Example: Configuring Transmit Rates That Add Up to More Than 100 Percent
In the following example, ef is an expedited forwarding
traffic queue; nc is a network control traffic queue; af_01, af_02, af_03, and af_04 are assured forwarding traffic queues; and be is a best
effort forwarding queue. so-2/2/0 unit 0 is the logical
interface.
[edit class-of-service]
traffic-control profiles tcp {
shaping-rate 300M;
}
interfaces {
so-2/2/0 {
unit 0 {
output-traffic-control-profiles tcp;
}
}
schedulers {
ef {
transmit-rate percent 50 rate-limit;
priority strict-high;
}
nc {
transmit-rate percent 5;
priority high;
}
af_04 {
transmit-rate percent 20;
priority medium;
}
af_03 {
transmit-rate percent 35;
priority low;
}
af_02 {
transmit-rate percent 30;
priority low;
}
af_01 {
transmit-rate percent 9;
priority low;
}
be {
transmit-rate percent 1;
priority low;
}
}
The ef and the nc queues are at the same
priority. Therefore, both these queues take precedence over all the
other queues. The ef queue consumes 100 Mbps (50 percent
of the CIR; that is, 50 percent of 200 Mpbs) bandwidth. The remaining
200 Mbps is rate limited. The nc queue continues to consume
the bandwidth till the logical interface reaches its CIR of 200 Mbps.
Therefore, the nc queue gets 100 Mbps bandwidth. When the
logical interface reaches its CIR, all queues transition into the
excess region and the scheduler allocates the remaining bandwidth
to the non-expedited forwarding queues based on their default excess
priorities and default excess rates (same as the transmit rates).
As per Table 1, all the non-strict-high queues are in the same excess priority (in this case, low priority), these non-strict-high queues get the bandwidth out of the remaining 100 Mbps in the ratio of 5:20:35:30:9:1 until the logical interface consumes its shaping rate of 300 Mbps. Thus, the non-strict-high queues add up to 100 percent of bandwidth utilization to optimize the bandwidth usage.