We have a 155Mbps OC-3 WAN link from our carrier. However, the carrier hand-off to us is Gig-E. We want to apply QoS to this circuit to prioritize important traffic.
The question: since the carrier hands us Gig-E instead of native OC-3, will traffic ever queue up on the Gig-E hand-off interface so that our QoS policy will be effective?
What will solve your problems is called hierarchical policies. Basically a simple queueing policy will not help in your case, because queueing on an interface only sets in, if the interface is overloaded. If, however, you already send more that 1 GE, your OC3 would be overrun long before.
Hierarchical policies example:
match protocol telnet
match protocol citrix
match protocol http
shape average 140000000
service-policy output Prio
bandwidth percent 10
bandwidth percent 30
bandwidth percent 50
ip address 10.1.1.1 255.255.255.252
service-policy output shapeOC3
The first policy shapes to f.e. 140 mbps. Do not go to 155 mbps, because you need room for Layer2 overhead. The second policy allows you to prioritize the traffic, which is important to you. You need to adjust classes and values to your environment.
Hope this helps! Please rate all posts.