VOIP over ADSL for Campus

[gfxrelay]

Hi, I am baffeled I am trying to run VOIP traffic from an elastix server over a Cisco 870 router. Call quality is fine untill more then a few people start surfing the internet. I have tried to enable some QOS on the router but with it I can make one call and the rest just drops. I spend nearly a day surfing Cisco website and managed to come up with this config:

 

 

 

ip access-list extended DATA_TRAFFIC

 

permit tcp any any eq www

 

permit tcp any any eq 443

 

ip access-list extended VOIP_TRAFFIC

 

permit udp any any

 

permit tcp any any eq 5060

 

permit tcp any any eq 5061

 

permit tcp any any eq 10000

 

permit udp any any range 16348 32768

 

permit tcp any any eq 5060

 

permit ip 10.6.49.66 255.255.255.255 any

 

 

 

class-map VOIP_TRAFFIC

 

match access-name VOIP_TRAFFIC

 

class-map DATA_TRAFFIC

 

match DATA_TRAFFIC

 

 

 

policy-map VOICE_QOS

 

class VOIP_TRAFFIC

 

priority percent 30

 

policy-map DATA_TRAFFIC

 

class DATA_TRAFFIC

 

bandwith percent 50

 

policy-map class-default

 

fairqeue

 

 

 

I have tried applying it to the Dialer and ATM interface. The show policy map command shows hits on every class, but call quality still drops and line availaibility drops to one line availaible. Does any know what I am doing wrong or of a better config?