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]

[Guybrush85]

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@RidingTheFlow wrote:

Most likely attacks are already happening here and there - but people have no idea that they are attacked and just think its their modem or connection acting up, and customer services are asking them to use paperclip to reset their modem 😉

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Problem is, a DoS can happen on any of the routers, so it'd be hard to prove one way or the other whether it was the puma fault in particular that caused it to fail and most likely not.

[itinfocus]

Truly fed up with this ongoing situation.

very much doubt any pressure applied will result in a better outcome but also submitted the below to Watchdog.

The current hardware choice (Hub 3.0) for access is plagued with serious and ongoing issues.

1) serious latency and packet loss which disrupts all services

All internet access is delivered with below acceptable performance but latency sensitive applications such as gaming, VoIP or VPN the most noticeable use cases.

2) A trivial denial of service attack, with published code, can take any virgin customer off line indefinitely.

Virgin are not making customer service staff, customers or engineering staff aware of the issue. They are also actively trying to replace the existing customer installed hardware (Superhub 2 family).

Detailed discussion on this is available at the following links:
http://community.virginmedia.com/t5/Gaming-Support/Hub-3-Compal-CH7465-LG-TG2492LG-and-CGNV4-Latency...

https://www.dslreports.com/forum/r31122204-SB6190-Puma6-TCP-UDP-Network-Latency-Issue-Discussion~sta...

Https://www.badmodems.com

I have ongoing issues since my hardware was upgraded. Wasted many days waiting for engineer visits and talking with support staff. Obviously this has not resolved what is a fundamental hardware flaw.

Once upgraded Virgin refuse to allow customers to switch back to the previous generation technology which works as advertised.

[itinfocus]

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@Guybrush85 wrote:

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@RidingTheFlow wrote:

Most likely attacks are already happening here and there - but people have no idea that they are attacked and just think its their modem or connection acting up, and customer services are asking them to use paperclip to reset their modem 😉

---

Problem is, a DoS can happen on any of the routers, so it'd be hard to prove one way or the other whether it was the puma fault in particular that caused it to fail and most likely not.

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The difference is that most DoS attacks can't take down a 2 to 300 Mbit connection with a dial up modem.

As I stated much earlier even a modest bot net type DDoS attack could take down every Hub 3 in the U.K. 

Would chief apologist Shane suggest that in those circumstances everything is just fine and it's perfectly normal for ISPs to have downtime occasionally?

[Guybrush85]

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@itinfocus wrote:

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@Guybrush85 wrote:

---

@RidingTheFlow wrote:

Most likely attacks are already happening here and there - but people have no idea that they are attacked and just think its their modem or connection acting up, and customer services are asking them to use paperclip to reset their modem 😉

---

Problem is, a DoS can happen on any of the routers, so it'd be hard to prove one way or the other whether it was the puma fault in particular that caused it to fail and most likely not.

---

The difference is that most DoS attacks can't take down a 2 to 300 Mbit connection with a dial up modem.

As I stated much earlier even a modest bot net type DDoS attack could take down every Hub 3 in the U.K. 

Would chief apologist Shane suggest that in those circumstances everything is just fine and it's perfectly normal for ISPs to have downtime occasionally?

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I'm fully aware of the difference. The point is the attacks are pretty much always single target, so it's hard to say one way or the other whether the puma issue was the reason someone had a DoS or not, thus it's not receiving the same kind of reaction as the latency.

And I've already made my point about a multiple IP attack although taking out every hub is a little overzealous... think a bottleneck or 2 higher up might come into play.

[wotusaw]

itinfocus:

"Would chief apologist Shane suggest that in those circumstances everything is just fine and it's perfectly normal for ISPs to have downtime occasionally?"

Lol. Ouch and meeeoooow.

Shane does seem to have inside knowledge of how these big powerful companies play with all of us like a cat plays with a wounded mouse.

Virgin have a van that appears in my town centre every saturday. I make a point of engaging the occupant and asking about Pumaggedon. Of the three reps whinged upon none had a clue about it. I of course enlightened them.

[Drewley]

After speaking to technical support on the phone, the rep seemed aware of the issue but without admitting to anything.
He was very helpful and was happy to arrange a SH2AC to be sent out to me, although he advised me stock was low. Said he would call back once delivery had been made to ensure I did not receive another SH3. He said if I received a SH3 he would contact the area manager - sadly there's no way for me to call this rep back.

Lo and behold, after staying home from work to accept the delivery, what's in the box? A SH3 of course.

Phoned up technical support again, this time got an offshore rep, I was told SH2AC is not compatible with 200mbit (untrue).
Spoke to retentions who did some phoning around to other departments, only to be told that they don't have stock.

So, all in all a day wasted sat around.

I'd be interested to know how the chap who replied further up this forum thread obtained his.

[mobculture]

If you mean me, it was dumb luck really. Check my post history and you should send how it happened (Thurs 10 aug).

[RidingTheFlow]

Well, I've also managed to get SuperHub 2AC back (details on how I've lost it and what transpired in my own thread - http://community.virginmedia.com/t5/QuickStart-set-up-and/Hard-to-pinpoint-daily-connection-sync-dis...). Its a joy finally to be able use Citrix without cursor moving at like 10fps.

My written complaint was processed and I've got a call from head office last Friday.

Gentleman I've spoken to confirmed with their "broadband specialist" that problem is known (quote: "yes, its the chipset"). However from his overall attitude I've got idea that VM is not considering issue too high-priority. In his own words "but speeds are fine right? its just this little thing". However he did not disagree with any of points I've brought which made it a big issue for *me*.

He said that he also aware why I had second SH3 send last time and why system defaulting to it even when they order SH2. He assured me that they will send SH2AC to me this time for sure.

And indeed, I've received it 2 hours ago. It was clearly a used return, all dusty and box even still had "return kit" label left inside it. But who cares, if it works (which I've also made sure them to be aware of that I don't care if its a used one).

It didn't automatically activate, I was redirected to offshore support, so naturally was a bit anxious again. But it went with no problems whatsoever - they've just asked me "what is the MAC address", then it was activated in 5 minutes. And now its working fine.

So, I think its clear now:

- Absolutely nothing prevents activation of used hubs. They maybe just need to remove their MAC from other account before they send it to you).

- They can send SH2 to people if they want to. It probably requires them to post it manually instead of using their standard system, so they are just lazy about it.

- They are perfectly aware of problem. Just don't consider it big enough, and still prefer just to placate people who complain loud enough (and just try to persuade other people to give up).

- They do absolutely care about complaints. But only its *official complaint*, and not just which you think it is, but one following proper procedure with potential escalation to CICAS for arbitration if VM does not solve it.

Shame you need to throw a royal poo-storm if you want any staff just to do a bit extra to help you except bullet points on their standard daily cheat-sheet.

[mobculture]

Great news, riding. Welcome back to the land of stable(ish) pings!

I think the official complaint route is the one that everyone affected should use, at it seems to result in a success each time.

[mjpartyboy]

I have no interest in upgrading our broadband from Vivid 200 and giving up our fit for purpose SH2, whilst the SH3 is in circulation. I was considering going for the Vivid Gaming service, but as we stream and game a lot in our house, the SH3 is not an option, especially as it has an adverse effect on other services you pay for, such as Netflix and Xbox Live.