on 02-12-2016 05:31
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:
Yesterday, DSLReports issued a news story covering the thread:
Today, Arris responded:
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:
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]
on 15-12-2016 15:00
on 15-12-2016 15:03
@benjumi wrote:
I don't stream that often, more of a dabbling than an occupation to be honest. Does the throttling of the connection they apply to the 200Vivid standard package apply to download speeds specifically?
Is there information anywhere about what the typical Vivid 200 standard package, upload speeds are?
I think my Sky ADSL is 20 down and 6/7 up.
Throttling only applies to upload speeds, details HERE. The upload speed on the standard Vivid 200 is 12Mbps.
______________________
Scott
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out so my answers may be wrong If my answer solves your problem please mark it as helpful as it may help others
My setup: Vivid 200 Optical fibre with Superhub 2 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks
on 15-12-2016 15:08
@SCA1972 wrote:
@benjumi wrote:
I don't stream that often, more of a dabbling than an occupation to be honest. Does the throttling of the connection they apply to the 200Vivid standard package apply to download speeds specifically?
Is there information anywhere about what the typical Vivid 200 standard package, upload speeds are?
I think my Sky ADSL is 20 down and 6/7 up.Throttling only applies to upload speeds, details HERE. The upload speed on the standard Vivid 200 is 12Mbps.
______________________
Scott
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out so my answers may be wrong If my answer solves your problem please mark it as helpful as it may help others
My setup: Vivid 200 Optical fibre with Superhub 2 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.
Indeed and if you want the *un-throttled upload at 20Mbps you need the Vivid 200 Gamer Edition. (Note: This will increase the amount of channels and as mentioned would probably impact your latency more severely)
*I have not really tested it out to be sure, but I've not had any issues either.
on 15-12-2016 15:17
on 15-12-2016 15:17
on 15-12-2016 15:24
Sorry wrong link -
http://www.thinkbroadband.com/ping/share/cc3699f904d77c0396c56b4125ef3a54-15-12-2016.html
Perhaps it's the levels I have:
Downstream bonded channels Channel Frequency(Hz) Power(dBmV) SNR(dB) Modulation Channel ID 1 299000000 12 38.9 256 qam 17 2 323000000 11.5 38.6 256 qam 20 3 315000000 12 40.9 256 qam 19 4 307000000 12.3 40.9 256 qam 18 5 291000000 11.6 40.3 256 qam 16 6 283000000 11.5 40.3 256 qam 15 7 275000000 11.6 40.3 256 qam 14 8 267000000 12 38.9 256 qam 13 9 259000000 12.3 38.9 256 qam 12 10 251000000 12.5 40.3 256 qam 11 11 243000000 13 40.3 256 qam 10 12 235000000 13 40.3 256 qam 9 13 227000000 13.5 40.3 256 qam 8 14 219000000 13.4 40.3 256 qam 7 15 211000000 13.9 40.3 256 qam 6 16 203000000 13.9 40.9 256 qam 5 17 195000000 14.5 40.3 256 qam 4 18 187000000 15 40.3 256 qam 3 19 179000000 15.1 40.9 256 qam 2 20 171000000 15.5 40.3 256 qam 1 Upstream bonded channels Channel ID Frequency(Hz) Mode Power (dBmV) Modulation Channel Bandwidth(Hz) Symbol Rate (ksps) 61 46200000 ATDMA 44 64 qam 6400000 5120 63 32600000 ATDMA 44 64 qam 6400000 5120
Support didn't seem to care and tried to tell me it was the MTU!!
on 15-12-2016 15:36
@mbmaplethorpe Your downstream power levels are all above the recommended max of 10dBmv, so if you haven't already I suggest creating a new thread and posting those figures in order to get an engineer sent out to adjust them.
______________________
Scott
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out so my answers may be wrong If my answer solves your problem please mark it as helpful as it may help others
My setup: Vivid 200 Optical fibre with Superhub 2 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks
on 15-12-2016 15:43
Hi mbmaplethorpe,
Thanks for posting!
Sorry to hear you're having trouble with your connection.
As SCA1972 has said, there's an issue with your downstream power levels that will need to be adjusted by our technicians. I've sent you a private message (purple envelope at the top right of your screen) so I can arrange an appointment.
Look forward to hearing from you! 😄
Josh
on 15-12-2016 17:57
@Josh_RW, can we get a VM response that this issue has been acknowledged and the relevant departments are approaching Intel regarding the fix? Yet again VM's complete silence on a massive issue is astounding.
on 15-12-2016 18:04