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Proper way to configure QoS for VOIP on DD-WRT

mxnerd

Diamond Member
I just signed up with DSL Extreme (3M down / 768k) up and would like to run SIP VOIP and Skype over it and I would like to have these 2 protocol has priority over others when it's in use.

However, when I try to configure QoS on dd-wrt but can't get it right. Everytime I turned on DD-WRT's QoS, the QoS test at PhonePower (http://www.phonepower.com/Support/SpeedTest.aspx) showed that the QoS is not up to par, once I turn DD-WRT's QoS off, the test showed the VOIP QoS is perfectly fine, what gives? What's the correct way to setup for SIP VOIP? or Should I just turn it off?

ASUS DD-WRT (v24) configuration

Uplink:
Set this to 80%-95% (max) of your total upload limit. I set it at 650 kbps

Downlink:
Set this to 80%-100% (max) of your total download limit. I set it at 2700 kbps

(What's the purpose reducing the Ulink/Downlink limit?)


QoS setting

Services Priority

sip Premium
stun Express


(Does QoS always allocate a fixed bandwidth for the protocols that's turned on here, or just when they are in use?)


I tried HFB/HFSC Packet Scheduler and does not make a big difference. (But HFSC seems a bit better)


The most significant difference:

With QoS turned on : The Download quality of servicewill drop below under 90 %, as bad as 54%,
and Maximum TCP delay always above 170ms, can be as high as 440ms

With QoS turned off: The Download quality of service with QoS turned off will is always 99 %,
and Maximum TCP delay never exceed 70ms


With QoS

VoIP test statistics
--------------------
Jitter: you --> server: 0.0 ms
Jitter: server --> you: 4.1 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 0.0 %
Packet discards: 0.0 %
Packets out of order: 0.0 %
Estimated MOS score: 4.0

Speed test statistics
---------------------
Download speed: 2593096 bps
Upload speed: 685496 bps
Download quality of service: 90 % <- can be as low as 50%, I don't know how they calculate it.
Upload quality of service: 80-90 %

Download test type: socket
Upload test type: socket
Maximum TCP delay: 187 ms <- can be as high as 400ms
Average download pause: 5 ms
Minimum round trip time to server: 29 ms
Average round trip time to server: 31 ms
Estimated download bandwidth: 2800000bps
Route concurrency: 1.0802569
Download TCP forced idle: 0 %
Maximum route speed: 18078616bps


=============================================
without QoS


VoIP test statistics
--------------------
Jitter: you --> server: 0.0 ms
Jitter: server --> you: 4.0 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 0.0 %
Packet discards: 0.0 %
Packets out of order: 0.0 %
Estimated MOS score: 4.0

Speed test statistics
---------------------
Download speed: 2873536 bps
Upload speed: 739680 bps
Download quality of service: 99 %
Upload quality of service: 99 %

Download test type: socket
Upload test type: socket
Maximum TCP delay: 60 ms
Average download pause: 4 ms
Minimum round trip time to server: 27 ms
Average round trip time to server: 27 ms
Estimated download bandwidth: 2880000bps
Route concurrency: 1.0022495
Download TCP forced idle: 0 %
Maximum route speed: 19417776bps
 
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