draft-ietf-detnet-architecture-08.txt   draft-ietf-detnet-architecture-09.txt 
DetNet N. Finn DetNet N. Finn
Internet-Draft Huawei Internet-Draft Huawei
Intended status: Standards Track P. Thubert Intended status: Standards Track P. Thubert
Expires: March 16, 2019 Cisco Expires: April 25, 2019 Cisco
B. Varga B. Varga
J. Farkas J. Farkas
Ericsson Ericsson
September 12, 2018 October 22, 2018
Deterministic Networking Architecture Deterministic Networking Architecture
draft-ietf-detnet-architecture-08 draft-ietf-detnet-architecture-09
Abstract Abstract
This document provides the overall Architecture for Deterministic This document provides the overall architecture for Deterministic
Networking (DetNet), which provides a capability to carry specified Networking (DetNet), which provides a capability to carry specified
unicast or multicast data flows for real-time applications with unicast or multicast data flows for real-time applications with
extremely low data loss rates and bounded latency. Techniques used extremely low data loss rates and bounded latency within a network
include: 1) reserving data plane resources for individual (or domain. Techniques used include: 1) reserving data plane resources
aggregated) DetNet flows in some or all of the intermediate nodes for individual (or aggregated) DetNet flows in some or all of the
(e.g., bridges or routers) along the path of the flow; 2) providing intermediate nodes along the path of the flow; 2) providing explicit
explicit routes for DetNet flows that do not immediately change with routes for DetNet flows that do not immediately change with the
the network topology; and 3) distributing data from DetNet flow network topology; and 3) distributing data from DetNet flow packets
packets over time and/or space to ensure delivery of each packet's over time and/or space to ensure delivery of each packet's data in
data in spite of the loss of a path. DetNet operates at the IP layer spite of the loss of a path. DetNet operates at the IP layer and
and delivers service over sub-network technologies such as MPLS and delivers service over sub-network technologies such as MPLS and IEEE
IEEE 802.1 TSN. 802.1 Time-Sensitive Networking (TSN).
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 March 16, 2019. This Internet-Draft will expire on April 25, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 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 Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 28 skipping to change at page 2, line 28
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Terms used in this document . . . . . . . . . . . . . . . 4 2.1. Terms used in this document . . . . . . . . . . . . . . . 4
2.2. IEEE 802.1 TSN to DetNet dictionary . . . . . . . . . . . 7 2.2. IEEE 802.1 TSN to DetNet dictionary . . . . . . . . . . . 7
3. Providing the DetNet Quality of Service . . . . . . . . . . . 7 3. Providing the DetNet Quality of Service . . . . . . . . . . . 7
3.1. Primary goals defining the DetNet QoS . . . . . . . . . . 7 3.1. Primary goals defining the DetNet QoS . . . . . . . . . . 7
3.2. Mechanisms to achieve DetNet QoS . . . . . . . . . . . . 9 3.2. Mechanisms to achieve DetNet QoS . . . . . . . . . . . . 10
3.2.1. Congestion protection . . . . . . . . . . . . . . . . 9 3.2.1. Congestion protection . . . . . . . . . . . . . . . . 10
3.2.1.1. Eliminate congestion loss . . . . . . . . . . . . 9 3.2.1.1. Eliminate congestion loss . . . . . . . . . . . . 10
3.2.1.2. Jitter Reduction . . . . . . . . . . . . . . . . 10 3.2.1.2. Jitter Reduction . . . . . . . . . . . . . . . . 10
3.2.2. Service Protection . . . . . . . . . . . . . . . . . 11 3.2.2. Service Protection . . . . . . . . . . . . . . . . . 11
3.2.2.1. In-Order Delivery . . . . . . . . . . . . . . . . 11 3.2.2.1. In-Order Delivery . . . . . . . . . . . . . . . . 11
3.2.2.2. Packet Replication and Elimination . . . . . . . 11 3.2.2.2. Packet Replication and Elimination . . . . . . . 12
3.2.2.3. Packet encoding for service protection . . . . . 13 3.2.2.3. Packet encoding for service protection . . . . . 14
3.2.3. Explicit routes . . . . . . . . . . . . . . . . . . . 13 3.2.3. Explicit routes . . . . . . . . . . . . . . . . . . . 14
3.3. Secondary goals for DetNet . . . . . . . . . . . . . . . 14 3.3. Secondary goals for DetNet . . . . . . . . . . . . . . . 15
3.3.1. Coexistence with normal traffic . . . . . . . . . . . 15 3.3.1. Coexistence with normal traffic . . . . . . . . . . . 15
3.3.2. Fault Mitigation . . . . . . . . . . . . . . . . . . 15 3.3.2. Fault Mitigation . . . . . . . . . . . . . . . . . . 15
4. DetNet Architecture . . . . . . . . . . . . . . . . . . . . . 16 4. DetNet Architecture . . . . . . . . . . . . . . . . . . . . . 16
4.1. DetNet stack model . . . . . . . . . . . . . . . . . . . 16 4.1. DetNet stack model . . . . . . . . . . . . . . . . . . . 16
4.1.1. Representative Protocol Stack Model . . . . . . . . . 16 4.1.1. Representative Protocol Stack Model . . . . . . . . . 16
4.1.2. DetNet Data Plane Overview . . . . . . . . . . . . . 18 4.1.2. DetNet Data Plane Overview . . . . . . . . . . . . . 19
4.1.3. Network reference model . . . . . . . . . . . . . . . 20 4.1.3. Network reference model . . . . . . . . . . . . . . . 21
4.2. DetNet systems . . . . . . . . . . . . . . . . . . . . . 22 4.2. DetNet systems . . . . . . . . . . . . . . . . . . . . . 22
4.2.1. End system . . . . . . . . . . . . . . . . . . . . . 22 4.2.1. End system . . . . . . . . . . . . . . . . . . . . . 22
4.2.2. DetNet edge, relay, and transit nodes . . . . . . . . 23 4.2.2. DetNet edge, relay, and transit nodes . . . . . . . . 23
4.3. DetNet flows . . . . . . . . . . . . . . . . . . . . . . 23 4.3. DetNet flows . . . . . . . . . . . . . . . . . . . . . . 24
4.3.1. DetNet flow types . . . . . . . . . . . . . . . . . . 23 4.3.1. DetNet flow types . . . . . . . . . . . . . . . . . . 24
4.3.2. Source transmission behavior . . . . . . . . . . . . 24 4.3.2. Source transmission behavior . . . . . . . . . . . . 24
4.3.3. Incomplete Networks . . . . . . . . . . . . . . . . . 25 4.3.3. Incomplete Networks . . . . . . . . . . . . . . . . . 26
4.4. Traffic Engineering for DetNet . . . . . . . . . . . . . 25 4.4. Traffic Engineering for DetNet . . . . . . . . . . . . . 26
4.4.1. The Application Plane . . . . . . . . . . . . . . . . 26 4.4.1. The Application Plane . . . . . . . . . . . . . . . . 26
4.4.2. The Controller Plane . . . . . . . . . . . . . . . . 26 4.4.2. The Controller Plane . . . . . . . . . . . . . . . . 27
4.4.3. The Network Plane . . . . . . . . . . . . . . . . . . 27 4.4.3. The Network Plane . . . . . . . . . . . . . . . . . . 27
4.5. Queuing, Shaping, Scheduling, and Preemption . . . . . . 28 4.5. Queuing, Shaping, Scheduling, and Preemption . . . . . . 28
4.6. Service instance . . . . . . . . . . . . . . . . . . . . 29 4.6. Service instance . . . . . . . . . . . . . . . . . . . . 29
4.7. Flow identification at technology borders . . . . . . . . 30 4.7. Flow identification at technology borders . . . . . . . . 31
4.7.1. Exporting flow identification . . . . . . . . . . . . 30 4.7.1. Exporting flow identification . . . . . . . . . . . . 31
4.7.2. Flow attribute mapping between layers . . . . . . . . 32 4.7.2. Flow attribute mapping between layers . . . . . . . . 32
4.7.3. Flow-ID mapping examples . . . . . . . . . . . . . . 33 4.7.3. Flow-ID mapping examples . . . . . . . . . . . . . . 33
4.8. Advertising resources, capabilities and adjacencies . . . 35 4.8. Advertising resources, capabilities and adjacencies . . . 35
4.9. Scaling to larger networks . . . . . . . . . . . . . . . 35 4.9. Scaling to larger networks . . . . . . . . . . . . . . . 36
4.10. Compatibility with Layer-2 . . . . . . . . . . . . . . . 35 4.10. Compatibility with Layer-2 . . . . . . . . . . . . . . . 36
5. Security Considerations . . . . . . . . . . . . . . . . . . . 36 5. Security Considerations . . . . . . . . . . . . . . . . . . . 36
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 36 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 37
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 36 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 37
9. Informative References . . . . . . . . . . . . . . . . . . . 37 9. Informative References . . . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41
1. Introduction 1. Introduction
This document provides the overall Architecture for Deterministic This document provides the overall architecture for Deterministic
Networking (DetNet), which provides a capability for the delivery of Networking (DetNet), which provides a capability for the delivery of
data flows with extremely low packet loss rates and bounded end-to- data flows with extremely low packet loss rates and bounded end-to-
end delivery latency. DetNet operates at the IP layer and delivers end delivery latency. DetNet is for networks that are under a single
service over sub-network technologies such as MPLS and IEEE 802.1 administrative control or within a closed group of administrative
TSN. DetNet accomplishes these goals by dedicating network resources control; these include campus-wide networks and private WANs. DetNet
such as link bandwidth and buffer space to DetNet flows and/or is not for large groups of domains such as the Internet.
classes of DetNet flows, and by replicating packets along multiple
paths. Unused reserved resources are available to non-DetNet DetNet operates at the IP layer and delivers service over sub-network
packets. technologies such as MPLS and IEEE 802.1 Time-Sensitive Networking
(TSN). DetNet accomplishes these goals by dedicating network
resources such as link bandwidth and buffer space to DetNet flows
and/or classes of DetNet flows, and by replicating packets along
multiple paths. Unused reserved resources are available to non-
DetNet packets as long as all guarantees are fulfilled.
The Deterministic Networking Problem Statement The Deterministic Networking Problem Statement
[I-D.ietf-detnet-problem-statement] introduces Deterministic [I-D.ietf-detnet-problem-statement] introduces Deterministic
Networking, and Deterministic Networking Use Cases Networking, and Deterministic Networking Use Cases
[I-D.ietf-detnet-use-cases] summarizes the need for it. See [I-D.ietf-detnet-use-cases] summarizes the need for it. See
[I-D.ietf-detnet-dp-sol-mpls] and [I-D.ietf-detnet-dp-sol-ip] for [I-D.ietf-detnet-dp-sol-mpls] and [I-D.ietf-detnet-dp-sol-ip] for
specific techniques that can be used to identify DetNet flows and specific techniques that can be used to identify DetNet flows and
assign them to specific paths through a network. assign them to specific paths through a network.
A goal of DetNet is a converged network in all respects. That is, A goal of DetNet is a converged network in all respects. That is,
the presence of DetNet flows does not preclude non-DetNet flows, and the presence of DetNet flows does not preclude non-DetNet flows, and
the benefits offered DetNet flows should not, except in extreme the benefits offered DetNet flows should not, except in extreme
cases, prevent existing QoS mechanisms from operating in a normal cases, prevent existing Quality of Service (QoS) mechanisms from
fashion, subject to the bandwidth required for the DetNet flows. A operating in a normal fashion, subject to the bandwidth required for
single source-destination pair can trade both DetNet and non-DetNet the DetNet flows. A single source-destination pair can trade both
flows. End systems and applications need not instantiate special DetNet and non-DetNet flows. End systems and applications need not
interfaces for DetNet flows. Networks are not restricted to certain instantiate special interfaces for DetNet flows. Networks are not
topologies; connectivity is not restricted. Any application that restricted to certain topologies; connectivity is not restricted.
generates a data flow that can be usefully characterized as having a Any application that generates a data flow that can be usefully
maximum bandwidth should be able to take advantage of DetNet, as long characterized as having a maximum bandwidth should be able to take
as the necessary resources can be reserved. Reservations can be made advantage of DetNet, as long as the necessary resources can be
by the application itself, via network management, by an reserved. Reservations can be made by the application itself, via
application's controller, or by other means, e.g., a dynamic control network management, by an application's controller, or by other
plane (e.g., [RFC2205]). means, e.g., a dynamic control plane (e.g., [RFC2205]). Network
nodes supporting DetNet flows have to implement some of the DetNet
capabilities (not necessarily all) in order to treat DetNet flows
such that their QoS requirements are met.
Many applications that are intended to be served by Deterministic Many applications that are intended to be served by Deterministic
Networking require the ability to synchronize the clocks in end Networking require the ability to synchronize the clocks in end
systems to a sub-microsecond accuracy. Some of the queue control systems to a sub-microsecond accuracy. Some of the queue control
techniques defined in Section 4.5 also require time synchronization techniques defined in Section 4.5 also require time synchronization
among relay and transit nodes. The means used to achieve time among network nodes. The means used to achieve time synchronization
synchronization are not addressed in this document. DetNet can are not addressed in this document. DetNet can accommodate various
accommodate various time synchronization techniques and profiles that time synchronization techniques and profiles that are defined
are defined elsewhere to address the needs of different market elsewhere to address the needs of different market segments.
segments.
2. Terminology 2. Terminology
2.1. Terms used in this document 2.1. Terms used in this document
The following terms are used in the context of DetNet in this The following terms are used in the context of DetNet in this
document: document:
allocation allocation
Resources are dedicated to support a DetNet flow. Depending Resources are dedicated to support a DetNet flow. Depending
on an implementation, the resource may be reused by non- on an implementation, the resource may be reused by non-
DetNet flows when it is not used by the DetNet flow. DetNet flows when it is not used by the DetNet flow.
App-flow App-flow
The native format of a DetNet flow. The native format of a DetNet flow.
DetNet destination
An end system capable of terminating a DetNet flow.
DetNet domain
The portion of a network that is DetNet aware. It includes
end systems and other DetNet nodes.
DetNet flow
A DetNet flow is a sequence of packets to which the DetNet
service is to be provided.
DetNet compound flow and DetNet member flow DetNet compound flow and DetNet member flow
A DetNet compound flow is a DetNet flow that has been A DetNet compound flow is a DetNet flow that has been
separated into multiple duplicate DetNet member flows for separated into multiple duplicate DetNet member flows for
service protection at the DetNet service layer. Member flows service protection at the DetNet service sub-layer. Member
are merged back into a single DetNet compound flow such that flows are merged back into a single DetNet compound flow such
there are no duplicate packets. "Compound" and "member" are that there are no duplicate packets. "Compound" and "member"
strictly relative to each other, not absolutes; a DetNet are strictly relative to each other, not absolutes; a DetNet
compound flow comprising multiple DetNet member flows can, in compound flow comprising multiple DetNet member flows can, in
turn, be a member of a higher-order compound. turn, be a member of a higher-order compound.
DetNet intermediate node DetNet destination
A DetNet relay node or transit node. An end system capable of terminating a DetNet flow.
DetNet domain
The portion of a network that is DetNet aware. It includes
end systems and DetNet nodes.
DetNet edge node DetNet edge node
An instance of a DetNet relay node that acts as a source and/ An instance of a DetNet relay node that acts as a source and/
or destination at the DetNet service layer. For example, it or destination at the DetNet service sub-layer. For example,
can include a DetNet service layer proxy function for DetNet it can include a DetNet service sub-layer proxy function for
service protection (e.g., the addition or removal of packet DetNet service protection (e.g., the addition or removal of
sequencing information) for one or more end systems, or packet sequencing information) for one or more end systems,
starts or terminates congestion protection at the DetNet or starts or terminates congestion protection at the DetNet
transport layer, or aggregates DetNet services into new transport sub-layer, or aggregates DetNet services into new
DetNet flows. It is analogous to a Label Edge Router (LER) DetNet flows. It is analogous to a Label Edge Router (LER)
or a Provider Edge (PE) router. or a Provider Edge (PE) router.
DetNet flow
A DetNet flow is a sequence of packets from one source to one
or more destinations, which conform uniquely to a flow
identifier, and to which the DetNet service is to be
provided.
DetNet intermediate node
A DetNet relay node or DetNet transit node.
DetNet node
A DetNet edge node, a DetNet relay node, or a DetNet transit
node.
DetNet relay node
A DetNet node including a service sub-layer function that
interconnects different DetNet transport sub-layer paths to
provide service protection. A DetNet relay node participates
in the DetNet service sub-layer. It typically incorporates
DetNet transport sub-layer functions as well, in which case
it is collocated with a transit node.
DetNet service sub-layer
The DetNet sub-layer at which A DetNet service, e.g., service
protection is provided.
DetNet service proxy
Maps between App-flows and DetNet flows.
DetNet source
An end system capable of originating a DetNet flow.
DetNet system
A DetNet aware end system, transit node, or relay node.
"DetNet" may be omitted in some text.
DetNet transit node
A DetNet node operating at the DetNet transport sub-layer,
that utilizes link layer and/or network layer switching
across multiple links and/or sub-networks to provide paths
for DetNet service sub-layer functions. Typically provides
congestion protection over those paths. An MPLS LSR is an
example of a DetNet transit node.
DetNet transport sub-layer
The DetNet layer that optionally provides congestion
protection for DetNet flows over paths provided by the
underlying network.
DetNet-UNI DetNet-UNI
User-to-Network Interface with DetNet specific User-to-Network Interface with DetNet specific
functionalities. It is a packet-based reference point and functionalities. It is a packet-based reference point and
may provide multiple functions like encapsulation, status, may provide multiple functions like encapsulation, status,
synchronization, etc. synchronization, etc.
end system end system
Commonly called a "host" in IETF documents, and an "end Commonly called a "host" in IETF documents, and an "end
station" is IEEE 802 documents. End systems of interest to station" is IEEE 802 documents. End systems of interest to
this document are either sources or destinations of DetNet this document are either sources or destinations of DetNet
flows. And end system may or may not be DetNet transport flows. And end system may or may not be DetNet transport
layer aware or DetNet service layer aware. sub-layer aware or DetNet service sub-layer aware.
link link
A connection between two DetNet nodes. It may be composed of A connection between two DetNet nodes. It may be composed of
a physical link or a sub-network technology that can provide a physical link or a sub-network technology that can provide
appropriate traffic delivery for DetNet flows. appropriate traffic delivery for DetNet flows.
DetNet system
A DetNet aware end system, transit node, or relay node.
"DetNet" may be omitted in some text.
DetNet relay node
A DetNet node including a service layer function that
interconnects different DetNet transport layer paths to
provide service protection. A DetNet relay node can be a
bridge, a router, a firewall, or any other system that
participates in the DetNet service layer. It typically
incorporates DetNet transport layer functions as well, in
which case it is collocated with a transit node.
PEF A Packet Elimination Function (PEF) eliminates duplicate PEF A Packet Elimination Function (PEF) eliminates duplicate
copies of packets to prevent excess packets flooding the copies of packets to prevent excess packets flooding the
network or duplicate packets being sent out of the DetNet network or duplicate packets being sent out of the DetNet
domain. PEF can be implemented by an edge node, a relay domain. PEF can be implemented by a DetNet edge node, a
node, or an end system. DetNet relay node, or an end system.
PRF A Packet Replication Function (PRF) replicates DetNet flow PRF A Packet Replication Function (PRF) replicates DetNet flow
packets and forwards them to one or more next hops in the packets and forwards them to one or more next hops in the
DetNet domain. The number of packet copies sent to each next DetNet domain. The number of packet copies sent to the next
hop is a DetNet flow specific parameter at the node doing the hops is a DetNet flow specific parameter at the point of
replication. PRF can be implemented by an edge node, a relay replication. PRF can be implemented by a DetNet edge node, a
node, or an end system. DetNet relay node, or an end system.
PREOF Collective name for Packet Replication, Elimination, and PREOF Collective name for Packet Replication, Elimination, and
Ordering Functions. Ordering Functions.
POF A Packet Ordering Function (POF) re-orders packets within a POF A Packet Ordering Function (POF) re-orders packets within a
DetNet flow that are received out of order. This function DetNet flow that are received out of order. This function
can be implemented by an edge node, a relay node, or an end can be implemented by a DetNet edge node, a DetNet relay
system. node, or an end system.
reservation reservation
The set of resources allocated between a source and one or The set of resources allocated between a source and one or
more destinations through transit nodes and subnets more destinations through DetNet nodes and subnets associated
associated with a DetNet flow, to provide the provisioned with a DetNet flow, to provide the provisioned DetNet
DetNet service. service.
DetNet service layer
The layer at which A DetNet service, e.g., service protection
is provided.
DetNet service proxy
Maps between App-flows and DetNet flows.
DetNet source
An end system capable of originating a DetNet flow.
DetNet transit node
A node operating at the DetNet transport layer, that utilizes
link layer and/or network layer switching across multiple
links and/or sub-networks to provide paths for DetNet service
layer functions. Typically provides congestion protection
over those paths. An MPLS LSR is an example of a DetNet
transit node.
DetNet transport layer
The layer that optionally provides congestion protection for
DetNet flows over paths provided by the underlying network.
2.2. IEEE 802.1 TSN to DetNet dictionary 2.2. IEEE 802.1 TSN to DetNet dictionary
This section also serves as a dictionary for translating from the This section also serves as a dictionary for translating from the
terms used by the Time-Sensitive Networking (TSN) Task Group terms used by the Time-Sensitive Networking (TSN) Task Group
[IEEE802.1TSNTG] of the IEEE 802.1 WG to those of the DetNet WG. [IEEE802.1TSNTG] of the IEEE 802.1 WG to those of the DetNet WG.
Listener Listener
The IEEE 802.1 term for a destination of a DetNet flow. The IEEE 802.1 term for a destination of a DetNet flow.
skipping to change at page 7, line 49 skipping to change at page 8, line 14
o An upper bound on out-of-order packet delivery. It is worth o An upper bound on out-of-order packet delivery. It is worth
noting that some DetNet applications are unable to tolerate any noting that some DetNet applications are unable to tolerate any
out-of-order delivery. out-of-order delivery.
It is a distinction of DetNet that it is concerned solely with worst- It is a distinction of DetNet that it is concerned solely with worst-
case values for the end-to-end latency, jitter, and misordering. case values for the end-to-end latency, jitter, and misordering.
Average, mean, or typical values are of little interest, because they Average, mean, or typical values are of little interest, because they
do not affect the ability of a real-time system to perform its tasks. do not affect the ability of a real-time system to perform its tasks.
In general, a trivial priority-based queuing scheme will give better In general, a trivial priority-based queuing scheme will give better
average latency to a data flow than DetNet, but of course, the worst- average latency to a data flow than DetNet; however, it may not be a
case latency can be essentially unbounded. suitable option for DetNet because of its worst-case latency.
Three techniques are used by DetNet to provide these qualities of Three techniques are used by DetNet to provide these qualities of
service: service:
o Congestion protection (Section 3.2.1). o Congestion protection (Section 3.2.1).
o Service protection (Section 3.2.2). o Service protection (Section 3.2.2).
o Explicit routes (Section 3.2.3). o Explicit routes (Section 3.2.3).
skipping to change at page 9, line 20 skipping to change at page 9, line 32
topology as described, e.g., in [IEC62439-3-2016]. In this topology as described, e.g., in [IEC62439-3-2016]. In this
example, explicit routes are achieved by limiting the physical example, explicit routes are achieved by limiting the physical
topology of the network to a ring. Sequentialization, topology of the network to a ring. Sequentialization,
replication, and duplicate elimination are facilitated by packet replication, and duplicate elimination are facilitated by packet
tags added at the front or the end of Ethernet frames. [RFC8227] tags added at the front or the end of Ethernet frames. [RFC8227]
provides another example in the context of MPLS. provides another example in the context of MPLS.
o Congestion protection alone is offered by IEEE 802.1 Audio Video o Congestion protection alone is offered by IEEE 802.1 Audio Video
bridging [IEEE802.1BA]. As long as the network suffers no bridging [IEEE802.1BA]. As long as the network suffers no
failures, zero congestion loss can be achieved through the use of failures, zero congestion loss can be achieved through the use of
a reservation protocol (MSRP [IEEE802.1Q-2018]), shapers in every a reservation protocol (e.g., Multiple Stream Registration
bridge, and proper dimensioning. Protocol [IEEE802.1Q-2018]), shapers in every bridge, and proper
dimensioning.
o Using all three together gives maximum protection. o Using all three together gives maximum protection.
There are, of course, simpler methods available (and employed, today) There are, of course, simpler methods available (and employed, today)
to achieve levels of latency and packet loss that are satisfactory to achieve levels of latency and packet loss that are satisfactory
for many applications. Prioritization and over-provisioning is one for many applications. Prioritization and over-provisioning is one
such technique. However, these methods generally work best in the such technique. However, these methods generally work best in the
absence of any significant amount of non-critical traffic in the absence of any significant amount of non-critical traffic in the
network (if, indeed, such traffic is supported at all), or work only network (if, indeed, such traffic is supported at all), or work only
if the critical traffic constitutes only a small portion of the if the critical traffic constitutes only a small portion of the
skipping to change at page 9, line 50 skipping to change at page 10, line 15
industry) to make selections among the available means of industry) to make selections among the available means of
implementing DetNet networks. implementing DetNet networks.
3.2. Mechanisms to achieve DetNet QoS 3.2. Mechanisms to achieve DetNet QoS
3.2.1. Congestion protection 3.2.1. Congestion protection
3.2.1.1. Eliminate congestion loss 3.2.1.1. Eliminate congestion loss
The primary means by which DetNet achieves its QoS assurances is to The primary means by which DetNet achieves its QoS assurances is to
reduce, or even completely eliminate, congestion within a node as a reduce, or even completely eliminate, congestion within a DetNet node
cause of packet loss. Given that a DetNet flow cannot be throttled, as a cause of packet loss. This can be achieved only by the
this can be achieved only by the provision of sufficient buffer provision of sufficient buffer storage at each node through the
storage at each hop through the network to ensure that no packets are network to ensure that no packets are dropped due to a lack of buffer
dropped due to a lack of buffer storage. storage. Note that a DetNet flow cannot be throttled, i.e., its
transmission rate cannot be reduced via explicit congestion
notification.
Ensuring adequate buffering requires, in turn, that the source, and Ensuring adequate buffering requires, in turn, that the source, and
every intermediate node along the path to the destination (or nearly every DetNet node along the path to the destination (or nearly every
every node, see Section 4.3.3) be careful to regulate its output to node, see Section 4.3.3) be careful to regulate its output to not
not exceed the data rate for any DetNet flow, except for brief exceed the data rate for any DetNet flow, except for brief periods
periods when making up for interfering traffic. Any packet sent when making up for interfering traffic. Any packet sent ahead of its
ahead of its time potentially adds to the number of buffers required time potentially adds to the number of buffers required by the next
by the next hop and may thus exceed the resources allocated for a hop DetNet node and may thus exceed the resources allocated for a
particular DetNet flow. particular DetNet flow.
The low-level mechanisms described in Section 4.5 provide the The low-level mechanisms described in Section 4.5 provide the
necessary regulation of transmissions by an end system or necessary regulation of transmissions by an end system or DetNet node
intermediate node to provide congestion protection. The allocation to provide congestion protection. The allocation of the bandwidth
of the bandwidth and buffers for a DetNet flow requires provisioning and buffers for a DetNet flow requires provisioning. A DetNet node
A DetNet node may have other resources requiring allocation and/or may have other resources requiring allocation and/or scheduling, that
scheduling, that might otherwise be over-subscribed and trigger the might otherwise be over-subscribed and trigger the rejection of a
rejection of a reservation. reservation.
3.2.1.2. Jitter Reduction 3.2.1.2. Jitter Reduction
A core objective of DetNet is to enable the convergence of sensitive A core objective of DetNet is to enable the convergence of sensitive
non-IP networks onto a common network infrastructure. This requires non-IP networks onto a common network infrastructure. This requires
the accurate emulation of currently deployed mission-specific the accurate emulation of currently deployed mission-specific
networks, which for example rely on point-to-point analog (e.g., networks, which for example rely on point-to-point analog (e.g.,
4-20mA modulation) and serial-digital cables (or buses) for highly 4-20mA modulation) and serial-digital cables (or buses) for highly
reliable, synchronized and jitter-free communications. While the reliable, synchronized and jitter-free communications. While the
latency of analog transmissions is basically the speed of light, latency of analog transmissions is basically the speed of light,
skipping to change at page 11, line 43 skipping to change at page 12, line 10
misordering would be a valid service constraint to reflect that the misordering would be a valid service constraint to reflect that the
end system(s) of the flow cannot tolerate any out-of-order delivery. end system(s) of the flow cannot tolerate any out-of-order delivery.
DetNet Packet Ordering Functionality (POF) (Section 3.2.2.2) can be DetNet Packet Ordering Functionality (POF) (Section 3.2.2.2) can be
used to provide in-order delivery. used to provide in-order delivery.
3.2.2.2. Packet Replication and Elimination 3.2.2.2. Packet Replication and Elimination
This section describes a service protection method that sends copies This section describes a service protection method that sends copies
of the same packets over multiple paths. of the same packets over multiple paths.
The DetNet service layer includes the packet replication (PRF), the The DetNet service sub-layer includes the packet replication (PRF),
packet elimination (PEF), and the packet ordering functionality (POF) the packet elimination (PEF), and the packet ordering functionality
for use in DetNet edge, relay node, and end system packet processing. (POF) for use in DetNet edge, relay node, and end system packet
Either of these functions can be enabled in a DetNet edge node, relay processing. Either of these functions can be enabled in a DetNet
node or end system. The collective name for all three functions is edge node, relay node or end system. The collective name for all
PREOF. The packet replication and elimination service protection three functions is PREOF. The packet replication and elimination
method altogether involves four capabilities: service protection method altogether involves four capabilities:
o Providing sequencing information to the packets of a DetNet o Providing sequencing information to the packets of a DetNet
compound flow. This may be done by adding a sequence number or compound flow. This may be done by adding a sequence number or
time stamp as part of DetNet, or may be inherent in the packet, time stamp as part of DetNet, or may be inherent in the packet,
e.g., in a transport protocol, or associated to other physical e.g., in a Layer-4 transport protocol, or associated to other
properties such as the precise time (and radio channel) of physical properties such as the precise time (and radio channel)
reception of the packet. This is typically done once, at or near of reception of the packet. This is typically done once, at or
the source. near the source.
o The Packet Replication Function (PRF) replicates these packets o The Packet Replication Function (PRF) replicates these packets
into multiple DetNet member flows and typically sends them along into multiple DetNet member flows and typically sends them along
multiple different paths to the destination(s), e.g., over the multiple different paths to the destination(s), e.g., over the
explicit routes of Section 3.2.3. The location within a node, and explicit routes of Section 3.2.3. The location within a DetNet
the mechanism used for the PRF is implementation specific. node, and the mechanism used for the PRF is implementation
specific.
o The Packet Elimination Function (PEF) eliminates duplicate packets o The Packet Elimination Function (PEF) eliminates duplicate packets
of a DetNet flow based on the sequencing information and a history of a DetNet flow based on the sequencing information and a history
of received packets. The output of the PEF is always a single of received packets. The output of the PEF is always a single
packet. This may be done at any node along the path to save packet. This may be done at any DetNet node along the path to
network resources further downstream, in particular if multiple save network resources further downstream, in particular if
Replication points exist. But the most common case is to perform multiple Replication points exist. But the most common case is to
this operation at the very edge of the DetNet network, preferably perform this operation at the very edge of the DetNet network,
in or near the receiver. The location within a node, and preferably in or near the receiver. The location within a DetNet
mechanism used for the PEF is implementation specific. node, and mechanism used for the PEF is implementation specific.
o The Packet Ordering Function (POF) uses the sequencing information o The Packet Ordering Function (POF) uses the sequencing information
to re-order a DetNet flow's packets that are received out of to re-order a DetNet flow's packets that are received out of
order. order.
The order in which a node applies PEF, POF, and PRF to a DetNet flow The order in which a DetNet node applies PEF, POF, and PRF to a
is implementation specific. DetNet flow is implementation specific.
Some service protection mechanisms rely on switching from one flow to Some service protection mechanisms rely on switching from one flow to
another when a failure of a flow is detected. Contrarily, packet another when a failure of a flow is detected. Contrarily, packet
replication and elimination combines the DetNet member flows sent replication and elimination combines the DetNet member flows sent
along multiple different paths, and performs a packet-by-packet along multiple different paths, and performs a packet-by-packet
selection of which to discard, e.g., based on sequencing information. selection of which to discard, e.g., based on sequencing information.
In the simplest case, this amounts to replicating each packet in a In the simplest case, this amounts to replicating each packet in a
source that has two interfaces, and conveying them through the source that has two interfaces, and conveying them through the
network, along separate (disjoint non-SRLG) paths, to the similarly network, along separate (SRLG disjoint) paths, to the similarly dual-
dual-homed destinations, that discard the extras. This ensures that homed destinations, that discard the extras. This ensures that one
one path (with zero congestion loss) remains, even if some path (with zero congestion loss) remains, even if some DetNet
intermediate node fails. The sequencing information can also be used intermediate node fails. The sequencing information can also be used
for loss detection and for re-ordering. for loss detection and for re-ordering.
DetNet relay nodes in the network can provide replication and DetNet relay nodes in the network can provide replication and
elimination facilities at various points in the network, so that elimination facilities at various points in the network, so that
multiple failures can be accommodated. multiple failures can be accommodated.
This is shown in Figure 1, where the two relay nodes each replicate This is shown in Figure 1, where the two relay nodes each replicate
(R) the DetNet flow on input, sending the DetNet member flows to both (R) the DetNet flow on input, sending the DetNet member flows to both
the other relay node and to the end system, and eliminate duplicates the other relay node and to the end system, and eliminate duplicates
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combining information from multiple packets into any given combining information from multiple packets into any given
transmission unit. Such techniques, also known as "network coding", transmission unit. Such techniques, also known as "network coding",
can be used as a DetNet service protection technique. can be used as a DetNet service protection technique.
3.2.3. Explicit routes 3.2.3. Explicit routes
In networks controlled by typical dynamic control protocols such as In networks controlled by typical dynamic control protocols such as
IS-IS or OSPF, a network topology event in one part of the network IS-IS or OSPF, a network topology event in one part of the network
can impact, at least briefly, the delivery of data in parts of the can impact, at least briefly, the delivery of data in parts of the
network remote from the failure or recovery event. Even the use of network remote from the failure or recovery event. Even the use of
redundant paths through a network defined, e.g., as defined by redundant paths through a network, e.g., as defined by [RFC6372] do
[RFC6372] do not eliminate the chances of packet loss. Furthermore, not eliminate the chances of packet loss. Furthermore, out-of-order
out-of-order packet delivery can be a side effect of route changes. packet delivery can be a side effect of route changes.
Many real-time networks rely on physical rings of two-port devices, Many real-time networks rely on physical rings of two-port devices,
with a relatively simple ring control protocol. This supports with a relatively simple ring control protocol. This supports
redundant paths for service protection with a minimum of wiring. As redundant paths for service protection with a minimum of wiring. As
an additional benefit, ring topologies can often utilize different an additional benefit, ring topologies can often utilize different
topology management protocols than those used for a mesh network, topology management protocols than those used for a mesh network,
with a consequent reduction in the response time to topology changes. with a consequent reduction in the response time to topology changes.
Of course, this comes at some cost in terms of increased hop count, Of course, this comes at some cost in terms of increased hop count,
and thus latency, for the typical path. and thus latency, for the typical path.
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different explicit routes. different explicit routes.
3.3. Secondary goals for DetNet 3.3. Secondary goals for DetNet
Many applications require DetNet to provide additional services, Many applications require DetNet to provide additional services,
including coexistence with other QoS mechanisms Section 3.3.1 and including coexistence with other QoS mechanisms Section 3.3.1 and
protection against misbehaving transmitters Section 3.3.2. protection against misbehaving transmitters Section 3.3.2.
3.3.1. Coexistence with normal traffic 3.3.1. Coexistence with normal traffic
A DetNet network supports the dedication of a high proportion (e.g. A DetNet network supports the dedication of a high proportion of the
75%) of the network bandwidth to DetNet flows. But, no matter how network bandwidth to DetNet flows. But, no matter how much is
much is dedicated for DetNet flows, it is a goal of DetNet to coexist dedicated for DetNet flows, it is a goal of DetNet to coexist with
with existing Class of Service schemes (e.g., DiffServ). It is also existing Class of Service schemes (e.g., DiffServ). It is also
important that non-DetNet traffic not disrupt the DetNet flow, of important that non-DetNet traffic not disrupt the DetNet flow, of
course (see Section 3.3.2 and Section 5). For these reasons: course (see Section 3.3.2 and Section 5). For these reasons:
o Bandwidth (transmission opportunities) not utilized by a DetNet o Bandwidth (transmission opportunities) not utilized by a DetNet
flow is available to non-DetNet packets (though not to other flow is available to non-DetNet packets (though not to other
DetNet flows). DetNet flows).
o DetNet flows can be shaped or scheduled, in order to ensure that o DetNet flows can be shaped or scheduled, in order to ensure that
the highest-priority non-DetNet packet is also ensured a worst- the highest-priority non-DetNet packet is also ensured a worst-
case latency (at any given hop). case latency.
o When transmission opportunities for DetNet flows are scheduled in o When transmission opportunities for DetNet flows are scheduled in
detail, then the algorithm constructing the schedule should leave detail, then the algorithm constructing the schedule should leave
sufficient opportunities for non-DetNet packets to satisfy the sufficient opportunities for non-DetNet packets to satisfy the
needs of the users of the network. Detailed scheduling can also needs of the users of the network. Detailed scheduling can also
permit the time-shared use of buffer resources by different DetNet permit the time-shared use of buffer resources by different DetNet
flows. flows.
Ideally, the net effect of the presence of DetNet flows in a network Traffic policing functions (e.g., [RFC2475]) are used to avoid the
on the non-DetNet packets is primarily a reduction in the available starvation of non-DetNet traffic. Thus, the net effect of the
bandwidth. presence of DetNet flows in a network on the non-DetNet flows is
primarily a reduction in the available bandwidth.
3.3.2. Fault Mitigation 3.3.2. Fault Mitigation
One key to building robust real-time systems is to reduce the Robust real-time systems require to reduce the number of possible
infinite variety of possible failures to a number that can be failures. Filters and policers should be used in a DetNet network to
analyzed with reasonable confidence. DetNet aids in the process by detect if DetNet packets are received on the wrong interface, or at
allowing for filters and policers to detect DetNet packets received the wrong time, or in too great a volume. Furthermore, filters and
on the wrong interface, or at the wrong time, or in too great a policers can take actions to discard the offending packets or flows,
volume, and to then take actions such as discarding the offending or trigger shutting down the offending flow or the offending
packet, shutting down the offending DetNet flow, or shutting down the interface.
offending interface.
It is also essential that filters and service remarking be employed It is also essential that filters and service remarking be employed
at the network edge to prevent non-DetNet packets from being mistaken at the network edge to prevent non-DetNet packets from being mistaken
for DetNet packets, and thus impinging on the resources allocated to for DetNet packets, and thus impinging on the resources allocated to
DetNet packets. DetNet packets.
There exist techniques, at present and/or in various stages of There exist techniques, at present and/or in various stages of
standardization, that can perform these fault mitigation tasks that standardization, that can perform these fault mitigation tasks that
deliver a high probability that misbehaving systems will have zero deliver a high probability that misbehaving systems will have zero
impact on well-behaved DetNet flows, except of course, for the impact on well-behaved DetNet flows, except of course, for the
receiving interface(s) immediately downstream of the misbehaving receiving interface(s) immediately downstream of the misbehaving
device. Examples of such techniques include traffic policing device. Examples of such techniques include traffic policing
functions (e.g. [RFC2475]) and separating flows into per-flow rate- functions (e.g., [RFC2475]) and separating flows into per-flow rate-
limited queues. limited queues.
4. DetNet Architecture 4. DetNet Architecture
4.1. DetNet stack model 4.1. DetNet stack model
DetNet functionality (Section 3) is implemented in two adjacent DetNet functionality (Section 3) is implemented in two adjacent sub-
layers in the protocol stack: the DetNet service layer and the DetNet layers in the protocol stack: the DetNet service sub-layer and the
transport layer. The DetNet service layer provides DetNet service, DetNet transport sub-layer. The DetNet service sub-layer provides
e.g., service protection, to higher layers in the protocol stack and DetNet service, e.g., service protection, to higher layers in the
applications. The DetNet transport layer supports DetNet service in protocol stack and applications. The DetNet transport sub-layer
the underlying network, e.g., by providing explicit routes and supports DetNet service in the underlying network, e.g., by providing
congestion protection to DetNet flows. explicit routes and congestion protection to DetNet flows.
4.1.1. Representative Protocol Stack Model 4.1.1. Representative Protocol Stack Model
Figure 2 illustrates a conceptual DetNet data plane layering model. Figure 2 illustrates a conceptual DetNet data plane layering model.
One may compare it to that in [IEEE802.1CB], Annex C. One may compare it to that in [IEEE802.1CB], Annex C.
| packets going | ^ packets coming ^ | packets going | ^ packets coming ^
v down the stack v | up the stack | v down the stack v | up the stack |
+----------------------+ +-----------------------+ +----------------------+ +-----------------------+
| Source | | Destination | | Source | | Destination |
+----------------------+ +-----------------------+ +----------------------+ +-----------------------+
| Service layer: | | Service layer: | | Service sub-layer: | | Service sub-layer: |
| Packet sequencing | | Duplicate elimination | | Packet sequencing | | Duplicate elimination |
| Flow replication | | Flow merging | | Flow replication | | Flow merging |
| Packet encoding | | Packet decoding | | Packet encoding | | Packet decoding |
+----------------------+ +-----------------------+ +----------------------+ +-----------------------+
| Transport layer: | | Transport layer: | | Transport sub-layer: | | Transport sub-layer: |
| Congestion prot. | | Congestion prot. | | Congestion prot. | | Congestion prot. |
| Explicit routes | | Explicit routes | | Explicit routes | | Explicit routes |
+----------------------+ +-----------------------+ +----------------------+ +-----------------------+
| Lower layers | | Lower layers | | Lower layers | | Lower layers |
+----------------------+ +-----------------------+ +----------------------+ +-----------------------+
v ^ v ^
\_________________________/ \_________________________/
Figure 2: DetNet data plane protocol stack Figure 2: DetNet data plane protocol stack
Not all layers are required for any given application, or even for Not all sub-layers are required for any given application, or even
any given network. The functionality shown in Figure 2 is: for any given network. The functionality shown in Figure 2 is:
Application Application
Shown as "source" and "destination" in the diagram. Shown as "source" and "destination" in the diagram.
Packet sequencing Packet sequencing
As part of DetNet service protection, supplies the sequence As part of DetNet service protection, supplies the sequence
number for packet replication and elimination number for packet replication and elimination
(Section 3.2.2). Peers with Duplicate elimination. This (Section 3.2.2). Peers with Duplicate elimination. This
layer is not needed if a higher-layer transport protocol is sub-layer is not needed if a Layer-4 transport protocol is
expected to perform any packet sequencing and duplicate expected to perform any packet sequencing and duplicate
elimination required by the DetNet flow replication. elimination required by the DetNet flow replication.
Duplicate elimination Duplicate elimination
As part of the DetNet service layer, based on the sequenced As part of the DetNet service sub-layer, based on the
number supplied by its peer, packet sequencing, Duplicate sequenced number supplied by its peer, packet sequencing,
elimination discards any duplicate packets generated by Duplicate elimination discards any duplicate packets
DetNet flow replication. It can operate on member flows, generated by DetNet flow replication. It can operate on
compound flows, or both. The replication may also be member flows, compound flows, or both. The replication may
inferred from other information such as the precise time of also be inferred from other information such as the precise
reception in a scheduled network. The duplicate elimination time of reception in a scheduled network. The duplicate
layer may also perform resequencing of packets to restore elimination sub-layer may also perform resequencing of
packet order in a flow that was disrupted by the loss of packets to restore packet order in a flow that was disrupted
packets on one or another of the multiple paths taken. by the loss of packets on one or another of the multiple
paths taken.
Flow replication Flow replication
As part of DetNet service protection, packets that belong to As part of DetNet service protection, packets that belong to
a DetNet compound flow are replicated into two or more DetNet a DetNet compound flow are replicated into two or more DetNet
member flows. This function is separate from packet member flows. This function is separate from packet
sequencing. Flow replication can be an explicit replication sequencing. Flow replication can be an explicit replication
and remarking of packets, or can be performed by, for and remarking of packets, or can be performed by, for
example, techniques similar to ordinary multicast example, techniques similar to ordinary multicast
replication, albeit with resource allocation implications. replication, albeit with resource allocation implications.
Peers with DetNet flow merging. Peers with DetNet flow merging.
skipping to change at page 18, line 11 skipping to change at page 18, line 40
Peers with Packet decoding. Peers with Packet decoding.
Packet decoding Packet decoding
As part of DetNet service protection, as an alternative to As part of DetNet service protection, as an alternative to
flow merging and duplicate elimination, packet decoding takes flow merging and duplicate elimination, packet decoding takes
packets from different DetNet member flows, and computes from packets from different DetNet member flows, and computes from
those packets the original DetNet packets from the compound those packets the original DetNet packets from the compound
flows input to packet encoding. Peers with Packet encoding. flows input to packet encoding. Peers with Packet encoding.
Congestion protection Congestion protection
The DetNet transport layer provides congestion protection. The DetNet transport sub-layer provides congestion
See Section 4.5. The actual queuing and shaping mechanisms protection. See Section 4.5. The actual queuing and shaping
are typically provided by underlying subnet layers, these can mechanisms are typically provided by underlying subnet, these
be closely associated with the means of providing paths for can be closely associated with the means of providing paths
DetNet flows, the path and the congestion protection are for DetNet flows, the path and the congestion protection are
conflated in this figure. conflated in this figure.
Explicit routes Explicit routes
The DetNet transport layer provides mechanisms to ensure that The DetNet transport sub-layer provides mechanisms to ensure
fixed paths are provided for DetNet flows. These explicit that fixed paths are provided for DetNet flows. These
paths avoid the impact of network convergence. explicit paths avoid the impact of network convergence.
Operations, Administration, and Maintenance (OAM) leverages in-band Operations, Administration, and Maintenance (OAM) leverages in-band
and out-of-band signaling that validates whether the service is and out-of-band signaling that validates whether the service is
effectively obtained within QoS constraints. OAM is not shown in effectively obtained within QoS constraints. OAM is not shown in
Figure 2; it may reside in any number of the layers. OAM can involve Figure 2; it may reside in any number of the layers. OAM can involve
specific tagging added in the packets for tracing implementation or specific tagging added in the packets for tracing implementation or
network configuration errors; traceability enables to find whether a network configuration errors; traceability enables to find whether a
packet is a replica, which relay node performed the replication, and packet is a replica, which DetNet relay node performed the
which segment was intended for the replica. Active and hybrid OAM replication, and which segment was intended for the replica. Active
methods require additional bandwidth to perform fault management and and hybrid OAM methods require additional bandwidth to perform fault
performance monitoring of the DetNet domain. OAM may, for instance, management and performance monitoring of the DetNet domain. OAM may,
generate special test probes or add OAM information into the data for instance, generate special test probes or add OAM information
packet. into the data packet.
The packet sequencing and replication elimination functions at the The packet sequencing and replication elimination functions at the
source and destination ends of a DetNet compound flow may be source and destination ends of a DetNet compound flow may be
performed either in the end system or in a DetNet relay node. performed either in the end system or in a DetNet relay node.
4.1.2. DetNet Data Plane Overview 4.1.2. DetNet Data Plane Overview
A "Deterministic Network" will be composed of DetNet enabled end A "Deterministic Network" will be composed of DetNet enabled end
systems and nodes, i.e., edge nodes, relay nodes and collectively systems, DetNet edge nodes, DetNet relay nodes and collectively
deliver DetNet services. DetNet enabled nodes are interconnected via deliver DetNet services. DetNet relay and edge nodes are
transit nodes (e.g., LSRs) which support DetNet, but are not DetNet interconnected via DetNet transit nodes (e.g., LSRs) which support
service aware. All DetNet enabled nodes are connected to sub- DetNet, but are not DetNet service aware. All DetNet nodes are
networks, where a point-to-point link is also considered as a simple connected to sub-networks, where a point-to-point link is also
sub-network. These sub-networks will provide DetNet compatible considered as a simple sub-network. These sub-networks will provide
service for support of DetNet traffic. Examples of sub-networks DetNet compatible service for support of DetNet traffic. Examples of
include MPLS TE, IEEE 802.1 TSN and OTN. Of course, multi-layer sub-networks include MPLS TE, IEEE 802.1 TSN and OTN. Of course,
DetNet systems may also be possible, where one DetNet appears as a multi-layer DetNet systems may also be possible, where one DetNet
sub-network, and provides service to, a higher layer DetNet system. appears as a sub-network, and provides service to, a higher layer
A simple DetNet concept network is shown in Figure 3. DetNet system. A simple DetNet concept network is shown in Figure 3.
Note that in this and following figures "Transport" and "Trp" refer
to the DetNet transport sub-layer, "Service" and "Svc" refer to the
DetNet service sub-layer, which are described in detail in
Section 4.1.
TSN Edge Transit Relay DetNet TSN Edge Transit Relay DetNet
End System Node Node Node End System End System Node Node Node End System
+---------+ +.........+ +---------+ +---------+ +.........+ +---------+
| Appl. |<--:Svc Proxy:-- End to End Service ---------->| Appl. | | Appl. |<--:Svc Proxy:-- End to End Service ---------->| Appl. |
+---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+
| TSN | |TSN| |Svc|<-- DetNet flow ---: Service :-->| Service | | TSN | |TSN| |Svc|<-- DetNet flow ---: Service :-->| Service |
+---------+ +---+ +---+ +---------+ +---------+ +---------+ +---------+ +---+ +---+ +---------+ +---------+ +---------+
|Transport| |Trp| |Trp| |Transport| |Trp| |Trp| |Transport| |Transport| |Trp| |Trp| |Transport| |Trp| |Trp| |Transport|
+-------.-+ +-.-+ +-.-+ +--.----.-+ +-.-+ +-.-+ +---.-----+ +-------.-+ +-.-+ +-.-+ +--.----.-+ +-.-+ +-.-+ +---.-----+
: Link : / ,-----. \ : Link : / ,-----. \ : Link : / ,-----. \ : Link : / ,-----. \
+.......+ +-[ Sub ]-+ +........+ +-[ Sub ]-+ +.......+ +-[ Sub ]-+ +........+ +-[ Sub ]-+
[Network] [Network] [Network] [Network]
`-----' `-----' `-----' `-----'
Figure 3: A Simple DetNet Enabled Network Figure 3: A Simple DetNet Enabled Network
Distinguishing the function of two DetNet data plane layers, the Distinguishing the function of two DetNet data plane sub-layers, the
DetNet service layer and the DetNet transport layer, helps to explore DetNet service sub-layer and the DetNet transport sub-layer, helps to
and evaluate various combinations of the data plane solutions explore and evaluate various combinations of the data plane solutions
available, some are illustrated in Figure 4. This separation of available, some are illustrated in Figure 4. This separation of
DetNet layers, while helpful, should not be considered as formal DetNet sub-layers, while helpful, should not be considered as formal
requirement. For example, some technologies may violate these strict requirement. For example, some technologies may violate these strict
layers and still be able to deliver a DetNet service. sub-layers and still be able to deliver a DetNet service.
. .
. .
+-----------+ +----------------------------+
| Service | PW, UDP, GRE | DetNet Service sub-layer | PW, UDP, GRE
+-----------+ +----------------------------+
| Transport | IPv6, IPv4, MPLS TE LSPs, MPLS SR | DetNet Transport sub-layer | IPv6, IPv4, MPLS TE LSPs, MPLS SR
+-----------+ +----------------------------+
. .
. .
Figure 4: DetNet adaptation to data plane Figure 4: DetNet adaptation to data plane
In some networking scenarios, the end system initially provides a In some networking scenarios, the end system initially provides a
DetNet flow encapsulation, which contains all information needed by DetNet flow encapsulation, which contains all information needed by
DetNet nodes (e.g., Real-time Transport Protocol (RTP) [RFC3550] DetNet nodes (e.g., Real-time Transport Protocol (RTP) [RFC3550]
based DetNet flow transported over a native UDP/IP network or based DetNet flow carried over a native UDP/IP network or
PseudoWire). In other scenarios, the encapsulation formats might PseudoWire). In other scenarios, the encapsulation formats might
differ significantly. differ significantly.
There are many valid options to create a data plane solution for There are many valid options to create a data plane solution for
DetNet traffic by selecting a technology approach for the DetNet DetNet traffic by selecting a technology approach for the DetNet
service layer and also selecting a technology approach for the DetNet service sub-layer and also selecting a technology approach for the
transport layer. There are a high number of valid combinations. DetNet transport sub-layer. There are a high number of valid
combinations.
One of the most fundamental differences between different potential One of the most fundamental differences between different potential
data plane options is the basic headers used by DetNet nodes. For data plane options is the basic headers used by DetNet nodes. For
example, the basic service can be delivered based on an MPLS label or example, the basic service can be delivered based on an MPLS label or
an IP header. This decision impacts the basic forwarding logic for an IP header. This decision impacts the basic forwarding logic for
the DetNet service layer. Note that in both cases, IP addresses are the DetNet service sub-layer. Note that in both cases, IP addresses
used to address DetNet nodes. The selected DetNet transport layer are used to address DetNet nodes. The selected DetNet transport sub-
technology also needs to be mapped to the sub-net technology used to layer technology also needs to be mapped to the sub-net technology
interconnect DetNet nodes. For example, DetNet flows will need to be used to interconnect DetNet nodes. For example, DetNet flows will
mapped to TSN Streams. need to be mapped to TSN Streams.
4.1.3. Network reference model 4.1.3. Network reference model
Figure 5 shows another view of the DetNet service related reference Figure 5 shows another view of the DetNet service related reference
points and main components. points and main components.
DetNet DetNet DetNet DetNet
end system end system end system end system
_ _ _ _
/ \ +----DetNet-UNI (U) / \ / \ +----DetNet-UNI (U) / \
skipping to change at page 22, line 18 skipping to change at page 22, line 33
The native data flow between the source/destination end systems is The native data flow between the source/destination end systems is
referred to as application-flow (App-flow). The traffic referred to as application-flow (App-flow). The traffic
characteristics of an App-flow can be CBR (constant bit rate) or VBR characteristics of an App-flow can be CBR (constant bit rate) or VBR
(variable bit rate) and can have L1 or L2 or L3 encapsulation (e.g., (variable bit rate) and can have L1 or L2 or L3 encapsulation (e.g.,
TDM (time-division multiplexing), Ethernet, IP). These TDM (time-division multiplexing), Ethernet, IP). These
characteristics are considered as input for resource reservation and characteristics are considered as input for resource reservation and
might be simplified to ensure determinism during transport (e.g., might be simplified to ensure determinism during transport (e.g.,
making reservations for the peak rate of VBR traffic, etc.). making reservations for the peak rate of VBR traffic, etc.).
An end system may or may not be DetNet transport layer aware or An end system may or may not be DetNet transport sub-layer aware or
DetNet service layer aware. That is, an end system may or may not DetNet service sub-layer aware. That is, an end system may or may
contain DetNet specific functionality. End systems with DetNet not contain DetNet specific functionality. End systems with DetNet
functionalities may have the same or different transport layer as the functionalities may have the same or different transport sub-layer as
connected DetNet domain. Categorization of end systems are shown in the connected DetNet domain. Categorization of end systems are shown
Figure 6. in Figure 6.
End system End system
| |
| |
| DetNet aware ? | DetNet aware ?
/ \ / \
+------< >------+ +------< >------+
NO | \ / | YES NO | \ / | YES
| v | | v |
DetNet unaware | DetNet unaware |
End system | End system |
| Service/ | Service/Transport
| Transport | sub-layer
/ \ aware ? / \ aware ?
+--------< >-------------+ +--------< >-------------+
t-aware | \ / | s-aware t-aware | \ / | s-aware
| v | | v |
| | both | | | both |
| | | | | |
DetNet t-aware | DetNet s-aware DetNet t-aware | DetNet s-aware
End system | End system End system | End system
v v
DetNet st-aware DetNet st-aware
End system End system
Figure 6: Categorization of end systems Figure 6: Categorization of end systems
Note some known use case examples for end systems: Note some known use case examples for end systems:
o DetNet unaware: The classic case requiring service proxies. o DetNet unaware: The classic case requiring service proxies.
o DetNet t-aware: A DetNet transport-aware system. It knows about o DetNet t-aware: A DetNet transport sub-layer aware system. It
some TSN functions (e.g., reservation), but not about service knows about some TSN functions (e.g., reservation), but not about
protection. service protection.
o DetNet s-aware: A DetNet service-aware system. It supplies o DetNet s-aware: A DetNet service sub-layer aware system. It
sequence numbers, but doesn't know about zero congestion loss. supplies sequence numbers, but doesn't know about zero congestion
loss.
o DetNet st-aware: A full functioning DetNet end system, it has o DetNet st-aware: A full functioning DetNet end system, it has
DetNet functionalities and usually the same forwarding paradigm as DetNet functionalities and usually the same forwarding paradigm as
the connected DetNet domain. It can be treated as an integral the connected DetNet domain. It can be treated as an integral
part of the DetNet domain. part of the DetNet domain.
4.2.2. DetNet edge, relay, and transit nodes 4.2.2. DetNet edge, relay, and transit nodes
As shown in Figure 3, DetNet edge nodes providing proxy service and As shown in Figure 3, DetNet edge nodes providing proxy service and
DetNet relay nodes providing the DetNet service layer are DetNet- DetNet relay nodes providing the DetNet service sub-layer are DetNet-
aware, and DetNet transit nodes need only be aware of the DetNet aware, and DetNet transit nodes need only be aware of the DetNet
transport layer. transport sub-layer.
In general, if a DetNet flow passes through one or more DetNet- In general, if a DetNet flow passes through one or more DetNet-
unaware network nodes between two DetNet nodes providing the DetNet unaware network nodes between two DetNet nodes providing the DetNet
transport layer for that flow, there is a potential for disruption or transport sub-layer for that flow, there is a potential for
failure of the DetNet QoS. A network administrator needs to ensure disruption or failure of the DetNet QoS. A network administrator
that the DetNet-unaware network nodes are configured to minimize the needs to ensure that the DetNet-unaware network nodes are configured
chances of packet loss and delay, and provision enough extra buffer to minimize the chances of packet loss and delay, and provision
space in the DetNet transit node following the DetNet-unaware network enough extra buffer space in the DetNet transit node following the
nodes to absorb the induced latency variations. DetNet-unaware network nodes to absorb the induced latency
variations.
4.3. DetNet flows 4.3. DetNet flows
4.3.1. DetNet flow types 4.3.1. DetNet flow types
A DetNet flow can have different formats while it is transported A DetNet flow can have different formats while it is transported
between the peer end systems. Therefore, the following possible between the peer end systems. Therefore, the following possible
types / formats of a DetNet flow are distinguished in this document: types / formats of a DetNet flow are distinguished in this document:
o App-flow: native format of the data carried over a DetNet flow. o App-flow: native format of the data carried over a DetNet flow.
It does not contain any DetNet related attributes. It does not contain any DetNet related attributes.
o DetNet-t-flow: specific format of a DetNet flow. Only requires o DetNet-t-flow: specific format of a DetNet flow. Only requires
the congestion / latency features provided by the DetNet transport the congestion / latency features provided by the DetNet transport
layer. sub-layer.
o DetNet-s-flow: specific format of a DetNet flow. Only requires o DetNet-s-flow: specific format of a DetNet flow. Only requires
the service protection feature ensured by the DetNet service the service protection feature ensured by the DetNet service sub-
layer. layer.
o DetNet-st-flow: specific format of a DetNet flow. It requires o DetNet-st-flow: specific format of a DetNet flow. It requires
both DetNet service layer and DetNet transport layer functions both DetNet service sub-layer and DetNet transport sub-layer
during forwarding. functions during forwarding.
4.3.2. Source transmission behavior 4.3.2. Source transmission behavior
For the purposes of congestion protection, DetNet flows can be For the purposes of congestion protection, DetNet flows can be
synchronous or asynchronous. In synchronous DetNet flows, at least synchronous or asynchronous. In synchronous DetNet flows, at least
the intermediate nodes (and possibly the end systems) are closely the DetNet nodes (and possibly the end systems) are closely time
time synchronized, typically to better than 1 microsecond. By synchronized, typically to better than 1 microsecond. By
transmitting packets from different DetNet flows or classes of DetNet transmitting packets from different DetNet flows or classes of DetNet
flows at different times, using repeating schedules synchronized flows at different times, using repeating schedules synchronized
among the intermediate nodes, resources such as buffers and link among the DetNet nodes, resources such as buffers and link bandwidth
bandwidth can be shared over the time domain among different DetNet can be shared over the time domain among different DetNet flows.
flows. There is a tradeoff among techniques for synchronous DetNet There is a tradeoff among techniques for synchronous DetNet flows
flows between the burden of fine-grained scheduling and the benefit between the burden of fine-grained scheduling and the benefit of
of reducing the required resources, especially buffer space. reducing the required resources, especially buffer space.
In contrast, asynchronous DetNet flows are not coordinated with a In contrast, asynchronous DetNet flows are not coordinated with a
fine-grained schedule, so relay and end systems must assume worst- fine-grained schedule, so relay and end systems must assume worst-
case interference among DetNet flows contending for buffer resources. case interference among DetNet flows contending for buffer resources.
Asynchronous DetNet flows are characterized by: Asynchronous DetNet flows are characterized by:
o A maximum packet size; o A maximum packet size;
o An observation interval; and o An observation interval; and
skipping to change at page 24, line 43 skipping to change at page 25, line 27
interval. interval.
These parameters, together with knowledge of the protocol stack used These parameters, together with knowledge of the protocol stack used
(and thus the size of the various headers added to a packet), limit (and thus the size of the various headers added to a packet), limit
the number of bit times per observation interval that the DetNet flow the number of bit times per observation interval that the DetNet flow
can occupy the physical medium. can occupy the physical medium.
The source is required not to exceed these limits in order to obtain The source is required not to exceed these limits in order to obtain
DetNet service. If the source transmits less data than this limit DetNet service. If the source transmits less data than this limit
allows, the unused resource such as link bandwidth can be made allows, the unused resource such as link bandwidth can be made
available by the system to non-DetNet packets. However, making those available by the DetNet system to non-DetNet packets as long as all
resources available to DetNet packets in other DetNet flows would guarantees are fulfilled. However, making those resources available
serve no purpose. Those other DetNet flows have their own dedicated to DetNet packets in other DetNet flows would serve no purpose.
resources, on the assumption that all DetNet flows can use all of Those other DetNet flows have their own dedicated resources, on the
their resources over a long period of time. assumption that all DetNet flows can use all of their resources over
a long period of time.
There is no provision in DetNet for throttling DetNet flows (reducing There is no provision in DetNet for throttling DetNet flows, i.e.,
end-to-end transmission rate via any explicit congestion the transmission rate cannot be reduced via explicit congestion
notification); the assumption is that a DetNet flow, to be useful, notification. The assumption is that a DetNet flow, to be useful,
must be delivered in its entirety. That is, while any useful must be delivered in its entirety. That is, while any useful
application is written to expect a certain number of lost packets, application is written to expect a certain number of lost packets,
the real-time applications of interest to DetNet demand that the loss the real-time applications of interest to DetNet demand that the loss
of data due to the network is an extraordinarily event. of data due to the network is a rare event.
Although DetNet strives to minimize the changes required of an Although DetNet strives to minimize the changes required of an
application to allow it to shift from a special-purpose digital application to allow it to shift from a special-purpose digital
network to an Internet Protocol network, one fundamental shift in the network to an Internet Protocol network, one fundamental shift in the
behavior of network applications is impossible to avoid: the behavior of network applications is impossible to avoid: the
reservation of resources before the application starts. In the first reservation of resources before the application starts. In the first
place, a network cannot deliver finite latency and practically zero place, a network cannot deliver finite latency and practically zero
packet loss to an arbitrarily high offered load. Secondly, achieving packet loss to an arbitrarily high offered load. Secondly, achieving
practically zero packet loss for unthrottled (though bandwidth practically zero packet loss for unthrottled (though bandwidth
limited) DetNet flows means that bridges and routers have to dedicate limited) DetNet flows means that DetNet nodes have to dedicate buffer
buffer resources to specific DetNet flows or to classes of DetNet resources to specific DetNet flows or to classes of DetNet flows.
flows. The requirements of each reservation have to be translated
into the parameters that control each system's queuing, shaping, and The requirements of each reservation have to be translated into the
scheduling functions and delivered to the hosts, bridges, and parameters that control each DetNet system's queuing, shaping, and
routers. scheduling functions and delivered to the DetNet nodes and end
systems.
4.3.3. Incomplete Networks 4.3.3. Incomplete Networks
The presence in the network of transit nodes or subnets that are not The presence in the network of intermediate nodes or subnets that are
fully capable of offering DetNet services complicates the ability of not fully capable of offering DetNet services complicates the ability
the intermediate nodes and/or controller to allocate resources, as of the intermediate nodes and/or controller to allocate resources, as
extra buffering must be allocated at points downstream from the non- extra buffering must be allocated at points downstream from the non-
DetNet intermediate node for a DetNet flow. This extra buffering may DetNet intermediate node for a DetNet flow. This extra buffering may
increase latency and/or jitter. increase latency and/or jitter.
4.4. Traffic Engineering for DetNet 4.4. Traffic Engineering for DetNet
Traffic Engineering Architecture and Signaling (TEAS) [TEAS] defines Traffic Engineering Architecture and Signaling (TEAS) [TEAS] defines
traffic-engineering architectures for generic applicability across traffic-engineering architectures for generic applicability across
packet and non-packet networks. From a TEAS perspective, Traffic packet and non-packet networks. From a TEAS perspective, Traffic
Engineering (TE) refers to techniques that enable operators to Engineering (TE) refers to techniques that enable operators to
skipping to change at page 26, line 20 skipping to change at page 26, line 52
operator and performs requests for Deterministic Networking services operator and performs requests for Deterministic Networking services
via an abstract Flow Management Entity, (FME) which may or may not be via an abstract Flow Management Entity, (FME) which may or may not be
collocated with (one of) the end systems. collocated with (one of) the end systems.
At the Application Plane, a management interface enables the At the Application Plane, a management interface enables the
negotiation of flows between end systems. An abstraction of the flow negotiation of flows between end systems. An abstraction of the flow
called a Traffic Specification (TSpec) provides the representation. called a Traffic Specification (TSpec) provides the representation.
This abstraction is used to place a reservation over the (Northbound) This abstraction is used to place a reservation over the (Northbound)
Service Interface and within the Application plane. It is associated Service Interface and within the Application plane. It is associated
with an abstraction of location, such as IP addresses and DNS names, with an abstraction of location, such as IP addresses and DNS names,
to identify the end systems and eventually specify intermediate to identify the end systems and possibly specify DetNet nodes.
nodes.
4.4.2. The Controller Plane 4.4.2. The Controller Plane
The Controller Plane corresponds to the aggregation of the Control The Controller Plane corresponds to the aggregation of the Control
and Management Planes in [RFC7426], though Common Control and and Management Planes in [RFC7426], though Common Control and
Measurement Plane (CCAMP) [CCAMP] makes an additional distinction Measurement Plane (CCAMP) [CCAMP] makes an additional distinction
between management and measurement. When the logical separation of between management and measurement. When the logical separation of
the Control, Measurement and other Management entities is not the Control, Measurement and other Management entities is not
relevant, the term Controller Plane is used for simplicity to relevant, the term Controller Plane is used for simplicity to
represent them all, and the term Controller Plane Function (CPF) represent them all, and the term Controller Plane Function (CPF)
skipping to change at page 26, line 43 skipping to change at page 27, line 25
Computation Element (PCE) [RFC4655], or a Network Management entity Computation Element (PCE) [RFC4655], or a Network Management entity
(NME), or a distributed control plane. The CPF is a core element of (NME), or a distributed control plane. The CPF is a core element of
a controller, in charge of computing Deterministic paths to be a controller, in charge of computing Deterministic paths to be
applied in the Network Plane. applied in the Network Plane.
A (Northbound) Service Interface enables applications in the A (Northbound) Service Interface enables applications in the
Application Plane to communicate with the entities in the Controller Application Plane to communicate with the entities in the Controller
Plane as illustrated in Figure 7. Plane as illustrated in Figure 7.
One or more CPF(s) collaborate to implement the requests from the FME One or more CPF(s) collaborate to implement the requests from the FME
as Per-Flow Per-Hop Behaviors installed in the intermediate nodes for as Per-Flow Per-Hop Behaviors installed in the DetNet nodes for each
each individual flow. The CPFs place each flow along a deterministic individual flow. The CPFs place each flow along a deterministic
sequence of intermediate nodes so as to respect per-flow constraints sequence of DetNet nodes so as to respect per-flow constraints such
such as security and latency, and optimize the overall result for as security and latency, and optimize the overall result for metrics
metrics such as an abstract aggregated cost. The deterministic such as an abstract aggregated cost. The deterministic sequence can
sequence can typically be more complex than a direct sequence and typically be more complex than a direct sequence and include
include redundancy path, with one or more packet replication and redundancy path, with one or more packet replication and elimination
elimination points. points. Scaling to larger networks is discussed in Section 4.9.
4.4.3. The Network Plane 4.4.3. The Network Plane
The Network Plane represents the network devices and protocols as a The Network Plane represents the network devices and protocols as a
whole, regardless of the Layer at which the network devices operate. whole, regardless of the Layer at which the network devices operate.
It includes Forwarding Plane (data plane), Application, and It includes Forwarding Plane (data plane), Application, and
Operational Plane (e.g., OAM) aspects. Operational Plane (e.g., OAM) aspects.
The network Plane comprises the Network Interface Cards (NIC) in the The network Plane comprises the Network Interface Cards (NIC) in the
end systems, which are typically IP hosts, and intermediate nodes, end systems, which are typically IP hosts, and DetNet nodes, which
which are typically IP routers and switches. Network-to-Network are typically IP routers and MPLS switches. Network-to-Network
Interfaces such as used for Traffic Engineering path reservation in Interfaces such as used for Traffic Engineering path reservation in
[RFC5921], as well as User-to-Network Interfaces (UNI) such as [RFC5921], as well as User-to-Network Interfaces (UNI) such as
provided by the Local Management Interface (LMI) between network and provided by the Local Management Interface (LMI) between network and
end systems, are both part of the Network Plane, both in the control end systems, are both part of the Network Plane, both in the control
plane and the data plane. plane and the data plane.
A Southbound (Network) Interface enables the entities in the A Southbound (Network) Interface enables the entities in the
Controller Plane to communicate with devices in the Network Plane as Controller Plane to communicate with devices in the Network Plane as
illustrated in Figure 7. This interface leverages and extends TEAS illustrated in Figure 7. This interface leverages and extends TEAS
to describe the physical topology and resources in the Network Plane. to describe the physical topology and resources in the Network Plane.
End End End End
System System System System
-+-+-+-+-+-+-+ Northbound -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- -+-+-+-+-+-+-+ Northbound -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
CPF CPF CPF CPF CPF CPF CPF CPF
-+-+-+-+-+-+-+ Southbound -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- -+-+-+-+-+-+-+ Southbound -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
intermediate intermed. intermed. intermed. DetNet DetNet DetNet DetNet
Node Node Node Node Node Node Node Node
NIC NIC NIC NIC
intermediate intermed. intermed. intermed. DetNet DetNet DetNet DetNet
Node Node Node Node Node Node Node Node
Figure 7: Northbound and Southbound interfaces Figure 7: Northbound and Southbound interfaces
The intermediate nodes (and eventually the end systems NIC) expose The DetNet nodes (and possibly the end systems NIC) expose their
their capabilities and physical resources to the controller (the capabilities and physical resources to the controller (the CPF), and
CPF), and update the CPFs with their dynamic perception of the update the CPFs with their dynamic perception of the topology, across
topology, across the Southbound Interface. In return, the CPFs set the Southbound Interface. In return, the CPFs set the per-flow paths
the per-flow paths up, providing a Flow Characterization that is more up, providing a Flow Characterization that is more tightly coupled to
tightly coupled to the intermediate node Operation than a TSpec. the DetNet node Operation than a TSpec.
At the Network plane, intermediate nodes may exchange information At the Network plane, DetNet nodes may exchange information regarding
regarding the state of the paths, between adjacent systems and the state of the paths, between adjacent DetNet nodes and possibly
eventually with the end systems, and forward packets within with the end systems, and forward packets within constraints
constraints associated to each flow, or, when unable to do so, associated to each flow, or, when unable to do so, perform a last
perform a last resort operation such as drop or declassify. resort operation such as drop or declassify.
This document focuses on the Southbound interface and the operation This document focuses on the Southbound interface and the operation
of the Network Plane. of the Network Plane.
4.5. Queuing, Shaping, Scheduling, and Preemption 4.5. Queuing, Shaping, Scheduling, and Preemption
DetNet achieves congestion protection and bounded delivery latency by DetNet achieves congestion protection and bounded delivery latency by
reserving bandwidth and buffer resources at every hop along the path reserving bandwidth and buffer resources at each DetNet node along
of the DetNet flow. The reservation itself is not sufficient, the path of the DetNet flow. The reservation itself is not
however. Implementors and users of a number of proprietary and sufficient, however. Implementors and users of a number of
standard real-time networks have found that standards for specific proprietary and standard real-time networks have found that standards
data plane techniques are required to enable these assurances to be for specific data plane techniques are required to enable these
made in a multi-vendor network. The fundamental reason is that assurances to be made in a multi-vendor network. The fundamental
latency variation in one system results in the need for extra buffer reason is that latency variation in one DetNet system results in the
space in the next-hop system(s), which in turn, increases the worst- need for extra buffer space in the next-hop DetNet system(s), which
case per-hop latency. in turn, increases the worst-case per-hop latency.
Standard queuing and transmission selection algorithms allow a Standard queuing and transmission selection algorithms allow traffic
central controller to compute the latency contribution of each engineering Section 4.4 to compute the latency contribution of each
transit node to the end-to-end latency, to compute the amount of DetNet node to the end-to-end latency, to compute the amount of
buffer space required in each transit node for each incremental buffer space required in each DetNet node for each incremental DetNet
DetNet flow, and most importantly, to translate from a flow flow, and most importantly, to translate from a flow specification to
specification to a set of values for the managed objects that control a set of values for the managed objects that control each relay or
each relay or end system. For example, the IEEE 802.1 WG has end system. For example, the IEEE 802.1 WG has specified (and is
specified (and is specifying) a set of queuing, shaping, and specifying) a set of queuing, shaping, and scheduling algorithms that
scheduling algorithms that enable each transit node (bridge or enable each DetNet node, and/or a central controller, to compute
router), and/or a central controller, to compute these values. These these values. These algorithms include:
algorithms include:
o A credit-based shaper [IEEE802.1Qav] (superseded by o A credit-based shaper [IEEE802.1Qav] (superseded by
[IEEE802.1Q-2018]). [IEEE802.1Q-2018]).
o Time-gated queues governed by a rotating time schedule, o Time-gated queues governed by a rotating time schedule based on
synchronized among all transit nodes [IEEE802.1Qbv] (superseded by synchronized time [IEEE802.1Qbv] (superseded by
[IEEE802.1Q-2018]). [IEEE802.1Q-2018]).
o Synchronized double (or triple) buffers driven by synchronized o Synchronized double (or triple) buffers driven by synchronized
time ticks. [IEEE802.1Qch] (superseded by [IEEE802.1Q-2018]). time ticks. [IEEE802.1Qch] (superseded by [IEEE802.1Q-2018]).
o Pre-emption of an Ethernet packet in transmission by a packet with o Pre-emption of an Ethernet packet in transmission by a packet with
a more stringent latency requirement, followed by the resumption a more stringent latency requirement, followed by the resumption
of the preempted packet [IEEE802.1Qbu] (superseded by of the preempted packet [IEEE802.1Qbu] (superseded by
[IEEE802.1Q-2018]), [IEEE802.3br] (superseded by [IEEE802.1Q-2018]), [IEEE802.3br] (superseded by
[IEEE802.3-2018]). [IEEE802.3-2018]).
skipping to change at page 29, line 16 skipping to change at page 29, line 43
[IEEE802.3-2018] and bridging standards, we can note that they are [IEEE802.3-2018] and bridging standards, we can note that they are
all, except perhaps for packet preemption, equally applicable to all, except perhaps for packet preemption, equally applicable to
other media than Ethernet, and to routers as well as bridges. Other other media than Ethernet, and to routers as well as bridges. Other
media may have its own methods, see, e.g., media may have its own methods, see, e.g.,
[I-D.ietf-6tisch-architecture], [RFC7554]. DetNet may include such [I-D.ietf-6tisch-architecture], [RFC7554]. DetNet may include such
definitions in the future, or may define how these techniques can be definitions in the future, or may define how these techniques can be
used by DetNet nodes. used by DetNet nodes.
4.6. Service instance 4.6. Service instance
A Service instance represents all the functions required on a node to A Service instance represents all the functions required on a DetNet
allow the end-to-end service between the UNIs. node to allow the end-to-end service between the UNIs.
The DetNet network general reference model is shown in Figure 8 for a The DetNet network general reference model is shown in Figure 8 for a
DetNet service scenario (i.e., between two DetNet-UNIs). In this DetNet service scenario (i.e., between two DetNet-UNIs). In this
figure, end systems ("A" and "B") are connected directly to the edge figure, end systems ("A" and "B") are connected directly to the edge
nodes of an IP/MPLS network ("PE1" and "PE2"). End systems nodes of an IP/MPLS network ("PE1" and "PE2"). End systems
participating in DetNet communication may require connectivity before participating in DetNet communication may require connectivity before
setting up an App-flow that requires the DetNet service. Such a setting up an App-flow that requires the DetNet service. Such a
connectivity related service instance and the one dedicated for connectivity related service instance and the one dedicated for
DetNet service share the same access. Packets belonging to a DetNet DetNet service share the same access. Packets belonging to a DetNet
flow are selected by a filter configured on the access ("F1" and flow are selected by a filter configured on the access ("F1" and
"F2"). As a result, data flow specific access ("access-A + F1" and "F2"). As a result, data flow specific access ("access-A + F1" and
"access-B + F2") are terminated in the flow specific service instance "access-B + F2") are terminated in the flow specific service instance
("SI-1" and "SI-2"). A tunnel is used to provide connectivity ("SI-1" and "SI-2"). A tunnel is used to provide connectivity
between the service instances. between the service instances.
The tunnel is used to transport exclusively the packets of the DetNet The tunnel is exclusively used for the packets of the DetNet flow
flow between "SI-1" and "SI-2". The service instances are configured between "SI-1" and "SI-2". The service instances are configured to
to implement DetNet functions and a flow specific DetNet transport. implement DetNet functions and a flow specific DetNet forwarding.
The service instance and the tunnel may or may not be shared by The service instance and the tunnel may or may not be shared by
multiple DetNet flows. Sharing the service instance by multiple multiple DetNet flows. Sharing the service instance by multiple
DetNet flows requires properly populated forwarding tables of the DetNet flows requires properly populated forwarding tables of the
service instance. service instance.
access-A access-B access-A access-B
<-----> <-------- tunnel ----------> <-----> <-----> <-------- tunnel ----------> <----->
+---------+ ___ _ +---------+ +---------+ ___ _ +---------+
End system | +----+ | / \/ \_ | +----+ | End system End system | +----+ | / \/ \_ | +----+ | End system
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carrying only non-DetNet flows. If a DetNet flow to that same carrying only non-DetNet flows. If a DetNet flow to that same
address is requested, a separate LSP may be needed, in order that address is requested, a separate LSP may be needed, in order that
all of the Label Switch Routers (LSRs) along the path to the all of the Label Switch Routers (LSRs) along the path to the
destination give that flow special queuing and shaping. destination give that flow special queuing and shaping.
The need for a lower-layer node to be aware of individual higher- The need for a lower-layer node to be aware of individual higher-
layer flows is not unique to DetNet. But, given the endless layer flows is not unique to DetNet. But, given the endless
complexity of layering and relayering over tunnels that is available complexity of layering and relayering over tunnels that is available
to network designers, DetNet needs to provide a model for flow to network designers, DetNet needs to provide a model for flow
identification that is better than packet inspection. That is not to identification that is better than packet inspection. That is not to
say that packet inspection to layer 4 or 5 addresses will not be say that packet inspection to Layer-4 or Layer-5 addresses will not
used, or the capability standardized; but, there are alternatives. be used, or the capability standardized; but, there are alternatives.
A DetNet relay node can connect DetNet flows on different paths using A DetNet relay node can connect DetNet flows on different paths using
different flow identification methods. For example: different flow identification methods. For example:
o A single unicast DetNet flow passing from router A through a o A single unicast DetNet flow passing from router A through a
bridged network to router B may be assigned a TSN Stream bridged network to router B may be assigned a TSN Stream
identifier that is unique within that bridged network. The identifier that is unique within that bridged network. The
bridges can then identify the flow without accessing higher-layer bridges can then identify the flow without accessing higher-layer
headers. Of course, the receiving router must recognize and headers. Of course, the receiving router must recognize and
accept that TSN Stream. accept that TSN Stream.
skipping to change at page 32, line 10 skipping to change at page 32, line 25
Thus, rather than packet inspection, there is the option to export Thus, rather than packet inspection, there is the option to export
higher-layer information to the lower layer. The requirement to higher-layer information to the lower layer. The requirement to
support one or the other method for flow identification (or both) is support one or the other method for flow identification (or both) is
a complexity that is part of DetNet control models. a complexity that is part of DetNet control models.
4.7.2. Flow attribute mapping between layers 4.7.2. Flow attribute mapping between layers
Transport of DetNet flows over multiple technology domains may Transport of DetNet flows over multiple technology domains may
require that lower layers are aware of specific flows of higher require that lower layers are aware of specific flows of higher
layers. Such an "exporting of flow identification" is needed each layers. Such an "exporting of flow identification" is needed each
time when the forwarding paradigm is changed on the transport path time when the forwarding paradigm is changed on the forwarding path
(e.g., two LSRs are interconnected by a L2 bridged domain, etc.). (e.g., two LSRs are interconnected by a L2 bridged domain, etc.).
The three representative forwarding methods considered for The three representative forwarding methods considered for
deterministic networking are: deterministic networking are:
o IP routing o IP routing
o MPLS label switching o MPLS label switching
o Ethernet bridging o Ethernet bridging
skipping to change at page 33, line 43 skipping to change at page 34, line 33
|ETH-ID| |ETH-ID|
+======+ +======+
Ethernet domain Ethernet domain
<----------------> <---------------->
Figure 10: IP nodes interconnected by an Ethernet domain Figure 10: IP nodes interconnected by an Ethernet domain
End system "IP-A" uses the original App-flow specific ID ("L3-ID"), End system "IP-A" uses the original App-flow specific ID ("L3-ID"),
but as it is connected to an Ethernet domain it has to push an but as it is connected to an Ethernet domain it has to push an
Ethernet-domain specific flow-ID ("VID + multicast MAC address", Ethernet-domain specific flow-ID ("ETH-ID") before sending the packet
referred as "ETH-ID") before sending the packet to "ETH-1" node. to "ETH-1" node. Ethernet switch "ETH-1" can recognize the data flow
Ethernet switch "ETH-1" can recognize the data flow based on the based on the "ETH-ID" and it does forwarding toward "ETH-2". "ETH-2"
"ETH-ID" and it does forwarding toward "ETH-2". "ETH-2" switches the switches the packet toward the IP router. "IP-1" must be configured
packet toward the IP router. "IP-1" must be configured to receive to receive the Ethernet Flow-ID specific multicast flow, but (as it
the Ethernet Flow-ID specific multicast flow, but (as it is an L3 is an L3 node) it decodes the data flow ID based on the "L3-ID"
node) it decodes the data flow ID based on the "L3-ID" fields of the fields of the received packet.
received packet.
Figure 11 shows a scenario where MPLS domain nodes ("PE-n" and "P-m") Figure 11 shows a scenario where MPLS domain nodes ("PE-n" and "P-m")
are connected via two Ethernet switches ("ETH-n"). are connected via two Ethernet switches ("ETH-n").
MPLS domain MPLS domain
<-----------------------------------------------> <----------------------------------------------->
+=======+ +=======+ +=======+ +=======+
|MPLS-ID| |MPLS-ID| |MPLS-ID| |MPLS-ID|
+=======+ +-----+ +-----+ +=======+ +-----+ +=======+ +-----+ +-----+ +=======+ +-----+
skipping to change at page 34, line 36 skipping to change at page 35, line 33
+=======+ +=======+
|ETH-ID | |ETH-ID |
+=======+ +=======+
Ethernet domain Ethernet domain
<----------------> <---------------->
Figure 11: MPLS nodes interconnected by an Ethernet domain Figure 11: MPLS nodes interconnected by an Ethernet domain
"PE-1" uses the MPLS specific ID ("MPLS-ID"), but as it is connected "PE-1" uses the MPLS specific ID ("MPLS-ID"), but as it is connected
to an Ethernet domain it has to push an Ethernet-domain specific to an Ethernet domain it has to push an Ethernet-domain specific
flow-ID ("VID + multicast MAC address", referred as "ETH-ID") before flow-ID ("ETH-ID") before sending the packet to "ETH-1". Ethernet
sending the packet to "ETH-1". Ethernet switch "ETH-1" can recognize switch "ETH-1" can recognize the data flow based on the "ETH-ID" and
the data flow based on the "ETH-ID" and it does forwarding toward it does forwarding toward "ETH-2". "ETH-2" switches the packet
"ETH-2". "ETH-2" switches the packet toward the MPLS node ("P-2"). toward the MPLS node ("P-2"). "P-2" must be configured to receive
"P-2" must be configured to receive the Ethernet Flow-ID specific the Ethernet Flow-ID specific multicast flow, but (as it is an MPLS
multicast flow, but (as it is an MPLS node) it decodes the data flow node) it decodes the data flow ID based on the "MPLS-ID" fields of
ID based on the "MPLS-ID" fields of the received packet. the received packet.
One can appreciate from the above example that, when the means used One can appreciate from the above example that, when the means used
for DetNet flow identification is altered or exported, the means for for DetNet flow identification is altered or exported, the means for
encoding the sequence number information must similarly be altered or encoding the sequence number information must similarly be altered or
exported. exported.
4.8. Advertising resources, capabilities and adjacencies 4.8. Advertising resources, capabilities and adjacencies
There are three classes of information that a central controller or Provisioning of DetNet requires knowledge about:
distributed control plane needs to know that can only be obtained
from the end systems and/or nodes in the network. When using a peer-
to-peer control plane, some of this information may be required by a
system's neighbors in the network.
o Details of the system's capabilities that are required in order to o Details of the DetNet system's capabilities that are required in
accurately allocate that system's resources, as well as other order to accurately allocate that DetNet system's resources, as
systems' resources. This includes, for example, which specific well as other DetNet systems' resources. This includes, for
queuing and shaping algorithms are implemented (Section 4.5), the example, which specific queuing and shaping algorithms are
number of buffers dedicated for DetNet allocation, and the worst- implemented (Section 4.5), the number of buffers dedicated for
case forwarding delay and misordering. DetNet allocation, and the worst-case forwarding delay and
misordering.
o The dynamic state of a node's DetNet resources. o The dynamic state of a DetNet node's DetNet resources.
o The identity of the system's neighbors, and the characteristics of o The identity of the DetNet system's neighbors, and the
the link(s) between the systems, including the length (in characteristics of the link(s) between the DetNet systems,
nanoseconds) of the link(s). including the latency of the links (in nanoseconds).
4.9. Scaling to larger networks 4.9. Scaling to larger networks
Reservations for individual DetNet flows require considerable state Reservations for individual DetNet flows require considerable state
information in each transit node, especially when adequate fault information in each DetNet node, especially when adequate fault
mitigation (Section 3.3.2) is required. The DetNet data plane, in mitigation (Section 3.3.2) is required. The DetNet data plane, in
order to support larger numbers of DetNet flows, must support the order to support larger numbers of DetNet flows, must support the
aggregation of DetNet flows. Such aggregated flows can be viewed by aggregation of DetNet flows. Such aggregated flows can be viewed by
the transit nodes' data plane largely as individual DetNet flows. the DetNet nodes' data plane largely as individual DetNet flows.
Without such aggregation, the per-relay system may limit the scale of Without such aggregation, the per-relay system may limit the scale of
DetNet networks. Example techniques that may be used include MPLS DetNet networks. Example techniques that may be used include MPLS
hierarchy and IP DiffServ Code Points (DSCPs). hierarchy and IP DiffServ Code Points (DSCPs).
4.10. Compatibility with Layer-2 4.10. Compatibility with Layer-2
Standards providing similar capabilities for bridged networks (only) Standards providing similar capabilities for bridged networks (only)
have been and are being generated in the IEEE 802 LAN/MAN Standards have been and are being generated in the IEEE 802 LAN/MAN Standards
Committee. The present architecture describes an abstract model that Committee. The present architecture describes an abstract model that
can be applicable both at Layer-2 and Layer-3, and over links not can be applicable both at Layer-2 and Layer-3, and over links not
defined by IEEE 802. defined by IEEE 802.
DetNet enabled end systems and intermediate nodes can be DetNet enabled end systems and DetNet nodes can be interconnected by
interconnected by sub-networks, i.e., Layer-2 technologies. These sub-networks, i.e., Layer-2 technologies. These sub-networks will
sub-networks will provide DetNet compatible service for support of provide DetNet compatible service for support of DetNet traffic.
DetNet traffic. Examples of sub-networks include MPLS TE, 802.1 TSN, Examples of sub-networks include MPLS TE, 802.1 TSN, and a point-to-
and a point-to-point OTN link. Of course, multi-layer DetNet systems point OTN link. Of course, multi-layer DetNet systems may be
may be possible too, where one DetNet appears as a sub-network, and possible too, where one DetNet appears as a sub-network, and provides
provides service to, a higher layer DetNet system. service to, a higher layer DetNet system.
5. Security Considerations 5. Security Considerations
Security in the context of Deterministic Networking has an added Security in the context of Deterministic Networking has an added
dimension; the time of delivery of a packet can be just as important dimension; the time of delivery of a packet can be just as important
as the contents of the packet, itself. A man-in-the-middle attack, as the contents of the packet, itself. A man-in-the-middle attack,
for example, can impose, and then systematically adjust, additional for example, can impose, and then systematically adjust, additional
delays into a link, and thus disrupt or subvert a real-time delays into a link, and thus disrupt or subvert a real-time
application without having to crack any encryption methods employed. application without having to crack any encryption methods employed.
See [RFC7384] for an exploration of this issue in a related context. See [RFC7384] for an exploration of this issue in a related context.
skipping to change at page 36, line 33 skipping to change at page 37, line 23
accidental or intentional. See also Section 3.3.2. accidental or intentional. See also Section 3.3.2.
Security must cover: Security must cover:
o the protection of the signaling protocol o the protection of the signaling protocol
o the authentication and authorization of the controlling systems o the authentication and authorization of the controlling systems
o the identification and shaping of the DetNet flows o the identification and shaping of the DetNet flows
Security considerations for DetNet are described in detail in
[I-D.ietf-detnet-security].
6. Privacy Considerations 6. Privacy Considerations
DetNet is provides a Quality of Service (QoS), and as such, does not DetNet is provides a Quality of Service (QoS), and as such, does not
directly raise any new privacy considerations. directly raise any new privacy considerations.
However, the requirement for every (or almost every) node along the However, the requirement for every (or almost every) node along the
path of a DetNet flow to identify DetNet flows may present an path of a DetNet flow to identify DetNet flows may present an
additional attack surface for privacy, should the DetNet paradigm be additional attack surface for privacy, should the DetNet paradigm be
found useful in broader environments. found useful in broader environments.
skipping to change at page 37, line 15 skipping to change at page 38, line 13
various contribution with this work. various contribution with this work.
9. Informative References 9. Informative References
[CCAMP] IETF, "Common Control and Measurement Plane Working [CCAMP] IETF, "Common Control and Measurement Plane Working
Group", Group",
<https://datatracker.ietf.org/doc/charter-ietf-ccamp/>. <https://datatracker.ietf.org/doc/charter-ietf-ccamp/>.
[I-D.ietf-6tisch-architecture] [I-D.ietf-6tisch-architecture]
Thubert, P., "An Architecture for IPv6 over the TSCH mode Thubert, P., "An Architecture for IPv6 over the TSCH mode
of IEEE 802.15.4", draft-ietf-6tisch-architecture-14 (work of IEEE 802.15.4", draft-ietf-6tisch-architecture-15 (work
in progress), April 2018. in progress), October 2018.
[I-D.ietf-detnet-dp-sol-ip] [I-D.ietf-detnet-dp-sol-ip]
Korhonen, J. and B. Varga, "DetNet IP Data Plane Korhonen, J. and B. Varga, "DetNet IP Data Plane
Encapsulation", draft-ietf-detnet-dp-sol-ip-00 (work in Encapsulation", draft-ietf-detnet-dp-sol-ip-01 (work in
progress), July 2018. progress), October 2018.
[I-D.ietf-detnet-dp-sol-mpls] [I-D.ietf-detnet-dp-sol-mpls]
Korhonen, J. and B. Varga, "DetNet MPLS Data Plane Korhonen, J. and B. Varga, "DetNet MPLS Data Plane
Encapsulation", draft-ietf-detnet-dp-sol-mpls-00 (work in Encapsulation", draft-ietf-detnet-dp-sol-mpls-01 (work in
progress), July 2018. progress), October 2018.
[I-D.ietf-detnet-problem-statement] [I-D.ietf-detnet-problem-statement]
Finn, N. and P. Thubert, "Deterministic Networking Problem Finn, N. and P. Thubert, "Deterministic Networking Problem
Statement", draft-ietf-detnet-problem-statement-06 (work Statement", draft-ietf-detnet-problem-statement-07 (work
in progress), July 2018. in progress), October 2018.
[I-D.ietf-detnet-security]
Mizrahi, T., Grossman, E., Hacker, A., Das, S., Dowdell,
J., Austad, H., Stanton, K., and N. Finn, "Deterministic
Networking (DetNet) Security Considerations", draft-ietf-
detnet-security-03 (work in progress), October 2018.
[I-D.ietf-detnet-use-cases] [I-D.ietf-detnet-use-cases]
Grossman, E., "Deterministic Networking Use Cases", draft- Grossman, E., "Deterministic Networking Use Cases", draft-
ietf-detnet-use-cases-17 (work in progress), June 2018. ietf-detnet-use-cases-19 (work in progress), October 2018.
[IEC62439-3-2016] [IEC62439-3-2016]
International Electrotechnical Commission (IEC) TC 65/SC International Electrotechnical Commission (IEC) TC 65/SC
65C - Industrial networks, "IEC 62439-3:2016 Industrial 65C - Industrial networks, "IEC 62439-3:2016 Industrial
communication networks - High availability automation communication networks - High availability automation
networks - Part 3: Parallel Redundancy Protocol (PRP) and networks - Part 3: Parallel Redundancy Protocol (PRP) and
High-availability Seamless Redundancy (HSR)", 2016, High-availability Seamless Redundancy (HSR)", 2016,
<https://webstore.iec.ch/publication/24447>. <https://webstore.iec.ch/publication/24447>.
[IEEE802.1BA] [IEEE802.1BA]
skipping to change at page 38, line 13 skipping to change at page 39, line 13
<https://ieeexplore.ieee.org/document/6032690/>. <https://ieeexplore.ieee.org/document/6032690/>.
[IEEE802.1CB] [IEEE802.1CB]
IEEE Standards Association, "IEEE Std 802.1CB-2017 Frame IEEE Standards Association, "IEEE Std 802.1CB-2017 Frame
Replication and Elimination for Reliability", 2017, Replication and Elimination for Reliability", 2017,
<https://ieeexplore.ieee.org/document/8091139/>. <https://ieeexplore.ieee.org/document/8091139/>.
[IEEE802.1Q-2018] [IEEE802.1Q-2018]
IEEE Standards Association, "IEEE Std 802.1Q-2018 Bridges IEEE Standards Association, "IEEE Std 802.1Q-2018 Bridges
and Bridged Networks", 2018, and Bridged Networks", 2018,
<https://standards.ieee.org/findstds/ <https://ieeexplore.ieee.org/document/8403927>.
standard/802.1Q-2018.html>.
[IEEE802.1Qav] [IEEE802.1Qav]
IEEE Standards Association, "IEEE Std 802.1Qav-2009 IEEE Standards Association, "IEEE Std 802.1Qav-2009
Bridges and Bridged Networks - Amendment 12: Forwarding Bridges and Bridged Networks - Amendment 12: Forwarding
and Queuing Enhancements for Time-Sensitive Streams", and Queuing Enhancements for Time-Sensitive Streams",
2009, <https://ieeexplore.ieee.org/document/5375704/>. 2009, <https://ieeexplore.ieee.org/document/5375704/>.
[IEEE802.1Qbu] [IEEE802.1Qbu]
IEEE Standards Association, "IEEE Std 802.1Qbu-2016 IEEE Standards Association, "IEEE Std 802.1Qbu-2016
Bridges and Bridged Networks - Amendment 26: Frame Bridges and Bridged Networks - Amendment 26: Frame
skipping to change at page 38, line 47 skipping to change at page 39, line 46
Queuing and Forwarding", 2017, Queuing and Forwarding", 2017,
<https://ieeexplore.ieee.org/document/7961303/>. <https://ieeexplore.ieee.org/document/7961303/>.
[IEEE802.1TSNTG] [IEEE802.1TSNTG]
IEEE Standards Association, "IEEE 802.1 Time-Sensitive IEEE Standards Association, "IEEE 802.1 Time-Sensitive
Networking Task Group", 2013, Networking Task Group", 2013,
<http://www.ieee802.org/1/tsn>. <http://www.ieee802.org/1/tsn>.
[IEEE802.3-2018] [IEEE802.3-2018]
IEEE Standards Association, "IEEE Std 802.3-2018 Standard IEEE Standards Association, "IEEE Std 802.3-2018 Standard
for Ethernet", 2018, <http://standards.ieee.org/findstds/ for Ethernet", 2018,
standard/802.3-2018.html>. <https://ieeexplore.ieee.org/document/8457469>.
[IEEE802.3br] [IEEE802.3br]
IEEE Standards Association, "IEEE Std 802.3br-2016 IEEE Standards Association, "IEEE Std 802.3br-2016
Standard for Ethernet Amendment 5: Specification and Standard for Ethernet Amendment 5: Specification and
Management Parameters for Interspersing Express Traffic", Management Parameters for Interspersing Express Traffic",
2016, <http://ieeexplore.ieee.org/document/7900321/>. 2016, <http://ieeexplore.ieee.org/document/7900321/>.
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, DOI 10.17487/RFC2205, Functional Specification", RFC 2205, DOI 10.17487/RFC2205,
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