asterisk users - Jan 2005 - ulaw blank spots but gsm fine

ulaw blank spots but gsm fine

We've got plenty of QoSd bandwidth to run ulaw. Yet when we do, we get
drops (blank spots) in the call. GSM codec eliminates the blanks, but is of
course much less quality.

Any ideas as to what would be causing this? Is ulaw less loss tolerant than
gsm?

I've run tests using iperf, and I'm looking at maybe 10 per 50000
packets
are lost. (around 0.02%). Jitter and latency are low. We average about 30ms
to the provider, and jitter ranges from < 1 ms to 5-6 ms.

TIA!

-Ron