Voice dropout/port forwarding on Fritz!Box

[Daniel Neugebauer]

The number of connections in Online-Monitor is really funny - AVM seems to have changed the way this is counted: An older 7490 shows the number of reconnects per day but the 7560 seems to count the number of connections on a 24h day. Since an "always on" router is connected from 0:00 to "24:00" that's already 1 connection per day by the 7560 way of counting. Then we have the 24h reconnect which increases the number to 2. So it looks like you always get two connections counted per day on a 7560 even if the connection is perfectly stable and running 24/7. By that math, any number exceeding twice the number of days are extra reconnects (may occur due to maintenance work on ISP's side or bad connections). Dace's screenshots show 10 extra reconnects for December.

At the moment, I don't have any further idea on what could be wrong with VATSIM voice connections.

On your screenshots the momentary physical connection looks quite good to me as well. I'm just not sure about signal-to-noise ratio ("Störabstandsmarge") as I get ~20dB on my connection in worst case but your screenshot shows ~10dB which could be a bit low to keep up an error-free 100Mbit connection. To completely rule out the possibility of physical issues I'd keep an eye on Internet/DSL-Informationen/Statistik over a period of at least 24 hours as the statistics reset on reboot and will be less precise after 24h:

1. "Störabstandsmarge Empfangsrichtung (dB)" = Signal to Noise Ratio/Margin (SNR) measured in Decibel on downlink (Telekom to Fritzbox)
2. "nicht behebbare Fehler" = unrecoverable errors, i.e. lost packets due to bad physical connection where the modem failed to recover the correct information using checksums
3. "Synchronisationen" = DSL synchronizations (reconnection on physical level, i.e. modem was not just disconnected from the ISP but had to actually resynchronize with the DSL point-of-presence, the modem on the other end of the physical line)

On the bottom you also have the option to change the time period ("Zeitraum) between 24 hours (accumulated per hour) or 1 week (accumulated over 6 hours each).

What I would watch for:

• Resyncs, obviously. They should occur very rarely, only if the modem on the other end needs to be hard-reset by the ISP for whatever reason or maintenance is carried out by Telekom on modem or line itself. Any other resync indicates an issue with your connection on link level. Reconnects on logical level (e.g. daily reconnects) do not require a resync and thus will not show on DSL statistic pages, only on "Online-Monitor" pages (in the way described above).
• Signal-to-noise ratio (SNR) should not drop much further than 10dB as you are synced to maximum speed permitted by the ISP which is not far from overall estimated line quality*. A lower value means that noise is increased and it is harder for your modem to understand your ISPs modem on the other end. It also means that errors are more likely to occur up to a point where the modem has to resync with a lower connection speed to compensate for the bad line quality. For example, an ADSL2 line with nominal 16Mbit downlink is usually being throttled to 15Mbit with 6-7dB SNR. I would expect VDSL at 100MBit to be even harder to read over a noisy line.
• Uncorrectable errors ideally should not increase above 10 per hour for a stable connection (rule of thumb from my previous experience with 3 Fritzboxes; for comparison I currently get 0-4 errors per hour on VDSL 25 with ~20dB SNR).
• If a reconnect happens, check if a resync has happened as well. Also check if there has been an increased number of uncorrectable errors or a decrease on SNR coinciding with (most-likely causing) the reconnect.
• If resyncs happen, check if your connection speed has changed* which means that either modem has decided it is not able to keep up full link speed depending on SNR, line attenuation and/or error count.

If a resync or reconnect happens, Fritz!Box will log messages on System/Ereignisse/Internetverbindung. However, I never found those messages to be of any help.

*) Your current connection speed and quality is listed on Internet/DSL-Informationen/DSL:

• first column "Empfangsrichtung" shows downlink values (Telekom => Fritzbox), second column "Senderichtung" shows uplink (Fritzbox => Telekom)
• "Aktuelle Datenrate" = current data rate; what link speed are you currently synced to
• "DSLAM-Datenrate Max.": what Telekom is currently permitting you to sync with as maximum data rate depending on their hardware and your subscription plan
• "DSLAM-Datenrate Min.": same for minimum data rate
• "Leitungskapazität": estimated maximum speed theoretically achievable as seen by your Fritz!Box - not what the ISP may allow or see
• "Störabstandsmarge": Signal-to-Noise Ratio (the higher the better)
• "Leitungsdämpfung": Line attenuation (the lower the better)

[Marcel Semelka]

Taking a look into the log (System->Ereignisse) should show how those reconnections happened, at least if the are loosing synchronization or something like that.
But looking at your connection Information, as Daniel already said, they are looking really good and I can't imagine that your loosing synchronization or some like that. But the log should show the reason for the disconnect.

Also, may I ask why you are shutting down your router at night? Usually the router is one of the few devices at home you never turn off. A lot of ISPs have their customers connect their telephones to the router, because their telephone line is not analog anymore, but VoIP, using the internet connection of the router.
If this is the case with you, that would mean, that your telephone doesn't work at night.
Also I would rather use my ISPs internet for my smartphone than my "expensive" mobile data, also at night, my Android for example updates it's installed apps as soon as I connect it to the charger at night. If my router would be turned off at that moment it would eat up my mobile data.

Another tip, in my 6490 Cable I can swtich the language of my FritzBox under "System->Region und Sprache". Maybe yours is able to do that too.

[Björn Labitzke]

After a bit of thinking the number of connections should be around two times the number of days. This number is a counter for the internet connections, NOT an information about the DSL sync. The statistics for DSL looked quite solid to me. And the number of connections has to be at least one per day because of the forced reconnect from the provider. And here is the hint for the double value: In "olden times" you had IPv4, now you have IPv6 as well, that makes two connections per day. Any extra above that is a possible problem. :-)

Oh, we talked about the F!Box. But what about so called "security products" like AntiVirus or firewall on you computer?

Björn

[Dace Nicmane]

I haven't changed anything in my settings and I didn't have this problem before I moved, so I have every reason to think it's the ISP/router.

I do get an extra disconnect on some days, but as I said, it's not related to my disconnects from the VATSIM voice rooms, as the latter happens every 20-something minutes after connecting to a frequency.

Why do you think port forwarding won't work? I still want to try it, especially when there are no other ideas.

[Daniel Neugebauer]

Zitat von Dace Nicmane

Why do you think port forwarding won't work? I still want to try it, especially when there are no other ideas.

That's because we have the same router and (at least I) also have the same provider and do not require port forwarding. You can still try but I'd be very surprised if it changed anything.

In Internet/Freigaben, Gerät (device) choose the PC you want the port to be forwarded to.

If you then click on "Neue Freigabe" (new forwarding rule) you get the dialog you already had open on your first post. Select "Andere Anwendung" (other application) and enter some label for it as "Bezeichnung". I'm not sure if VATSIM voice servers speak UDP, TCP or both - it shouldn't hurt to define the same rule for both protocols, however you can only add one protocol per rule so you need to set up a second rule for the other protocol. You want to forward the port 1:1 so you enter the same port number for both "Port an Gerät" (port at device) and "Port extern gewünscht" (requested external port). "bis Port" (up to port ...) is meant for forwarding port ranges - keep it set to the same port as you do not want to forward a full range of consecutive ports at once. On the last option you get to choose if you want to forward IPv4, IPv6 or both protocols. AFAIK VATSIM does not speak IPv6 yet so either keep this set to either IPv4 or both.

After confirming the dialog you should see your forwarding rule on the list. Click OK one more time to enable it.

[Björn Labitzke]

Zitat von Dace Nicmane

Why do you think port forwarding won't work? I still want to try it, especially when there are no other ideas.

If you needed to configure port forwarding, you would not be able to get any voice service in X-Plane at all. Either the ports are blocked from the beginning or they are not.

In general you need to configure port forwarding if you have some kind of server running on your system. If a new host from the outside tried to contact you, it would need to establish a new connection. For this connection to happen, the F!Box would need to know under which internal IP address your server would be reachable. So, if your server is waiting for connections on port 80, you would have to configure a port forwarding for this port in your F!Box, telling it that it should forward packets for a new connection on port 80 to the IP address of your server on port 80.

In the case of the voice connections your PC starts the connection. It connects via the F!Box to the voice server. Now the F!Box remembers the internal IP of your PC and the started connection and will additionally allow the response packets into your network and send them to your PC. So in this case you do not need to configure port forwarding, because the connection is started from the inside and the F!Box configures its own port forwarding for this specific connection and knows what to do. After closing the connection, it will forget this specific port forwarding again.

And yes, I use a F!Box with X-Plane as well without any specially configured port forwarding for online flying.

[Dace Nicmane]

Well, it's clearly not working in my case. I'll try the port forwarding and report back if it fixes the issue.

[Dace Nicmane]

I set up the port forwarding and I'm still having this problem.

What else can I do?

I do have a disconnect/resync sometimes (not every day), but as I said before, it's not related to the voice dropouts which happen every 20-30 min after joining a frequency, there are no events on the router pages related to these. I've never seen unrecoverable errors. The internet connection seems fine.

[Björn Labitzke]

How about some kind of software on your system? Antivirus? Firewall? Some addon? Try flying with a clean XPlane installation. If there is no problem, add your addons again, until you know which one causes the problem. If there is a firewall, that might be faulty.
But at the moment I have no other ideas.