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]

[cje85]

I've read about customers getting the new firmware as soon as they upgrade to 350 so it seems a widespread roll out of the new firmware may be limited to that package at present.

[philjohn]

It makes sense - they are more likely to be impacted as they'll tend to have more bonded channels (albeit only 4 more as the SH3 can only do 24)

It's also a smaller customer base than the other packages, once you get up to 200Mbps the only real gain is the increased upload speed, so not many people plump for it.

[Loui79]

Having the 350 package doesn't necessarily mean more channels.
People are on 350 with 20 channels.
We're on 200/20 and my parents are on 70mb, both with 24 downstream and 3 upstream.

Firmware updates have been testing for 6 months now and its over 2 months since 603 was released. While it's great that some people are getting the FW rolled out to them on the 350mb packages, everyone should have the updates by now. 

[Guybrush85]

Phil, I finally got round to sorting out Entware and getting iPerf running on the R7800 again. I don't unfortunately have any before and after to show you, but this is on .603 in modem mode:

Downstream:

[ ID] Interval           Transfer     Bitrate         Jitter    Lost/Total Datagrams
[  5]   0.00-1.00   sec   129 KBytes  1.05 Mbits/sec  0.063 ms  0/91 (0%)  (omitted)
[  5]   1.00-2.00   sec   129 KBytes  1.05 Mbits/sec  0.062 ms  0/91 (0%)  (omitted)
[  5]   0.00-1.00   sec   127 KBytes  1.04 Mbits/sec  0.053 ms  0/90 (0%)  
[  5]   1.00-2.00   sec   129 KBytes  1.05 Mbits/sec  0.050 ms  0/91 (0%)  
[  5]   2.00-3.00   sec   127 KBytes  1.04 Mbits/sec  0.060 ms  0/90 (0%)  
[  5]   3.00-4.00   sec   129 KBytes  1.05 Mbits/sec  0.090 ms  0/91 (0%)  
[  5]   4.00-5.00   sec   127 KBytes  1.04 Mbits/sec  0.057 ms  0/90 (0%)  
[  5]   5.00-6.00   sec   129 KBytes  1.05 Mbits/sec  0.072 ms  0/91 (0%)  
[  5]   6.00-7.00   sec   127 KBytes  1.04 Mbits/sec  0.039 ms  0/90 (0%)  
[  5]   7.00-8.00   sec   129 KBytes  1.05 Mbits/sec  0.067 ms  0/91 (0%)  
[  5]   8.00-9.00   sec   127 KBytes  1.04 Mbits/sec  0.063 ms  0/90 (0%)  
[  5]   9.00-10.00  sec   129 KBytes  1.05 Mbits/sec  0.039 ms  0/91 (0%)  
[  5]  10.00-11.00  sec   127 KBytes  1.04 Mbits/sec  0.075 ms  0/90 (0%)  
[  5]  11.00-12.00  sec   129 KBytes  1.05 Mbits/sec  0.041 ms  0/91 (0%)  
[  5]  12.00-13.00  sec   127 KBytes  1.04 Mbits/sec  0.059 ms  0/90 (0%)  
[  5]  13.00-14.00  sec   129 KBytes  1.05 Mbits/sec  0.058 ms  0/91 (0%)  
[  5]  14.00-15.00  sec   127 KBytes  1.04 Mbits/sec  0.078 ms  0/90 (0%)  
[  5]  15.00-16.00  sec   129 KBytes  1.05 Mbits/sec  0.035 ms  0/91 (0%)  
[  5]  16.00-17.00  sec   127 KBytes  1.04 Mbits/sec  0.050 ms  0/90 (0%)  
[  5]  17.00-18.00  sec   129 KBytes  1.05 Mbits/sec  0.045 ms  0/91 (0%)  
[  5]  18.00-19.00  sec   127 KBytes  1.04 Mbits/sec  0.087 ms  0/90 (0%)  
[  5]  19.00-20.00  sec   129 KBytes  1.05 Mbits/sec  0.041 ms  0/91 (0%)  
[  5]  20.00-21.00  sec   127 KBytes  1.04 Mbits/sec  0.070 ms  0/90 (0%)  
[  5]  21.00-22.00  sec   129 KBytes  1.05 Mbits/sec  0.115 ms  0/91 (0%)  
[  5]  22.00-23.00  sec   129 KBytes  1.05 Mbits/sec  0.039 ms  0/91 (0%)  
[  5]  23.00-24.00  sec   127 KBytes  1.04 Mbits/sec  0.098 ms  0/90 (0%)  
[  5]  24.00-25.00  sec   129 KBytes  1.05 Mbits/sec  0.042 ms  0/91 (0%)  
[  5]  25.00-26.00  sec   127 KBytes  1.04 Mbits/sec  0.071 ms  0/90 (0%)  
[  5]  26.00-27.00  sec   129 KBytes  1.05 Mbits/sec  0.057 ms  0/91 (0%)  
[  5]  27.00-28.00  sec   127 KBytes  1.04 Mbits/sec  0.065 ms  0/90 (0%)  
[  5]  28.00-29.00  sec   129 KBytes  1.05 Mbits/sec  0.042 ms  0/91 (0%)  
[  5]  29.00-30.00  sec   127 KBytes  1.04 Mbits/sec  0.047 ms  0/90 (0%)  
[  5]  30.00-31.00  sec   129 KBytes  1.05 Mbits/sec  0.036 ms  0/91 (0%)  
[  5]  31.00-32.00  sec   127 KBytes  1.04 Mbits/sec  0.056 ms  0/90 (0%)  
[  5]  32.00-33.00  sec   129 KBytes  1.05 Mbits/sec  0.140 ms  0/91 (0%)  
[  5]  33.00-34.00  sec   127 KBytes  1.04 Mbits/sec  0.050 ms  0/90 (0%)  
[  5]  34.00-35.00  sec   129 KBytes  1.05 Mbits/sec  0.024 ms  0/91 (0%)  
[  5]  35.00-36.00  sec   127 KBytes  1.04 Mbits/sec  0.033 ms  0/90 (0%)  
[  5]  36.00-37.00  sec   129 KBytes  1.05 Mbits/sec  0.067 ms  0/91 (0%)  
[  5]  37.00-38.00  sec   127 KBytes  1.04 Mbits/sec  0.043 ms  0/90 (0%)  
[  5]  38.00-39.00  sec   129 KBytes  1.05 Mbits/sec  0.058 ms  0/91 (0%)  
[  5]  39.00-40.00  sec   127 KBytes  1.04 Mbits/sec  0.043 ms  0/90 (0%)  
[  5]  40.00-41.00  sec   129 KBytes  1.05 Mbits/sec  0.047 ms  0/91 (0%)  
[  5]  41.00-42.00  sec   127 KBytes  1.04 Mbits/sec  0.033 ms  0/90 (0%)  
[  5]  42.00-43.00  sec   129 KBytes  1.05 Mbits/sec  0.056 ms  0/91 (0%)  
[  5]  43.00-44.00  sec   127 KBytes  1.04 Mbits/sec  0.113 ms  0/90 (0%)  
[  5]  44.00-45.00  sec   129 KBytes  1.05 Mbits/sec  0.036 ms  0/91 (0%)  
[  5]  45.00-46.00  sec   127 KBytes  1.04 Mbits/sec  0.066 ms  0/90 (0%)  
[  5]  46.00-47.00  sec   129 KBytes  1.05 Mbits/sec  0.107 ms  0/91 (0%)  
[  5]  47.00-48.00  sec   127 KBytes  1.04 Mbits/sec  0.041 ms  0/90 (0%)  
[  5]  48.00-49.00  sec   129 KBytes  1.05 Mbits/sec  0.133 ms  0/91 (0%)  
[  5]  49.00-50.00  sec   129 KBytes  1.05 Mbits/sec  0.034 ms  0/91 (0%)  
[  5]  50.00-51.00  sec   127 KBytes  1.04 Mbits/sec  0.075 ms  0/90 (0%)  
[  5]  51.00-52.00  sec   129 KBytes  1.05 Mbits/sec  0.028 ms  0/91 (0%)  
[  5]  52.00-53.00  sec   127 KBytes  1.04 Mbits/sec  0.044 ms  0/90 (0%)  
[  5]  53.00-54.00  sec   129 KBytes  1.05 Mbits/sec  0.043 ms  0/91 (0%)  
[  5]  54.00-55.00  sec   127 KBytes  1.04 Mbits/sec  0.042 ms  0/90 (0%)  
[  5]  55.00-56.00  sec   129 KBytes  1.05 Mbits/sec  0.046 ms  0/91 (0%)  
[  5]  56.00-57.00  sec   127 KBytes  1.04 Mbits/sec  0.061 ms  0/90 (0%)  
[  5]  57.00-58.00  sec   129 KBytes  1.05 Mbits/sec  0.192 ms  0/91 (0%)  
[  5]  58.00-59.00  sec   127 KBytes  1.04 Mbits/sec  0.065 ms  0/90 (0%)  
[  5]  59.00-60.00  sec   129 KBytes  1.05 Mbits/sec  0.104 ms  0/91 (0%)  
[  5]  60.00-61.00  sec   127 KBytes  1.04 Mbits/sec  0.039 ms  0/90 (0%)  
[  5]  61.00-62.00  sec   129 KBytes  1.05 Mbits/sec  0.048 ms  0/91 (0%)  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Jitter    Lost/Total Datagrams
[  5]   0.00-62.00  sec  7.76 MBytes  1.05 Mbits/sec  0.000 ms  0/5612 (0%)  sender
[  5]   0.00-62.00  sec  7.75 MBytes  1.05 Mbits/sec  0.048 ms  0/5612 (0%)  receiver

iperf Done.

Upstream:

[ ID] Interval           Transfer     Bitrate         Total Datagrams
[  5]   0.00-1.00   sec   129 KBytes  1.05 Mbits/sec  91  (omitted)
[  5]   1.00-2.00   sec   127 KBytes  1.04 Mbits/sec  90  (omitted)
[  5]   0.00-1.00   sec   129 KBytes  1.05 Mbits/sec  91  
[  5]   1.00-2.00   sec   127 KBytes  1.04 Mbits/sec  90  
[  5]   2.00-3.00   sec   129 KBytes  1.05 Mbits/sec  91  
[  5]   3.00-4.00   sec   129 KBytes  1.05 Mbits/sec  91  
[  5]   4.00-5.00   sec   127 KBytes  1.04 Mbits/sec  90  
[  5]   5.00-6.00   sec   129 KBytes  1.05 Mbits/sec  91  
[  5]   6.00-7.00   sec   127 KBytes  1.04 Mbits/sec  90  
[  5]   7.00-8.00   sec   129 KBytes  1.05 Mbits/sec  91  
[  5]   8.00-9.00   sec   127 KBytes  1.04 Mbits/sec  90  
[  5]   9.00-10.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  10.00-11.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  11.00-12.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  12.00-13.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  13.00-14.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  14.00-15.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  15.00-16.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  16.00-17.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  17.00-18.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  18.00-19.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  19.00-20.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  20.00-21.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  21.00-22.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  22.00-23.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  23.00-24.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  24.00-25.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  25.00-26.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  26.00-27.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  27.00-28.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  28.00-29.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  29.00-30.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  30.00-31.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  31.00-32.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  32.00-33.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  33.00-34.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  34.00-35.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  35.00-36.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  36.00-37.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  37.00-38.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  38.00-39.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  39.00-40.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  40.00-41.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  41.00-42.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  42.00-43.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  43.00-44.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  44.00-45.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  45.00-46.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  46.00-47.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  47.00-48.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  48.00-49.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  49.00-50.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  50.00-51.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  51.00-52.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  52.00-53.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  53.00-54.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  54.00-55.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  55.00-56.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  56.00-57.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  57.00-58.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  58.00-59.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  59.00-60.00  sec   129 KBytes  1.05 Mbits/sec  91  
[  5]  60.00-61.00  sec   127 KBytes  1.04 Mbits/sec  90  
[  5]  61.00-62.00  sec   129 KBytes  1.05 Mbits/sec  91  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Jitter    Lost/Total Datagrams
[  5]   0.00-62.00  sec  7.75 MBytes  1.05 Mbits/sec  0.000 ms  0/5613 (0%)  sender
[  5]   0.00-62.00  sec  7.75 MBytes  1.05 Mbits/sec  3.372 ms  0/5613 (0%)  receiver

iperf Done.

[Guybrush85]

For now, here's the DSLR Reports test, however as/when I can get hold of a windows machine I'll do ping plotter again as that I do have old screenshots from:

45ms : xxxxxx
46ms : xxxxxxxxxxxxxxxxx
47ms : xxxxxxxxxxxxxxxxxxxxxxxxxxxx
48ms : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
49ms : xxxxxxxxxxxxxxxxxxxxx
50ms : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
51ms : xxxxxxxxxxxxxxxxxxx
52ms : xxxxxxx
53ms : xxxxxx
54ms : xxxxxxx
55ms : xx
56ms : x
58ms : xxx
59ms : x
60ms : xx
61ms : x
62ms : x
63ms : x
65ms : x
66ms : x
67ms : x
76ms : x

[lynxblaine]

Your results are looking promising. 

I have 100Mb broadband and 24 channels so definitely the amount of channels do not relate to the speed of broadband. 

[philjohn]

Looking very good!

Here's my latest BQM from today, whole family has been out riding rollercoasters so very minimal traffic (mostly keepalive from VOIP phone to SipGate) and showing a very stable connection:

[Gymato]

So, just to clarify, only vivid 350 got the updates, rest of us have to wait, correct?

[philjohn]

---

@Gymato wrote:

So, just to clarify, only vivid 350 got the updates, rest of us have to wait, correct?

---

It certainly seems that way - I only got it (after trying a pinhole reset 4-5 times) when I upgraded to Vivid 350.

It's still going through the trial from what can be gathered, so doing a phased rollout to bigger and bigger sets of customers is the prudent move to make, and people on the highest tier will tend to be heavier users of their connection.

[madnessx9]

Why is this such an issue still...

I think this will be my last year with VM, almost tempted to just deny payments and move to a new provider