As part of enhancements, CPU queues are increased from 8 to 12 on CPU port. However, the front-end port and the backplane ports
support only 8 queues. As a result, when packets are transmitted to the local CPU, the CPU uses Q0-Q11 queues. The control packets that
are tunneled to the master unit are isolated from the data queues and the control queues in the backplane links. Control trac must be sent
over the control queues Q4-Q7 on higig links. After reaching the master unit tunneled packets must be transmitted to the CPU using the
Q0-Q11 queues.
The backplane ports can have a maximum of 4 control queues. So, when we have more than ‘n’ CMIC queues for well-known protocols and
n > 4, then streams on ‘n’ CMIC queues must be multiplexed on 4 control queues on back-plane ports and on the Master unit, these
streams must be de-multiplexed to ‘n’ CMIC queues on the Master CPU.
After control packets reach the CPU through the CMIC port, the software schedules to process trac on each 12 CPU queues. This
aspect must be ensured even in case of stand-alone systems and there is no dependency with stacking.
Policing provides a method for protecting CPU bound control plane packets by policing packets transmited to CPU with a specied rate
and from undesired or malicious trac. 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 ow 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 specic ICMPv6 NDP protocol entry when user congures the rst 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 trac. For CPU bound trac route
entry have CPU action. Below are packets are CPU bound trac.
• Packets destined to chassis.
• Route with Unresolved Arp
• Unknown trac in IP Subnet range
• Unknown trac hitting the default route entry.
• Multicast NDP packets
• NDP packets with destination MAC is multicast
• DST MAC 33:33:XX:XX:XX:XX
Control Plane Policing (CoPP)
237
To Next Page
Loading...
Need help?
General
