Understanding Strict-Priority Queues
You use strict-priority queuing and policing as follows:
Identify delay-sensitive traffic by configuring a behavior aggregate (BA) or multifield (MF) classifier.
Minimize delay by assigning all delay-sensitive packets to the strict-priority queue.
Prevent starvation on other queues by configuring a policer that checks the data stream entering the strict-priority queue. The policer defines a lower bound, marks the packets that exceed the lower bound as out-of-profile, and drops the out-of-profile packets if the physical interface is congested. If there is no congestion, the software forwards all packets, including the out-of-profile packets.
Optionally, configure another policer that defines an upper bound and drops the packets that exceed the upper bound, regardless of congestion on the physical interface.
To configure strict-priority queuing and prevent
starvation of other queues, include the priority strict-high statement at the [edit class-of-service schedulers scheduler-name] hierarchy level and the if-exceeding and then out-of-profile statements at the [edit
firewall policer policer-name] hierarchy
level:
[edit class-of-service schedulers scheduler-name]
priority strict-high;
[edit firewall policer policer-name]
if-exceeding {
bandwidth-limit bps;
bandwidth-percent number;
burst-size-limit bytes;
}
then out-of-profile;