Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide ...

LP CPU packet statistics 10TABLE 6FieldOutput from the show lp-cpu packet statistics command (Continued)DescriptionL2 unknown unicast packetsfloodedL2 broadcast packets floodedL2 multicast packets floodedPackets received for SA learningOther packets receivedTotal packets droppedPacket drop causesPacket drop causes(continued)The number of Layer 2 unknown-unicast packets flooded by the LP CPU.The number of Layer 2 broadcast packets flooded by the LP CPU.The number of Layer 2 multicast packet (including packets forwarded by IGMPsnooping and multi-port MAC packets) received by the LP CPU.The number of packets received for source MAC address learning.The number of miscellaneous packets received by the LP CPU. The Otherpackets received counter is incremented when a packet is not processed byany of the forwarding counters displayed previously (for example, MPLSuplinks packets received counter, ARP packets received counter, and so on).The total number of packets dropped by the LP CPU.The reasons for dropping a packet, and the number of packets that aredropped for a given reason. The LP CPU forwards the packet to a destinationport or destination FID, drops the packet based on the forwarding decision, ordrops the packet due to errors in packet processing by the LP CPU. Packetscan be dropped based on following reasons:• Post Processing (PP) Drops - The packets are dropped because thepackets were forwarded in hardware by the LP CPU and copied to theCPU to learn SA or DA MAC addresses, or for sFlow logging. The PP dropsare to be expected and are not harmful to the LP CPU packet processing.For a complete list of all PP drop causes, refer to Table 7 on page 354.• Configuration Violation (CV) Drops- The packets are dropped because ofconfiguration violations, such as Layer 2 packets received on a route-onlyswitch. A route-only switch implies that Layer 2 packets are only routed,not switched. Layer 2 packets are usually forwarded within the sameVLAN and are not routed to a different VLAN. If packets are configured toroute only, then Layer 2 packets are dropped. A CV drop can also occurwhen the number of broadcast packets has exceeded the configuredlimit set by the user. A port in a blocking state constitutes a CV drop. Fora complete list of all CV drop causes, refer to Table 7 on page 354.Packets can be dropped based on following reasons (continued):• Packet Error (PE) Drop - A packet is dropped because it is received witherrors because the packet is corrupted, or the packet contains incorrectinformation such as an invalid SA or DA MAC address. For a complete listof all PE drop causes, refer to Table 7 on page 354.• Potential Forwarding Error (PFE) Drops - A PFE drop occurs when theinformation required to forward a packet to its destination is notavailable in the LP software. For example, the destination FID is invalid,or ARP is not resolved. For a complete list of all PFE drop causes, refer toTable 7 on page 354.• Other Drops (OD) - OD drops are drops that cannot be classified into anyof the preceding drop causes. For a complete list of all OD drop causes,refer to Table 7 on page 354.For example, the following is displayed in the output:3-L2 packet forwarded in hardware(PP):9619• 3 refers to the drop code.• L2 packet forwarded in hardware refers to the type of packet drop cause.For a list of all packet drop causes, refer to Table 2.• 9619 refers to the number of packets that are dropped.Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide 35353-1002426-02