| Internet-Draft | IPFIX MPLS MNA | December 2025 |
| Liu | Expires 26 June 2026 | [Page] |
This document introduces new IPFIX IEs for exporting MPLS Network Action (MNA) information in IPFIX, covering both in-stack and post-stack MNAs.¶
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MPLS Network Actions (MNAs), as introduced in [RFC9789], are used to indicate actions that impact the forwarding or other processing (such as monitoring) of the packet along the Label Switched Path (LSP) of the packet and to transfer any additional data needed for these actions.¶
Two types of MNAs solutions are defined:¶
When monitoring a traffic flow with MPLS MNA encoding, the following information may be required by the network operator.¶
In the existing IPFIX mechanism, mplsLabelStackSection(IE 316) can be used to carry a series of n octets from the MPLS label stack of a sampled packet, starting sectionOffset(IE 409) octets into the MPLS label stack, and mplsPayloadPacketSection(IE 317) carries a series of n octets from the MPLS payload of a sampled packet, starting sectionOffset(IE 409) octets into the MPLS payload.¶
If mplsLabelStackSection(IE 316) and mplsPayloadPacketSection(IE 317) are used to carry the MNA information, additional procedures are required at the network analyzer to parse the mplsLabelStackSection or the mplsPayloadPacketSection information to see if there's any MNA information carried in it and what's the detailed MNA information. And this would bring extra complexity in the network analyzer.¶
This document introduces new IPFIX IEs for exporting MNA information in IPFIX, covering both in-stack and post-stack MNAs.¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
This document makes use of the terms defined in [RFC7011] and [RFC9789].¶
This section defines several Encapsulation Layer IEs for MPLS MNAs. Section 3.1 defines IEs for MNAs carried in the MPLS label stack (in-Stack MNA) and section 3.2 defines IEs for MNAs carried after the bottom of the MPLS label stack (post-Stack MNA).¶
mplsMnaSubStack¶
TBD1¶
The MNA Sub-Stack in the MPLS label stack with the MNA Sub-Stack Indicator excluded. This Information Element has a variable length. Multiple mplsMnaSubStack IEs can be specified within a single Template since multiple MPLS Network Action Sub-Stacks (NASes) may appear in a label stack as described in section 3 of [I-D.ietf-mpls-mna-hdr].¶
octetArray¶
default¶
See [I-D.ietf-mpls-mna-hdr].¶
mplsMnaLseFormatB¶
TBD2¶
The LSE Format B carried in the MPLS Network Action Sub-Stack(NAS). As defined in section 5 of [I-D.ietf-mpls-mna-hdr], the second LSE in a NAS MUST be a Format B LSE. This LSE contains an initial opcode plus additional fields that describe the NAS. The size of this Information Element is 3 octets.¶
If multiple mplsMnaLseFormatB Information Elements are specified within a single Template, then they apply to the mplsMnaSubStack Information Elements in order: the first mplsMnaLseFormatB applies to the first mplsMnaSubStack, the second to the second, and so on. Note that the "closest" mplsMnaLseFormatB and mplsMnaSubStack Information Elements within a given Template are not necessarily related. If there are fewer mplsMnaLseFormatB Information Elements than mplsMnaSubStack Information Elements, then subsequent mplsMnaSubStack Information Elements have no LSE Format B information in this template. If there are more mplsMnaLseFormatB Information Elements than the number of mplsMnaSubStack Information Elements, then the additional mplsMnaLseFormatB Information Elements are meaningless.¶
octetArray¶
default¶
See section 4.2 in [I-D.ietf-mpls-mna-hdr] for the definition of LSE Format B.¶
This document.¶
mnaPostStackMplsHeaderSection¶
TBD3¶
The Post-Stack MPLS Header encoded after the Bottom of the MPLS label stack. This Information Element has a variable length.¶
octetArray¶
default¶
See section 3 of [I-D.ietf-mpls-mna-ps-hdr].¶
This document.¶
mnaPostStackMplsHeaderType¶
TBD4¶
This IE carries the Post-Stack MPLS Header Type defined in section 3.2.1 of [I-D.ietf-mpls-mna-ps-hdr]. The Post-Stack MPLS Header type is the top-header for all the Post-Stack Network Actions that are encoded in the PSMH for each scope. The size of this Information Element is 4 octets.¶
octetArray¶
default¶
See section 3.2.1 of [I-D.ietf-mpls-mna-ps-hdr].¶
This document.¶
For the in-stack MNAs, as specified in [I-D.ietf-mpls-mna-hdr], the presence of the MNA Sub-Stack Indicator is indicated by the MNA Sub-Stack Indicator which is a Base Special-Purpose MPLS Label with value TBA. To generate Flow Records with the in-Stack MNA IEs included, the metering process MUST understand the MNA Sub-Stack Indicator. If the Base Special-Purpose MPLS Label with value TBA is absent in the label stack, when the in-Stack MNA IEs appear in the template record, the corresponding field in the data record is RECOMMENDED to set to all zeros.¶
For the post-stack MNAs, since the presence of the Post-Stack MPLS Header is indicated by the P-bit in the LSE Format B [I-D.ietf-mpls-mna-ps-hdr] which is carried in the label stack following the MNA Sub-Stack Indicator, the metering process MUST understand the MNA Sub-Stack Indicator and the P-bit in the LSE Format B. Only when the P-bit is set SHOULD the metering process capture the post-stack MNA information after the bottom of the stack.¶
There are no additional security considerations regarding allocation of these new IPFIX IEs compared to [RFC7012].¶
This document requests IANA to create new IEs under the "IPFIX Information Elements" registry [RFC7012] available at [IANA-IPFIX].¶
| Element ID | Name | Reference |
| TBD1 | mplsMnaSubStack | This document |
| TBD2 | mplsMnaLseFormatB | This document |
| TBD3 | mnaPostStackMplsHeaderSection | This document |
| TBD4 | mnaPostStackMplsHeaderType | This document |