Configure Control Plane Policing - Dell S4048–ON Configuration Manual

Figure 26. CoPP Implemented Versus CoPP Not Implemented

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.
242 Control Plane Policing (CoPP)