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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

Signed up to 200Mb Gamer for the extra upload and was forced to get a SH3, I now have a connection that's actually worse for gaming.

My switch from SH2 to SH3:

 

rj9X97N

Yes, unfortunately.  Have a look at the last post on the previous page.

Here are additional pingplots from the SB6190 experimental firmware version testing.  In this particular instance UDP pings to www.pingplotter.com are shown, first with a Broadcom based SB6183 and then from the Puma 6 SB6190 (read Hub 3).  The UDP ping spikes in the second plot, with packet loss, are a very good illustration of what happens to your DNS lookup which uses UDP, causing web pages or any application which is loading site date to load slowly or fail and retry.  This also illustrates what happens to online games which use UDP.  The UDP data arrives late, or is transmitted late, or fails altogether due to the packet loss.  You could be knocked out of a game and not even know it.  Gamers please chime in here if you know what online games happen to use UDP.  

For the UDP protocol, the presence of the latency spikes and packet loss will be a failure point in the test phase:

https://www.dslreports.com/forum/r31122039-

 

Fishpan
On our wavelength

I have been playing Battlefield 1 multiplayer on PC since its release. I have noticed huge lag spikes ingame that take the ping from 17-20ms all the way up to 400-800ms ping at times causing me to either miss 5 seconds of action or be disconnected from the game entirely. I am on Vivid Gamer 200/20 using a wired ethernet connection from my PC to the HUB 3 and with the latest drivers for everything including the Intel I219-V ethernet driver in my PC.

Talking to Virgin about this issue I have always been dismissed, with them stating that everyone in my area suffers with higher latency/ping spikes - a fact I know is simply NOT true. My friend is on the Vivid 200/12 package with a SuperHub 2ac and his ping is consistently low from 15-20ms whilst living very close to me. 

Running a traceroute to multiple BF1 servers and other servers such as EA, Google, Microsoft, BBC etc showed that most of the latency accrued before packets even reached the VM network! I tried to explain this to technical support but appeared like a fool when I could not definitively say what the issue was with the modem. Seeing this thread has been emotional and vindictive for me as well as others who have been suffering for a long time, being treated like 'tinfoil hat people.' I look forward to the day where we gamers are getting the premium service that we are paying a premium for. 

jhuk
Trouble shooter
My Broadband Ping - SH3-300Mb/s

This is going to take several weeks to correct.  If anyone is interested to keeping an eye on the progress of this, or lack thereof, watch the following thread, which was started today.  The conversation regarding this issue on the DSLReports forum has been shifted to this thread:

https://www.dslreports.com/forum/r31122204-SB6190-TCP-UDP-Network-Latency-Issue-Discussion#31122759

 

Have virgin actually acknowledged the problem yet?

Easy solution if they just keep ignoring it - phone for an engineer every week about it.
Hit them the only place they notice, their wallets.

I'm thinking of ringing them and asking for compensation.  Firstly for my wasted time trying troubleshoot the problem and Secondly the extra charge I pay each month for Vivid Gamer.

Sky_Lord
Up to speed
I've recently changed from the hub 2 to the hub 3 as every 4-6 weeks I was losing internet connection. I have noticed on the graphs that latency spikes are more frequent on the hub 3 compared to the SH2 I had but not much different, when the SH2 was used in modem mode with my Asus connected it was flat with literally just the odd slight spike over the course of a few days.

However when I put the Hub 3 into modem mode to try my Asus RT-AC68U the latency was much worse which I found odd, not as severe as what you guys have mind. I can't say I've noticed any problems in gaming if in modem mode or router mode, I've left the hub 3 in router mode as the latency is far better.

I'll try and put a picture if my graph for comparison.

<a title="Broadband Ping" href="http://www.thinkbroadband.com/ping/share/25e3cc6cfa18d883f66a4e79000c4781-10-12-2016.html"><img alt="My Broadband Ping - Hub 3.0" src="http://www.thinkbroadband.com/ping/share-thumb/25e3cc6cfa18d883f66a4e79000c4781-10-12-2016.png" /></a>