Poor calling quality on VoIP

I’am looking for some hints on behalfe of the following problem:

  • the internet connection is established via fritz.box and ipfire as an exposed host, 200 MBit down, 40 MBit up
  • the gateway diagramm shows a steady grow up during the day and reaching >1100 ms
  • after requests to the provider distinct ports (UDP/TCP: 5060 … and 16384 …) has been linked between the server address outside and the internal telephone system (Agfeo ES522IT) in the “rules” section of ipFire
  • the calliing quality is very poor: the connection is dropping out (seldom), choppy sentences, echoes and so on
    my question: are there some “best practices” for the settings of the QoS ?
    any other suggestions ?
    many thanks in advance

Yes, before you can set up the QoS to be in control of every single packet that is leaving the firewall, you will need to get rid of the router and replace it with a modem.

Otherwise you can only limit the bandwidth so that you are only allowing IPFire to pass 90-ish % of traffic and hope for the best that no other traffic is coming from anywhere else.

hello Michael,
thanks for your first suggestions.
we are using a FritzBox 7583 and this router knows only one client, the ipFire, therefore nothing else conquer with the bandwith.
on the other hand, I do not know a modem, which is suitable for this VDSL-connection.

I have successfully attached a DrayTek Vigor 130,
running it as a Router first, enjoying its excellent connection diagnostic capabilites,
then switching it into MoDem mode.
Next I exploited the corresponding PCIe card version DrayTek VigorNIC 132 inside my ipfire HW,
switching that into MoDem mode also, which is running rock-stable for > 2 years now.
[ https://www.draytek.co.uk ]

[ https://www.heise.de/preisvergleich/?cat=rdsl&xf=1461_DrayTek&asuch=13&bpmin=&bpmax=&v=e&hloc=de&filter=aktualisieren&plz=&dist=&sort=p ]

Choose the model for your country: Annex A or Annex B, respectively.

As soon a client decides not to depend upon the provider supplied box / installation / configuration,
he might be on his own, having to cope with e.g. VDSL / VLAN configuration etc.

hello Manfred,
I will follow your suggestion and therefore just ordered the DrayTrek Vigor 165.
I’ll keep you informed.