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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

Adduxi
Very Insightful Person
Very Insightful Person

@nickking wrote:

Has anyone with the new firmware had any response from the trial teams?  I was asked to message if any problems, I have twice but I've had no response.


Nope, I've sent in a couple of comments, but have had no response.  I guess they are collating data before making any more announcements.

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Andrew-G
Alessandro Volta

@vm_eg

Should you go from SH1 to SH3, or wait for SH4?

Depends on what you're doing.  If you're not into on line gaming, VOIP and video conferencing, then by all means, take an SH3, for undemanding use its is fabulously mediocre.

If you do gaming or other latency sensitive things, on no account swap an SH1 for an SH3.  Whilst we're promised a fix, the difficulties of the Puma 6 chipset are a mix of hardware and firmware, so changing the firmware may not resolve all the problems (although some of the BQM charts for the trial SH3 firmware look very good).  Moreover, if you accept an SH3 now, and they launch an SH4 in three months, they may refuse to offer you an SH3 to SH4 upgrade, or expect you to pay for the privilege.

If you use the built in router, another reason to wait is that BT have upped the game with their claim to wifi dominance with the BT Smarthub.  There's a moderate chance that the SH4 will respond with a better wifi router specification than the lacklustre SH3.  The SH3 router usually works, it just isn't the sort of performance you'd expect if you were buying even a low cost router, which is why some people are putting the SH3 into modem mode and using their own router..  

 

Kingseh
On our wavelength

Finally got my hands on a Superhub 2ac after speaking to a Broadband Specialist.

Gaming feels a lot smoother and I get much more consistent speeds. Ran a ping test on dslreports and got a A+ rating compared to a the D I received while using my Superhub 3. Going to hold on to the SH3 to test it out when the new firmware becomes available. 

Here's a before and after BQM for when I swapped out my hub 3 for the 2ac.

hub3.pnghub2.png

[MOD EDIT: Personal and private information has been removed from this post. The image contains your WAN IP address. Please do not post personal or private information in your public posts. Please review the Forum Guidelines]

vm_eg
On our wavelength

Hi guys, thanks for the comments about my query (SH1 to SH3). I play quite a bit of online gaming and relucant to lose that to the SH3. Will wait for the SH4. Thanks again! Hopefully vm won't now force me to swap. One final question. I am 100mb connection. Will the v6 box work with SH1 and that speed connection?

dasBOT
On our wavelength

another day of fantastic VM's broadband .. the best in the UK

m4.png


@dasBOT wrote:

another day of fantastic VM's broadband .. the best in the UK

m4.png


Same here m8 Smiley Frustrated

We get that you and Tomney here are pretty bitter towards VM but it's not the broadband you're mad at. It's the crappy hardware. Like it or not VM are not the worst ISP in the game. Relax.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/41f7de24bc948013845495e88f097bb78c...

Not ideal but it's proof not everyone is as badly affected as others.


@ShadowOfDeth69 wrote:
We get that you and Tomney here are pretty bitter towards VM but it's not the broadband you're mad at. It's the crappy hardware. Like it or not VM are not the worst ISP in the game. Relax.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/41f7de24bc948013845495e88f097bb78c...

Not ideal but it's proof not everyone is as badly affected as others.

Looks pretty awful to me...

 

@RidingTheFlow

"Not ideal but it's proof not everyone is as badly affected as others"

OllyC
On our wavelength

Its been a while since I posted in this thread, I was one of the first people in here to show the Broadband Quality Monitor differences switching from the Hub 3.0 down to the regular Hub 2.0 as I had both in my possession at the time and tested the differences first hand, I thought I'd post in here again just to update that since the switch I haven't really had any major problems, here are my recent speed test and quality monitor pics:

Speedtest 26 11 17.jpg

Monitor 20 11 17.jpg

I'm on Virgin Media VIVID 200 Optical Fibre, I run my Superhub 2.0 (non-AC but it makes no difference) in modem mode attached to a NETGEAR R7000-100UKS Nighthawk AC1900 router.