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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
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Chapter 13 Configuring CEF for PFC2 and PFC3A
Default CEF for PFC2/PFC3A Configuration
NetFlow statistics support unicast and multicast flows as follows:
•
A unicast flow can be any of the following:
–
Destination only: All traffic to a particular IP destination
–
Destination-source: All traffic from a particular IP source to a particular IP destination
–
Full-flow: All traffic from a particular IP source to a particular IP destination that shares the
same protocol and transport-layer information
•
A multicast flow is all traffic with the same protocol and transport-layer information from a
particular source to the members of a particular destination multicast group.
NetFlow Table Entry Aging
The state and identity of flows are maintained while packet traffic is active; when traffic for a flow
ceases, the entry ages out. You can configure the aging time for the NetFlow table entries that are kept
in the NetFlow table. If an entry is not used for the specified period of time, the entry ages out and
statistics for that flow can be exported to a flow collector application.
Flow Masks
Flow masks determine how the NetFlow table entries are created. CEF for PFC2 supports only one flow
mask (the most specific one) for all statistics. If NetFlow for PFC2 detects different flow masks from
different MSFCs for which it is performing Layer 3 switching, it changes its flow mask to the most
specific flow mask detected (this applies to the PFC2/MSFC2 only).
When the flow mask changes, the entire NetFlow table is purged. When CEF for PFC2/PFC3A exports
cached entries, flow records are created based on the current flow mask. Depending on the current flow
mask, some fields in the flow record might not have values. Unsupported fields are filled with a zero (0).
The statistics flow masks are as follows:
•
destination-ip—The least-specific flow mask for IP
•
destination-ipx—The only flow mask for IPX
•
source-destination-ip—For IP
•
source-destination-vlan—For IP multicast
•
full flow—The most-specific flow mask
•
full vlan—The same fields as in full flow plus the source VLAN
Enter the
show mls statistics entry
command to display the contents of the NetFlow table and the
current flow mask. Use the keyword options to display information for specific traffic (refer to the
Catalyst 6500 Series Switch Command Reference
publication for more information).
Default CEF for PFC2/PFC3A Configuration
Table 13-2
shows the default CEF for PFC2/PFC3A configuration.