• The Microflow Policing feature shares the NetFlow hardware resource with Flexible NetFlow.
• One flow monitor per interface, per direction, is supported.
• Layer 2, IPv4 and IPv6 traffic types are supported. However, a flow monitor can be applied to only one of these types at a time for a given direction and interface.
• Layer 2, VLAN, and Layer 3 interfaces are supported. Switched virtual interfaces and tunnels are not supported.
• The Ingress and Egress NetFlow tables do not support LAN base license level.
• The Ingress NetFlow table supports an IP base license level of 8K on a per Application Specific Integrated Circuit (ASIC) basis.
• The Egress NetFlow table supports an IP base license level of 16K on a per ASIC basis.
• The Ingress NetFlow table supports an IP services license level of 8K on a per ASIC basis.
• The Egress NetFlow table supports an IP services license level of 16K on a per ASIC basis.
• Depending on the switch type, Cisco Catalyst 3850 Series Switches have one or two forwarding ASICs.
• The Cisco 5700 Wireless Controller supports three ASICs.
• The NetFlow tables are on separate compartments and cannot be combined. Depending on which ASIC processed the packet, the flows will be created in the table in the corresponding ASIC.
• Only full flow accounting is supported for wireless traffic.
• For information about the fields supported by Flexible NetFlow, refer to the Cisco IOS Flexible NetFlow Command Reference.
• NetFlow hardware uses hash tables internally. It is possible that hash collisions happen in the hardware. So, in spite of the internal overflow CAM, the actual NetFlow table utilization could be about 80%.

• Depending on what fields are used for the flow, a single flow could take two consecutive entries. Also, IPv6 flows take two entries. So, for these cases, the effective usage of NetFlow entries is half the table size. This is apart from the hash collision limitation.

• Up to 16 flow monitors are supported. Microflow policing uses a separate set of flow monitors.

• Service Set Identifier (SSID)-based NetFlow accounting is supported. SSID is treated like an interface. However, fields like AP MAC address and user ID are not supported.

• The NetFlow software supports distributed NetFlow export, so the flows are exported from the same switch in which the flow was created.

• Ingress flows are present in the ASIC that first received the packets for the flow. Egress flows are present in the ASIC from which the packets actually left the switch setup.

• The reported value for the bytes count field (IN_BYTES) is (layer-2-packet-size - 18 bytes). For classic Ethernet traffic, this will be accurate. For all other Ethernet types, this field will not be accurate. Please use the "bytes Layer 2" field which will always report the accurate layer 2 packet size.

Related Documents

Standards/RFCs

MIBs

Technical Assistance

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.