Users Guide

Figure 28. CoPP Implemented Versus CoPP Not Implemented
Topics:
• Configure Control Plane Policing
Configure Control Plane Policing
The system can process a maximum of 4200 packets per second (PPS). Protocols that share a single queue may experience
flaps if one of the protocols receives a high rate of control traffic even though per protocol CoPP is applied. This happens
because queue-based rate limiting is applied first.
For example, border gateway protocol (BGP) and internet control message protocol (ICMP) share same queue (Q6); Q6 has
400 PPS of bandwidth by default. The desired rate of ICMP is 100 PPS and the remaining 300 PPS is assigned to BGP. If ICMP
packets come at 400 PPS, BGP packets may be dropped though ICMP packets are rate-limited to 100 PPS. You can solve this
by increasing Q6 bandwidth to 700 PPS to allow both ICMP and BGP packets and then applying per-flow CoPP for ICMP and
BGP packets. The setting of this Q6 bandwidth is dependent on the incoming traffic for the set of protocols sharing the same
queue. If you are not aware of the incoming protocol traffic rate, you cannot set the required queue rate limit value. You must
complete queue bandwidth tuning carefully because the system cannot open up to handle any rate, including traffic coming at
the line rate.
CoPP policies are assigned on a per-protocol or a per-queue basis, and are assigned in CONTROL-PLANE mode to each port-
pipe.
CoPP policies are configured by creating extended ACL rules and specifying rate-limits through QoS policies. The ACLs and QoS
policies are assigned as service-policies.
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Control Plane Policing (CoPP)