Why is my laptop continuously reading 20Mbps from Flex-4K?

[DSperber]

This is very strange. I happened to be working in Win11 on one of my LAN computers tonight, a Lenovo P70 laptop, on which I have DUMeter installed. This is a software product that monitors download/upload traffic on LAN and internet. Although I was doing absolutely nothing, DUMeter reported a continuous download of 20Mbps and a continuous upload of about 920Kbps.

Thinking it might have been something caused by my recent upgrade from Win11 23H2 to 24H2, I re-booted to Win10 22H2 which I also have installed on this laptop. Well, remarkably, DUMeter on the Win10 system reported the identical symptom of a continuous 20Mbps down and 920Kbps up. Again, nothing at all was going on, and yet there was this traffic being reported by DUMeter.

Looking deeper into the traffic, I first determined it was LAN traffic, and not internet traffic.



And then using "filter by IP address" capability of DUMeter, I was able to look at each of the "attached devices" on my router so as to determine which device was carrying on this mysterious conversation with the laptop. And all of them except one reported 0 bytes traffic. But the one device which reported the full 20Mbps download was my SD Flex-4K!!!

Now on this laptop I did install both (a) HDHR client app from MS Store, and also (b) HDHR software, Setup and Config. I do not run the DVR server on this laptop but I did want to have the ability to have control capability on the laptop, which is why I installed the HDHR software. But I've done the same thing on my other Win11 laptop, and it does not show this continuous 20Mbps download traffic.

Nevertheless, thinking it might be the HDHR software which is the culprit I uninstalled it and re-booted the laptop. And it made no difference. Still showing continuous 20Mbps download from Flex-4K to the laptop and 920Kbps upload to Flex-4K.

I'm at a loss to imagine what might be going on. Can anyone suggest what this traffic could be, and of course how to stop it?

Any thoughts on gathering any additional diagnostic clues to get to the bottom of this? Why only on this laptop (and for both Win10 and Win11 operating systems on the laptop) and none of the other two desktops and one other laptop on my LAN?

[DSperber]

Well I decided to try pulling the power cord out of the Flex-4K. And of course sure enough the continuous 20Mbps data being pumped to the laptop stopped.

Then I plugged it back in, and amazingly it did NOT resume pumping data to the laptop! I even re-booted the laptop and still everything seems back to normal.

I then reinstalled the HDHR software which I'd just uninstalled thinking it might be the culprit. And once again, even after reinstalling the software there still was NO data pumping from the Flex-4K to the laptop.

Furthermore, the HDHR client app delivers all the expected TV channels just as it's always done.

So, I'm at a loss to understand why just this one PC on my LAN saw this "20Mbps data pumping" from the Flex-4K to it, while none of my other PCs did. But apparently power cycling the Flex-4K resolved whatever was going on. It's gone now. Normalcy has returned.

So I guess it's "case closed". I have emerged victorious.


NOTE: there is one fact here that might be relevant as to why only this laptop saw the symptom and no other PC on the LAN saw the symptom. Turns out the laptop is in my upstairs office where the Flex-4K is also located, and BOTH of these devices are plugged into the same Netgear GS108 switch via CAT6. And the switch is then connected via CAT6 to the downstairs router. The upstairs desktop PC doesn't go through the switch but connects directly through its own dedicated CAT6 to the router. And the other laptop connects via wifi to a wifi access point connected by CAT6 to the router, again not going through the upstairs switch where the Flex-4K and problem laptop live.

So maybe this "data pumping" had something to do with their both going through the GS108 switch, with some kind of communication between these devices both going through the switch. Now I didn't power cycle the switch, but I only power cycled the Flex-4K. But perhaps it was this common switch that saw both devices which was really the culprit here and somehow responsible for generating the "data pumping" that I observed And then something happened to magically clear up the problem when I power cycled the Flex-4K, even without also power cycling the switch. Obviously the Flex-4K reset itself.

Anyway, again, it's now gone due to power cycling the Flex-4K, whatever truly was the underlying cause.

[oaks37]

Windows Task Manager would have told you what process was using the network (edit: ... if the process was still running.) Sure sounds like something was tuning in a channel on the hdhomerun from the pc. TSReader or somesuch.

[nickk]

20Mbps (19.2Mbps + UDP/IP overhead) is what you get if you take the full mux of a physical channel.

The HDHomeRun app doesn't do this but apps that use BDA drivers often do. It is possible for the stream to continue after the app closed if the app terminated without telling the HDHomeRun combined with a firewall that prevents ICMP traffic (ie Windows Firewall).

[DSperber]

Well, something "residual", like an app still tuning or whatever... seems plausible as a maybe.

But initially it was from a brand new fresh boot to Win11 on that laptop. Zero had been running. Just Windows desktop initialization, including DUMeter. And that 20Mbps "flood" coming in from the Flex-4K (to what which must be listening on the laptop??) was simply right after Windows desktop initialization.

So no TSReader, not HDHR client app running, nothing that would have communicated with the Flex-4K in any way to listen to a physical RF channel.

And then, suspicious it might be something tied to the recent upgrade to 24H2 I decided to re-boot to Win10. And once again, identical symptom. Just get the Windows desktop initialized and stabilized including DUMeter, and the 20Mbps "flood" was there as well.

So it wasn't related to Win10 or Win11. It wasn't related to any app having been started, run, and terminated (incompletely or otherwise), and nothing "residual".

Clearly it was COMING FROM THE FLEX-4K iITSELF (and/or the Netgear GS108 switch somehow malfunctioning in some way, with both the Flex-4K and laptop plugged into it)!

Whatever was going on instantly disappeared once I pulled the power cable out of the Flex-4K. And the power reset obviously cleared up whatever might have been cooking previously, because once the re-booted Flex-4K stabilized I DID NOT HAVE A "FLOOD". Things had truly returned to normal.

Yes Nick, there probably was some non-coincidental non-random significance to that 20Mbps number for the "data flood. But whatever the explanation, it's gone now. Power cycling the Flex-4K apparently got everything back to normal.

Thanks for all thoughts and comments.

[nickk]

Something on the laptop asked the HDHomeRun to tune a channel and stream the full mux unfiltered.

Nothing told the HDHomeRun to stop so it kept doing its job.

[DSperber]

AHA!!! You sir are a gentleman and a scholar!

Sure enough, over the past week or so I've been involved on the 'OTA LA" thread on AVS Forum, discussing assorted issues relating to several KTLA sub-channels and their statmux-assigned low bitrates, resulting video image anomalies, etc. And so I have used all of the tools available to me to measure the analytics, and these have certainly included TSReader for use with my Hauppauge Quad-HD ATSC tuner and how it tunes the channels of concern. TSReader was not used for the Flex-4K.

But absolutely I used HDHR Config GUI to measure bitrates on RF35 (where the KTLA sub-channels are located) as seen by the Flex-4K.

And in order to have an HDHR Client App to see the video image quality, I used the laptop since it was Win10/Win11. My desktop machine is Win7 (to run Windows Media Center).

So you are absolutely correct, I absolutely HAD opened up a "measurement channel" between the Flex-4K and this laptop repeatedly over the past week. I don't know how to terminate that measurement other than to close the programs involved, which of course is what I did. I don't remember which one was closed first or second but I woudln't think it should be that critical.

Anyway, you are almost certainly correct, in that it would appear the Flex-4K was somehow "still tuning to RF35 and feeding RF35 to the laptop", from my measurements earlier in the week. I don't know how it somehow didn't get terminated properly, but you're probably right to conclude that must have been what was going on here.

And then only when I power cycled the Flex-4K did whatever improper state it was left in previously now get wiped clean and reset. Hence why things "returned to normal" with no "data flood coming from the Flex-4K".

Ok. That has to be the explanation. So the only mystery is what and/or how did the Flex-4K get left in this somehow residual state while at the same time nothing on the laptop was officially running or listening as a 'partner". Why/how is it possible for the Flex-4K to get into this state? Would it have been reset correctly if I'd simply now opened the HDHR client app to watch a TV channel, and then closed HDHR app? would the "data flood" have stopped on its own that way?

Or is the condition state once entered irreparable by anything that can be done, and only resolvable through a power cycle?

[jasonl]

Once UDP streaming has started, it will stop if the target is unset, the channel is unset (set to 0 if using the GUI), or it receives an ICMP bounceback because the port is closed. If a firewall is running and is set to just drop traffic that doesn't match an allowed incoming rule, no rejection will ever happen, and the HDHomeRun will continue streaming and the firewall will continue dropping all of it. Assuming you didn't manually lock the tuner, the next time something used that tuner it would have stopped sending to the PC and been used for whatever the new purpose was.