DetNet Queue Encapsulation with MPLS Data Plane
draft-sx-detnet-mpls-queue-00
The information below is for an old version of the document.
| Document | Type |
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|---|---|---|---|
| Authors | Xueyan Song , Quan Xiong | ||
| Last updated | 2022-06-24 | ||
| Replaced by | draft-sx-mpls-detnet-bounded-latency | ||
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draft-sx-detnet-mpls-queue-00
DetNet Working Group X. Song
Internet-Draft Q. Xiong
Intended status: Standards Track ZTE Corp.
Expires: 26 December 2022 24 June 2022
DetNet Queue Encapsulation with MPLS Data Plane
draft-sx-detnet-mpls-queue-00
Abstract
This document specifies format and principals for the MPLS header
which contains the queuing delay information, designed for use over a
DetNet network with MPLS data plane. The guaranteed delay support
enables forwarding and scheduling decisions for time-sensitive
service running on DetNet transit nodes that operate within a
constrained network domain. This document also specifies a
representation for the delay field values in such networks.
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 26 December 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
3. DetNet queue encapsulation with MPLS data plane . . . . . . . 3
3.1. Queuing delay . . . . . . . . . . . . . . . . . . . . . . 4
3.2. DetNet MPLS Queue Encapsulation . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
As specified in [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. The
DetNet data planes specification refers to [RFC8938].
Based on the updates for DetNet Charter at March, 2022. It is
required to support a data plane method of packet treatment including
forwarding, service protection, and queuing over Layer 3. As defined
in [RFC8964], the DetNet MPLS data plane provides a foundation of
building blocks to enable PREOF (Packet Replication, Elimination and
Ordering Functions (PREOF)) functions to DetNet service and
forwarding sub-layer. The DetNet service sub-layer includes a DetNet
Control Word (d-CW) and an identifying service label (S-Label), an
aggregation label (A-Label) is a special case of S-Label used for
aggregation. The DetNet forwarding sub-layer supports one or more
forwarding labels (F-Labels) for providing necessary resource
allocation and explicit routes.
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To support time-sensitive service with ultra-low packet loss rates
and bounded end-to-end delivery latency, necessary and feasible
queuing mechanisms applied to specific applicability on DetNet flows
are required. As described in [I-D.ietf-detnet-bounded-latency], the
end-to-end bounded latency depends on the value of queuing delay
bound along with the queuing mechanisms. The queuing methodology,
mentioned in [I-D.ietf-detnet-bounded-latency] and [RFC8655],
describes queuing mechanisms that can be used in packets of control
and data plane to achieve DetNet service with bounded latency
guarantee. The queuing mechanisms include, time-scheduling queuing
mechanisms that include the Time Aware Shaping IEEE802.1Qbv,
priority-scheduling queuing mechanisms that include the Credit-Based
Shaper IEEE802.1Q-2014 with Asynchronous Traffic Shaping
IEEE802.1Qcr, the cyclic-scheduling queuing mechanism proposed in
IEEE802.1Qch.
This draft uses the queuing mechanisms described in
[I-D.ietf-detnet-bounded-latency] as the proof for queuing selection,
leverages the existing DetNet MPLS encapsulations and mechanisms
[RFC8964], and defines the extensible DetNet MPLS options for queuing
support over DetNet flows in the context of MPLS data plane so as to
make appropriate packet forwarding and scheduling decisions to
achieve the end-to-end bounded latency from customers' SLA
requirements.
2. Conventions
2.1. 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.
2.2. Terminology
Refer to [RFC8655], [RFC8964], and [I-D.ietf-detnet-bounded-latency]
for the key terms used in this document.
3. DetNet queue encapsulation with MPLS data plane
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3.1. Queuing delay
[RFC8655] provides the architecture for deterministic networking
(DetNet) enables the service delivery of DetNet flows with extremely
low packet loss rates and bounded end-to-end latency. The reference
for computation and selection for methodology of queuing is described
at [I-D.ietf-detnet-bounded-latency]. The end-to-end latency bound
for one DetNet flow is the sum of delay bound of non-queuing and
queuing processing. The delay bound for non-queuing processing may
include output delay, link delay, frame preemption delay, and
processing delay, the delay bound for queuing processing may include
regulator delay, queuing delay. It is assumed that the delay of non-
queuing processing is fixed or be ignorable, the delay of queuing
processing is variable. To realize the guarantee of bounded latency
service it is important to select right queuing methodology applied
to specific applications and carry necessary queuing delay
information for computation of end-to-end latency.
The DetNet data plane encapsulation in transport network with MPLS
data plane is specified in [RFC8964]. This document provides
additional encapsulation for the queuing delay of DetNet flows in
MPLS data plane.
3.2. DetNet MPLS Queue Encapsulation
DetNet MPLS Queue, uses DetNet-MPLS based encapsulation with queuing
option extension, listed as the below,
+---------------------------+
| DetNet App-Flow |
| Payload Packet |
+---------------------------+--\
| DetNet Control Word | |
+---------------------------+ |
| S-Label | | DetNet Data Plane
+---------------------------+ | MPLS Encapsulation
| F-Label(s) | |
+---------------------------+ |
| SPL (DetNet Queque) | |
+---------------------------+--/
| Data-Link |
+---------------------------+
| Physical |
+---------------------------+
Figure 1: DetNet queue encapsulation in MPLS data plane
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The SPL (Special Purpose Label) may be B-SPL [RFC9017], new-SPL,
extended SPL [RFC9017]. Refer to [I-D.andersson-mpls-mna-fwk], the
SPL carries the action indicator for queue support showed as the
Figure 2.
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 |x x x|S|H|x x x x x x x|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Label: Label value, 20 bits
x: Bit available for other solutions definition
S: Bottom of Stack, 1 bit
H: Indicator of hop-by-hop processing, 1 bit
Figure 2: SPL encapsulation for DetNet queuing indicator
Generally speaking the queuing mechanisms are processed hop by hop,
end-to-end processing for queuing support is FFS.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Flags | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLV(s) |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type : Type value, TBD, 1 Octet
Flags : Identifier for quequing mechanisms, 1 Octet
Length : Length value, 2 Octet
sub-TLV(s): Specific ququing information carried, 8 Octet
Figure 3: Uniform queuing options TLV
The Flags field is designed as follow:
0 1 2 3 4 5 6 7 8
+-+-+-+-+-+-+-+-+
|T|P|C| |
+-+-+-+-+-+-+-+-+
Figure 4: Flag field
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T flag: 1 bit, time-scheduling queuing indicator, e.g., Time Aware
Shaping [IIEEE802.1Qbv]. If the flag is set 1, the time-scheduling
queuing mechanism is used for the DetNet flows, the can be correlated
with the special label encapsulated in figure 2, or be mapped with
F-Label (s) or S-Label showed in figure 1.
P Flag: 1 bit, priority-scheduling queuing indicator, e.g., Credit-
Based Shaper [IEEE802.1q-2014].
C Flag: 1 bit, cyclic-scheduling queueing indicator, e.g., CQF
[IEEE802.1Qch].
Note: For one specific DetNet flow, there is one or more choices for
queuing mechanisms selection, the queuing mechanisms can be used
respectively or combined with each other.
If the flag field is set 1 it will associate its sub-TLV to carry
detailed or ancillary data for specific queuing delay information.
The encapsulation for sub-TLV is showed below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Special Queuing Ancillary Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Special Queuing options Sub-TLV
The encapsulation for queuing delay information will follow the
requirements and framework of MPLS MNA discussed in MPLS WG.
The encapsulation for Special Queuing Ancillary Data field is
specific for queuing mechanisms. E.g., the sub-TLV for queuing
scheduling mechanism may carry deadline time data related, refer to
[I-D.peng-6man-deadline-option].The sub-TLV for cyclic-scheduling
queuing mechanism may carry cycle time related, refer to
[I-D.dang-queuing-with-multiple-cyclic-buffers]
4. IANA Considerations
This document describes a new IANA-managed registry to identify
DetNet MPLS Queue Flags Bits. The registration procedure is "IETF
Review" [RFC8126]. The registry name is "DetNet MPLS Queue Flags".
There are 4 flags in the 8-bit Flags field, defined as in Table 1.
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+=====+=============+===============+
| Bit | Description | Reference |
+=====+=============+===============+
| 0-7 | unassigned | this document |
+-----+-------------+---------------+
Table 1: DetNet MPLS Queue Flags
5. Security Considerations
Security considerations for DetNet are covered in the DetNet
Architecture RFC8655 and DetNet Security Considerations [RFC9055].
MPLS security considerations are covered in [RFC8964], [RFC3031],
[RFC3032]. These security considerations also apply to this
document.
6. Acknowledgements
The authors would like to acknowledge Shaofu Peng for his thorough
review and very helpful comments.
7. References
7.1. Normative References
[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>.
[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>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[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>.
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[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>.
[RFC9017] Andersson, L., Kompella, K., and A. Farrel, "Special-
Purpose Label Terminology", RFC 9017,
DOI 10.17487/RFC9017, April 2021,
<https://www.rfc-editor.org/info/rfc9017>.
7.2. Informative References
[I-D.andersson-mpls-mna-fwk]
Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS
Network Actions Framework", Work in Progress, Internet-
Draft, draft-andersson-mpls-mna-fwk-03, 1 June 2022,
<https://www.ietf.org/archive/id/draft-andersson-mpls-mna-
fwk-03.txt>.
[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://www.ietf.org/archive/id/draft-dang-queuing-
with-multiple-cyclic-buffers-00.txt>.
[I-D.ietf-detnet-bounded-latency]
Finn, N., Boudec, J. L., Mohammadpour, E., Zhang, J., and
B. Varga, "DetNet Bounded Latency", Work in Progress,
Internet-Draft, draft-ietf-detnet-bounded-latency-10, 8
April 2022, <https://www.ietf.org/archive/id/draft-ietf-
detnet-bounded-latency-10.txt>.
[I-D.peng-6man-deadline-option]
Peng, S. and B. Tan, "Deadline Option", Work in Progress,
Internet-Draft, draft-peng-6man-deadline-option-00, 11
January 2022, <https://www.ietf.org/archive/id/draft-peng-
6man-deadline-option-00.txt>.
[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>.
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[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>.
Authors' Addresses
Xueyan Song
ZTE Corp.
Nanjing
China
Email: song.xueyan2@zte.com.cn
Quan Xiong
ZTE Corp.
Wuhan
China
Email: xiong.quan@zte.com.cn
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