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.
#51276 by oats
Wed Mar 24, 2010 5:58 pm
I've got a cable internet connection (Time Warner Cable, only thing available in my area), which has a terrible jitter problem. I see some people complaining about 10ms jitter... mine typically measures 100ms+. http://www.whichvoip.com/voip/speed_test/ppspeed.html tells me that with this jitter rating, VoIP isn't recommended. Outgoing audio is the problem... I usually hear the other person reasonably well, but the outgoing audio breaks up and stutters regularly.

I just bought the Telo from Amazon.com... should I return it (only have a few weeks left to make this decision) or wait for PureVoice, hoping that this solves my jitter problems?

It's strange, because I currently have VoIP with Time Warner Cable (which is what I am trying to replace). It works great... call quality is wonderful. It is using the same internet connection, so why is TWC VoIP working so much better than OOMA on the same internet connection?

Btw - i've tried both cable-->ooma-->router and cable-->router-->ooma. same diff.

here's my results from http://www.whichvoip.com/voip/speed_test/ppspeed.html

VoIP test statistics
--------------------
Jitter: you --> server: 103.1 ms
Jitter: server --> you: 4.8 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 0.4 %
Packet discards: 0.2 %
Packets out of order: 0.0 %
Estimated MOS score: 3.6

Speed test statistics
---------------------
Download speed: 718936 bps
Upload speed: 113040 bps
Download quality of service: 99 %
Upload quality of service: 84 %
Download test type: socket
Upload test type: socket
Maximum TCP delay: 27 ms
Average download pause: 16 ms
Minimum round trip time to server: 310 ms
Average round trip time to server: 439 ms
Estimated download bandwidth: 720000bps
Route concurrency: 1.00148
Download TCP forced idle: 0 %
Maximum route speed: 1691224bps
#51279 by murphy
Wed Mar 24, 2010 6:21 pm
oats wrote:I've got a cable internet connection (Time Warner Cable, only thing available in my area), which has a terrible jitter problem. I see some people complaining about 10ms jitter... mine typically measures 100ms+. http://www.whichvoip.com/voip/speed_test/ppspeed.html tells me that with this jitter rating, VoIP isn't recommended. Outgoing audio is the problem... I usually hear the other person reasonably well, but the outgoing audio breaks up and stutters regularly.

I just bought the Telo from Amazon.com... should I return it (only have a few weeks left to make this decision) or wait for PureVoice, hoping that this solves my jitter problems?

It's strange, because I currently have VoIP with Time Warner Cable (which is what I am trying to replace). It works great... call quality is wonderful. It is using the same internet connection, so why is TWC VoIP working so much better than OOMA on the same internet connection?

Btw - i've tried both cable-->ooma-->router and cable-->router-->ooma. same diff.

here's my results from http://www.whichvoip.com/voip/speed_test/ppspeed.html

VoIP test statistics
--------------------
Jitter: you --> server: 103.1 ms
Jitter: server --> you: 4.8 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 0.4 %
Packet discards: 0.2 %
Packets out of order: 0.0 %
Estimated MOS score: 3.6

Speed test statistics
---------------------
Download speed: 718936 bps
Upload speed: 113040 bps
Download quality of service: 99 %
Upload quality of service: 84 %
Download test type: socket
Upload test type: socket
Maximum TCP delay: 27 ms
Average download pause: 16 ms
Minimum round trip time to server: 310 ms
Average round trip time to server: 439 ms
Estimated download bandwidth: 720000bps
Route concurrency: 1.00148
Download TCP forced idle: 0 %
Maximum route speed: 1691224bps

Those are horrible numbers for a cable system. They look like DSL speeds.
What speeds are you paying for?

Connect to

http://192.168.100.1

which is the status page in your cable modem and report the downstream signal power, the upstream signal power, and the downstream SNR (signal to noise ratio).
#51280 by oats
Wed Mar 24, 2010 6:41 pm
i have "road runner lite", which is a lower-speed connection, similar to DSL speeds. but i don't think the speed is the problem, it is jitter. i think. anyway, here is my cable modem information:

Downstream
Freq/Power: 561.000 MHz -5 dBmV
Signal to Noise Ratio: 37 dB
Modulation: QAM256
Upstream
Freq/Power: 25.600 MHz 41 dBmV
Channel Type: DOCSIS 1.x (TDMA)
Symbol Rate: 2560 kSym/sec
Modulation: QAM16


just found this review of Time Warner Cable's VoIP:
The fact the "VoIP" traffic never touches the internet, it stays on Time Warner's privately owned SONET ring which sends your traffic to a data center that connects it to the PSTN. That is a HUGE advantage for me over the "other" VoIP providers. I don't have to worry about setting up QoS on my router, I don't have worry about latency. I also have E911 support, which as I understand it very few other providers offer.

I don't know what SONET or PSTN is, but I can say that the TWC VoIP audio quality is fantastic, but OOMA is suffering. Any way to get OOMA to use this SONET thing?
#51283 by murphy
Wed Mar 24, 2010 7:00 pm
oats wrote:i have "road runner lite", which is a lower-speed connection, similar to DSL speeds. but i don't think the speed is the problem, it is jitter. i think. anyway, here is my cable modem information:

Downstream
Freq/Power: 561.000 MHz -5 dBmV
Signal to Noise Ratio: 37 dB
Modulation: QAM256
Upstream
Freq/Power: 25.600 MHz 41 dBmV
Channel Type: DOCSIS 1.x (TDMA)
Symbol Rate: 2560 kSym/sec
Modulation: QAM16

Those signal levels look okay so the question is, what is causing the jitter?
I wonder what method they use to keep your speed down.
Hopefully they don't do it by discarding packets to force retries.
#51304 by oats
Thu Mar 25, 2010 9:26 am
so my next questions... will PureVoice save me, or is my internet connection beyond redemption?

also, if I upgrade to a higher-speed connection, will the jitter improve? probably no way to know for sure, but wondering if that is a reasonable hope.
#51306 by Groundhound
Thu Mar 25, 2010 9:37 am
oats wrote:so my next questions... will PureVoice save me, or is my internet connection beyond redemption?

also, if I upgrade to a higher-speed connection, will the jitter improve? probably no way to know for sure, but wondering if that is a reasonable hope.

I haven't seen a statement from Ooma specifically regarding PureVoice and jitter, just comments about it helping high packet-loss conditions.

I know Comcast will allow upgrades/downgrades of speed tiers without requiring any time commitment, billing on a prorated basis for the days you try the higher tier, so perhaps you can do the same with RR to see if it helps.
#51468 by oats
Sat Mar 27, 2010 7:33 am
UPDATE: i just switched from Road Runner Lite to RR Standard. I wasn't sure if this would work, since I technically didn't have a bandwidth problem, but a jitter problem. Still, it appears that RR standard has cleared up my jitter problem. Here are my new VoIP speed test results:

jitter went from 100+ ms to 1.2 ms!! I haven't placed a call yet, but I hope this has solved my outgoing voice quality problem...


VoIP test statistics
--------------------
Jitter: you --> server: 1.2 ms
Jitter: server --> you: 1.2 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: 4.1

Speed test statistics
---------------------
Download speed: 2479800 bps
Upload speed: 972536 bps
Download quality of service: 81 %
Upload quality of service: 99 %
Download test type: socket
Upload test type: socket
Maximum TCP delay: 525 ms
Average download pause: 5 ms
Minimum round trip time to server: 99 ms
Average round trip time to server: 104 ms
Estimated download bandwidth: 6080000bps
Route concurrency: 2.4518106
Download TCP forced idle: 17 %
Maximum route speed: 5295752bps

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