Internet-Draft MPLS OPT March 2024
Song, et al. Expires 5 September 2024 [Page]
Intended Status:
Standards Track
H. Song
Futurewei Technologies
G. Fioccola
Huawei Technologies
R. Gandhi
Cisco Systems

Flag-based MPLS On Path Telemetry Network Actions


This document describes the scheme to support two on-path telemetry techniques, PBT-M and Alternate Marking, as flag-based MPLS Network Actions for OAM in MPLS networks.

Status of This Memo

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This Internet-Draft will expire on 5 September 2024.

Table of Contents

1. Introduction

On-path telemetry, as described in [], is a kind of hybrid type I network OAM [RFC7799] which directly measure and monitor the user packets. Some on-path telemetry technique incur very little overhead but offer big benefits on network performance monitoring and troubleshooting. PBT-M [] (Postcard-Based On-Path Telemetry using Packet Marking) is such on-path telemetry technique which uses only a single flag bit to trigger the collection of the telemetry data regarding the packet. Alternate Marking Method [RFC9341] is another on-path performance measurement method which uses only two flag bits to measure packet loss, delay, and jitter for live data traffic.

In MPLS networks, MPLS Network Action (MNA) [I-D.ietf-mpls-mna-fwk] extends the MPLS label stack by supporting extra network actions encoded both in stack and post stack. The MNA header encoding is described in [I-D.ietf-mpls-mna-hdr].

This document describe the scheme to use flag-based MNAs to support PBT-M and Alternate Marking Method (AMM).

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.

2. PBT-M Action

A flag bit (TBA1) in the flag-based network action field is used as the PBT-M indicator. If the bit is set to '1', a configured node is triggered to collect and export the telemetry data as configured by the control plane. The detailed method on node configuration, data export and correlation are recommended in [].

3. Alternate Marking Action

Two flag bits (TBA2) in the flag-based network action field are used to support the alternate marking method as described in [RFC9341].

4. Action Encoding

The proposed action encoding is shown in Figure 1 adapted from [I-D.ietf-mpls-mna-hdr]. In the figure, 'P' stands for PBT-M flag and 'AM' stands for alternate marking flags.

     0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
   |      NASI=bSPL                        | TC  |S|    TTL        |
   |NAI-Opcode=2 |P|AM |                   |0|IHS|S| Res |U| NASL  |

Figure 1: Action Encoding

The scope of the Network Action is carried in the IHS field for Ingress-To-Egress (I2E), Hop-By-Hop (HBH) or Select.

Network Sub Stack Length is set to number of LSEs following this network action LSE which is 0 in this example.

No Post Stack Network Action is required for this.

Note that the in-stack MNA encoding may take different form, and these flag-based on-path telemetry use cases would adapt to it.

5. Security Considerations

Only the ingress edge node is allowed to set/reset these flag bits. The other on-path nodes can only react to the bit values. The tampering of these flag-based actions would result in DoS attack or unreliable measurements. Therefore, security measures must be taken to ensure the proper functioning of these actions.

6. IANA Considerations

This document requires IANA allocation a bit for PBT-M action (TBA1) and two bits for Alternate Marking (TBA2) from the MPLS "In-Stack MPLS Network Action Indicator Flags" registry created in [I-D.ietf-mpls-mna-hdr].

7. Acknowledgments

8. References

8.1. Normative References

Rajamanickam, J., Gandhi, R., Zigler, R., Song, H., and K. Kompella, "MPLS Network Action (MNA) Sub-Stack Solution", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-hdr-04, , <>.
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Morton, A., "Active and Passive Metrics and Methods (with Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.

8.2. Informative References

Bocci, M. and S. Bryant, "Requirements for MPLS Network Action Indicators and MPLS Ancillary Data", Work in Progress, Internet-Draft, draft-ietf-mpls-miad-mna-requirements-00, , <>.
Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS Network Actions Framework", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-fwk-06, , <>.
Song, H., Mirsky, G., Zhou, T., Li, Z., Graf, T., Mishra, G. S., Shin, J., and K. Lee, "On-Path Telemetry using Packet Marking to Trigger Dedicated OAM Packets", Work in Progress, Internet-Draft, draft-song-ippm-postcard-based-telemetry-16, , <>.
Song, H., Qin, F., Chen, H., Jin, J., and J. Shin, "Framework for In-situ Flow Information Telemetry", Work in Progress, Internet-Draft, draft-song-opsawg-ifit-framework-21, , <>.
Fioccola, G., Ed., Cociglio, M., Mirsky, G., Mizrahi, T., and T. Zhou, "Alternate-Marking Method", RFC 9341, DOI 10.17487/RFC9341, , <>.

Authors' Addresses

Haoyu Song
Futurewei Technologies
United States of America
Giuseppe Fioccola
Huawei Technologies
Rakesh Gandhi
Cisco Systems