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]

[itinfocus]

---

@theoven wrote:
I have made modem mode and I get the
Microsoft Windows [Version 10.0.16299.19]
(c) 2017 Microsoft Corporation. All rights reserved.

C:\Users\k****>ping -t 192.168.100.1

Pinging 192.168.100.1 with 32 bytes of data:
Reply from 192.168.100.1: bytes=32 time=3ms TTL=63
...
Reply from 192.168.100.1: bytes=32 time=5ms TTL=63
Reply from 192.168.100.1: bytes=32 time=3ms TTL=63
Reply from 192.168.100.1: bytes=32 time=57ms TTL=63

---

Pinging the gateway address of 192.168.100.1 isnt always the best target. Also using the standard windows ping utility doesnt check regularly enough to be effective.

Do a tracert in windows and ping against the second hop which should be your CMTS. Also try a web accessible destination such as google dns on 8.8.8.8

Google PsPing (Microsoft tool) and use psping -t -i 0 8.8.8.8 (this is for an ICMP ping). You can also use this free tool for latency monitoring and TCP ping tests.

With the new firmware my ICMP pings look consistent to web addresses but the TCP ping and latency tests still show serious issues.

[itinfocus]

Sorry if this is a double post but my firt one looks to have disappeared ?

Pinging the gateway address of 192.168.100.1 isn’t always the best target. Also using the standard windows ping utility doesn’t check regularly enough to be effective.

Do a tracert in windows and ping against the second hop which should be your CMTS. Also try a web accessible destination such as google dns on 8.8.8.8

Google PsPing (Microsoft tool) and use psping -t -i 0 8.8.8.8 (this is for an ICMP ping). You can also use this free tool for latency monitoring and TCP ping tests.

With the new firmware my ICMP pings look consistent to web addresses but the TCP ping and latency tests still show serious issues.

[Stoddy27]

I am sorry but to say pinging the gateway is not a good test is incorrect - If you are seeing latency in your internal network to internal devices consistently this highlights the problem and you will have the same latency outside of the network - I have never seen a network device which has anything but 1/2ms latency internally. 

My network uses high amounts of traffic hence why we are on the highest tier package to avoid slowdowns this problem really affects my network sometimes I see 15-16ms ping (any time of the day or night) sometimes I see 600ms ping. I can't use BQM as my router does not allow for external ping for security reasons so I can't provide that data but what I can say is since the SH3 went in my locally hosted websites suffer massively. 

Our network monitoring shows constant spikes at random times where there is little to no traffic hitting our network.Can anyone let me know the Beta test firmware version number I want to see if I can speak to someone at Virgin to request this my contract ends in 3 days.

[deviousiphone]

Stoddy27, I am assuming given your network requirement you are using your own router? probably with something like DD-WRT or some other enhanced firmware, you can enable the IP that the BQM server uses to do pings with a simple iptables command, that will only allow that 1 IP address to deliver the pings and block everything else.

[Stoddy27]

It's an Archer C3200 TP-Link which by their documentation won't enable Ping from WAN - I did have the ASUS RT-AC5300 but I sold it because there was no point having a £450 router on an internet connection that can't keep a stable latency 😄

Is there anyway to set this up so the BQM can ping an internal device through port redirection or my web server?

[deviousiphone]

I just looked at that router and DD-WRT is not supported yet, in regards to port redirection I am uncertain if that would be viable as I have never attempted such a procedure, mind you if you do have the Hub 3 you are effected regardless so using things like pingplotter would confirm the issue.

[Stoddy27]

ye I agree I know I am affected and setting up BQM won't help my issue - I spoke to customer services who were not aware of any trials going on and he did mention on their internal boards there had been a lot of staff complaining of the same issue. His words where "I haven't upgraded yet to the SH3 because of the issues"

He also said that the stock of SH2AC had run out and his manager couldn't get hold of any and that if I was to buy a SH2AC from eBay they wouldn't be able to activate it as the MAC from the SH2AC would be registered against someone else's address and their system only allows them to assign MAC's that are not in use.

The way to setup BQM if your router does not respond to ICMP is to set a device in your network as DMZ so that can respond but I would advise against this for any security conscience people. 

[deviousiphone]

Arguably it is possible to get a hub 2 as I just did today, but it took over 9 months of problems and complaints to finally speak to the one person who could make it happen, and really there are no guarantees you could ever bump into him at that time, I was just lucky.

[Datalink]

If you want to see the graphical image of the problem, download pingplotter and ping the CMTS, which is the first address beyond the modem or router (modem in Modem Mode) enroute to anywhere.  Pingplotter will run in pro mode for 14 days, after which it will kick down into freebie mode if you don't buy a standard or pro licence.  The one point to pingplotter is that you can override the interval settings, which you really have to do in order to see this issue.  Set the interval time to 0.010 ms if you want to give this a try. 

If you want a freebie, easy way to look at this, download hrping:

https://www.cfos.de/en/ping/ping.htm

Run a trace to anywhere to determine the CMTS address (second IP address in the trace)

Run a command prompt with admin privileges.  This is required to answer the Hrping warranty question on the very first run. 

Use the following command to ping the CMTS with a 10 ms interval:

hrping -s 10 -n 5000 -g xxx.xxx.xxx.xxx

-s 10 = 10 ms interval

-n 5000 = 5000 pings

-g = show graph   Right click on the graph and set the time scale to 30 seconds and the average time to 100 ms.  Unfortunately the average time minimum is only 100 ms, but, you should still see the latency spikes thru the modem enroute to the CMTS and back again to the modem.  

To run that again with the same plot, which already has the settings changed as indicated, change the -g to -G:

hrping -s 10 -n 5000 -G xxx.xxx.xxx.xxx

If you have a fast enough pc, drop the time interval to 5 milli-seconds

hrping -s 5 -n 5000 -g xxx.xxx.xxx.xxx

Hrping has the capability to use the server timestamps, if the server supplies them.  This allows you to look at the results which are broken out into upload and download times.   This will give you an idea if the problem is on the upload or download side, or equally divided.  When I was running a Puma 6 modem I didn't know about Hrping at the time, or at least not about the timestamp setting.  This would be worth trying:

hrping -s 10 -n 1000 -g -M xxx.xxx.xxx.xxx

The one problem with this is the error growth in the results.  At first, the upload and download times look reasonable, but, if you run longer ping tests, the results become inaccurate, to the point where the overall time, upload and download times don't make any sense.  I'd be very interested in seeing the section of results from a Puma 6 modem, where the ping time spikes to see the breakout of the upload and download times.  When the run is complete, scroll up to the top of the results for this particular run and read down thru the results looking for ping times that peak somewhere above 80 milli-seconds as a guess.  The normal time to the CMTS should be around 8 to 13 ms, so any high times should stand out. You can run longer tests simply by increasing the number of pings, but for using the timestamp option I don't recommend that due to the increasing inaccuracies that HRping appears to suffer from. 

 Keep in mind that the ping spikes occur ~1.9 seconds, so, the higher times should be easily visible in the text results and plot.  Essentially this is what the BQM provides, but, in this case, as its generated from your pc, what you're seeing is the latency thru the modem, without any other latency that the network beyond the CMTS provides.  This will give you a very good idea of the latency that the modem itself is causing.  Although this is only ICMP, the same situation exists for TCP/IP, and UDP for IPV4 and for ICMP, TCP/IP and UDP for IPV6.

[wotusaw]

boltedenergy@

For those who are in the know or got the firmware fix:

"Any ideas how many people got the trial firmware?

Since you have had it has it improved ICMP and DNS lookup requests?

Of course the TCP/UDP is not fixed but is the general latency conditions a marked improvement?

Have you received any further communication from VM?

Thanks,"

For those who are in the know or got the firmware fix:

Any ideas how many people got the trial firmware?= Nada. Best guess would be 25/50/75 or 100. I'll go for the 100 lucky punters.

Since you have had it has it improved ICMP and DNS lookup requests?= What the? Tell me how to find out and I will post that info....and don't ridicule me for being so dumb...I have powerful friends in high places. Just thought I'd mention it.

Of course the TCP/UDP is not fixed but is the general latency conditions a marked improvement?= Marked is too strong a word but yes, I see some improvement on gaming latency...crazy as this may seem. Also my Broadband latency widget is showing signs of improvement. What's more it seems to be improving very slowly as time goes by......very strange.

Have you received any further communication from VM?= Only a reply to my offer of $4,000,000 to buy them out...... Other than that nada. Oh, and excepting any spies(you know who you are).