Cisco Cisco IOS Software Release 12.2(27)SBC

The MPLS-Aware NetFlow feature requires the following for its operation:

NetFlow configured on the label switch router (LSR)

MPLS enabled on the LSR

Cisco Express Forwarding or distributed Cisco Express Forwarding enabled on the LSR

The following are also required if you are exporting MPLS-Aware NetFlow data to a Cisco NetFlow 
collector:

NetFlow Version 9 export format configured on the LSR

NetFlow collector and analyzer capable of using MPLS-Aware NetFlow export packets in Version 9 
format

The following restrictions apply to the MPLS-Aware NetFlow feature in Cisco IOS Releases 12.0(26)S, 
12.3(8)T, 12.2(28)SB, and later releases:

No more than three MPLS labels are allowed to be captured and exported for this implementation.

MPLS-Aware NetFlow reports the following fields in MPLS flows as 0: IP next-hop, source and 
destination Border Gateway Protocol (BGP) autonomous system numbers, and source and 
destination prefix masks.

For MPLS packets that contain non-IP packets under the MPLS label stack, MPLS-Aware NetFlow 
reports the following flow fields as 0: source and destination IP addresses, protocol, ToS, ports, and 
TCP flags. 

The following restriction applies to MPLS-Aware NetFlow in Cisco IOS Release 12.2(28)SB and later 
releases:

The MPLS label type and associated IP address are not captured. If you want this functionality, you 
need to enable the NetFlow MPLS Label Export feature.

The following sections contain information for understanding how to configure and use the 
MPLS-Aware NetFlow feature: