MPLS Network Action for Deterministic Networking
draft-songvar-mpls-mna-detnet-00
This document is an Internet-Draft (I-D).
Anyone may submit an I-D to the IETF.
This I-D is not endorsed by the IETF and has no formal standing in the
IETF standards process.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Xueyan Song , Greg Mirsky , Balazs Varga , Rakesh Gandhi , Quan Xiong | ||
| Last updated | 2025-10-20 | ||
| Replaces | draft-sxg-mpls-mna-deterministic-latency, draft-varmir-mpls-detnet-mna | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-songvar-mpls-mna-detnet-00
MPLS X. Song
Internet-Draft ZTE Corp.
Intended status: Standards Track G. Mirsky
Expires: 23 April 2026 B. Varga
Ericsson
R. Gandhi
Cisco Systems, Inc.
Q. Xiong
ZTE Corp.
20 October 2025
MPLS Network Action for Deterministic Networking
draft-songvar-mpls-mna-detnet-00
Abstract
This document specifies formats and mechanisms for using MPLS Network
Actions (MNA) to support Deterministic Networking (DetNet) services,
including bounded latency, low loss and in-order delivery. It
defines MPLS In-Stack and Post-Stack MNA for carrying DetNet-specific
information, such as flow identification, sequence number, and
latency information, which are forwarded over an MPLS technology-
based network domain.
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 23 April 2026.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
Song, et al. Expires 23 April 2026 [Page 1]
Internet-Draft DetNet MNA October 2025
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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Terms Used in This Document . . . . . . . . . . . . . . . 3
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3
2.3. Requirements Language . . . . . . . . . . . . . . . . . . 4
3. DetNet-specific MNA . . . . . . . . . . . . . . . . . . . . . 4
4. MPLS In-Stack Encoding for DetNet . . . . . . . . . . . . . . 5
4.1. DetNet-specific NASes . . . . . . . . . . . . . . . . . . 5
4.2. Characteristics of DetNet NASes . . . . . . . . . . . . . 6
4.3. Examples of DetNet NASes in MPLS In-Stack . . . . . . . . 7
4.4. Aggregation Example . . . . . . . . . . . . . . . . . . . 8
5. MPLS Post-Stack Encoding for DetNet . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Normative References . . . . . . . . . . . . . . . . . . 12
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
The DetNet work group has defined the Packet Replication Function
(PRF) and Packet Elimination Function (PEF) to achieve extremely low
packet loss. In general, usage of these per-packet replication and
elimination functions may result in out-of-order delivery of frames/
packets [RFC8655]. This characteristic of PRF/PEF has been
identified by the IETF, and a Packet Ordering Function (POF) was
defined [RFC9550]. The POF function is a DetNet service sub-layer
function similar to PRF and PEF. All the DetNet service sub-layer
functions are usually referred to as Packet Replication, Elimination,
and Ordering Functions (PREOF).
Song, et al. Expires 23 April 2026 [Page 2]
Internet-Draft DetNet MNA October 2025
These DetNet service sub-layer-related functions require ordering
information (e.g., sequence number). IETF DetNet WG has defined how
sequencing information (i.e., sequence number) travels with DetNet
packets using the d-CW [RFC8964] when PW (PseudoWire) technology is
used with an MPLS Data Plane.
The DetNet forwarding sub-layer-related functions focus on ensuring
the bounded latency requirements and may use packet-specific latency
information during forwarding. No solution was defined for adding
such latency-specific information to the PW encapsulated DetNet
packets.
This document presents MPLS MNA solutions for DetNet functions
support. It follows the MPLS MNA requirements specified at [RFC9613]
and MPLS MNA In-Stack header specifid at [I-D.ietf-mpls-mna-hdr] and
MNA Post-Stack header specified at [I-D.ietf-mpls-mna-ps-hdr] to
support basic DetNet service and DetNet service with enhanced DetNet
data plane requirements specified at
[I-D.ietf-detnet-scaling-requirements] .
2. Terminology
2.1. Terms Used in This Document
This document uses the terminology established in the DetNet
architecture [RFC8655]. The reader is assumed to be familiar with
that document and its terminology.
2.2. Abbreviations
The following abbreviations are used in this document:
DetNet Deterministic Networking
Flow-ID Flow Identifier
MNA MPLS Network Action
NAI Network Action Indicator
NAS Network Action Sub-Stack
LSE Label Stack Entry
PEF Packet Elimination Function
POF Packet Ordering Function
Song, et al. Expires 23 April 2026 [Page 3]
Internet-Draft DetNet MNA October 2025
PREOF Packet Replication, Elimination and Ordering Functions
PRF Packet Replication Function
PSD Post-Stack Data
SeqNum Sequence Number
2.3. 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.
3. DetNet-specific MNA
Three information elements may be required during the forwarding of
DetNet packets:
1. Flow identifier (Flow-ID)
2. Sequence information (SeqNum)
3. Latency information (LatencyInfo)
"1" and "2" are used by the DetNet service sub-layer (i.e., by
PREOF). "1" and "3" are used by the DetNet forwarding sub-layer to
ensure the bounded latency for a DetNet packet.
The use of a DetNet-specific MNA solution allows using a single
encapsulation format for all DetNet-specific parameters (Flow-ID,
SeqNum, LatencyInfo) as MNA data, meaning that the Network Action
Sub-stack (NAS) is carried as part of the MPLS label stack (i.e., In-
Stack MNA solution). DetNet-specific MNA enables more fine-tuned,
scalable handling of latency-bound requirements, with service
protection natively in MPLS.
This document introduces two options for DetNet-specific MNA: In-
Stack MPLS Network Action [see [I-D.ietf-mpls-mna-hdr]] and Post-
Stack MPLS Network Action [see [I-D.ietf-mpls-mna-ps-hdr]].
Song, et al. Expires 23 April 2026 [Page 4]
Internet-Draft DetNet MNA October 2025
4. MPLS In-Stack Encoding for DetNet
4.1. DetNet-specific NASes
The MPLS MNA encapsulation is used between DetNet Relay nodes.
DetNet-specific parameters used during forwarding are: (1) Flow-ID,
(2) SeqNum and (3) LatencyInfo. For each of them, a specific NAS can
be defined to carry the related variable in an MPLS MNA network:
1. PREOF-specific NAS (e.g., SeqNum)
2. Latency-specific NAS (e.g., LatencyClass)
3. Flow-specific NAS (i.e., Flow-ID)
Note: DetNet aggregate flows can be described with the same set of
parameters.
DetNet functions use these NASes as follows:
* DetNet PREOF requires Flow-ID+SeqNum parameters. They are used
only at DetNet Relay nodes implementing the service sub-layer.
* DetNet latency-bound related functions use Flow-ID+LatencyInfo, to
select proper queuing hop-by-hop along the transmission path.
They are used at DetNet Transit nodes to implement the forwarding
sub-layer.
Using these NASes in DetNet scenarios results in the following MPLS
encapsulation format example that ensures placing all DetNet
parameters in the NASes:
* LSP(s) = F-Label(s): used for describing the forwarding path.
* MNA Sub-Stack Indicator.
* NAS-3: (NAI: Flow-ID, Ancillary Data (AD): i.e., Flow-ID).
* NAS-2: (NAI: Latency, Ancillary Data (AD): e.g., LatencyClass).
* NAS-1: (NAI: SeqNum, Ancillary Data (AD): i.e., SeqNum (16/28
bits)).
* Payload.
Song, et al. Expires 23 April 2026 [Page 5]
Internet-Draft DetNet MNA October 2025
Note that using PW (S-Label) in the label stack is optional, it is
not prevented by the method described in this document and is not
shown in the above example.
4.2. Characteristics of DetNet NASes
Characteristics of the DetNet-specific NASes are as follows:
* Encoding a Network Action: Different Operation Codes are used for
the above DetNet-specific NASes.
* Scope is encoded implicitly, all DetNet NAIs (Network Action
Indicator) have a predefined scope.
- All DetNet-specific NAIs use "Select" mode, so the use of these
NAIs may be restricted for DetNet-aware nodes if the operator
intends to do so.
- Optional scope for the NAIs:
o NAI: Flow-ID can have a Hop-by-hop (HBH) scope.
o NAI: Latency can have a Hop-by-hop (HBH) scope.
o NAI: SeqNum can have an Ingress-to-Egress (I2E) scope.
* Recognition action:
- NAI: Flow-ID is used for flow identification, and this NAI MUST
be ignored if unrecognized.
- NAI: Latency is used by every node along the path that performs
a latency-related action (e.g., queuing). This NAI MUST be
ignored if unrecognized.
- NAI: SegNum is used only by the last node on the path defined
by the F-Label(s) that performs the PREOF action. This NAI
MUST be ignored if unrecognized.
* Encoding of Post-Stack Data: N/A for these NASes.
By using the "Select" mode for the DetNet-specific NASes, the network
operation can emulate the MS-PW (Multi-Segment PW) pop-push
characteristics on the S-Label. There is no need to define the whole
forwarding graph across the MPLS network at the ingress.
Furthermore, the "Select" mode allows the payload is an MPLS packet
using the same label stack (as used by the MNA).
Song, et al. Expires 23 April 2026 [Page 6]
Internet-Draft DetNet MNA October 2025
4.3. Examples of DetNet NASes in MPLS In-Stack
The figures show some possible DetNet-specific NAS formats and their
usage.
DetNet Latency NAS: Format-B provides enough bits to encode, e.g.,
several LatencyClass-es. For longer latency-related parameters
(e.g., timestamps) Format C/C+D can be used.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA1 | Data (Latency Info) |R|IHS|S| Res |U| NASL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: The short DetNet Latency Information (e.g., several
LatencyClass-es) Encoding Using LSE Format B
DetNet SeqNum NAS: Depending on the location of the SeqNum parameter
within the MNA part of the MPLS stack, a Format B+C/C/C+D is
necessary (which contains 28/16 bits of the SeqNum). In these
formats, there are unused "Data bits" to carry additional FLAGs
related to the SeqNum
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA2 | Data (SeqNum) |R|IHS|S| Res |U| NASL=1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA2 | Data (cont.) |S| Data | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: An Example of the DetNet Sequence Number Encoding Using
LSE Formats B and C
DetNet Flow-ID NAS: Depending on the location of the Flow-ID, a
Format C/B+C is necessary (which contains 20 bits of the ID).
Song, et al. Expires 23 April 2026 [Page 7]
Internet-Draft DetNet MNA October 2025
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA3 | Data (Flow-ID) |R|IHS|S| Res |U| NASL=1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA3 | Data (cont.) |S| Data | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: An Example of the DetNet Flow Identifier Encoding Using
LSE Formats B and C
Figure 4 below shows an MNA that contains all the DetNet-specific
NASes. MNA-6 contains the DetNet Latency parameter being encoded in
Format-B. MNA-7 contains the DetNet Flow-ID, and a 20-bit Flow-ID is
encoded in Format C. MNA-8 contains the DetNet SeqNum in Format C
with a 16-bit sequence number.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA1 | Data (Latency Info) |R|IHS|S| Res |U| NASL=2|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA3 | Data (Flow-ID) |S| (FID) | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA2 | Data (SeqNum) |S| 0 | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: An Example of the Combined DetNet Parameters Encoding
Using MNA
4.4. Aggregation Example
Figure 5 shows an aggregation example where multiple DetNet flows are
aggregated in a single aggregate. NAS-A part contains the aggregate
specific DetNet NASes, and NAS-F contains the flow-specific NASes of
the data packet.
Song, et al. Expires 23 April 2026 [Page 8]
Internet-Draft DetNet MNA October 2025
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA1 | Data (Aggr-Latency-Info)|R|IHS|S| Res |U| NASL=2|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA3 | Data (Aggr-Flow-ID) |S| (FID) | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA2 | Data (Aggr-SeqNum) |S| 0 | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA1 | Data (Latency Info) |R|IHS|S| Res |U| NASL=2|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA3 | Data (Flow-ID) |S| (FID) | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA2 | Data (SeqNum) |S| 0 | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: An Example of the DetNet Aggregate Flow Parameters
Encoding Using MNA
Note1: Opcodes are to be allocated by IANA during the
standardization.
Note2: Aggregation re-uses the same Options code points for the
aggregated and specific flows. The interpretation is based on the
order of NASes. During the de-aggregation of flows, the MNA
containing the aggregate parameters is removed from the label stack
(popped).
5. MPLS Post-Stack Encoding for DetNet
When the latency guarantee of a DetNet network is of the end-to-end
(E2E) forwarding type, for the hop-by-hop (hbh) forwarding type that
carries longer latency information, the carrying of latency
information changes with the number of hops. In such cases, it is
recommended to use PSD encapsulation. The opcode of DetNet used in
MPLS In-Stack is reused for indication of PSD presence.
Song, et al. Expires 23 April 2026 [Page 9]
Internet-Draft DetNet MNA October 2025
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA1 | Data |1|IHS|S| Res |U| NASL=0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: PSD presence for DetNet Latency Encoding Using LSE Format B
Opcode: In-Stack Opcode for DetNet action, requires allocation by
IANA. The PSD flag bit with P=1 is represented by the PSD encoding.
The scope field specifies the operation processing method of IHS.
Figure 7 shows an example of a PSD in which DetNet flow information
is encoded in the MPLS Post-Stack NAS. The latency information may
be variable in case of Hop-by-Hop processing in DetNet networks. In
this example, it's assumed to have two NSIs to carry latency
information (i.e., timestamps). The Flow-ID field length is 20 bits,
and the length of SeqNum is 28 bits carried in two NAIs.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (MNA bSPL) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA1 | Data |1|IHS|S| Res |U| NASL=0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label |1| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|firstNi|Version| PS-HDR-LEN | TYPE = MNA-POST-STACK-HDR = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA1 |R|R| PS-NAL=4 | Data (Latency Info) |NAL=1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data (Cont.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA3 |R|R| Data (Flow-ID) |NAL=0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=TBA2 |R|R| Data (SeqNum) |NAL=1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data (Cont.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: An Example of the DetNet Flow Parameters Encoding in
MPLS Post-Stack
Song, et al. Expires 23 April 2026 [Page 10]
Internet-Draft DetNet MNA October 2025
The first NAS in the Post-Stack is used to encapsulate the PSD
header, indicating the total length, version, and type of the PSD
header, and complies with [I-D.ietf-mpls-mna-ps-hdr].
Opcode: The R bit is reserved, and PS-NAL is used to indicate the
size of the NAS corresponding to DetNet network operations.
The Flow-ID Opcode identifies a DetNet flow at the receiving DetNet
service sub-layer processing node. The SeqNum Opcode identifies the
sequence number per DetNet-App flow, i.e., DetNet service. The
Sequence Number field lengths MUST be supported 0 bits, 16 bits and
28 bits. The Latency Opcode identifies the service type of DetNet
flows or the latency information carried in MPLS networks. The
detailed information for latency format is for further study.
6. Security Considerations
Security considerations for DetNet are covered in the DetNet
Architecture [RFC8655], DetNet Data Plane Framework [RFC8938] and
DetNet Security Considerations [RFC9055]. MPLS security
considerations are covered in [RFC8964], [RFC3031], [RFC3032]. These
security considerations also apply to this document. The MNA
security considerations speicified at [I-D.ietf-mpls-mna-hdr],
[I-D.ietf-mpls-mna-ps-hdr] and [RFC9789] are also applicable to the
procedures defined in this document.
7. IANA Considerations
This document requests new IANA-managed code-points for DetNet
encoded in MPLS In-Stack adn Post-Stack. IANA maintains the "Network
Action Opcodes" registry when created from IANA request in
[I-D.ietf-mpls-mna-hdr]. IANA is requested to allocate new values
for MPLS Network Action Opcode for DetNet Action from this registry:
Song, et al. Expires 23 April 2026 [Page 11]
Internet-Draft DetNet MNA October 2025
+========+=============+=======================+===============+
| Opcode | Description | In-Stack and Post- | Reference |
| Value | | Stack, In-Stack only, | |
| | | Post-Stack only | |
+========+=============+=======================+===============+
| TBA1 | Latency | In-Stack and Post- | This document |
| | Information | Stack | |
+--------+-------------+-----------------------+---------------+
| TBA2 | Sequence | In-Stack and Post- | This document |
| | Number | Stack | |
+--------+-------------+-----------------------+---------------+
| TBA3 | Flow | In-Stack and Post- | This document |
| | Identifier | Stack | |
+--------+-------------+-----------------------+---------------+
Table 1: DetNet MNA Opcode
8. Acknowledgements
Authors extend their appreciation to Adrian Farrel, Lou Berger, Joel
Halpern, Janos Farkas, Ferenc Fejes, Tony Li, Tarek Saad, Jie Dong,
Shaofu Peng and Loa Andersson for their insightful comments and
contributions.
9. References
9.1. 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-
16, 3 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
mna-hdr-16>.
[I-D.ietf-mpls-mna-ps-hdr]
Rajamanickam, J., Gandhi, R., Zigler, R., Li, T., and J.
Dong, "Post-Stack MPLS Network Action (MNA) Solution",
Work in Progress, Internet-Draft, draft-ietf-mpls-mna-ps-
hdr-03, 1 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-mpls-
mna-ps-hdr-03>.
[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>.
Song, et al. Expires 23 April 2026 [Page 12]
Internet-Draft DetNet MNA October 2025
[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>.
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>.
[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, January
2021, <https://www.rfc-editor.org/info/rfc8964>.
9.2. Informative References
[I-D.ietf-detnet-scaling-requirements]
Liu, P., Li, Y., Eckert, T. T., Xiong, Q., Ryoo, J.,
zhushiyin, and X. Geng, "Requirements for Scaling
Deterministic Networks", Work in Progress, Internet-Draft,
draft-ietf-detnet-scaling-requirements-09, 7 September
2025, <https://datatracker.ietf.org/doc/html/draft-ietf-
detnet-scaling-requirements-09>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
[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>.
[RFC8938] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane
Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020,
<https://www.rfc-editor.org/info/rfc8938>.
[RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker,
"Deterministic Networking (DetNet) Security
Considerations", RFC 9055, DOI 10.17487/RFC9055, June
2021, <https://www.rfc-editor.org/info/rfc9055>.
[RFC9550] Varga, B., Ed., Farkas, J., Kehrer, S., and T. Heer,
"Deterministic Networking (DetNet): Packet Ordering
Function", RFC 9550, DOI 10.17487/RFC9550, March 2024,
<https://www.rfc-editor.org/info/rfc9550>.
Song, et al. Expires 23 April 2026 [Page 13]
Internet-Draft DetNet MNA October 2025
[RFC9613] Bocci, M., Ed., Bryant, S., and J. Drake, "Requirements
for Solutions that Support MPLS Network Actions (MNAs)",
RFC 9613, DOI 10.17487/RFC9613, August 2024,
<https://www.rfc-editor.org/info/rfc9613>.
[RFC9789] Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS
Network Actions (MNAs) Framework", RFC 9789,
DOI 10.17487/RFC9789, July 2025,
<https://www.rfc-editor.org/info/rfc9789>.
Authors' Addresses
Xueyan Song
ZTE Corp.
Email: song.xueyan2@zte.com.cn
Greg Mirsky
Ericsson
Email: gregimirsky@gmail.com
Balazs Varga
Ericsson
Email: balazs.a.varga@ericsson.com
Rakesh Gandhi
Cisco Systems, Inc.
Email: rgandhi@cisco.com
Quan Xiong
ZTE Corp.
Email: xiong.quan@zte.com.cn
Song, et al. Expires 23 April 2026 [Page 14]