Priority Queuing takes a lot of memory and CPU to do properly. Often, the performance hit of priority queueing may negate the advantage that is supposed to be given to a specific protocol.
For low-speed links, ip precedence can be much more efficient. Try something like the following:
access-list 110 permit ip any host 172.16.0.41
access-list 120 permit ip any host 172.16.0.3
access-list 130 permit ip any host 172.16.0.15
!
route-map frame permit 10
match ip address 110
set ip precedence flash
!
route-map frame permit 20
match ip address 120
set ip precedence immediate
!
route-map frame permit 30
match ip address 130
set ip precedence priority
!
route-map frame permit 40
set ip precedence routine
!
interface Ethernet0/0
ip address 172.16.4.1 255.255.255.0
ip route-cache policy
ip route-cache flow
ip policy route-map frame
This will classify all incoming packets on the ethernet interface, so that critical hosts receive priority on the Weighted-fair-queued serial lines..
