Cisco Asr 9000 Series Aggregation Services Router Modular Quality Of Service Configuration Guide, Release - Cisco ASR 9000 Series Configuration Manual

Configuring Modular QoS Congestion Management
placed into one of these categories. Within these three categories, users can decide packet treatments. For
instance, packets that conform can be configured to be sent; packets that exceed can be configured to be sent
with a decreased priority; and packets that violate can be configured to be dropped.
Two-Rate Policer, on page 58
action to the packet.
Figure 5: Marking Packets and Assigning Actions — 2-Rate Policer
For example, if a data stream with a rate of 250 kbps arrives at the two-rate policer, and the CIR is 100 kbps
and the PIR is 200 kbps, the policer marks the packet in the following way:
• 100 kbps conforms to the rate
• 100 kbps exceeds the rate
• 50 kbps violates the rate
The router updates the tokens for both the committed and peak token buckets in the following way:
• The router updates the committed token bucket at the CIR value each time a packet arrives at the interface.
The committed token bucket can contain up to the committed burst (bc) value.
• The router updates the peak token bucket at the PIR value each time a packet arrives at the interface.
The peak token bucket can contain up to the peak burst (be) value.
• When an arriving packet conforms to the CIR, the router takes the conform action on the packet and
decrements both the committed and peak token buckets by the number of bytes of the packet.
• When an arriving packet exceeds the CIR, the router takes the exceed action on the packet, decrements
the committed token bucket by the number of bytes of the packet, and decrements the peak token bucket
by the number of overflow bytes of the packet.
shows how the two-rate policer marks a packet and assigns a corresponding
Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide, Release 6.1.x
Regulation of Traffic with the Policing Mechanism
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