Tethering & internet connection sharing to connect voip phone

[burntfrank]

Hello:  In an attempt to leverage the strong LTE signal I have at my house, I've done the folllwoing.  Razr Maxx tethered to laptop using Pdanet (also tried Android-inherent tethering).  Polycom IP phone connected to laptop Ethernet port.  Using Internet connection sharing to allow Polycom IP phone to connect via LTE.

The reason I'm even attempting this is because my Comcast Internet connection has been latent and dropping packets ever since Sandy.  It seems to be a widespread and intermittent problem on the Comcast network as a whole...likely something to do with bandwidth availability at peers with other providers.  It's wreaking havoc on my company VOIP service that I use when working from home...specifically, my upstream traffic.  I hear everything crystal clear, while the person I'm talking to hears me breaking up pretty badly.

Anyway, I had the tether with sharing working like a charm two weeks ago.  However, sometime early last week, my Polycom IP phone stopped registering over the shared LTE connection.  If I switch the internet connection sharing over to my laptop wifi (which connects to my problematic Comcast connection), it registers just fine.

Is anyone aware of any filtering that may have been put in place last week that impacts non-standard UDP ports used by my voip provider?  Any other thoughts?

Thanks.