[SOLVED] DrayTek Vigor 2820n QoS

[Vic D'Elfant]

Hi all,

We have swapped our ISP's SpeedTouch modem with a proper DrayTek Vigor 2820n, but have been encountering problems with the good old QoS settings ever since. I have (just to be safe) followed the QoS steps described in http://www.3cx.com/blog/voip-howto/draytek-firewall-voip/, but people we call still complain about stuttering. Especially when sending out a large mail during the conversation... so a classic QoS problem.

The server running 3CX has a proper static public IP, and calling, getting called and terminating conversations work as expected... so no NAT issue there.

We have a dual-WAN setup but VoIP and RTP traffic is forced through WAN1 since WAN2 is behind a consumer modem which blocks proper VoIP communication completely:



Basic overview of the QoS settings is as follows:



VoIP class settings look alright as well:



... as do the service types:



BUT: during a 1-minute call, the "status" view spikes when initiating the call and when putting the call on hold... so I'd guess that it's only tagging VoIP traffic and not the actual RTP traffic. During an active conversation or "on hold" music, VoIP traffic drops back to 0 Bps:



APP QoS is disabled because I didn't want to risk enabling other "fancy" features that might interfere with very basic QoS.

Any ideas?

 

[Vic D'Elfant]

Just to update this topic: issue has been solved. A closer look at the logs revealed that RTP wasn't going through 9000-9049 at all, but rather in the range 10000-20000. As such, it wasn't being tagged as VoIP traffic thus wasn't getting the prioritity it should.

Setting a QoS rule on the provider's IP range did the trick, as well as using the range 10000-20000. We set it to the IP range just to be sure.

 

[thames]

Hi Vic

A bit of useful info there. Thanks - I'll keep this one to hand. I'm also using a 2820n so will go off and make sure I'm not having any of the same issues.

Cheers
Chris

 

[Vic D'Elfant]

Hi Chris,

You're welcome! Another thing to keep in mind is that the Vigor appears to limit traffic to 80% as soon as QoS is enabled. We didn't get a chance to find out exactly why it does this, but it can be set to 100% quite easily: http://forums.thinkbroadband.com/zen/3832650-router-speed-advice.html?fpart=2#Post3833246. Rates went up to 100% right after the "adsl reboot".

Good luck!

 

[thames]

Hi Vic

It sounded like "just get rid of the QoS" so I switched it off using the web interface. I have yet to reboot the router so not yet able to tell whether it makes any difference. Actually - this broadband line is only used at our place for the phone and for ant mobiles that connect to it internally, so QoS is probably not needed?

All the best
Chris

 

[Vic D'Elfant]

Hi Chris,

Enabling/disabled QoS should work as soon as you hit the Save/OK button, so there's no actual reboot necessary. If you're only using this one WAN connection to route your VoIP traffic then it's safe to say that you won't need QoS since it can use the entire bandwidth for VoIP only. But as soon as there's anything else (e-mail, regular internet use, etc.) going through this line then I'd recommend to enable QoS.

 

[thames]

Super, Vic. Will keep that in mind. People here using mobiles have been told to connect to the secondary network, so that they are able to leave Email running in the background on their phones. However, if they want to and they have definitely disabled Email on their phones while making the calls, they are allowed to use the VOIP network.

Here's hoping it all works!

Cheers
Chris