When an interface becomes congested and packets start to queue, you can apply a queueing method to packets that are waiting
to be transmitted. Logical interfaces--tunnel interfaces in this example--do not inherently support a state of congestion
and do not support the direct application of a service policy that applies a queueing method. Instead, you must apply a hierarchical
policy. Create a "child" or lower-level policy that configures a queueing mechanism, such as low-latency queueing, with the
command and CBWFQ with the
Create a "parent" or top-level policy that applies class-based shaping. Apply the child policy as a command under the parent
policy because admission control for the child class is done according to the shaping rate for the parent class.
shape average 2000000
Apply the parent policy to the tunnel interface.
interface tunnel 0
In the following example, a tunnel interface is configured with a service policy that applies queueing without shaping. A
log message is displayed noting that this configuration is not supported.
Router(config)# interface tunnel1
Router(config-if)# service-policy output child
Class Based Weighted Fair Queueing not supported on this interface