[asterisk-users] Audio problems on cable modem link

[Michelle Dupuis]

We have a small office installation running over a cable modem.  (8M down, 500k up confirmed with numerous speed test sites)

When a single call is up, call quality is fine.  When a second call is up, outbound audio is immediately choppy.  We're using ulaw, and confirmed that traffic with 2 calls is <175kbps in/out.  (IAX connection out)

Asterisk doesn't report any dropped frames, the internet connection looks fine, etc.   We have a linux router in place running wondershaper that seems to be running fine (same as our other installations).

Can someone suggest where to look?  Could this be the ITSP?