This forum includes tips for maintaining the best audio quality possible with the Ooma System. If your Ooma system is having issues with dropped calls, static audio or echo, look here for assistance.
#82546 by CodeMasterG
Tue May 31, 2011 6:34 pm
I've had my Telo since March and overall I like it. I have had some problems with noticeable delay and have seen posts suggesting that if I adjust the Telo's QoS settings it may remedy the delay situation. I've seen some folks setting upstream and downstream bandwidth to muti-megabit values, but have to wonder if that much bandwidth is really needed just to make a voice call. It seems to me that delay and jitter are the real issues impacting call quaility and not the amount of bandwidth allocated for a call (obviously a minimum amount is needed to support a call). If this is correct, what is the minimum bandwidth required to make a voice call?
#82547 by Aveamantium
Tue May 31, 2011 6:46 pm
for iLBC it is about 40kbps in each direction. I typically like to see 80kbps in each direction to be safe. You are correct about latency/jitter having the greatest impact on voice quality. Also dropped packets are a big deal... Anymore, bandwidth has become a very small part of the equation given today's speeds.
#82550 by WayneDsr
Tue May 31, 2011 7:07 pm
Aveamantium wrote:for iLBC it is about 40kbps in each direction. I typically like to see 80kbps in each direction to be safe. You are correct about latency/jitter having the greatest impact on voice quality. Also dropped packets are a big deal... Anymore, bandwidth has become a very small part of the equation given today's speeds.

Agree with Avemantium, 41 kbps in either direction.

Wayne
#82552 by lbmofo
Tue May 31, 2011 8:12 pm
40kbps is about right.

Here is what Dennis had to say about it:

Dennis P wrote:
lbmofo wrote:Ooma uses iLBC; there are conflicting reports on how much the codec uses per minute. However, I observed (through the info function during a call) ~140,000 bytes each way which translates to (depending on how you calc) ~137 Kbytes or 0.1335 Mbytes each way; this translates to about 750 minutes per 200 MB.


I haven't tried measuring using the same method as you, but my theoretical calculations give me something different. iLBC with IP/UDP/RTP headers should be about 35kbps or 4.375KB per sec. That's 525KB per minute if you are counting both directions. So a 200MB quota would yield 381 minutes.
#82562 by thunderbird
Wed Jun 01, 2011 3:48 am
CodeMasterG wrote:I've had my Telo since March and overall I like it. I have had some problems with noticeable delay and have seen posts suggesting that if I adjust the Telo's QoS settings it may remedy the delay situation. I've seen some folks setting upstream and downstream bandwidth to muti-megabit values, but have to wonder if that much bandwidth is really needed just to make a voice call. It seems to me that delay and jitter are the real issues impacting call quaility and not the amount of bandwidth allocated for a call (obviously a minimum amount is needed to support a call). If this is correct, what is the minimum bandwidth required to make a voice call?

Ooma recommends setting both Upstream and Downstream Internet Speeds to zero to disable the Ooma device's QoS.
Setting the setting upstream and downstream bandwidth to muti-megabit values (to values above the measured Upstream and Downstream Internet Speeds) is just another way to disable the Ooma device's QoS.
There has been a "bug" in some Ooma devices, where setting the QoS values to zero didn't work. Setting the Upstream and Downstream Internet Speeds QoS values to a higher than measured Internet provider set of speeds, than is the only way QoS settings control can be shut off.

Also some people have found that for QoS settings, using around 90% of measured stream and Downstream Internet Speeds, instead of the suggested around 80% values, is working very well for them, since the last firmware update.
#82720 by CodeMasterG
Sat Jun 04, 2011 10:28 am
Thanks all. Per Thunderbird's post, I have set my up/down stream speeds to zero to disable QoS. I think it makes sense to do so since my telo sits behind my router/firewall. I'll see how my calls go.
#110547 by domm
Mon Jun 03, 2013 10:04 am
Aveamantium wrote:for iLBC it is about 40kbps in each direction. I typically like to see 80kbps in each direction to be safe. You are correct about latency/jitter having the greatest impact on voice quality. Also dropped packets are a big deal... Anymore, bandwidth has become a very small part of the equation given today's speeds.


When I test my sustained upload speed using http://testmy.net/ I get 150 Kbps. If I understand the above statement correctly I only need 41kbps upload speed for Ooma to work correctly. I think I read somewhere else that I would need over 300kbps for Ooma to work. Which one is correct? Thanks
#110552 by lbmofo
Mon Jun 03, 2013 11:37 am
Image

Outside of recommending a hardwired internet service, Ooma also requires a minimum of 256 Kbps upstream network speed (384 Kbps recommended). Since downstream is usually higher, they don't mention it but have got to be same or higher.

The 30Kbps to 40Kbps is what is required by iLBC protocol (what is mainly used by Ooma hardware and the mobile app) but when your Telo is in other modes such as FAX or redundancy, the hardware may require x2 or even x3 the basic Kbps needed by the protocol. Ooma has required a minimum of 256 Kbps for upload speed not because it may need all of it but because anything lower than that, chances are, the internet quality might be terrible and not suitable for VoIP.
#110559 by domm
Mon Jun 03, 2013 2:09 pm
lbmofo wrote:Image

Outside of recommending a hardwired internet service, Ooma also requires a minimum of 256 Kbps upstream network speed (384 Kbps recommended). Since downstream is usually higher, they don't mention it but have got to be same or higher.

The 30Kbps to 40Kbps is what is required by iLBC protocol (what is mainly used by Ooma hardware and the mobile app) but when your Telo is in other modes such as FAX or redundancy, the hardware may require x2 or even x3 the basic Kbps needed by the protocol. Ooma has required a minimum of 256 Kbps for upload speed not because it may need all of it but because anything lower than that, chances are, the internet quality might be terrible and not suitable for VoIP.



So if my "hardware may require x2 or even x3 the basic Kbps" then 3 x 40 Kbps would equal 120Kbps which should mean as long as my ISP connection stays at 150Kbps or above I should be able to successfully use Ooma as long as I am not using my internet for anything else while using Ooma?
#110560 by lbmofo
Mon Jun 03, 2013 2:21 pm
In theory, yes. Unless you have 2 concurrent calls going on which Ooma Premier allows.

But speed isn't the only component at play for VoIP to work nicely.

Also, do a VoIP quality test: http://www.phonepower.com/speedtest

Note: check the "Advanced" tab

murphy wrote:Jitter should be less than 5 ms.
Packet loss should be 0.
Download and upload QOS should be at least 70%.
Maximum TCP delay should be under 100 ms.

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