NetFlow and sFlow Configuration Guide on Cisco 8000 Series Routers, Cisco IOS XR Releases

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NetFlow and sFlow Configuration Guide on Cisco 8000 Series Routers, Cisco IOS XR Releases

Monitoring post-QoS data in NetFlow and IPFIX

Updated: June 9, 2026

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Describes how monitoring post-QoS data in NetFlow and IPFIX enables in-depth analysis of network performance and QoS policy effectiveness.

A monitoring post-QoS data in NetFlow and IPFIX feature is a network visibility enhancement that

  • enables export of post-QoS information elements for NetFlow and IPFIX

  • allows in-depth analysis of packet-level QoS characteristics, and

  • provides comprehensive visibility into how QoS policies affect network traffic.

The post-QoS information element field export for NetFlow and IPFIX allows monitoring of QoS policies. This improvement focuses on the analysis of packet-level information by incorporating the export of Post-QoS details, specifically the Differentiated Services Code Point (DSCP) in IPv4 and Traffic Class in IPv6.

Post-QoS monitoring in NetFlow and IPFIX

Describes how monitoring post-QoS data in NetFlow and IPFIX enables in-depth analysis of network performance and QoS policy effectiveness. This feature facilitates in-depth monitoring of sampled packets, emphasizing their post-processing QoS characteristics.

In NetFlow v9 or IPFIX packets, the post-QoS field utilizes the information element postIpClassOfService (IE55) for collecting post-QoS data. This feature also provides visibility to both pre- and post-QoS Type of Service (TOS)/DSCP values within the show command, enabling comprehensive assessment of network performance.

Note

The ingress QoS (pre-QoS) parameters are already exported in prior IOS-XR software releases.

Key information elements:

  • ipClassOfService: For IPv4, represents the value of the Type of Service (TOS) field in the IPv4 packet header. For IPv6 packets, signifies the value of the Traffic Class field in the IPv6 packet header. Available prior to IOS-XR software release 24.1.1.

  • postIpClassOfService: Identical to ipClassOfService, except it reports a potentially modified value caused by a router function after the packet has passed the observation point. Introduced in IOS-XR software release 24.1.1.

Lists the feature history and supported platforms for monitoring post-QoS data in NetFlow and IPFIX.