Phone calls resetting Comcast modem

[dtalwar]

Oomaforums, Do you also have Comcast Business Internet and a static IP?

[oomaforums]

Hello dtalwar,

* Its not Business class
* We have 12 Mbps download and 6 Mbps upload
* We dont have a static IP, but the IP has almost never changed

Thanks & Regards

[dtalwar]

Wow, that's a very interesting problem. I have Comcast too and never had this problem. Could you share more details about your network? What router are you using? Your router settings? How many devices? Things such as whether or not DHCP is enabled on the router? What is the DHCP range? What is the subnet mask? What DNS servers are you using? Comcast's or OpenDNS? Provide as much information as possible for us to be able to figure out what might be happening.

[niknak]

...the Comcast modem resets and one minute in to the call, the person on the other side is unable to hear us.

I can consistently reproduce this problem.
...

I would call Comcast and complain that your modem keeps dropping its connection

[oomaforums]

Hello @ niknak

Thanks.

I did call them, but they are not able to help because all systems at their end are showing up fine. And Ooma is not responding back with any possible solutions as well.

To be a little fair on Comcast, it is "only" when a make a call to with Ooma that this happens. We've had comcast for a decade and it is only with a Ooma call that we are facing this problem. So i am inclined to believe this is a Ooma problem rather than a Comcast problem.

I am hoping that there is a simple configuration change that would solve this problem.

Thanks & Regards

[oomaforums]

Thanks to one of the post (earlier in this thread), i believe the problem is solved for our setup.

1) I changed the Modem port MAC address in the Ooma setup (http://172.27.35.1) from "Automatic" to "Use Built-in". I then restarted the entire setup, but this did not help - same problem of call disconnect, one way voice and internet disconnect as before.

2) I placed the IP address that Ooma is using on the router in the DMZ of my router and restarted the entire setup and since then all is fine. No more dropped calls, no internet disconnect and no one way voice - all problems solved.

I don't know if it is a combination of 1 and 2 that did it, or just 2. But i am keeping these changes at this time.

To improve the call quality, i further changed the QoS settings:
a) upload speed to 1024 from 384
b) Reserved bandwidth for calls to 215 from 130

I will update this thread in a few days if anything changes.

Hope this helps others. Thanks to all.