Data Fields for DetNet Enhanced Data Plane
draft-xiong-detnet-data-fields-edp-02
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| Document | Type | Active Internet-Draft (individual) | |
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| Authors | Quan Xiong , Aihua Liu , Rakesh Gandhi , Dong Yang | ||
| Last updated | 2024-07-01 | ||
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draft-xiong-detnet-data-fields-edp-02
DETNET Q. Xiong
Internet-Draft A. Liu
Intended status: Standards Track ZTE Corporation
Expires: 2 January 2025 R. Gandhi
Cisco Systems, Inc.
D. Yang
Beijing Jiaotong University
1 July 2024
Data Fields for DetNet Enhanced Data Plane
draft-xiong-detnet-data-fields-edp-02
Abstract
The DetNet-specific metadata should be carried in enhanced data plane
based on the enhancement requirements. This document proposes the
common DetNet data fields and option types such as Aggregation Option
and Deterministic Latency Option. The common DetNet Data-Fields can
be encapsulated into a variety of protocols such as MPLS, IPv6 and
SRv6 networks.
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 2 January 2025.
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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
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and restrictions with respect to this document. Code Components
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. Specific Metadata for DetNet Enhanced Data Plane . . . . . . 4
3.1. Aggregation-based Metadata . . . . . . . . . . . . . . . 4
3.2. Deterministic Latency Metadata . . . . . . . . . . . . . 5
4. Data Fields for DetNet Enhanced Data Plane . . . . . . . . . 6
4.1. DetNet Option-Types and Data-Fields . . . . . . . . . . . 6
5. Aggregation Option . . . . . . . . . . . . . . . . . . . . . 7
6. Deterministic Latency Option . . . . . . . . . . . . . . . . 9
6.1. Deterministic Latency Option Header . . . . . . . . . . . 9
6.2. Deterministic Latency Option Data . . . . . . . . . . . . 10
6.2.1. Cycle Information . . . . . . . . . . . . . . . . . . 10
6.2.2. Timeslot Information . . . . . . . . . . . . . . . . 11
6.2.3. Deadline Information . . . . . . . . . . . . . . . . 11
6.2.4. Ratio Information . . . . . . . . . . . . . . . . . . 12
6.2.5. Damper Information . . . . . . . . . . . . . . . . . 12
7. Encapsulation Considerations for DetNet Enhanced Data
Plane . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Metadata for DetNet Enhanced Data Plane . . . . . . . . . 13
7.2. Encoding for DetNet Enhanced Data Plane . . . . . . . . . 13
7.2.1. Reuse of the Existing DSCP/TC Field . . . . . . . . . 13
7.2.2. New Common Data Fields . . . . . . . . . . . . . . . 14
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
11. Normative References . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
According to [RFC8655], Deterministic Networking (DetNet) operates at
the IP layer and delivers service which provides extremely low data
loss rates and bounded latency within a network domain. DetNet data
planes has been specified in [RFC8938]. As described in [RFC9320],
the end-to-end bounded latency depends on the value of queuing delay
bound along with the queuing mechanisms. Multiple queuing mechanisms
has been proposed to guarantee the bounded latency in IEEE802.1 TSN
(Time-Sensitive Networking) Task Group. But the existing
deterministic technologies are facing large-scale number of nodes and
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long-distance transmission, traffic scheduling, dynamic flows, and
other controversial issues in large-scale networks. The DetNet
Enhanced Data Plane (EDP)is required to support a data plane method
of flow identification and packet treatment.
[I-D.ietf-detnet-dataplane-taxonomy] has discussed the data plane
enhancement solutions and queuing mechanisms in DetNet, and also
described the classification criteria and the suitability of the
solutions for various services. For scaling networks,
[I-D.ietf-detnet-scaling-requirements] has described the enhancement
requirements for DetNet enhanced data plane, such as aggregated flow
identification and deterministic latency guarantees. For example,
the flow identification with service-level aggregation and explicit
aggregated flow identification should be supported. And queuing
mechanisms and solutions require different information to be defined
as the DetNet-specific metadata to help the functions of ensuring
deterministic latency, including regulation, queue management, etc.
This document discusses the specific metadata which should be carried
in enhanced data plane and proposes the common DetNet data fields and
option types such as Aggregation Option and Deterministic Latency
Option. The common DetNet Data-Fields can be encapsulated into a
variety of protocols such as MPLS, IPv6 and SRv6 networks.
2. Conventions used in this document
2.1. Terminology
The terminology is defined as [RFC8655], [RFC8938] and
[I-D.ietf-detnet-scaling-requirements].
Deterministic Latency (DL): The bound of network latency and delay
variation between two DetNet endpoints.
2.2. 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.
Abbreviations and definitions used in this document:
SRH: Segment Routing Header
SRv6: Segment Routing for IPv6 forwarding plane
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DL: Deterministic Latency
CSQF: Cycle Specified Queuing and Forwarding
TQF: Timeslot Queuing and Forwarding
C-SCORE: Work Conserving Stateless Core Fair Queuing
EDF: Earliest Deadline First
TAS: Time Aware Shaper
ATS: Asynchronous Traffic Shaping
CQF: Cyclic Queuing and Forwarding
FQ: Fair Queuing
TSN: Time-Sensitive Networking
ECQF: Enhanced Cyclic Queuing and Forwarding
gLBF: guaranteed Latency Based Forwarding
PDV: Packet Delay-Variation
EDP: DetNet Enhanced Data Plane
3. Specific Metadata for DetNet Enhanced Data Plane
3.1. Aggregation-based Metadata
As per [RFC8655], the DetNet data plane must support the aggregation
of DetNet flows in order to support larger numbers of DetNet flows
and improve scalability by reducing the per-hop states. And the flow
aggregation may be necessary for scaling networks. As per
[I-D.ietf-detnet-scaling-requirements], the deterministic services
may demand different deterministic QoS requirements according to
different levels of application requirements. For example,
industrial applications may demand tight jitter, strict latency limit
requirements. The video applications may demand relative loose
latency requirements and so on. The flow identification with
service-level aggregation and explicit aggregated flow identification
should be supported.
The flow identification is required to be dynamic and simplified to
ensure the aggregated flows have compatible DetNet flow-specific QoS
characteristics. In DetNet MPLS, A-Label defined as per [RFC8964]
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can be added explicitly to the packets. But in other DetNet data
plane, no aggregated flow specific information is available. And for
the data plane, individual flows may be aggregated for treatment
based on shared service specification on aggregated-class level which
identified by an aggregation class as per
[I-D.xiong-detnet-flow-aggregation]. The aggregation-based metadata
should be defined as the DetNet-specific metadata for DetNet enhanced
data plane. The DetNet nodes along the path can identify the
aggregated flow to achieve the end-to-end QoS in scaling networks.
3.2. Deterministic Latency Metadata
As described in [RFC9320], the end-to-end bounded latency depends on
the queuing delay bound and the queuing mechanisms. Multiple queuing
mechanisms have been proposed such as TAS [IIEEE802.1Qbv], CBS
[IEEE802.1Q-2014],ATS [IEEE802.1Qcr], CQF [IEEE802.1Qch] and so on.
In scaling networks which has large variation in latency among hops,
great number of flows and multiple domains,
[I-D.ietf-detnet-scaling-requirements] has described the technical
requirements for enhanced data plane solutions. Many variations and
extensions of queuing mechanisms have been proposed to resolve the
scalability issues in DetNet. [I-D.ietf-detnet-dataplane-taxonomy]
has described the classification criteria of the solutions. As shown
in Figure 1, the CQF variations for cyclic-based scheduling includes
the ECQF [IEEE 802.1Qdv], Multi-CQF
[I-D.dang-queuing-with-multiple-cyclic-buffers], TCQF
[I-D.eckert-detnet-tcqf] and CSQF
[I-D.chen-detnet-sr-based-bounded-latency]. The TAS variations for
timeslot-based scheduling includes TQF
[I-D.peng-detnet-packet-timeslot-mechanism]. The FQ variations for
rate-based scheduling includes C-SCORE
[I-D.joung-detnet-stateless-fair-queuing] ATS [IEEE802.1Qcr] and gLBF
[I-D.eckert-detnet-glbf]. The EDF variations for deadline-based
scheduling includes EDF[I-D.peng-detnet-deadline-based-forwarding]
and Local Deadline [I-D.stein-srtsn]. The Damper variations for
damper-based scheduling includes Damper
[I-D.mohammadpour-detnet-bounded-delay-variation] and gLBF
[I-D.eckert-detnet-glbf].
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+---------------------------------------------------------------------------------------------+
| Scheduling Type | Queuing Type | Queuing Mechanisms | Metadata |
+---------------------------------------------------------------------------------------------+
|Cyclic-based scheduling |CQF and variations |CSQF/TCQF/Multi-CQF/ECQF|Cycle Information |
+---------------------------------------------------------------------------------------------+
|Timeslot-based scheduling|TAS and variations |TQF |Timeslot Information|
+---------------------------------------------------------------------------------------------+
|Deadline-based scheduling|EDF and variations |EDF/Local Deadline |Deadline Information|
+---------------------------------------------------------------------------------------------+
|Rate-based scheduling |FQ and variations |C-SCORE/ATS/gLBF |Ratio Information |
+---------------------------------------------------------------------------------------------+
|Damper-based scheduling |Damper and variations|Damper/gLBF |Damper Information |
+---------------------------------------------------------------------------------------------+
Figure 1: Queuing and Scheduling Mechanisms
And when queuing mechanisms used in large-scale networks, the per-
flow states can not be maintained with scalability issues. Some
queuing parameters should be carried for coordination between nodes
so as to make appropriate packet forwarding and scheduling decisions
to meet the time bounds. As per
[I-D.ietf-detnet-scaling-requirements], the information used by
functions ensuring deterministic latency should be supported as such
queuing-based information. And queuing mechanisms and solutions
require different information to help the functions of ensuring
deterministic latency, including regulation, queue management. The
deterministic latency metadata should be defined as the DetNet-
specific metadata for DetNet enhanced data plane. The DetNet
forwarding nodes along the path can apply the queuing mechanisms and
get the related deterministic latency metadata in the packet to
achieve the end-to-end bounded latency.
4. Data Fields for DetNet Enhanced Data Plane
4.1. DetNet Option-Types and Data-Fields
The enhanced functions and related metadata for DetNet should be
confirmed before the encapsulations. While more than one metadata
should be carried in enhanced data plane, the common DetNet header
should be considered to cover all option-types and data.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DetNet-Type | DetNet-Length | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ DetNet Option and Data Space ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: DetNet Header for Enhanced Data Plane
DetNet-Type: 8-bit unsigned integer, defining the DetNet Option-type
for enhanced DetNet. This document defines two options and option-
types:
Aggregation Option as defined in section 5.
Deterministic Latency Option as defined in section 6.
DetNet-Length: 8-bit unsigned integer, defined the Length of the
DetNet Header 4-octet units.
5. Aggregation Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Aggregation Type | Flag |E| Data Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Aggregation Option Header
Aggregation type(16 bits): indicates the aggregation type of packet
treatment ensuring the deterministic latency as following shown.
This type can also indicate the aggregated class.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value | Aggregation Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0000 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0100 | Bandwidth guarantee |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0200 | Jitter guarantee |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0300 | Delay guarantee |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0400 | Low delay and jitter guarantee |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0500 |Ultra-low delay and jitter guarantee |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Aggregation Type
Flag: 8-bit flags field. When E is set to 1, it indicates the
explicit aggregated flow identification. The related option data is
defined as following section.
Data Len:8-bit unsigned integer. Length of option data, in octets.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Aggregation ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End-to-end Delay Budget |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End-to-end Delay Variation Budget |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Aggregation Option Data
Aggregation ID: 32bits. It provides explicit and unique identifier
for aggregated flow identification. DetNet nodes performing
aggregation using aggregation ID.
End-to-end Delay Budget: 32bits. It provides the value of end-to-end
delay budget for the aggregated flow.
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End-to-end Delay Variation Budget: 32bits. It provides the value of
end-to-end delay variation budget for the aggregated flow.
6. Deterministic Latency Option
The DetNet Deterministic Latency Option carries data that is added by
the DetNet encapsulating node and interpreted by the decapsulating
node. The DetNet transit nodes MAY process the data by forwarding
the option data determined by option type and may modify it. The
DetNet Deterministic Latency Option consist of a fixed-size
"Deterministic Latency Option Header" and a variable-size
"Deterministic Latency Option Data". The Header and Data may be
encapsulated continuously or separately. A Data or more than one
Data in lists can be carried in packets.
6.1. Deterministic Latency Option Header
DetNet Deterministic Latency Option header:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Deterministic Latency Type | Flag | Data Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Deterministic Latency Option header
Deterministic Latency Type(16 bits): indicates the type of
deterministic latency information and related queuing and scheduling
metadata.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value | Deterministic Latency Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0000 | Unassigned |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0001 | Cycle Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0002 | Timeslot Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0003 | Deadline Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0004 | Ratio Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0x0005 | Damper Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 7: Deterministic Latency Type
Flag: 8-bit flags field.
Data Len: 8-bit unsigned integer. Length of option data, in octets.
6.2. Deterministic Latency Option Data
DetNet Deterministic Latency Action option data MUST be aligned by 4
octets:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Deterministic latency option data field (variable) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Deterministic latency Option Data Field
Deterministic latency option data: Variable-length field. It
provides function-based or queuing-based information for a node to
forward a DetNet flow. The data of which is determined by the
deterministic latency type. The DetNet option data can be provided
one time or in list. The examples of different types of data is as
following sections shown.
6.2.1. Cycle Information
When the type is set to 0x0001, indicates the Cyclic-based queuing
and scheduling solutions. The cycle information may be carried and
designed as following shown:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cycle Profile ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cycle ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Cycle Information
Cycle Profile ID (32bits): indicates the profile ID which the cyclic
queue applied at a node.
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Cycle ID (32bits): indicates the Cycle ID for a node to forward a
DetNet flow.
6.2.2. Timeslot Information
When the type is set to 0x0002, indicates the timeslot-based queuing
and scheduling solutions. The timeslot information may be carried
and designed as follow:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timeslot ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Timeslot Information
Timeslot ID: indicates the identifier of the timeslot as defined in
[I-D.peng-detnet-packet-timeslot-mechanism].
6.2.3. Deadline Information
When the type is set to 0x0003, indicates the deadline-based queuing
and scheduling solutions. The deadline information may be carried
and designed as follow:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |M|D| Planned Deadline/Local Deadline |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Accumulated Planned Deadline / Accumulated Deadline Deviation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Accumulated Actual Residence Time / Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Deadline Information
Planned and deadline Deviation has been provided as defined in
[I-D.peng-6man-deadline-option]. Local deadline has been proposed in
[I-D.stein-srtsn].
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6.2.4. Ratio Information
When the type is set to 0x0004, indicates the rate-based queuing and
scheduling solutions. The ratio information may be carried and
designed as follow:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum packet size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Ratio Information
Maximum packet size and service rate has been described as per
C-SCORE [I-D.joung-detnet-stateless-fair-queuing] which the latency
bound is primarily influenced by the ratio of a flow's maximum packet
size to its allocated service rate.
6.2.5. Damper Information
When the type is set to 0x0005, indicates the damper-based queuing
and scheduling solutions. The damper information may be carried and
designed as follow:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Budget delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: Damper Information
Damper information such as timestamps and budget delay should be
carried to compute the compensate PDV by means of dampers as per
[I-D.mohammadpour-detnet-bounded-delay-variation].
7. Encapsulation Considerations for DetNet Enhanced Data Plane
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7.1. Metadata for DetNet Enhanced Data Plane
The packet treatment should indicate the behaviour action ensuring
the deterministic latency at DetNet nodes such as queuing-based
mechanisms. The deterministic latency action type and related
parameters such as queuing-based information should be carried as
metadta in data plane. And the definitions may follow these polices.
The data plane enhancement must be generic and the format must be
applied to all functions and queuing mechanisms. The metadata and
definitions should be common among different candidate queuing
solutions.
Information and metadata MUST be simplified and limited to be carried
in DetNet packets for provided deterministic latency related
scheduling along the forwarding path. For example, the queuing-based
information should be carried in metadata for coordination between
nodes.
The requirement of the flow or service may be not suitable to be
carried explicitly in DetNet data plane. The packet treatment should
schedule the resources and indicate the behaviour to ensure the
deterministic latency in forwarding sub-layer. So the queuing
mechanisms could be viewed as a type of deterministic resources. The
resources type and queuing type should be explicitly indicated.
7.2. Encoding for DetNet Enhanced Data Plane
DetNet needs to encode specific aggregated flow and deterministic
latency metadata in packets by reusing the existing fields or new
fields.
7.2.1. Reuse of the Existing DSCP/TC Field
Reusing the DSCP or existing field is reasonable and simple to define
and easy to standardize. For example, in IPv4 and traditional MPLS
networks, it is not suitable to carry new metadata and it is
suggested to reuse the original bits such as DSCP
[I-D.eckert-detnet-tcqf]. The mapping from DSCP and the metadata
such as queuing information MUST be provided in the controller plane.
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7.2.2. New Common Data Fields
DSCP value may be not sufficient and hard to distinguish between the
original DiffServ service and the deterministic service. The DetNet-
specific metadata can also be encoded as a common data fields and the
definition of data fields is independent from the encapsulating
protocols. The data fields could be encapsulated into a variety of
protocols, such as MPLS 2.0 [I-D.sxg-mpls-mna-deterministic-latency],
IPv6 [I-D.xiong-detnet-6man-queuing-option], SRv6
[I-D.xiong-detnet-spring-srh-extensions] and so on.
8. Security Considerations
Security considerations for DetNet are covered in the DetNet
Architecture [RFC8655] and DetNet data plane [RFC8938], [RFC8939],
[RFC8964] and DetNet security considerations [RFC9055]. The security
considerations specified in [I-D.ietf-detnet-scaling-requirements]
are also applicable to the procedures defined in this document.
9. IANA Considerations
IANA has defined a registry group named "DetNet Data Fields". This
group includes the DetNet Option-Type registry. This registry
defines code points for the DetNet Option-Type field for identifying
DetNet-Option-Types. The following code points are defined in this
document:
TBD1: DetNet Aggregation Option-Type
TBD2: DetNet Deterministic Latency Option-Type
10. Acknowledgements
The authors would like to acknowledge Peng Liu, Bin Tan for his
thorough review and very helpful comments.
11. Normative References
[I-D.chen-detnet-sr-based-bounded-latency]
Chen, M., Geng, X., Li, Z., Joung, J., and J. Ryoo,
"Segment Routing (SR) Based Bounded Latency", Work in
Progress, Internet-Draft, draft-chen-detnet-sr-based-
bounded-latency-03, 7 July 2023,
<https://datatracker.ietf.org/doc/html/draft-chen-detnet-
sr-based-bounded-latency-03>.
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[I-D.dang-queuing-with-multiple-cyclic-buffers]
Liu, B. and J. Dang, "A Queuing Mechanism with Multiple
Cyclic Buffers", Work in Progress, Internet-Draft, draft-
dang-queuing-with-multiple-cyclic-buffers-00, 22 February
2021, <https://datatracker.ietf.org/doc/html/draft-dang-
queuing-with-multiple-cyclic-buffers-00>.
[I-D.eckert-detnet-glbf]
Eckert, T. T., Clemm, A., Bryant, S., and S. Hommes,
"Deterministic Networking (DetNet) Data Plane - guaranteed
Latency Based Forwarding (gLBF) for bounded latency with
low jitter and asynchronous forwarding in Deterministic
Networks", Work in Progress, Internet-Draft, draft-eckert-
detnet-glbf-02, 5 January 2024,
<https://datatracker.ietf.org/doc/html/draft-eckert-
detnet-glbf-02>.
[I-D.eckert-detnet-tcqf]
Eckert, T. T., Li, Y., Bryant, S., Malis, A. G., Ryoo, J.,
Liu, P., Li, G., Ren, S., and F. Yang, "Deterministic
Networking (DetNet) Data Plane - Tagged Cyclic Queuing and
Forwarding (TCQF) for bounded latency with low jitter in
large scale DetNets", Work in Progress, Internet-Draft,
draft-eckert-detnet-tcqf-05, 5 January 2024,
<https://datatracker.ietf.org/doc/html/draft-eckert-
detnet-tcqf-05>.
[I-D.ietf-detnet-dataplane-taxonomy]
Joung, J., Geng, X., Peng, S., and T. T. Eckert,
"Dataplane Enhancement Taxonomy", Work in Progress,
Internet-Draft, draft-ietf-detnet-dataplane-taxonomy-00,
24 May 2024, <https://datatracker.ietf.org/doc/html/draft-
ietf-detnet-dataplane-taxonomy-00>.
[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-06, 22 May 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
scaling-requirements-06>.
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[I-D.joung-detnet-asynch-detnet-framework]
Joung, J., Ryoo, J., Cheung, T., Li, Y., and P. Liu,
"Asynchronous Deterministic Networking Framework for
Large-Scale Networks", Work in Progress, Internet-Draft,
draft-joung-detnet-asynch-detnet-framework-04, 17 March
2024, <https://datatracker.ietf.org/doc/html/draft-joung-
detnet-asynch-detnet-framework-04>.
[I-D.joung-detnet-stateless-fair-queuing]
Joung, J., Ryoo, J., Cheung, T., Li, Y., and P. Liu,
"Latency Guarantee with Stateless Fair Queuing", Work in
Progress, Internet-Draft, draft-joung-detnet-stateless-
fair-queuing-02, 29 February 2024,
<https://datatracker.ietf.org/doc/html/draft-joung-detnet-
stateless-fair-queuing-02>.
[I-D.mohammadpour-detnet-bounded-delay-variation]
Mohammadpour, E. and J. Le Boudec, "DetNet Bounded Packet-
Delay-Variation", Work in Progress, Internet-Draft, draft-
mohammadpour-detnet-bounded-delay-variation-00, 10
September 2021, <https://datatracker.ietf.org/doc/html/
draft-mohammadpour-detnet-bounded-delay-variation-00>.
[I-D.peng-6man-deadline-option]
Peng, S., Tan, B., and P. Liu, "Deadline Option", Work in
Progress, Internet-Draft, draft-peng-6man-deadline-option-
01, 11 July 2022, <https://datatracker.ietf.org/doc/html/
draft-peng-6man-deadline-option-01>.
[I-D.peng-detnet-deadline-based-forwarding]
Peng, S., Du, Z., Basu, K., cheng, Yang, D., and C. Liu,
"Deadline Based Deterministic Forwarding", Work in
Progress, Internet-Draft, draft-peng-detnet-deadline-
based-forwarding-10, 20 June 2024,
<https://datatracker.ietf.org/doc/html/draft-peng-detnet-
deadline-based-forwarding-10>.
[I-D.peng-detnet-packet-timeslot-mechanism]
Peng, S., Liu, P., Basu, K., Liu, A., Yang, D., and G.
Peng, "Timeslot Queueing and Forwarding Mechanism", Work
in Progress, Internet-Draft, draft-peng-detnet-packet-
timeslot-mechanism-07, 20 June 2024,
<https://datatracker.ietf.org/doc/html/draft-peng-detnet-
packet-timeslot-mechanism-07>.
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[I-D.stein-srtsn]
Stein, Y. J., "Segment Routed Time Sensitive Networking",
Work in Progress, Internet-Draft, draft-stein-srtsn-01, 29
August 2021, <https://datatracker.ietf.org/doc/html/draft-
stein-srtsn-01>.
[I-D.sxg-mpls-mna-deterministic-latency]
Song, X., Xiong, Q., and R. Gandhi, "MPLS Network Action
for Deterministic Latency", Work in Progress, Internet-
Draft, draft-sxg-mpls-mna-deterministic-latency-00, 28 May
2024, <https://datatracker.ietf.org/doc/html/draft-sxg-
mpls-mna-deterministic-latency-00>.
[I-D.xiong-detnet-6man-queuing-option]
Xiong, Q., Zhao, J., and R. Gandhi, "IPv6 Option for
DetNet Data Fields", Work in Progress, Internet-Draft,
draft-xiong-detnet-6man-queuing-option-05, 12 October
2023, <https://datatracker.ietf.org/doc/html/draft-xiong-
detnet-6man-queuing-option-05>.
[I-D.xiong-detnet-flow-aggregation]
Xiong, Q., Jiang, T., and J. Joung, "Flow Aggregation for
Enhanced DetNet", Work in Progress, Internet-Draft, draft-
xiong-detnet-flow-aggregation-00, 1 March 2024,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
flow-aggregation-00>.
[I-D.xiong-detnet-large-scale-enhancements]
Xiong, Q., Du, Z., Zhao, J., and D. Yang, "Enhanced DetNet
Data Plane Framework for Scaling Deterministic Networks",
Work in Progress, Internet-Draft, draft-xiong-detnet-
large-scale-enhancements-04, 26 February 2024,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
large-scale-enhancements-04>.
[I-D.xiong-detnet-spring-srh-extensions]
Xiong, Q., Wu, H., and D. Yang, "Segment Routing Header
Extensions for DetNet Data Fields", Work in Progress,
Internet-Draft, draft-xiong-detnet-spring-srh-extensions-
01, 13 October 2023,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
spring-srh-extensions-01>.
[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>.
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[RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212,
DOI 10.17487/RFC2212, September 1997,
<https://www.rfc-editor.org/info/rfc2212>.
[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>.
[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>.
[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane:
IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
<https://www.rfc-editor.org/info/rfc8939>.
[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>.
[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>.
[RFC9320] Finn, N., Le Boudec, J.-Y., Mohammadpour, E., Zhang, J.,
and B. Varga, "Deterministic Networking (DetNet) Bounded
Latency", RFC 9320, DOI 10.17487/RFC9320, November 2022,
<https://www.rfc-editor.org/info/rfc9320>.
Authors' Addresses
Quan Xiong
ZTE Corporation
No.6 Huashi Park Rd
Wuhan
Hubei, 430223
China
Email: xiong.quan@zte.com.cn
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Aihua Liu
ZTE Corporation
China
Email: liu.aihua@zte.com.cn
Rakesh Gandhi
Cisco Systems, Inc.
Canada
Email: rgandhi@cisco.com
Dong Yang
Beijing Jiaotong University
Beijing
China
Email: dyang@bjtu.edu.cn
Xiong, et al. Expires 2 January 2025 [Page 19]