Some had reported that the lower tier of cable ISP has high jitter/latency that unsuitable for voip, and the problem goes away after the poster upgraded to the standard tier service (cost more $$)
There is a voip test, you can try to see if your connection is good enough:
Test your broadband internet connection for the key components required for VoIP.
or a combine of speed test and ping test
tommies is right on VoIP needing more than just bandwidth.tommies wrote:ooma only needs around 50Kb for each direction, or 100Kb if uncompressed. Any high speed/broad band ISP will be good enough. However, voip need more than just speed/bandwidth.
I get great speeds with my laptop's mobile broadband 3Mbps/1.5Mbps or even faster (AT&T 3G) but it won't support quality VoIP because of the high jitter values (therefore, wired ISP is needed):
VoIP test statistics
Jitter: you --> server: 96.5 ms
Jitter: server --> you: 80.2 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 0.0 %
Packet discards: 0.2 %
Packets out of order: 0.0 %
Estimated MOS score: 3.6
Speed test statistics
Download speed: 3128944 bps
Upload speed: 1588736 bps
Download quality of service: 85 %
Upload quality of service: 83 %
Download test type: socket
Upload test type: socket
Maximum TCP delay: 405 ms
Average download pause: 11 ms
Minimum round trip time to server: 105 ms
Average round trip time to server: 114 ms
Estimated download bandwidth: 11200000bps
Route concurrency: 3.5794823
Download TCP forced idle: 59 %
Maximum route speed: 4993136bps
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.