VoIP good priority

Question

Hello,
I'm looking for good solution to priority VoIP packages in routers.
We have about 10 Cisco routers, and sometimes when someone downloading files
from internet connection over VoIP telephone is slow/disconnent. Is this
solution is good to priority packages:
access-list 100 permit ip any 'IP_VOIP_SERVER'
access-list 100 permit ip 'IP_VOIP_SERVER' any
class-map test_speed
match access-group 100
policy-map test
class test_speed
set ip precedence 5
class class-default
set ip precedence 0
interface Ethernet0/0
service-policy input test
Maybe there is a better solution ? Those packages are only marked with
higher prioryty, is this part of config I should write on all my routers'???
Thanks
Pawel R.

Answer 1

Your packets are marked with ipp 5, but you're not really putting it in the priority queue. Class class-default has already been set at dscp 0, so there's no need to specifiy it there.
You can try something like this:
class-map match all VoIP
match ip dscp ef
class-map match-any Call-Signaling
match ip dscp cs3
policy-map test_speed
class VoIP
priority 512 **VoIP packets are placed in the priority queue( or you can use " priority percent" of T1 bandwidth if you like)
class Call-Signaling
bandwith percent 5
class class-default
fair-queue
random-detect dscp-based
Then apply the test_speed policy to the serial int, outbound (service-policy output test_speed)
Take a look at the document link from the Brandon. It contains very good explanation and examples that you can follow to create the optimum QoS for your enviroment.
HTH,
hieu