RE: VoIP QOS best practices

There are two aspects to QoS that you have direct control over: 1)
traffic leaving your network (easy to QoS since you (most of the time)
have access to the egress equipment) and 2) traffic arriving on your
end-point which is harder to do, but more and more service providers are
assisting with QoS on that final ingress link to your network to ensure
timely delivery of voice vs your regular traffic.

Ray Burkholder