Dell S4048–ON Configuration Manual page 237

Policing provides a method for protecting CPU bound control plane packets by policing packets transmited to CPU with a specified
rate and from undesired or malicious traffic. This is done at each CPU queue on each unit.
FP Entries for Distribution of NDP Packets to Various CPU Queues
• At present generic mac based entries in system flow region will take IPv6 packets to CPU.
– OSPFv3 – 33:33:0:0:0:5 – Q7
– - 33:33:0:0:0:6 – Q7
– IPv6 Multicast – 33:33:0:0:0:0 – Q1
• Add/remove specific ICMPv6 NDP protocol entry when user configures the first ipv6 address in the front panel port
– Distribute ICMPv6 NS/RS packets to Q5.
– Distribute ICMPv6 NA/RA packets to Q6.
FP is installed for all Front panel ports.
NDP Packets
Neighbor discovery protocol has 4 types of packets NS, NA, RA, RS. These packets need to be taken to CPU for neighbor discovery.
• Unicast NDP packets:
– Packets hitting the L3 host/route table and discovered as local terminated packets/CPU bound traffic. For CPU bound traffic
route entry have CPU action. Below are packets are CPU bound traffic.
* Packets destined to chassis.
* Route with Unresolved Arp
* Unknown traffic in IP Subnet range
* Unknown traffic hitting the default route entry.
• Multicast NDP packets
– NDP packets with destination MAC is multicast
* DST MAC 33:33:XX:XX:XX:XX
• NDP Packets in VLT peer routing enable
– VLT peer routing enable cases each VLT node will have route entry for link local address of both self and peer VLT node. Peer
VLT link local entry will have egress port as ICL link. And Actual link local address will have entry to CopyToCpu. But NDP
packets destined to peer VLT node needs to be taken to CPU and tunneled to the peer VLT node..
• NDP packets in VLT peer routing disable case
– NDP packets intended to peer VLT chassis taken to CPU and tunnel to peer.
The following table describes the protocol to queue mapping with the CPU queues increased to be 12.
Table 15. Redirecting Control Traffic to 12 CPU queues
CPU Queue Weights
0 100
1 1
Rate (pps)
1300
300
Protocol
BFD
MC
Control Plane Policing (CoPP)
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