Internet DRAFT - draft-peng-detnet-traffic-shaping-solutions
draft-peng-detnet-traffic-shaping-solutions
Deterministic Networking Working Group G. Peng
Internet-Draft S. Wang
Intended status: InformationalBeijing University of Posts and Telecommunications
Expires: 28 September 2023 Z. Cheng
L. Zhou
New H3C Technologies
P. Liu
China Mobile
27 March 2023
Traffic Shaping Solutions for Bounded Latency in Large-scale Networks
draft-peng-detnet-traffic-shaping-solutions-02
Abstract
This document presents a traffic shaping solution for DetNet service
with bounded latency in large-scale networks. The traffic shaping
solution includes the edge access control, enqueue cycle mapping and
jitter compression mechanisms. These mechanisms support appropriate
resource reservation algorithms, reasonably calculate the end-to-end
delay in DetNet IP network in advance, and adjust, manage and control
the resources after real-time detection. Using the traffic shaping
solution, it is possible for an implementer, user, or standards
development organization to realize bounded delay based on the
existing TSN/DetNet queuing models.
Status of This Memo
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This Internet-Draft will expire on 28 September 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology and Definitions . . . . . . . . . . . . . . . . . 3
3. Bounded Latency Model for Large-scale Networks . . . . . . . 4
3.1. Flow admission . . . . . . . . . . . . . . . . . . . . . 4
3.2. Relay node model and edge node model . . . . . . . . . . 5
3.3. End-to-end transmission model for large-scale networks . 6
4. Traffic Shaping Mechanisms . . . . . . . . . . . . . . . . . 7
4.1. Traffic shaping at the network edge . . . . . . . . . . . 7
4.2. Inter/Intra-domain traffic shaping . . . . . . . . . . . 9
5. Jitter Compression for Large-scale Networks . . . . . . . . . 11
5.1. Explicit route planning . . . . . . . . . . . . . . . . . 12
5.2. Delay detection . . . . . . . . . . . . . . . . . . . . . 13
5.3. Jitter compression . . . . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 15
10. Normative References . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
The standard documents related to deterministic networks provide
bounded latency and zero congestion loss for time-sensitive services
(or real-time services). e.g., IETF Deterministic Networking (DetNet)
and IEEE 802.1 Time-sensitive Networking [IEEE802.1TSN]. DetNet
enables these capabilities based on the following aspects
[I-D.ietf-detnet-bounded-latency]: A) configuring and allocating
network resources for the exclusive use of DetNet flows; B)
identifying, in the data plane, the resources to be utilized by any
given packet, and C) the detailed behavior of those resources,
especially transmission queue selection.
In [RFC8655], DetNet flows are set with maximum bandwidth and the
worst-case end-to-end transmission latency, which is usually ensured
by strict input metering and forwarding policies. The bounded
transmission latency of DetNet flows can provide appropriate buffer
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space for devices in the same network domain, further ensuring zero
congestion loss for DetNet services. To meet such strictly bounded
latency, DetNet flows need to ensure that their explicit routes,
queue buffers, and bandwidth requirements are computable before
arrival. This document refers to the relevant queuing models in TSN
[IEEE802.1Qbv][IEEE802.1Qch] and DetNet [RFC8655] documents, which
guarantee the Quality of Service (QoS) of DetNet flows by controlling
packet forwarding and transmission on each node. In this document, a
traffic shaping solution is proposed to provide edge access control,
cycle mapping and jitter compression mechanisms to enhance the
typical TSN/DetNet queue models, so as to support end-to-end bounded
latency and jitter transmission across network domains. The above
mechanisms in the traffic shaping solution are based on the DetNet
timing model [I-D.ietf-detnet-bounded-latency]. This document
improved the bounded latency timing model so that it could be applied
to large-scale deterministic network for traffic scheduling.
Using the traffic shaping solution presented in this document, it is
possible for an implementer, user, or standards development
organization to realize bounded regulation delay and queuing delay
based on the existing queuing models. The edge access control,
enqueue cycle mapping and delay detection operations in this document
support appropriate resource reservation algorithms so that the end-
to-end latency in the DetNet IP network can be reasonably calculated
in advance, and resources can be adjusted and managed and controlled
after real-time detection.
This document does not specify any resource reservation protocol,
transmission selection algorithm, and control plane function. It
does describe methods for the regulation of DetNet flows with
existing queuing models. Any protocol and model can be applied as
long as it complies with the traffic shaping solution rules.
2. Terminology and Definitions
This document uses the terms defined in [RFC8655]. Moreover, the
following terms are used in this document:
TSN
Time-Sensitive Networking.
CNC
Central Network Controller.
TAS
Time Awareness Shaper.
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CQF
Cyclic Queuing and Forwarding.
TSN
Time-Sensitive Networking.
CSQF
Cycle Specified Queuing and Forwarding
[I-D.qiang-detnet-large-scale-detnet].
SQ/RQ
Sending Queue and Receiving Queue.
SID
Segment Routing Identifier.
3. Bounded Latency Model for Large-scale Networks
This section presents the DetNet basic model for traffic shaping
solutions in large-scale networks. We establish the flow admission
paradigm of DetNet flow scheduling in large-scale networks, and
propose DetNet Relay Nodes and Edge Nodes to build the end-to-end
transport model, which further supports our solution of bounded delay
in large-scale networks.
3.1. Flow admission
1. Describe the characteristics of the newly arrived DetNet flow,
such as the worst-case end-to-end delay, jitter, bandwidth
requirements, and flow sending frequency, packet number, etc.
2. The end-to-end latency model of DetNet transit nodes includes
DetNet edge nodes and DetNet relay nodes. For aggregation of
DetNet flows, any configuration required by DetNet relay nodes in
the network can be performed. The configuration is done
beforehand, and not tied to any particular DetNet flow. The
configuration of DetNet edge nodes supports edge access control
and cycle mapping operation.
3. The cooperative work of DetNet edge nodes and DetNet relay nodes
supports the traffic shaping solution for DetNet flows (time-
sensitive traffic) across domains in a large-scale network.
4. Establish the explicit route that the DetNet flow will take
through the network from the source to the destination(s). This
can be a point-to-point or a point-to-multipoint path.
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5. Performs the cross-domain end-to-end transmission of DetNet flows
over large-scale networks. The traffic shaping solution can
realize the cross-domain end-to-end explicit route transmission
after DetNet flows are injected into the network domain. In this
process, delay detection is used to calibrate the jitter
compressible range of DetNet flows to ensure the bounded latency
and jitter requirements.
6. Assuming that the resources are available, commit those resources
to the DetNet flow. This may require dynamic adjustment of
control filtering rules or enqueue cycle mapping parameters at
each hop along the explicit route.
This paradigm can implement unified management and control based on
Centralized User Configuration (CUC)/ Centralized Network
Configuration (CNC) node’s requirements for collecting flow
characteristics and sending DetNet relay/edge node configurations.
3.2. Relay node model and edge node model
A relay node model for the operation of a DetNet transit node is
detailed in [I-D.ietf-detnet-bounded-latency]. The per-hop delay
experienced by a packet passing through a DetNet transit node is
decomposed into six types of delays: 1) output delay; 2) link delay;
3) frame preemption delay; 4) processing delay; 5) regulation delay;
6) queuing delay. This decomposition applies to the calculation of
hop-by-hop delay and hop-by-hop buffer requirements.
An edge node model makes some changes based on the existing DetNet
relay node model, adding additional buffers before entering the
regulator to dynamically adjust the interdomain timeslot (cycle)
offset and absorb additional jitter at the network edge. The
regulation delay included in processing delay is the extra time slot
offset to be mapped plus the delay of node forwarding operation. The
regulation delay contained in per-hop delay introduces an additional
timeslot offset for traffic shaping.
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DetNet transit node A DetNet transit node B
+----------------------+ +-------------------------------+
| Queuing | | Queuing |
| Regulator subsystem | | Buffer Regulator subsystem |
| +-+-+-+ +-+-+-+ | | +-+-+-+ +-+-+-+ +-+-+-+ |
-->+ | | | | | | | | +---->+ | | | | | | | | | | | | +-->
| +-+-+-+ +-+-+-+ | | +-+-+-+ +-+-+-+ +-+-+-+ |
| DetNet relay node | | DetNet edge node |
+----------------------+ +-------------------------------+
4 5 6 1 2,3 4 5 6 1
<-> <----> <------> <-> <--> <-> <-------------> <-----> <->
1: Output delay 4: Processing delay
2: Link delay 5: Regulation delay
3: Frame preemption delay 6: Queuing delay
Figure 1: Relay node and edge node models for DetNet transit nodes
In Figure 1, the two DetNet nodes are connected via a link. Transit
nodes A and B represent the DetNet relay node and the DetNet edge
node respectively. In each transit node, a packet experiences six
delays from hop to hop. Among them, link propagation, receiving
processing, frame preemption and output delay are affected by
hardware, Precise Time Protocol ([IEEE8023] [RFC8655]) and other
factors, but are relatively a constant value. So, in order to obtain
hop-by-hop bounded delay, the key of traffic shaping solution is to
get the regulation delay and queuing delay bounds. The edge access
control, enqueue cycle mapping and delay detection operations are
proposed to adjust these two kinds of delay in DetNet transit node
models in Section 4 and Section 5 .
3.3. End-to-end transmission model for large-scale networks
In Figure 2, the end-to-end transmission model consists of TSN end
systems, TSN domains, DetNet relay nodes and DetNet edge nodes.
Because in large-scale networks, DetNet service flows need to be
transmitted across multiple network domains, new requirements are put
forward for DetNet nodes to deal with transmission delay of network
edge and interdomain communication
[I-D.liu-detnet-large-scale-requirements]. The edge nodes in this
model can perform edge access control when flows are injected into
the DetNet domain, and perform timeslot offset after flows injecting
entering the edge node. When leaving the DetNet domain, bounded
delay and jitter are controlled by jitter compression scheme at
DetNet edge nodes. The whole deterministic communication in a large-
scale network includes: TSN end system access -> TSN network domain
-> DetNet edge node -> DetNet relay node -> ... -> DetNet edge node
-> peer TSN network domain -> TSN end system.
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DetNet service flows
<-------------------------------------->
TSN DetNet DetNet DetNet TSN
end system edge node relay node edge node end system
+-----+ +-----+ +-----+ +-----+ +-----+
| | | +<-->+ +<-...->+ | | |
+--+--+ +--+--+ +-----+ +--+--+ +--+--+
^ ^ ^ ^
| +----+ | | +----+ |
+->+ +<-+ +->+ +<-+
+----+ +----+
TSN domain TSN domain
Figure 2: End-to-end transmission model in large-scale networks
4. Traffic Shaping Mechanisms
For the cross-domain traffic scheduling in large-scale networks, this
document presents a traffic shaping mechanism between network domains
(e.g., TSN domain, DetNet domain) for edge access control and
management of DetNet flows. The traffic shaping mechanism
establishes cross-domain cycle mapping relationship between different
network domains according to the requirements of upper-layer
application latency and jitter, and supports deterministic queuing
model of different domains (such as CQF and CSQF mechanisms).
In this document the traffic shaping mechanism solves problems such
as inter/intra-domain multi-flow aggregation, traffic burst,
uncertain enqueue selection, and bandwidth resource mismatch. Based
on the cross-domain one-to-one deterministic cycle mapping
relationship, end-to-end DetNet flows are scheduled within each
domain, and bounded latency guarantee is realized by inter-domain
cooperation.
4.1. Traffic shaping at the network edge
The idea of network edge traffic shaping mechanism is to plan the
injection time of time-sensitive traffic at the network edge to
achieve edge access control. As each packet enters a new network
domain, it gains a timeslot offset in the buffer. With such
mechanism, we can centrally plan and manage the timeslot offset of
time-sensitive traffic based on the state information of interdomain
network and characteristic parameters of DetNet flow. For example,
In Figure 3, When end systems send/receive time-sensitive application
traffic to a network domain (TSN/DetNet), we leverage the additional
edge buffer to adjust the injection timeslot offset of traffic
entering the queue model (e.g., CQF). Based on network information
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and traffic characteristics, we can dynamically adjust the timeslot
offset when cross-domain traffic enters different domains, plan queue
resources in advance, and alleviate inter-domain flow aggregation and
burst.
The traffic shaping at the network process is as follows:
1. CNC discovers and connects terminal/network devices through API
interface. Obtain the information of network topology, link
capacity, and port transmission rate in the current network
domain. Obtain time-sensitive traffic information injected into
the network domain, including end-to-end delay bounds
requirements, packet sending frequency, packet size and quantity,
and source/destination address.
2. CNC performs DetNet flow scheduling for the traffic in this
domain and obtains the traffic output timeslot from the initial
TSN domain to the DetNet domain. The specific flow scheduling
algorithm is not restricted in this traffic shaping solution.
3. CNC plans the injection timeslot offset of time-sensitive traffic
injected into the network domain according to the existing
timeslot conflict situation, and comprehensively considers the
link capacity, end-to-end delay bounds requirements and other
factors to adjust the injection timeslot of some packets.
4. Based on the edge access control of time-sensitive flow, CNC
reschedules the flow offset by injection time to reduce the
aggregation and burst of some timeslot flows transmitted between
domains.
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+-------------------------------------------+
| CNC/CUC |
+----+----------------+----------------+----+
| |API |
v v v
End systems TSN domain DetNet domain
+---------+ +----------+ +----------+
| +<--->+ +<--->+ |
+---------+ +----------+ +----------+
^ Edge ^
| access control |
+------------+----------------+-------------+
| +-----------+ |
| Edge buffer +-> RQ | |
| packets +-------+ | +-----------+ |
| +------> | +--+ +-----------+ |
| +-------+ | SQ -> |
| +-----------+ |
| Timeslot offset Cyclic forwarding |
+-------------------------------------------+
Figure 3: Traffic shaping at the network edge: edge access control
4.2. Inter/Intra-domain traffic shaping
This section proposes a one-to-one deterministic cycle mapping
relationship for inter/intra-domain traffic shaping. After edge
access control management of cross-domain traffic by offsetting the
injection timeslot at the network edge, we establish a enqueue cycle
mapping relationship between cross-domain traffic from TSN domain to
DetNet domain (or DetNet domain to TSN domain). When there is no
serious inter-domain multi-flow aggregation and burst phenomenon
between domains, this mechanism needs to obtain the parameter of the
queue models (e.g., CQF and CSQF model) between adjacent domain,
including queue number, cycle time slot size, output port bandwidth,
transmission delay, clock synchronization of fixed frequency offset
parameters, and then establishes a cross-domain one-to-one enqueue
cycle mapping relationship. The cycle mapping relationship is
defined as follows: if packets sent in cycle X in a node A will all
be received no later than cycle Y in the downstream node B. It can
be expressed by the formula:
Cycle_mapping(A,B)(X)=Y
Since the Cycle_mapping is a periodic function, the correspondence of
index X within each scheduling hyper-period is consistent, as
follows:
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Cycle_mapping(A,B)(X+m*N) = Cycle_mapping(A,B)(X)
Where N is the number of cycles within a scheduling hyper-period, and
m is a natural number.
The mapping relationship between cycle X of node A and cycle Y of
node B is as follows:
Cycle_mapping(A,B)(X)=((X+1) mod N_A)*cycle_A+link_delay)/cycle_B)
mod N_B = Y
Where cycle_A and cycle_B are the cycle sizes of nodes A and b
respectively, N_A and N_B are the numbers of cycles with in a
scheduling hyper-period, and link_delay is the link delay.
In Figure 4, after the clock synchronization of edge devices, the
controller can obtain the fixed clock frequency difference between
devices, and then establish a one-to-one cycle mapping relationship:
from the sending queue in TSN domain to the next hop receiving queue
in DetNet domain. The mapping information is added to the packet's
Segment Routing Identifier (SID) tag for enqueue selection after
packets exiting the edge buffer. Because the controller can plan the
inter-domain enqueue selection in advance, it can ensure that the
upper and lower bounds of regulation delay and queuing delay of
cross-domain traffic are deterministic.
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TSN domain DetNet domain
+-----------------+ +------------------+
| TSN devices | | DetNet devices |
| +----+ +----+ | | +----+ +----+ |
| | +--+ +------->+ +---+ | |
| +----+ +----+ | | +----+ +----+ |
| | ^^ | |
+-----------------+ || +------------------+
||
+-------------------++--------------------+
| +---------+ |
| The last hop Edge RQ | |
|sending queue Buffer +---------+ |
| +-------+ +----+ +---------+ |
| | SQ -> | +---> RQ | |
| +-------+ +----+ +---------+ |
| .... |
| SID specifies the next +---------+ |
| hop receiving queue | SQ --> |
| +---------+ |
+-----------------------------------------+
1. Edge devices clock synchronization.
2. Enqueue cycle mapping relationship.
Figure 4: Inter/Intra-domain traffic shaping: cycle mapping
5. Jitter Compression for Large-scale Networks
A large-scale network may span multiple networks, and one of the
goals of DetNet is to connect each network domain to provide end-to-
end deterministic delay service. The adoption techniques and
capabilities of each network are different, and the corresponding
topology models are either piecewise or nested. In this way, mutual
coupling (dependency) should be reduced as much as possible. As long
as the network meets certain range requirements, the jitter
compression of the two-end device with Asynchronous/synchronous
clocks can support end-to-end deterministic delay service.
In this document, the jitter compression scheme is compatible with
the edge access control and enqueue cycle mapping mechanisms
(Section 4.1 and Section 4.2). The jitter compression utilizes the
explicit route planning, delay detection, jitter compression
mechanisms to support end-to-end time-sensitive traffic scheduling
across multiple domains to ensure bounded and jitter DetNet service
requirements.
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+-----------------+
TS1 XXX>+ SDN controller +<XXXX TS7
X +-----------------+ X Control plane
+-------------------X--------------------------X-----------------+
Gateway A X X Data plane
+--+ +---+ +---+ +---+ +---+ X
| +-->+ +-->+ R1+-->+ R2+---+ R3+------+ X
+--+ +---+ +-+-+ +-+-+ +-+-+ | X Gateway B
Host A ^ | | | ++--+ +---+ +--+
| | | | | R7+--->+ +-->+ |
Add SIDs + | v | ++--+ +---+ +--+
+-+-+ +-+-+ +-+-+ ^ + Host B
| R4+---+ R5+-->+ R6+------+ |
+---+ +---+ +---+ v Remove SIDs
Explicit route: R1->R2->R5->R6->R7 Data packets: ----->
Relay nodes: R2, R3, R4, R5, R6 INT/NQA packets: XXXX>
Edge nodes: R1, R7
Figure 5: Explicit route planning and delay detection for jitter
compression scheme
5.1. Explicit route planning
In this document, explicit routing planning adopts the new SID type
for DetNet transit nodes (e.g., edge nodes, relay nodes). The SIDs
contain information about the output port interface, queue (e.g.,
receiving queue, sending queue), and control gate period. Relay
nodes and edge nodes interact with each other through protocols to
learn mapping of gating cycles. SIDs can be configured by the SDN
controller or generated on the device side and reported to the SDN
controller.
In Figure 5, the SDN controller uses BGP-LS to collect topology
information of the entire network, and uses the detection technology
to collect end-to-end SLA network service quality information,
including latency, packet loss, and jitter, between edge devices (R1
and R7). Based on the quality constraint requirements of different
SLA levels, the SDN controller can generate feasible explicit routes
(e.g., R1->R2->R5->R6->R7) that can meet the SLA requirements and
sends the corresponding SID stack to the edge nodes (R1). This
document is not limited to the specific techniques used to generate
SIDs.
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5.2. Delay detection
In this document, network telemetry technologies such as INT/NQA can
be used to detect end-to-end delay on the network. INT-Band
telemetry packets are encapsulated by inserting the INT header into
the TCP or UDP header of the original packet, such as INT over TCP,
INT over UDP. As shown in Figure 6, INT probe HDR is the inherent
header of INT, and the device identifies INT packets through this
field. MD #1-N is meta-data, and Timestamp (TS) is the INT
information added at the end of the packet. Each TS includes an
ingress timestamp and an egress timestamp.
UDP/TCP Packets
+------+-------+-----+----+---+----+--------+----+---+-----
|ETH/IP|UDP/TCP| INT |MD N|...|MD 1|Playload|TS 1|...|TS M|
| HDR | HDR | HDR | | | | | | | |
+------+-------+-----+----+---+----+--------+----+---+----+
|<----------------->| |<----------->|
INT Encapsulation INT encapsulation
Figure 6: INT-Band telemetry packet encapsulation
In Figure 5, the source node (R1) periodically sends NQA packets to
the destination node (R7). After receiving the probe packets, the
destination device replies the packets. The source node calculates
the packet delay based on the time of receiving and replying packets
and reports the packet delay to the controller. If the network scale
is large, end-to-end detection causes heavy pressure on the device.
Alternatively, the device can only perform detection between
neighboring devices and report the detection to the controller. The
controller collects information and calculates the end-to-end delay.
The maximum and minimum end-to-end delay values are calculated as
follows:
End-to-End min = min (TS7 - TS1)
End-to-End max = max (TS7 - TS1)
5.3. Jitter compression
Since the end side network is carried by the carrier's network, only
the carrier's network promises its end-to-end delay, jitter and
reliability capabilities for deterministic flows. In this document,
the terminals can use the carrier's network as a tunnel, deploy the
gateway on the end side to perform edge access control, traffic
shaping, and deterministic scheduling, and perform jitter compression
on the peer end side to meet the end-to-end bounded latency service.
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This document implements global control and jitter compression based
on end-to-end deterministic transmission in SDN management. The
specific process is as follows:
1. Hosts A and B are located at the two ends of the network in
Figure 5. Each end uses its own clock. To prevent clock drift,
the SDN controller needs to calibrate the time slots at both
ends. End-to-end deterministic transmission is required between
hosts A and B to ensure bounded low latency and small jitter. It
may span a WAN or multiple DetNet transit nodes. R1 and R7, as
DetNet transit nodes, are key nodes of end-to-end deterministic
transmission.
2. The SDN controller implements end-to-end viewing, explicit routes
planning, and bandwidth reservation through segment routing
technology (e.g., SRv6).
3. Cycle mapping is performed based on the specified SID tag to
specify the jitter range of data packets in a receiving queue.
R1 and R7 are DetNet transit nodes with the same scheduling
frequency synchronization clock. The scheduler divides many
cycles according to the same frequency and adopts the DetNet
queue model (e.g., CSQF) of a specified cycle to schedule
forwarding.
For example, if A new DetNet service needs deterministic transmission
between hosts A and B, A request is sending to the SDN Controller via
API. Based on the detection and analysis in advance, the SDN
controller plans the corresponding explicit routes and distributes
SIDs mapping rules to the transit nodes along the path. The edge
node encapsulates the packets according to the rules and forwards the
packets through reassembly, caching, and scheduling, thus realizing
the end-to-end deterministic transmission with bounded latency and
jitter. In SIDs, the FlowID can be used for reassembly and out-of-
order recovery on the peer end side. According to Cycle, enqueue
cycle mapping scheduling can be carried out at the peer end side.
When uneven cycle mapping occurs on the peer device, the controller
can adjust the arrival time of DetNet flows so that the flows can be
mapped to different cycles. Thus, some queues won't be completely
filled and some queues won't starve to death. In this way, it is
possible to realize bounded latency and jitter for end-to-end
communication in large-scale networks.
6. Security Considerations
This section will be described later.
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7. IANA Considerations
This document has no IANA actions.
8. Acknowledgements
9. Contributors
[RFC7322] limits the number of authors listed on the front page to a
maximum of 5. The editor wishes to thank and acknowledge the
following author for contributing text to this document.
Tao Huang
Beijing University of Posts and Telecommunications
100876
Email: htao@bupt.edu.cn
Yunjie Liu
Beijing University of Posts and Telecommunications
100876
Email: liuyj@bupt.edu.cn
Wei Wang
New H3C Technologies
100094
Email: david_wang@h3c.com
10. Normative References
[I-D.ietf-detnet-bounded-latency]
Finn, N., Le Boudec, J., Mohammadpour, E., Zhang, J., and
B. Varga, "Deterministic Networking (DetNet) Bounded
Latency", Work in Progress, Internet-Draft, draft-ietf-
detnet-bounded-latency-10, 8 April 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
bounded-latency-10>.
[I-D.liu-detnet-large-scale-requirements]
Liu, P., Li, Y., Eckert, T. T., Xiong, Q., Ryoo, J.,
zhushiyin, and X. Geng, "Requirements for Large-Scale
Deterministic Networks", Work in Progress, Internet-Draft,
draft-liu-detnet-large-scale-requirements-05, 20 October
2022, <https://datatracker.ietf.org/doc/html/draft-liu-
detnet-large-scale-requirements-05>.
[I-D.qiang-detnet-large-scale-detnet]
Qiang, L., Geng, X., Liu, B., Eckert, T. T., Geng, L., and
G. Li, "Large-Scale Deterministic IP Network", Work in
Peng, et al. Expires 28 September 2023 [Page 15]
Internet-Draft Deterministic Networking March 2023
Progress, Internet-Draft, draft-qiang-detnet-large-scale-
detnet-05, 2 September 2019,
<https://datatracker.ietf.org/doc/html/draft-qiang-detnet-
large-scale-detnet-05>.
[IEEE802.1Qbv]
IEEE, "IEEE Standard for Local and metropolitan area
networks -- Bridges and Bridged Networks - Amendment 25:
Enhancements for Scheduled Traffic", IEEE 802.1Qbv-2015,
DOI 10.1109/IEEESTD.2016.8613095, 18 March 2016,
<https://doi.org/10.1109/IEEESTD.2016.8613095>.
[IEEE802.1Qch]
IEEE, "IEEE Standard for Local and metropolitan area
networks -- Bridges and Bridged Networks - Amendment 29:
Cyclic Queuing and Forwarding", IEEE 802.1Qch-2017,
DOI 10.1109/IEEESTD.2017.7961303, 28 June 2017,
<https://doi.org/10.1109/IEEESTD.2017.7961303>.
[IEEE802.1TSN]
IEEE Standards Association, "IEEE 802.1 Time-Sensitive
Networking Task Group",
<https://www.ieee802.org/1/pages/tsn.html>.
[IEEE8023] IEEE 802.3, "IEEE Std 802.3-2018: IEEE Standard for
Ethernet", 2018,
<http://ieeexplore.ieee.org/document/8457469>.
[RFC7322] Flanagan, H. and S. Ginoza, "RFC Style Guide", RFC 7322,
DOI 10.17487/RFC7322, September 2014,
<https://www.rfc-editor.org/info/rfc7322>.
[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>.
Authors' Addresses
Guoyu Peng
Beijing University of Posts and Telecommunications
Beijing
100876
China
Email: guoyupeng@bupt.edu.cn
Peng, et al. Expires 28 September 2023 [Page 16]
Internet-Draft Deterministic Networking March 2023
Shou Wang
Beijing University of Posts and Telecommunications
Beijing
100876
China
Email: shuowang@bupt.edu.cn
Zuopin Cheng
New H3C Technologies
Beijing
100094
China
Email: czp@h3c.com
Lei Zhou
New H3C Technologies
Beijing
100094
China
Email: zhou.leih@h3c.com
Peng Liu
China Mobile
Beijing
100053
China
Email: liupengyjy@chinamobile.com
Peng, et al. Expires 28 September 2023 [Page 17]
