MPLS Network Actions for Network Resource Partition Selector

Internet-Draft	MNA NRP Sel	May 2023
Li, et al.	Expires 6 November 2023	[Page]

Abstract

An IETF Network Slice service provides connectivity coupled with a set of network resource commitments and is expressed in terms of one or more connectivity constructs. A Network Resource Partition (NRP) is a collection of resources identified in the underlay network to support IETF Network Slice services. A Slice-Flow Aggregate refers to the set of traffic streams from one or more connectivity constructs belonging to one or more IETF Network Slices that are mapped to a specific NRP and provided the same forwarding treatment. The packets associated with a Slice-Flow Aggregate may carry a marking in the packet's network layer header to identify this association and this marking is referred to as NRP Selector. The NRP Selector is used to map the packet to the associated NRP and provide the corresponding forwarding treatment to the packet.¶

MPLS Network Actions (MNA) technologies are used to indicate actions for Label Switched Paths (LSPs) and/or MPLS packets and to transfer data needed for these actions. This document discusses options for using MPLS Network Actions (MNAs) to carry the NRP Selector in MPLS packets.¶

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/.¶

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This Internet-Draft will expire on 6 November 2023.¶

Copyright Notice

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

An IETF Network Slice [I-D.ietf-teas-ietf-network-slices] service provides connectivity coupled with a set of specific commitments of network resources between a number of endpoints over a shared underlay network. The IETF Network Slice service is expressed in terms of one or more connectivity constructs. A Network Resource Partition (NRP) [I-D.ietf-teas-ietf-network-slices] is a collection of resources identified in the underlay network to support IETF Network Slice services (or any other services that need logical network structures with required characteristics to be created). An NRP Policy [I-D.ietf-teas-ns-ip-mpls] is a policy construct that enables instantiation of mechanisms in support of service specific control and data plane behaviors on select topological elements associated with the NRP.¶

A Slice-Flow Aggregate refers to the set of traffic streams from one or more connectivity constructs belonging to one or more IETF Network Slices that are mapped to a specific NRP and are provided the same forwarding treatment. The NRP policy dictates the identification of the flow aggregate that the packet belongs to and the corresponding forwarding treatment that needs to be applied to the packet. The packets associated with a Slice-Flow Aggregate may carry a marking in the packet's network layer header to identify this association and this marking is referred to as NRP Selector (NRPS). [I-D.ietf-teas-ns-ip-mpls] discusses a few options for carrying the NRP Selector in MPLS packets, including overloading the semantics of forwarding/service labels and using a dedicated identifier field.¶

[I-D.ietf-mpls-mna-fwk] specifies an architectural framework for the MPLS Network Actions (MNA) technologies. MNA technologies are used to indicate actions for Label Switched Paths (LSPs) and/or MPLS packets and to transfer data needed for these actions. The MNA architecture can facilitate carrying the dedicated identifier based NRP Selector in the MPLS label stack. This document discusses a few options for using MPLS network actions to carry the NRP Selector. The proposed encodings are compliant with the MNA header encoding formats defined in [I-D.ietf-mpls-mna-hdr].¶

The reader is expected to be familiar with terminology specified in [I-D.ietf-mpls-mna-fwk] and MNA header encoding formats defined in [I-D.ietf-mpls-mna-hdr].¶

1.1. Requirements Language

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. MPLS Network Actions

2.1. 13-bit NRP Selector (NRPS13) Action

The format of the 13-bit NRP Selector (NRPS13) Action (when encoded in the second label stack entry in the Network Action Sub-Stack):¶

  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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Opcode=TBA1 |         NRPS            |R|IHS|S| Res |U|  NASL |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

*: Name: 13-bit NRP Selector (NRPS13) Action¶
*: Network Action Indication: The NRPS13 Action indication is opcode TBA1.¶
*: Scope: The NRPS13 Action is valid in all scopes.¶
*: In-Stack Data: The NRPS13 Action carries 13 bits of ancillary data. The NRPS is encoded in the 13 bits. The packet carrying the NRPS13 action should be given the forwarding treatment specified by the associated policy.¶
*: LSE Format: B.¶
*: Post-Stack Data: None.¶

2.2. 20-bit NRP Selector (NRPS20) Action

The format of the 20-bit NRP Selector (NRPS20) Action:¶

  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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |  Opcode=TBA2|             NRPS              |S|  NRPS |  NAL  |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

*: Name: 20-bit NRP Selector (NRPS20) Action¶
*: Network Action Indication: The NRPS20 Action indication is opcode TBA2.¶
*: Scope: The NRPS20 Action is valid in all scopes.¶
*: In-Stack Data: The NRPS20 Action carries 20 bits of ancillary data. The NRPS is encoded in the 20 bits. The packet carrying the NRPS20 action should be given the forwarding treatment specified by the associated policy.¶
*: LSE Format: C. The Network Action Length (NAL) field SHOULD be transmitted as zero.¶
*: Post-Stack Data: None.¶

2.3. 20-bit Entropy and NRP Selector (ENRPS20) Action

The format of the 20-bit Entropy and NRP Selector (ENRPS20) Action:¶

 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Opcode=TBA3|        Entropy        | NRPS  |S| NRPS  |  NAL  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

*: Name: 20-bit Entropy and NRP Selector (ENRPS20) Action¶
*: Network Action Indication: The ENRPS20 Action indication is opcode TBA3.¶
*: Scope: The ENRPS20 Action is valid in all scopes.¶
*: In-Stack Data: The ENRPS20 Action carries 20 bits of ancillary data. The most significant 12 bits of ancillary data is the Entropy Value. The least significant 8 bits of ancillary data is the NRPS. The Entropy Value has semantics consistent with the Entropy Label [RFC6790]. While the RFC 6790 Entropy Label has some restrictions to avoid collisions with the reserved label space (0-15) [RFC3032], those restrictions are not necessary for the Entropy Value and do not apply. The packet carrying the ENRPS20 action should be given the forwarding treatment specified by the associated policy.¶
*: LSE Format: C. The Network Action Length (NAL) field SHOULD be transmitted as zero.¶
*: Post-Stack Data: None.¶

3. IANA Considerations

3.1. 13-bit NRP Selector Action

This document requests that IANA allocate a codepoint (TBA1) from the "Multiprotocol Label Switching Architecture (MPLS)"/"MPLS Network Actions Parameters"/"Network Action Opcodes" registry for the 13-bit NRP Selector Action. The allocation should reference this document.¶

3.2. 20-bit NRP Selector Action

This document requests that IANA allocate a codepoint (TBA2) from the "Multiprotocol Label Switching Architecture (MPLS)"/"MPLS Network Actions Parameters"/"Network Action Opcodes" registry for the 20-bit NRP Selector Action. The allocation should reference this document.¶

3.3. 20-bit Entropy and NRP Selector Action

This document requests that IANA allocate a codepoint (TBA3) from the "Multiprotocol Label Switching Architecture (MPLS)"/"MPLS Network Actions Parameters"/"Network Action Opcodes" registry for the 20-bit Entropy and NRP Selector Action. The allocation should reference this document.¶

6. References

6.1. 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-02, 29 March 2023, <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mna-hdr-02>.
[RFC2119]: Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
[RFC3032]: Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001, <https://www.rfc-editor.org/info/rfc3032>.
[RFC6790]: Kompella, K., Drake, J., Amante, S., Henderickx, W., and L. Yong, "The Use of Entropy Labels in MPLS Forwarding", RFC 6790, DOI 10.17487/RFC6790, November 2012, <https://www.rfc-editor.org/info/rfc6790>.
[RFC8174]: Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.

6.2. Informative References

[I-D.ietf-mpls-mna-fwk]: Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS Network Actions Framework", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-fwk-03, 11 March 2023, <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mna-fwk-03>.
[I-D.ietf-teas-ietf-network-slices]: Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani, K., Contreras, L. M., and J. Tantsura, "A Framework for IETF Network Slices", Work in Progress, Internet-Draft, draft-ietf-teas-ietf-network-slices-19, 21 January 2023, <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ietf-network-slices-19>.
[I-D.ietf-teas-ns-ip-mpls]: Saad, T., Beeram, V. P., Dong, J., Wen, B., Ceccarelli, D., Halpern, J. M., Peng, S., Chen, R., Liu, X., Contreras, L. M., Rokui, R., and L. Jalil, "Realizing Network Slices in IP/MPLS Networks", Work in Progress, Internet-Draft, draft-ietf-teas-ns-ip-mpls-02, 13 March 2023, <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ns-ip-mpls-02>.