Internet-Draft | MNA Flow ID | July 2024 |
Zhou & Song | Expires 9 January 2025 | [Page] |
- Workgroup:
- MPLS
- Internet-Draft:
- draft-zhou-mpls-mna-flow-id-00
- Published:
- Intended Status:
- Standards Track
- Expires:
A General Flow ID for MPLS Network Action
Abstract
This document specifies a general flow ID as an in-stack data item for MPLS network action. The flow ID can be used by multiple network actions which require to identify flows.¶
Status of This Memo
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.¶
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This Internet-Draft will expire on 9 January 2025.¶
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved.¶
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
1. Introduction
Many MNAs affiliate to specific flows or exhibit different behavior to different flows. For example, the network operator may apply certain OAM on a number of selected flows and collect per flow data. However, in MPLS networks, the labels are used to identify paths but not flows. If multiple flows sharing the same path require the same MNA, the LSR may need to differentiate the flows and execute the action on a per-flow basis.¶
The flow information can be extracted from the L3/L4 header in the MPLS payload by deep packet inspection, which incurs significant processing overhead. Alternatively, each flow-based MNA may carry its own unique identifier to differentiate the flows. However, this approach has several issues.¶
First, one packet may have multiple MNAs that require a flow identification. There will be obvious data redundancy if each MNA carries its own flow identifier. Second, limited by the MNA ISD encoding and size, the flow identifier may have to be tailored to a sub-optimal size, resulting in poor scalability. Third, A customized flow identifier per MNA may cause network management difficulties and waste network resources.¶
Therefore, it is desired to have a General Flow Identifier (GFI) which can be shared by all the MNAs relying on it. In this draft, we propose a new ISD item for GFI using the encoding format described in [I-D.ietf-mpls-mna-hdr]. We also list the possible use cases which can use the GFI.¶
1.1. Terminology and Acronyms
The following terminology and acronyms are used in this document.¶
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. GFI Encoding
As shown in Figure 1, an Opcode is assigned for GFI and the encoding of GFI takes the LSE Format C as specified in [I-D.ietf-mpls-mna-hdr], in which the GFI uses the 20-bit data field.¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OC(TBD) | GFI |S| GFI | 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3. Use Cases
The GFI can have multiple possible use cases:¶
- IOAM-DEX:
- IOAM-DEX [RFC9326] is used as a trigger for collecting IOAM data [RFC9197] locally or exporting it to a receiving entity (or entities). The Flow ID in the IOAM-DEX Option-Type is an optional field representing the flow identifier. The Flow ID can be used to correlate the exported data of the same flow from multiple nodes and from multiple packets.¶
- PBT-M:
- An on-path telemetry method using packet-marking, referred to as PBT-M [I-D.song-ippm-postcard-based-telemetry], does not carry the telemetry data in user packets but sends the telemetry data through a dedicated packet. The MPLS encoding of PBT-M described in [I-D.song-mpls-flag-based-opt] can take advantage of the GFI to help correlate the postcards and identify the flow under test.¶
- AM:
- The Alternate Marking [RFC9341]technique described in [I-D.song-mpls-flag-based-opt] can use GFI to identify the flow under test.¶
- Entropy:
- The GFI can be used as an entropy label for load balancing on multiple paths.¶
- DetNet:
- RFC8964 [RFC8964] defines the MPLS dataplane for Deterministic Networking. A DetNet "service" label is used between DetNet nodes that implement the DetNet service sub-layer functions. An S-Label is used to identify a DetNet flow at the DetNet service sub-layer at a receiving DetNet node. Within MNA architecture, the GFI can be used as the S-Lable.¶
5. IANA Considerations
This document requires a new option code assigned to indicate GFI.¶
6. Acknowledgments
The comments and suggestions of the following are gratefully acknowledged:¶
-
TBD¶
7. References
7.1. Normative References
- [I-D.ietf-mpls-mna-hdr]
- 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-07, , <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mna-hdr-07>.
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- [RFC8174]
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
7.2. Informative References
- [I-D.song-ippm-postcard-based-telemetry]
- 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, , <https://datatracker.ietf.org/doc/html/draft-song-ippm-postcard-based-telemetry-16>.
- [I-D.song-mpls-flag-based-opt]
- Song, H., Fioccola, G., and R. Gandhi, "Flag-based MPLS On Path Telemetry Network Actions", Work in Progress, Internet-Draft, draft-song-mpls-flag-based-opt-03, , <https://datatracker.ietf.org/doc/html/draft-song-mpls-flag-based-opt-03>.
- [RFC8964]
- Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant, S., and J. Korhonen, "Deterministic Networking (DetNet) Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, , <https://www.rfc-editor.org/info/rfc8964>.
- [RFC9197]
- Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi, Ed., "Data Fields for In Situ Operations, Administration, and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197, , <https://www.rfc-editor.org/info/rfc9197>.
- [RFC9326]
- Song, H., Gafni, B., Brockners, F., Bhandari, S., and T. Mizrahi, "In Situ Operations, Administration, and Maintenance (IOAM) Direct Exporting", RFC 9326, DOI 10.17487/RFC9326, , <https://www.rfc-editor.org/info/rfc9326>.
- [RFC9341]
- Fioccola, G., Ed., Cociglio, M., Mirsky, G., Mizrahi, T., and T. Zhou, "Alternate-Marking Method", RFC 9341, DOI 10.17487/RFC9341, , <https://www.rfc-editor.org/info/rfc9341>.