saturdays for about a month now.

None of their reps have a clue about the Superhub 3 problems. I enlightened them alot.

Think they thought I was a crazy person........intolerable!

Seriously, I was amazed how uninformed they were.