Internet-Draft MNA Flow ID July 2024
Zhou & Song Expires 9 January 2025 [Page]
Workgroup:
MPLS
Internet-Draft:
draft-zhou-mna-flow-id-00
Published:
Intended Status:
Standards Track
Expires:
Authors:
T. Zhou
Huawei Technologies
H. Song
Futurewei Technologies

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.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 9 January 2025.

Table of Contents

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.

GFI -
General Flow Identifier
MNA -
MPLS Network Action
ISD -
In Stack Data

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   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 1: GFI ISD Encoding

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.

4. Security Considerations

TBD

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:

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>.

Authors' Addresses

Tianran Zhou
Huawei Technologies
Beijing
China
Haoyu Song
Futurewei Technologies
Santa Clara, CA
United States of America