Hello,
I think the 836 suppots Low Latency Queuing, try the following configuration (the IP addresses I have used are fictional):
class-map PRIORITY
match access-group 1
!
policy-map USER_PRIORITY
class PRIORITY
priority 200 (this would give 200K to that class)
!
access-list 1 permit host 192.168.1.1
!
interface ATM0/0
service-policy input USER_PRIORITY
Can you try and see if this works ?
Regards,
Georg