< draft-ietf-detnet-bounded-latency-09.txt   draft-ietf-detnet-bounded-latency-10.txt >
DetNet N. Finn DetNet N. Finn
Internet-Draft Huawei Technologies Co. Ltd Internet-Draft Huawei Technologies Co. Ltd
Intended status: Informational J-Y. Le Boudec Intended status: Informational J-Y. Le Boudec
Expires: 20 August 2022 E. Mohammadpour Expires: 10 October 2022 E. Mohammadpour
EPFL EPFL
J. Zhang J. Zhang
Huawei Technologies Co. Ltd Huawei Technologies Co. Ltd
B. Varga B. Varga
J. Farkas
Ericsson Ericsson
16 February 2022 8 April 2022
DetNet Bounded Latency DetNet Bounded Latency
draft-ietf-detnet-bounded-latency-09 draft-ietf-detnet-bounded-latency-10
Abstract Abstract
This document presents a timing model for sources, destinations, and This document presents a timing model for sources, destinations, and
DetNet transit nodes. Using the model, it provides a methodology to DetNet transit nodes. Using the model, it provides a methodology to
compute end-to-end latency and backlog bounds for various queuing compute end-to-end latency and backlog bounds for various queuing
methods. The methodology can be used by the management and control methods. The methodology can be used by the management and control
planes and by resource reservation algorithms to provide bounded planes and by resource reservation algorithms to provide bounded
latency and zero congestion loss for the DetNet service. latency and zero congestion loss for the DetNet service.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 20 August 2022. This Internet-Draft will expire on 10 October 2022.
Copyright Notice Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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extracted from this document must include Revised BSD License text as extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License. provided without warranty as described in the Revised BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Definitions . . . . . . . . . . . . . . . . . 4 2. Terminology and Definitions . . . . . . . . . . . . . . . . . 4
3. DetNet bounded latency model . . . . . . . . . . . . . . . . 4 3. DetNet bounded latency model . . . . . . . . . . . . . . . . 4
3.1. Flow admission . . . . . . . . . . . . . . . . . . . . . 4 3.1. Flow admission . . . . . . . . . . . . . . . . . . . . . 4
3.1.1. Static latency calculation . . . . . . . . . . . . . 5 3.1.1. Static latency-calculation . . . . . . . . . . . . . 5
3.1.2. Dynamic latency calculation . . . . . . . . . . . . . 6 3.1.2. Dynamic latency-calculation . . . . . . . . . . . . . 6
3.2. Relay node model . . . . . . . . . . . . . . . . . . . . 6 3.2. Relay node model . . . . . . . . . . . . . . . . . . . . 7
4. Computing End-to-end Delay Bounds . . . . . . . . . . . . . . 9 4. Computing End-to-end Delay Bounds . . . . . . . . . . . . . . 9
4.1. Non-queuing delay bound . . . . . . . . . . . . . . . . . 9 4.1. Non-queuing delay bound . . . . . . . . . . . . . . . . . 9
4.2. Queuing delay bound . . . . . . . . . . . . . . . . . . . 10 4.2. Queuing delay bound . . . . . . . . . . . . . . . . . . . 10
4.2.1. Per-flow queuing mechanisms . . . . . . . . . . . . . 11 4.2.1. Per-flow queuing mechanisms . . . . . . . . . . . . . 11
4.2.2. Aggregate queuing mechanisms . . . . . . . . . . . . 11 4.2.2. Aggregate queuing mechanisms . . . . . . . . . . . . 11
4.3. Ingress considerations . . . . . . . . . . . . . . . . . 12 4.3. Ingress considerations . . . . . . . . . . . . . . . . . 12
4.4. Interspersed DetNet-unaware transit nodes . . . . . . . . 13 4.4. Interspersed DetNet-unaware transit nodes . . . . . . . . 13
5. Achieving zero congestion loss . . . . . . . . . . . . . . . 13 5. Achieving zero congestion loss . . . . . . . . . . . . . . . 13
6. Queuing techniques . . . . . . . . . . . . . . . . . . . . . 14 6. Queuing techniques . . . . . . . . . . . . . . . . . . . . . 14
6.1. Queuing data model . . . . . . . . . . . . . . . . . . . 15 6.1. Queuing data model . . . . . . . . . . . . . . . . . . . 15
6.2. Frame Preemption . . . . . . . . . . . . . . . . . . . . 17 6.2. Frame Preemption . . . . . . . . . . . . . . . . . . . . 17
6.3. Time Aware Shaper . . . . . . . . . . . . . . . . . . . . 17 6.3. Time-Aware Shaper . . . . . . . . . . . . . . . . . . . . 17
6.4. Credit-Based Shaper with Asynchronous Traffic Shaping . . 18 6.4. Credit-Based Shaper with Asynchronous Traffic Shaping . . 18
6.4.1. Delay Bound Calculation . . . . . . . . . . . . . . . 20 6.4.1. Delay Bound Calculation . . . . . . . . . . . . . . . 20
6.4.2. Flow Admission . . . . . . . . . . . . . . . . . . . 21 6.4.2. Flow Admission . . . . . . . . . . . . . . . . . . . 21
6.5. Guaranteed-Service IntServ . . . . . . . . . . . . . . . 22 6.5. Guaranteed-Service IntServ . . . . . . . . . . . . . . . 22
6.6. Cyclic Queuing and Forwarding . . . . . . . . . . . . . . 23 6.6. Cyclic Queuing and Forwarding . . . . . . . . . . . . . . 23
7. Example application on DetNet IP network . . . . . . . . . . 24 7. Example application on DetNet IP network . . . . . . . . . . 24
8. Security considerations . . . . . . . . . . . . . . . . . . . 26 8. Security considerations . . . . . . . . . . . . . . . . . . . 26
9. IANA considerations . . . . . . . . . . . . . . . . . . . . . 27 9. IANA considerations . . . . . . . . . . . . . . . . . . . . . 27
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 27 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 27
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 27 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 27
11.1. Normative References . . . . . . . . . . . . . . . . . . 27 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
11.2. Informative References . . . . . . . . . . . . . . . . . 28 12.1. Normative References . . . . . . . . . . . . . . . . . . 27
12.2. Informative References . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
The ability for IETF Deterministic Networking (DetNet) or IEEE 802.1 The ability for IETF Deterministic Networking (DetNet) or IEEE 802.1
Time-Sensitive Networking [IEEE8021TSN] to provide the DetNet Time-Sensitive Networking [IEEE8021TSN] to provide the DetNet
services of bounded latency and zero congestion loss depends upon A) services of bounded latency and zero congestion loss depends upon
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, so that latency
bounds can be reliably assured.
As explained in [RFC8655], DetNet flows are characterized by 1) a A) configuring and allocating network resources for the exclusive
maximum bandwidth, guaranteed either by the transmitter or by strict use of DetNet flows;
input metering; and 2) a requirement for a guaranteed worst-case end-
to-end latency. That latency guarantee, in turn, provides the B) identifying, in the data plane, the resources to be utilized by
opportunity for the network to supply enough buffer space to any given packet;
guarantee zero congestion loss. It is assumed in this document that
the paths of DetNet flows are fixed. Before the transmission of a C) the detailed behavior of those resources, especially
DetNet flow, it is possible to calculate end-to-end latency bounds transmission queue selection, so that latency bounds can be
and the amount of buffer space required at each hop to ensure zero reliably assured.
congestion loss; this can be used by the applications identified in
[RFC8578]. As explained in [RFC8655], DetNet flows are notably characterized by
1. a maximum bandwidth, guaranteed either by the transmitter or by
strict input metering;
2. a requirement for a guaranteed worst-case end-to-end latency.
That latency guarantee, in turn, provides the opportunity for the
network to supply enough buffer space to guarantee zero congestion
loss. It is assumed in this document that the paths of DetNet flows
are fixed. Before the transmission of a DetNet flow, it is possible
to calculate end-to-end latency bounds and the amount of buffer space
required at each hop to ensure zero congestion loss; this can be used
by the applications identified in [RFC8578].
This document presents a timing model for sources, destinations, and This document presents a timing model for sources, destinations, and
the DetNet transit nodes; using this model, it provides a methodology the DetNet transit nodes; using this model, it provides a methodology
to compute end-to-end latency and backlog bounds for various queuing to compute end-to-end latency and backlog bounds for various queuing
mechanisms that can be used by the management and control planes to mechanisms that can be used by the management and control planes to
provide DetNet qualities of service. The methodology used in this provide DetNet qualities of service. The methodology used in this
document account for the possibility of packet reordering within a document account for the possibility of packet reordering within a
DetNet node. The bounds on the amount of packet reordering is out of DetNet node. The bounds on the amount of packet reordering is out of
the scope of this document and can be found in the scope of this document and can be found in
[PacketReorderingBounds]. Moreover, this document references [PacketReorderingBounds]. Moreover, this document references
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Using the model presented in this document, it is possible for an Using the model presented in this document, it is possible for an
implementer, user, or standards development organization to select a implementer, user, or standards development organization to select a
set of queuing mechanisms for each device in a DetNet network, and to set of queuing mechanisms for each device in a DetNet network, and to
select a resource reservation algorithm for that network, so that select a resource reservation algorithm for that network, so that
those elements can work together to provide the DetNet service. those elements can work together to provide the DetNet service.
Section 7 provides an example application of the timing model Section 7 provides an example application of the timing model
introduced in this document on a DetNet IP network with a combination introduced in this document on a DetNet IP network with a combination
of different queuing mechanisms. of different queuing mechanisms.
This document does not specify any resource reservation protocol or This document does not specify any resource reservation protocol or
control plane function. It disregards the in-band packets that can control plane function. It does not describe all of the requirements
be part of the stream such as OAM and necessary re-transmissions. It for that protocol or control plane function. It does describe
does not describe all of the requirements for that protocol or requirements for such resource reservation methods, and for queuing
control plane function. It does describe requirements for such mechanisms that, if met, will enable them to work together.
resource reservation methods, and for queuing mechanisms that, if
met, will enable them to work together.
2. Terminology and Definitions 2. Terminology and Definitions
This document uses the terms defined in [RFC8655]. Moreover, the This document uses the terms defined in [RFC8655]. Moreover, the
following terms are used in this document: following terms are used in this document:
T-SPEC T-SPEC
TrafficSpecification as defined in Section 5.5 of [RFC9016]. TrafficSpecification as defined in Section 5.5 of [RFC9016].
arrival curve arrival curve
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CQF CQF
Cyclic Queuing and Forwarding. Cyclic Queuing and Forwarding.
CBS CBS
Credit-based Shaper. Credit-based Shaper.
TSN TSN
Time-Sensitive Networking. Time-Sensitive Networking.
PROEF PREOF
A collective name for Packet Replication, Elimination, and A collective name for Packet Replication, Elimination, and
Ordering Functions. Ordering Functions.
Packet Ordering Function (POF) Packet Ordering Function (POF)
A function that reorders packets within a DetNet flow that are A function that reorders packets within a DetNet flow that are
received out of order. This function can be implemented by a received out of order. This function can be implemented by a
DetNet edge node, a DetNet relay node, or an end system. DetNet edge node, a DetNet relay node, or an end system.
3. DetNet bounded latency model 3. DetNet bounded latency model
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This paradigm can be implemented using peer-to-peer protocols or This paradigm can be implemented using peer-to-peer protocols or
using a central controller. In some situations, a lack of resources using a central controller. In some situations, a lack of resources
can require backtracking and recursing through the above list. can require backtracking and recursing through the above list.
Issues such as service preemption of a DetNet flow in favor of Issues such as service preemption of a DetNet flow in favor of
another, when resources are scarce, are not considered here. Also another, when resources are scarce, are not considered here. Also
not addressed is the question of how to choose the path to be taken not addressed is the question of how to choose the path to be taken
by a DetNet flow. by a DetNet flow.
3.1.1. Static latency calculation 3.1.1. Static latency-calculation
The static problem: The static problem:
Given a network and a set of DetNet flows, compute an end-to- Given a network and a set of DetNet flows, compute an end-to-
end latency bound (if computable) for each DetNet flow, and end latency bound (if computable) for each DetNet flow, and
compute the resources, particularly buffer space, required in compute the resources, particularly buffer space, required in
each DetNet transit node to achieve zero congestion loss. each DetNet transit node to achieve zero congestion loss.
In this calculation, all of the DetNet flows are known before the In this calculation, all of the DetNet flows are known before the
calculation commences. This problem is of interest to relatively calculation commences. This problem is of interest to relatively
static networks, or static parts of larger networks. It provides static networks, or static parts of larger networks. It provides
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flow with tighter constraints. flow with tighter constraints.
This calculation may be more difficult to perform than the dynamic This calculation may be more difficult to perform than the dynamic
calculation (Section 3.1.2), because the DetNet flows passing through calculation (Section 3.1.2), because the DetNet flows passing through
one port on a DetNet transit node affect each other's latency. The one port on a DetNet transit node affect each other's latency. The
effects can even be circular, from a node A to B to C and back to A. effects can even be circular, from a node A to B to C and back to A.
On the other hand, the static calculation can often accommodate On the other hand, the static calculation can often accommodate
queuing methods, such as transmission selection by strict priority, queuing methods, such as transmission selection by strict priority,
that are unsuitable for the dynamic calculation. that are unsuitable for the dynamic calculation.
3.1.2. Dynamic latency calculation 3.1.2. Dynamic latency-calculation
The dynamic problem: The dynamic problem:
Given a network whose maximum capacity for DetNet flows is Given a network whose maximum capacity for DetNet flows is
bounded by a set of static configuration parameters applied bounded by a set of static configuration parameters applied
to the DetNet transit nodes, and given just one DetNet flow, to the DetNet transit nodes, and given just one DetNet flow,
compute the worst-case end-to-end latency that can be compute the worst-case end-to-end latency that can be
experienced by that flow, no matter what other DetNet flows experienced by that flow, no matter what other DetNet flows
(within the network's configured parameters) might be created (within the network's configured parameters) might be created
or deleted in the future. Also, compute the resources, or deleted in the future. Also, compute the resources,
particularly buffer space, required in each DetNet transit particularly buffer space, required in each DetNet transit
node to achieve zero congestion loss. node to achieve zero congestion loss.
This calculation is dynamic, in the sense that DetNet flows can be This calculation is dynamic, in the sense that DetNet flows can be
added or deleted at any time, with a minimum of computation effort, added or deleted at any time, with a minimum of computation effort,
and without affecting the guarantees already given to other DetNet and without affecting the guarantees already given to other DetNet
flows. flows.
Dynamic latency calculation can be done based on the static one Dynamic latency-calculation can be done based on the static one
described in Section 3.1.1; when a new DetNet flow is created or described in Section 3.1.1; when a new DetNet flow is created or
deleted, the entire calculation for all DetNet flows is repeated. If deleted, the entire calculation for all DetNet flows is repeated. If
an already-established DetNet flow would be pushed beyond its latency an already-established DetNet flow would be pushed beyond its latency
requirements by the new DetNet flow, then the new DetNet flow can be requirements by the new DetNet flow request, then the new DetNet flow
refused, or some other suitable action taken. request can be refused, or some other suitable action taken.
The choice of queuing methods is critical to the applicability of the The choice of queuing methods is critical to the applicability of the
dynamic calculation. Some queuing methods (e.g. CQF, Section 6.6) dynamic calculation. Some queuing methods (e.g., CQF, Section 6.6)
make it easy to configure bounds on the network's capacity, and to make it easy to configure bounds on the network's capacity, and to
make independent calculations for each DetNet flow. Some other make independent calculations for each DetNet flow. Some other
queuing methods (e.g. strict priority with the credit-based shaper queuing methods (e.g., strict priority with the credit-based shaper
defined in [IEEE8021Q] section 8.6.8.2) can be used for dynamic defined in [IEEE8021Q] section 8.6.8.2) can be used for dynamic
DetNet flow creation, but yield poorer latency and buffer space DetNet flow creation, but yield poorer latency and buffer space
guarantees than when that same queuing method is used for static guarantees than when that same queuing method is used for static
DetNet flow creation (Section 3.1.1). DetNet flow creation (Section 3.1.1).
3.2. Relay node model 3.2. Relay node model
A model for the operation of a DetNet transit node is required, in A model for the operation of a DetNet transit node is required, in
order to define the latency and buffer calculations. In Figure 1 we order to define the latency and buffer calculations. In Figure 1 we
see a breakdown of the per-hop latency experienced by a packet see a breakdown of the per-hop latency experienced by a packet
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2,3 4 5 6 1 2,3 4 5 6 1 2,3 2,3 4 5 6 1 2,3 4 5 6 1 2,3
1: Output delay 4: Processing delay 1: Output delay 4: Processing delay
2: Link delay 5: Regulation delay 2: Link delay 5: Regulation delay
3: Frame preemption delay 6: Queuing delay 3: Frame preemption delay 6: Queuing delay
Figure 1: Timing model for DetNet or TSN Figure 1: Timing model for DetNet or TSN
In Figure 1, we see two DetNet transit nodes that are connected via a In Figure 1, we see two DetNet transit nodes that are connected via a
link. In this model, the only queues, that we deal with explicitly, link. In this model, the only queues, that we deal with explicitly,
are attached to the output port; other queues are modeled as are attached to the output port; other queues are modeled as
variations in the other delay times. (E.g., an input queue could be variations in the other delay times (e.g., an input queue could be
modeled as either a variation in the link delay (2) or the processing modeled as either a variation in the link delay (2) or the processing
delay (4).) There are six delays that a packet can experience from delay (4).) There are six delays that a packet can experience from
hop to hop. hop to hop.
1. Output delay 1. Output delay
The time taken from the selection of a packet for output from a The time taken from the selection of a packet for output from a
queue to the transmission of the first bit of the packet on the queue to the transmission of the first bit of the packet on the
physical link. If the queue is directly attached to the physical physical link. If the queue is directly attached to the physical
port, output delay can be a constant. But, in many port, output delay can be a constant. But, in many
implementations, the queuing mechanism in a forwarding ASIC is implementations, the queuing mechanism in a forwarding ASIC is
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packet to the reception of the last bit, assuming that the packet to the reception of the last bit, assuming that the
transmission is not suspended by a frame preemption event. This transmission is not suspended by a frame preemption event. This
delay has two components, the first-bit-out to first-bit-in delay delay has two components, the first-bit-out to first-bit-in delay
and the first-bit-in to last-bit-in delay that varies with packet and the first-bit-in to last-bit-in delay that varies with packet
size. The former is typically measured by the Precision Time size. The former is typically measured by the Precision Time
Protocol and is constant (see [RFC8655]). However, a virtual Protocol and is constant (see [RFC8655]). However, a virtual
"link" could exhibit a variable link delay. "link" could exhibit a variable link delay.
3. Frame preemption delay 3. Frame preemption delay
If the packet is interrupted in order to transmit another packet If the packet is interrupted in order to transmit another packet
or packets, (e.g. [IEEE8023] clause 99 frame preemption) an or packets, (e.g., [IEEE8023] clause 99 frame preemption) an
arbitrary delay can result. arbitrary delay can result.
4. Processing delay 4. Processing delay
This delay covers the time from the reception of the last bit of This delay covers the time from the reception of the last bit of
the packet to the time the packet is enqueued in the regulator the packet to the time the packet is enqueued in the regulator
(queuing subsystem, if there is no regulator) as shown in (queuing subsystem, if there is no regulator) as shown in
Figure 1. This delay can be variable, and depends on the details Figure 1. This delay can be variable, and depends on the details
of the operation of the forwarding node. of the operation of the forwarding node.
5. Regulator delay 5. Regulator delay
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context is how to deal with the burstiness cascade: individual flows context is how to deal with the burstiness cascade: individual flows
that share a resource dedicated to a macro-flow may see their that share a resource dedicated to a macro-flow may see their
burstiness increase, which may in turn cause increased burstiness to burstiness increase, which may in turn cause increased burstiness to
other flows downstream of this resource. Computing delay upper other flows downstream of this resource. Computing delay upper
bounds for such cases is difficult, and in some conditions impossible bounds for such cases is difficult, and in some conditions impossible
[CharnyDelay][BennettDelay]. Also, when bounds are obtained, they [CharnyDelay][BennettDelay]. Also, when bounds are obtained, they
depend on the complete configuration, and must be recomputed when one depend on the complete configuration, and must be recomputed when one
flow is added. (The dynamic calculation, Section 3.1.2.) flow is added. (The dynamic calculation, Section 3.1.2.)
A solution to deal with this issue for the DetNet flows is to reshape A solution to deal with this issue for the DetNet flows is to reshape
them at every hop. This can be done with per-flow regulators (e.g. them at every hop. This can be done with per-flow regulators (e.g.,
leaky bucket shapers), but this requires per-flow queuing and defeats leaky bucket shapers), but this requires per-flow queuing and defeats
the purpose of aggregate queuing. An alternative is the interleaved the purpose of aggregate queuing. An alternative is the interleaved
regulator, which reshapes individual DetNet flows without per-flow regulator, which reshapes individual DetNet flows without per-flow
queuing ([SpechtUBS], [IEEE8021Qcr]). With an interleaved regulator, queuing ([SpechtUBS], [IEEE8021Qcr]). With an interleaved regulator,
the packet at the head of the queue is regulated based on its (flow) the packet at the head of the queue is regulated based on its (flow)
regulation constraints; it is released at the earliest time at which regulation constraints; it is released at the earliest time at which
this is possible without violating the constraint. One key feature this is possible without violating the constraint. One key feature
of per-flow or interleaved regulator is that, it does not increase of per-flow or interleaved regulator is that, it does not increase
worst-case latency bounds [LeBoudecTheory]. Specifically, when an worst-case latency bounds [LeBoudecTheory]. Specifically, when an
interleaved regulator is appended to a FIFO subsystem, it does not interleaved regulator is appended to a FIFO subsystem, it does not
increase the worst-case delay of the latter; in Figure 1, when the increase the worst-case delay of the latter; in Figure 1, when the
order of packets from output of queuing subsystem at node A to the order of packets from output of queuing subsystem at node A to the
entrance of regulator at node B is preserved, then the regulator does entrance of regulator at node B is preserved, then the regulator does
not increase the worst-case latency bounds; this is made possible if not increase the worst-case latency bounds; this is made possible if
all the systems are FIFO or a DetNet packet-ordering function (POF) all the systems are FIFO or a DetNet packet-ordering function (POF)
is implemented just before the regulator. This property does not is implemented just before the regulator. This property does not
hold if packet reordering occurs from the output of a queuing hold if packet reordering occurs from the output of a queuing
subsystem to the entrance of next downstream interleaved regulator, subsystem to the entrance of next downstream interleaved regulator,
e.g. at a non-FIFO switching fabric. e.g., at a non-FIFO switching fabric.
Figure 2 shows an example of a network with 5 nodes, aggregate Figure 2 shows an example of a network with 5 nodes, aggregate
queuing mechanism and interleaved regulators as in Figure 1. An end- queuing mechanism and interleaved regulators as in Figure 1. An end-
to-end delay bound for DetNet flow f, traversing nodes 1 to 5, is to-end delay bound for DetNet flow f, traversing nodes 1 to 5, is
calculated as follows: calculated as follows:
end_to_end_latency_bound_of_flow_f = C12 + C23 + C34 + S4 end_to_end_latency_bound_of_flow_f = C12 + C23 + C34 + S4
In the above formula, Cij is a bound on the delay of the queuing In the above formula, Cij is a bound on the delay of the queuing
subsystem in node i and interleaved regulator of node j, and S4 is a subsystem in node i and interleaved regulator of node j, and S4 is a
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The backlog bound is counted in data units (bytes, or words of The backlog bound is counted in data units (bytes, or words of
multiple bytes) that are relevant for buffer allocation. For every multiple bytes) that are relevant for buffer allocation. For every
flow or an aggregate of flows, we need one buffer space for the flow or an aggregate of flows, we need one buffer space for the
packet in transmission, plus space for the packets that are waiting packet in transmission, plus space for the packets that are waiting
to be selected for output. to be selected for output.
Let Let
* total_in_rate be the sum of the line rates of all input ports that * total_in_rate be the sum of the line rates of all input ports that
send traffic to this output port. The value of total_in_rate is send traffic to this output port. The value of total_in_rate is
in data units (e.g. bytes) per second. in data units (e.g., bytes) per second.
* nb_input_ports be the number input ports that send traffic to this * nb_input_ports be the number input ports that send traffic to this
output port output port
* max_packet_length be the maximum packet size for packets that may * max_packet_length be the maximum packet size for packets that may
be sent to this output port. This is counted in data units. be sent to this output port. This is counted in data units.
* max_delay456 be an upper bound, in seconds, on the sum of the * max_delay456 be an upper bound, in seconds, on the sum of the
processing delay (4) and the queuing delays (5,6) for any packet processing delay (4) and the queuing delays (5,6) for any packet
at this output port. at this output port.
Then a bound on the backlog of traffic in the queue at this output Then a bound on the backlog of traffic in the queue at this output
port is port is
backlog_bound = (nb_input_ports * max_packet_length) + backlog_bound = (nb_input_ports * max_packet_length) +
(total_in_rate * max_delay456) (total_in_rate * max_delay456)
The above bound is over the backlog caused by the traffic entering
the queue from the input ports of a DetNet node. If the DetNet node
also generates packets (e.g., creation of new packets, replication of
arriving packets), the bound must accordingly incorporate the
introduced backlog.
6. Queuing techniques 6. Queuing techniques
In this section, we present a general queuing data model as well as In this section, we present a general queuing data model as well as
some examples of queuing mechanisms. For simplicity of latency bound some examples of queuing mechanisms. For simplicity of latency bound
computation, we assume leaky-bucket arrival curve for each DetNet computation, we assume leaky-bucket arrival curve for each DetNet
flow at source. Also, at each DetNet transit node, the service for flow at source. Also, at each DetNet transit node, the service for
each queue is abstracted with a minimum guaranteed rate and a latency each queue is abstracted with a minimum guaranteed rate and a latency
[NetCalBook]. [NetCalBook].
6.1. Queuing data model 6.1. Queuing data model
skipping to change at page 16, line 51 skipping to change at page 16, line 51
Ideally, neither of these actions are performed on DetNet packets. Ideally, neither of these actions are performed on DetNet packets.
Full queues for DetNet packets occurs only when a DetNet flow is Full queues for DetNet packets occurs only when a DetNet flow is
misbehaving, and the DetNet QoS does not include "yellow" service for misbehaving, and the DetNet QoS does not include "yellow" service for
packets in excess of committed rate. packets in excess of committed rate.
The queue assignment function can be quite complex, even in a bridge The queue assignment function can be quite complex, even in a bridge
[IEEE8021Q], since the introduction of per-stream filtering and [IEEE8021Q], since the introduction of per-stream filtering and
policing ([IEEE8021Q] clause 8.6.5.1). In addition to the Layer 2 policing ([IEEE8021Q] clause 8.6.5.1). In addition to the Layer 2
priority expressed in the 802.1Q VLAN tag, a DetNet transit node can priority expressed in the 802.1Q VLAN tag, a DetNet transit node can
utilize any of the following information to assign a packet to a utilize the information from the non-exhaustive list below to assign
particular queue: a packet to a particular queue:
* Input port. * Input port.
* Selector based on a rotating schedule that starts at regular, * Selector based on a rotating schedule that starts at regular,
time-synchronized intervals and has nanosecond precision. time-synchronized intervals and has nanosecond precision.
* MAC addresses, VLAN ID, IP addresses, Layer 4 port numbers, DSCP * MAC addresses, VLAN ID, IP addresses, Layer 4 port numbers, DSCP
[RFC8939], [RFC8964]. [RFC8939], [RFC8964].
* The queue assignment function can contain metering and policing * The queue assignment function can contain metering and policing
skipping to change at page 17, line 38 skipping to change at page 17, line 38
interrupted, and one for packets that can interrupt the interruptible interrupted, and one for packets that can interrupt the interruptible
packets. Only one layer of frame preemption is supported -- a packets. Only one layer of frame preemption is supported -- a
transmitter cannot have more than one interrupted frame in progress. transmitter cannot have more than one interrupted frame in progress.
DetNet flows typically pass through the interrupting MAC. For those DetNet flows typically pass through the interrupting MAC. For those
DetNet flows with T-SPEC, latency bounds can be calculated by the DetNet flows with T-SPEC, latency bounds can be calculated by the
methods provided in the following sections that account for the methods provided in the following sections that account for the
effect of frame preemption, according to the specific queuing effect of frame preemption, according to the specific queuing
mechanism that is used in DetNet nodes. Best-effort queues pass mechanism that is used in DetNet nodes. Best-effort queues pass
through the interruptible MAC, and can thus be preempted. through the interruptible MAC, and can thus be preempted.
6.3. Time Aware Shaper 6.3. Time-Aware Shaper
In [IEEE8021Q], the notion of time-scheduling queue gates is In [IEEE8021Q], the notion of time-scheduling queue gates is
described in section 8.6.8.4. On each node, the transmission described in section 8.6.8.4. On each node, the transmission
selection for packets is controlled by time-synchronized gates; each selection for packets is controlled by time-synchronized gates; each
output queue is associated with a gate. The gates can be either open output queue is associated with a gate. The gates can be either open
or closed. The states of the gates are determined by the gate or closed. The states of the gates are determined by the gate
control list (GCL). The GCL specifies the opening and closing times control list (GCL). The GCL specifies the opening and closing times
of the gates. The design of GCL must satisfy the requirement of of the gates. The design of GCL must satisfy the requirement of
latency upper bounds of all DetNet flows; therefore, those DetNet latency upper bounds of all DetNet flows; therefore, those DetNet
flows that traverse a network that uses this kind of shaper must have flows that traverse a network that uses this kind of shaper must have
skipping to change at page 19, line 50 skipping to change at page 19, line 50
are served by a transmission selection subsystem that serves packets are served by a transmission selection subsystem that serves packets
from each class based on its priority. All subsystems are non- from each class based on its priority. All subsystems are non-
preemptive. Guarantees for classes A and B traffic can be provided preemptive. Guarantees for classes A and B traffic can be provided
only if CDT traffic is bounded; it is assumed that the CDT traffic only if CDT traffic is bounded; it is assumed that the CDT traffic
has a leaky bucket arrival curve with two parameters r_h as rate and has a leaky bucket arrival curve with two parameters r_h as rate and
b_h as bucket size, i.e., the amount of bits entering a node within a b_h as bucket size, i.e., the amount of bits entering a node within a
time interval t is bounded by r_h * t + b_h. time interval t is bounded by r_h * t + b_h.
Additionally, it is assumed that the classes A and B flows are also Additionally, it is assumed that the classes A and B flows are also
regulated at their source according to a leaky bucket arrival curve. regulated at their source according to a leaky bucket arrival curve.
At the source, the traffic satisfies its regulation constraint, i.e. At the source, the traffic satisfies its regulation constraint, i.e.,
the delay due to interleaved regulator at the source is ignored. the delay due to interleaved regulator at the source is ignored.
At each DetNet transit node implementing an interleaved regulator, At each DetNet transit node implementing an interleaved regulator,
packets of multiple flows are processed in one FIFO queue; the packet packets of multiple flows are processed in one FIFO queue; the packet
at the head of the queue is regulated based on its leaky bucket at the head of the queue is regulated based on its leaky bucket
parameters; it is released at the earliest time at which this is parameters; it is released at the earliest time at which this is
possible without violating the constraint. possible without violating the constraint.
The regulation parameters for a flow (leaky bucket rate and bucket The regulation parameters for a flow (leaky bucket rate and bucket
size) are the same at its source and at all DetNet transit nodes size) are the same at its source and at all DetNet transit nodes
skipping to change at page 21, line 13 skipping to change at page 21, line 13
If the flow is of class B: If the flow is of class B:
R_B = I_B * (c-r_h)/ c R_B = I_B * (c-r_h)/ c
T_B = (L_BE + L_A + L_nA * I_A/(c_h-I_A) + b_h + r_h * L_n/ T_B = (L_BE + L_A + L_nA * I_A/(c_h-I_A) + b_h + r_h * L_n/
c)/(c-r_h) c)/(c-r_h)
where I_B is the idle slope for class B; L_A is the maximum packet where I_B is the idle slope for class B; L_A is the maximum packet
length of class A; L_BE is the maximum packet length of class BE. length of class A; L_BE is the maximum packet length of class BE.
Then, as discussed in Section 4.2.2; an interleaved regulators does Then, as discussed in Section 4.2.2; an interleaved regulator does
not increase the delay bound of the upstream queuing subsystem; not increase the delay bound of the upstream queuing subsystem;
therefore an end-to-end delay bound for a DetNet flow of class X (A therefore an end-to-end delay bound for a DetNet flow of class X (A
or B) is the sum of d_X_i for all node i in the path the flow, where or B) is the sum of d_X_i for all node i in the path the flow, where
d_X_i is the delay bound of queuing subsystem in node i which is d_X_i is the delay bound of queuing subsystem in node i which is
computed as above. According to the notation in Section 4.2.2, the computed as above. According to the notation in Section 4.2.2, the
delay bound of queuing subsystem in a node i and interleaved delay bound of queuing subsystem in a node i and interleaved
regulator in node j, i.e., Cij, is: regulator in node j, i.e., Cij, is:
Cij = d_X_i Cij = d_X_i
More information of delay analysis in such a DetNet transit node is More information of delay analysis in such a DetNet transit node is
described in [TSNwithATS]. described in [TSNwithATS].
6.4.2. Flow Admission 6.4.2. Flow Admission
The delay bound calculation requires some information about each The delay bound calculation requires some information about each
node. For each node, it is required to know the idle slope of CBS node. For each node, it is required to know the idle slope of CBS
for each class A and B (I_A and I_B), as well as the transmission for each class A and B (I_A and I_B), as well as the transmission
rate of the output link (c). Besides, it is necessary to have the rate of the output link (c). Besides, it is necessary to have the
information on each class, i.e. maximum packet length of classes A, information on each class, i.e., maximum packet length of classes A,
B, and BE. Moreover, the leaky bucket parameters of CDT (r_h,b_h) B, and BE. Moreover, the leaky bucket parameters of CDT (r_h,b_h)
must be known. To admit a flow/flows of classes A and B, their delay must be known. To admit a flow/flows of classes A and B, their delay
requirements must be guaranteed not to be violated. As described in requirements must be guaranteed not to be violated. As described in
Section 3.1, the two problems, static and dynamic, are addressed Section 3.1, the two problems, static and dynamic, are addressed
separately. In either of the problems, the rate and delay must be separately. In either of the problems, the rate and delay must be
guaranteed. Thus, guaranteed. Thus,
The static admission control: The static admission control:
The leaky bucket parameters of all class A or B flows are The leaky bucket parameters of all class A or B flows are
known, therefore, for each class A or B flow f, a delay bound known, therefore, for each class A or B flow f, a delay bound
skipping to change at page 23, line 23 skipping to change at page 23, line 23
the flow traversing the node is T + b / R. the flow traversing the node is T + b / R.
Consider a Guaranteed-Service IntServ path including a sequence of Consider a Guaranteed-Service IntServ path including a sequence of
nodes, where the i-th node provides a guaranteed rate R_i and maximum nodes, where the i-th node provides a guaranteed rate R_i and maximum
service latency of T_i. Then, the end-to-end delay bound for a flow service latency of T_i. Then, the end-to-end delay bound for a flow
on this can be calculated as sum(T_i) + b / min(R_i). on this can be calculated as sum(T_i) + b / min(R_i).
The provided delay bound is based on a simple case of Guaranteed- The provided delay bound is based on a simple case of Guaranteed-
Service IntServ where only a guaranteed rate and maximum service Service IntServ where only a guaranteed rate and maximum service
latency and a leaky bucket arrival curve are available. If more latency and a leaky bucket arrival curve are available. If more
information about the flow is known, e.g. the peak rate, the delay information about the flow is known, e.g., the peak rate, the delay
bound is more complicated; the details are available in [RFC2212] and bound is more complicated; the details are available in [RFC2212] and
Section 1.4.1 of [NetCalBook]. Section 1.4.1 of [NetCalBook].
6.6. Cyclic Queuing and Forwarding 6.6. Cyclic Queuing and Forwarding
Annex T of [IEEE8021Q] describes Cyclic Queuing and Forwarding (CQF), Annex T of [IEEE8021Q] describes Cyclic Queuing and Forwarding (CQF),
which provides bounded latency and zero congestion loss using the which provides bounded latency and zero congestion loss using the
time-scheduled gates of [IEEE8021Q] section 8.6.8.4. For a given time-scheduled gates of [IEEE8021Q] section 8.6.8.4. For a given
class of DetNet flows, a set of two or more buffers is provided at class of DetNet flows, a set of two or more buffers is provided at
the output queue layer of Figure 3. A cycle time T_c is configured the output queue layer of Figure 3. A cycle time T_c is configured
skipping to change at page 24, line 5 skipping to change at page 24, line 5
buffer1 transmits the packets received in cycle (i). The duration of buffer1 transmits the packets received in cycle (i). The duration of
each cycle is T_c. each cycle is T_c.
The cycle time T_c must be carefully chosen; it needs to be large The cycle time T_c must be carefully chosen; it needs to be large
enough to accommodate all the DetNet traffic, plus at least one enough to accommodate all the DetNet traffic, plus at least one
maximum packet (or fragment) size from lower priority queues, which maximum packet (or fragment) size from lower priority queues, which
might be received within a cycle. Also, the value of T_c includes a might be received within a cycle. Also, the value of T_c includes a
time interval, called dead time (DT), which is the sum of the delays time interval, called dead time (DT), which is the sum of the delays
1,2,3,4 defined in Figure 1. The value of DT guarantees that the 1,2,3,4 defined in Figure 1. The value of DT guarantees that the
last packet of one cycle in a node is fully delivered to a buffer of last packet of one cycle in a node is fully delivered to a buffer of
the next node is the same cycle. A two-buffer CQF is recommended if the next node in the same cycle. A two-buffer CQF is recommended if
DT is small compared to T_c. For a large DT, CQF with more buffers DT is small compared to T_c. For a large DT, CQF with more buffers
can be used and a cycle identification label can be added to the can be used, and a cycle identification label can be added to the
packets. packets.
The per-hop latency is determined by the cycle time T_c: a packet The per-hop latency is determined by the cycle time T_c: a packet
transmitted from a node at a cycle (i), is transmitted from the next transmitted from a node at a cycle (i), is transmitted from the next
node at cycle (i+1). Then, if the packet traverses h hops, the node at cycle (i+1). Then, if the packet traverses h hops, the
maximum latency experienced by the packet is from the beginning of maximum latency experienced by the packet is from the beginning of
cycle (i) to the end of cycle (i+h); also, the minimum latency is cycle (i) to the end of cycle (i+h); also, the minimum latency is
from the end of cycle (i) before the DT, to the beginning of cycle from the end of cycle (i) before the DT, to the beginning of cycle
(i+h). Then, the maximum latency is: (i+h). Then, the maximum latency is:
skipping to change at page 26, line 25 skipping to change at page 26, line 25
Security aspects that are unique to DetNet are those whose aim is to Security aspects that are unique to DetNet are those whose aim is to
provide the specific QoS aspects of DetNet, specifically bounded end- provide the specific QoS aspects of DetNet, specifically bounded end-
to-end delivery latency and zero congestion loss. Achieving such to-end delivery latency and zero congestion loss. Achieving such
loss rates and bounded latency may not be possible in the face of a loss rates and bounded latency may not be possible in the face of a
highly capable adversary, such as the one envisioned by the Internet highly capable adversary, such as the one envisioned by the Internet
Threat Model of BCP 72 [RFC3552] that can arbitrarily drop or delay Threat Model of BCP 72 [RFC3552] that can arbitrarily drop or delay
any or all traffic. In order to present meaningful security any or all traffic. In order to present meaningful security
considerations, we consider a somewhat weaker attacker who does not considerations, we consider a somewhat weaker attacker who does not
control the physical links of the DetNet domain but may have the control the physical links of the DetNet domain but may have the
ability to control some resources within the boundary of the DetNet ability to control or change the behavior of some resources within
domain. the boundary of the DetNet domain.
Latency bound calculations use parameters that reflect physical Latency bound calculations use parameters that reflect physical
quantities. If an attacker finds a way to change the physical quantities. If an attacker finds a way to change the physical
quantities, unknown to the control and management planes, the latency quantities, unknown to the control and management planes, the latency
calculations fail and may result in latency violation and/or calculations fail and may result in latency violation and/or
congestion losses. An example of such attacks is to make some congestion losses. An example of such attacks is to make some
traffic sources under the control of the attacker send more traffic traffic sources under the control of the attacker send more traffic
than their assumed T-SPECs. This type of attack is typically avoided than their assumed T-SPECs. This type of attack is typically avoided
by ingress conditioning at the edge of a DetNet domain. However, it by ingress conditioning at the edge of a DetNet domain. However, it
must be insured that such ingress conditioning is done per-flow and must be insured that such ingress conditioning is done per-flow and
skipping to change at page 27, line 12 skipping to change at page 27, line 12
be detected only by their effects on latency bound violations and be detected only by their effects on latency bound violations and
congestion losses, which do not occur in normal DetNet operation. congestion losses, which do not occur in normal DetNet operation.
9. IANA considerations 9. IANA considerations
This document has no IANA actions. This document has no IANA actions.
10. Acknowledgement 10. Acknowledgement
We would like to thank Lou Berger, Tony Przygienda, John Scudder, We would like to thank Lou Berger, Tony Przygienda, John Scudder,
Watson Ladd, Yoshifumi Nishida, Ralf Weber, and Robert Sparks for Watson Ladd, Yoshifumi Nishida, Ralf Weber, Robert Sparks, Gyan
their useful feedback on this document. Mishra, Martin Duke, Eric Vyncke, Lars Eggert, Roman Danyliw, and
Paul Wouters for their useful feedback on this document.
11. References 11. Contributors
11.1. Normative References RFC 7322 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
Janos Farkas
Ericsson
Email: janos.farkas@ericsson.com
12. References
12.1. Normative References
[IEEE8021Q] [IEEE8021Q]
IEEE 802.1, "IEEE Std 802.1Q-2018: IEEE Standard for Local IEEE 802.1, "IEEE Std 802.1Q-2018: IEEE Standard for Local
and metropolitan area networks - Bridges and Bridged and metropolitan area networks - Bridges and Bridged
Networks", 2018, Networks", 2018,
<http://ieeexplore.ieee.org/document/8403927>. <https://ieeexplore.ieee.org/document/8403927>.
[RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification [RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212, of Guaranteed Quality of Service", RFC 2212,
DOI 10.17487/RFC2212, September 1997, DOI 10.17487/RFC2212, September 1997,
<https://www.rfc-editor.org/info/rfc2212>. <https://www.rfc-editor.org/info/rfc2212>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998, Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<https://www.rfc-editor.org/info/rfc2475>. <https://www.rfc-editor.org/info/rfc2475>.
skipping to change at page 28, line 16 skipping to change at page 28, line 30
S., and J. Korhonen, "Deterministic Networking (DetNet) S., and J. Korhonen, "Deterministic Networking (DetNet)
Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January
2021, <https://www.rfc-editor.org/info/rfc8964>. 2021, <https://www.rfc-editor.org/info/rfc8964>.
[RFC9016] Varga, B., Farkas, J., Cummings, R., Jiang, Y., and D. [RFC9016] Varga, B., Farkas, J., Cummings, R., Jiang, Y., and D.
Fedyk, "Flow and Service Information Model for Fedyk, "Flow and Service Information Model for
Deterministic Networking (DetNet)", RFC 9016, Deterministic Networking (DetNet)", RFC 9016,
DOI 10.17487/RFC9016, March 2021, DOI 10.17487/RFC9016, March 2021,
<https://www.rfc-editor.org/info/rfc9016>. <https://www.rfc-editor.org/info/rfc9016>.
11.2. Informative References 12.2. Informative References
[BennettDelay] [BennettDelay]
J.C.R. Bennett, K. Benson, A. Charny, W.F. Courtney, and J.C.R. Bennett, K. Benson, A. Charny, W.F. Courtney, and
J.-Y. Le Boudec, "Delay Jitter Bounds and Packet Scale J.-Y. Le Boudec, "Delay Jitter Bounds and Packet Scale
Rate Guarantee for Expedited Forwarding", Rate Guarantee for Expedited Forwarding",
<https://dl.acm.org/citation.cfm?id=581870>. <https://dl.acm.org/citation.cfm?id=581870>.
[CharnyDelay] [CharnyDelay]
A. Charny and J.-Y. Le Boudec, "Delay Bounds in a Network A. Charny and J.-Y. Le Boudec, "Delay Bounds in a Network
with Aggregate Scheduling", <https://link.springer.com/ with Aggregate Scheduling", <https://link.springer.com/
skipping to change at page 28, line 39 skipping to change at page 29, line 9
[DelayAttack] [DelayAttack]
S. Barreto, A. Suresh, and J.-Y. Le Boudec, "Cyber-attack S. Barreto, A. Suresh, and J.-Y. Le Boudec, "Cyber-attack
on packet-based time synchronization protocols: The on packet-based time synchronization protocols: The
undetectable Delay Box", undetectable Delay Box",
<https://ieeexplore.ieee.org/document/7520408>. <https://ieeexplore.ieee.org/document/7520408>.
[I-D.ietf-detnet-controller-plane-framework] [I-D.ietf-detnet-controller-plane-framework]
A. Malis, X. Geng, M. Chen, F. Qin, and B. Varga, A. Malis, X. Geng, M. Chen, F. Qin, and B. Varga,
"Deterministic Networking (DetNet) Controller Plane "Deterministic Networking (DetNet) Controller Plane
Framework draft-ietf-detnet-controller-plane-framework- Framework draft-ietf-detnet-controller-plane-framework-
00", <https://datatracker.ietf.org/doc/html/draft-ietf- 01", <https://datatracker.ietf.org/doc/html/draft-ietf-
detnet-controller-plane-framework>. detnet-controller-plane-framework>.
[IEEE1588] IEEE Std 1588-2008, "IEEE Standard for a Precision Clock [IEEE1588] IEEE Std 1588-2008, "IEEE Standard for a Precision Clock
Synchronization Protocol for Networked Measurement and Synchronization Protocol for Networked Measurement and
Control Systems", 2008, Control Systems", 2008,
<https://ieeexplore.ieee.org/document/4579760>. <https://ieeexplore.ieee.org/document/4579760>.
[IEEE8021Qcr] [IEEE8021Qcr]
IEEE 802.1, "IEEE P802.1Qcr: IEEE Draft Standard for Local IEEE 802.1, "IEEE P802.1Qcr: Bridges and Bridged Networks
and metropolitan area networks - Bridges and Bridged - Amendment: Asynchronous Traffic Shaping", 2017,
Networks - Amendment: Asynchronous Traffic Shaping", 2017, <https://1.ieee802.org/tsn/802-1qcr/>.
<http://www.ieee802.org/1/files/private/cr-drafts/>.
[IEEE8021TSN] [IEEE8021TSN]
IEEE 802.1, "IEEE 802.1 Time-Sensitive Networking (TSN) IEEE 802.1, "IEEE 802.1 Time-Sensitive Networking (TSN)
Task Group", <http://www.ieee802.org/1/>. Task Group", <http://www.ieee802.org/1/>.
[IEEE8023] IEEE 802.3, "IEEE Std 802.3-2018: IEEE Standard for [IEEE8023] IEEE 802.3, "IEEE Std 802.3-2018: IEEE Standard for
Ethernet", 2018, Ethernet", 2018,
<http://ieeexplore.ieee.org/document/8457469>. <http://ieeexplore.ieee.org/document/8457469>.
[LeBoudecTheory] [LeBoudecTheory]
skipping to change at page 30, line 30 skipping to change at page 31, line 4
<https://dl.acm.org/doi/10.1145/3393691.3394206>. <https://dl.acm.org/doi/10.1145/3393691.3394206>.
[TSNwithATS] [TSNwithATS]
E. Mohammadpour, E. Stai, M. Mohiuddin, and J.-Y. Le E. Mohammadpour, E. Stai, M. Mohiuddin, and J.-Y. Le
Boudec, "Latency and Backlog Bounds in Time-Sensitive Boudec, "Latency and Backlog Bounds in Time-Sensitive
Networking with Credit Based Shapers and Asynchronous Networking with Credit Based Shapers and Asynchronous
Traffic Shaping", Traffic Shaping",
<https://ieeexplore.ieee.org/document/8493026>. <https://ieeexplore.ieee.org/document/8493026>.
Authors' Addresses Authors' Addresses
Norman Finn Norman Finn
Huawei Technologies Co. Ltd Huawei Technologies Co. Ltd
3101 Rio Way 3101 Rio Way
Spring Valley, California 91977 Spring Valley, California 91977
United States of America United States of America
Phone: +1 925 980 6430 Phone: +1 925 980 6430
Email: nfinn@nfinnconsulting.com Email: nfinn@nfinnconsulting.com
Jean-Yves Le Boudec Jean-Yves Le Boudec
EPFL EPFL
IC Station 14 IC Station 14
CH-1015 Lausanne EPFL CH-1015 Lausanne EPFL
Switzerland Switzerland
Email: jean-yves.leboudec@epfl.ch Email: jean-yves.leboudec@epfl.ch
Ehsan Mohammadpour Ehsan Mohammadpour
EPFL EPFL
IC Station 14 IC Station 14
CH-1015 Lausanne EPFL CH-1015 Lausanne EPFL
Switzerland Switzerland
Email: ehsan.mohammadpour@epfl.ch Email: ehsan.mohammadpour@epfl.ch
Jiayi Zhang Jiayi Zhang
Huawei Technologies Co. Ltd Huawei Technologies Co. Ltd
Q27, No.156 Beiqing Road Q27, No.156 Beiqing Road
Beijing Beijing
100095 100095
China China
Email: zhangjiayi11@huawei.com Email: zhangjiayi11@huawei.com
Balázs Varga Balázs Varga
Ericsson Ericsson
Budapest Budapest
Konyves Kálmán krt. 11/B Konyves Kálmán krt. 11/B
1097 1097
Hungary Hungary
Email: balazs.a.varga@ericsson.com Email: balazs.a.varga@ericsson.com
János Farkas
Ericsson
Budapest
Konyves Kálmán krt. 11/B
1097
Hungary
Email: janos.farkas@ericsson.com
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