< draft-ietf-raw-technologies-02.txt   draft-ietf-raw-technologies-03.txt >
RAW P. Thubert, Ed. RAW P. Thubert, Ed.
Internet-Draft Cisco Systems Internet-Draft Cisco Systems
Intended status: Informational D. Cavalcanti Intended status: Informational D. Cavalcanti
Expires: 9 December 2021 Intel Expires: 30 January 2022 Intel
X. Vilajosana X. Vilajosana
Universitat Oberta de Catalunya Universitat Oberta de Catalunya
C. Schmitt C. Schmitt
Research Institute CODE, UniBwM Research Institute CODE, UniBwM
J. Farkas J. Farkas
Ericsson Ericsson
7 June 2021 29 July 2021
Reliable and Available Wireless Technologies Reliable and Available Wireless Technologies
draft-ietf-raw-technologies-02 draft-ietf-raw-technologies-03
Abstract Abstract
This document presents a series of recent technologies that are This document presents a series of recent technologies that are
capable of time synchronization and scheduling of transmission, capable of time synchronization and scheduling of transmission,
making them suitable to carry time-sensitive flows with high making them suitable to carry time-sensitive flows with high
reliability and availability. reliability and availability.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 9 December 2021. This Internet-Draft will expire on 30 January 2022.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
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3. On Scheduling . . . . . . . . . . . . . . . . . . . . . . . . 4 3. On Scheduling . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Benefits of Scheduling on Wires . . . . . . . . . . . . . 5 3.1. Benefits of Scheduling on Wires . . . . . . . . . . . . . 5
3.2. Benefits of Scheduling on Wireless . . . . . . . . . . . 5 3.2. Benefits of Scheduling on Wireless . . . . . . . . . . . 5
4. IEEE 802.11 . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. IEEE 802.11 . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Provenance and Documents . . . . . . . . . . . . . . . . 6 4.1. Provenance and Documents . . . . . . . . . . . . . . . . 6
4.2. 802.11ax High Efficiency (HE) . . . . . . . . . . . . . . 8 4.2. 802.11ax High Efficiency (HE) . . . . . . . . . . . . . . 8
4.2.1. General Characteristics . . . . . . . . . . . . . . . 8 4.2.1. General Characteristics . . . . . . . . . . . . . . . 8
4.2.2. Applicability to deterministic flows . . . . . . . . 9 4.2.2. Applicability to deterministic flows . . . . . . . . 9
4.3. 802.11be Extreme High Throughput (EHT) . . . . . . . . . 11 4.3. 802.11be Extreme High Throughput (EHT) . . . . . . . . . 11
4.3.1. General Characteristics . . . . . . . . . . . . . . . 11 4.3.1. General Characteristics . . . . . . . . . . . . . . . 11
4.3.2. Applicability to deterministic flows . . . . . . . . 11 4.3.2. Applicability to deterministic flows . . . . . . . . 12
4.4. 802.11ad and 802.11ay (mmWave operation) . . . . . . . . 12 4.4. 802.11ad and 802.11ay (mmWave operation) . . . . . . . . 13
4.4.1. General Characteristics . . . . . . . . . . . . . . . 13 4.4.1. General Characteristics . . . . . . . . . . . . . . . 13
4.4.2. Applicability to deterministic flows . . . . . . . . 13 4.4.2. Applicability to deterministic flows . . . . . . . . 13
5. IEEE 802.15.4 . . . . . . . . . . . . . . . . . . . . . . . . 13 5. IEEE 802.15.4 . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1. Provenance and Documents . . . . . . . . . . . . . . . . 13 5.1. Provenance and Documents . . . . . . . . . . . . . . . . 14
5.2. TimeSlotted Channel Hopping . . . . . . . . . . . . . . . 15 5.2. TimeSlotted Channel Hopping . . . . . . . . . . . . . . . 15
5.2.1. General Characteristics . . . . . . . . . . . . . . . 15 5.2.1. General Characteristics . . . . . . . . . . . . . . . 16
5.2.2. Applicability to Deterministic Flows . . . . . . . . 17 5.2.2. Applicability to Deterministic Flows . . . . . . . . 18
6. 5G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6. 5G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.1. Provenance and Documents . . . . . . . . . . . . . . . . 30 6.1. Provenance and Documents . . . . . . . . . . . . . . . . 31
6.2. General Characteristics . . . . . . . . . . . . . . . . . 32 6.2. General Characteristics . . . . . . . . . . . . . . . . . 33
6.3. Deployment and Spectrum . . . . . . . . . . . . . . . . . 33 6.3. Deployment and Spectrum . . . . . . . . . . . . . . . . . 34
6.4. Applicability to Deterministic Flows . . . . . . . . . . 34 6.4. Applicability to Deterministic Flows . . . . . . . . . . 35
6.4.1. System Architecture . . . . . . . . . . . . . . . . . 34 6.4.1. System Architecture . . . . . . . . . . . . . . . . . 35
6.4.2. Overview of The Radio Protocol Stack . . . . . . . . 36 6.4.2. Overview of The Radio Protocol Stack . . . . . . . . 37
6.4.3. Radio (PHY) . . . . . . . . . . . . . . . . . . . . . 37 6.4.3. Radio (PHY) . . . . . . . . . . . . . . . . . . . . . 38
6.4.4. Scheduling and QoS (MAC) . . . . . . . . . . . . . . 39 6.4.4. Scheduling and QoS (MAC) . . . . . . . . . . . . . . 40
6.4.5. Time-Sensitive Networking (TSN) Integration . . . . . 41 6.4.5. Time-Sensitive Networking (TSN) Integration . . . . . 42
6.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 45 6.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 46
7. L-band Digital Aeronautical Communications System . . . . . . 46 7. L-band Digital Aeronautical Communications System . . . . . . 47
7.1. Provenance and Documents . . . . . . . . . . . . . . . . 47 7.1. Provenance and Documents . . . . . . . . . . . . . . . . 48
7.2. General Characteristics . . . . . . . . . . . . . . . . . 48 7.2. General Characteristics . . . . . . . . . . . . . . . . . 49
7.3. Deployment and Spectrum . . . . . . . . . . . . . . . . . 49 7.3. Deployment and Spectrum . . . . . . . . . . . . . . . . . 50
7.4. Applicability to Deterministic Flows . . . . . . . . . . 49 7.4. Applicability to Deterministic Flows . . . . . . . . . . 50
7.4.1. System Architecture . . . . . . . . . . . . . . . . . 50 7.4.1. System Architecture . . . . . . . . . . . . . . . . . 51
7.4.2. Overview of The Radio Protocol Stack . . . . . . . . 50 7.4.2. Overview of The Radio Protocol Stack . . . . . . . . 51
7.4.3. Radio (PHY) . . . . . . . . . . . . . . . . . . . . . 51 7.4.3. Radio (PHY) . . . . . . . . . . . . . . . . . . . . . 52
7.4.4. Scheduling, Frame Structure and QoS (MAC) . . . . . . 52 7.4.4. Scheduling, Frame Structure and QoS (MAC) . . . . . . 53
7.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 54 7.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 55
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 55 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 56
9. Security Considerations . . . . . . . . . . . . . . . . . . . 55 9. Security Considerations . . . . . . . . . . . . . . . . . . . 56
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 55 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 56
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 55 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 56
12. Normative References . . . . . . . . . . . . . . . . . . . . 55 12. Normative References . . . . . . . . . . . . . . . . . . . . 56
13. Informative References . . . . . . . . . . . . . . . . . . . 56 13. Informative References . . . . . . . . . . . . . . . . . . . 57
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 64 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 66
1. Introduction 1. Introduction
When used in math or philosophy, the term "deterministic" generally When used in math or philosophy, the term "deterministic" generally
refers to a perfection where all aspect are understood and refers to a perfection where all aspect are understood and
predictable. A perfectly Deterministic Network would ensure that predictable. A perfectly Deterministic Network would ensure that
every packet reach its destination following a predetermined path every packet reach its destination following a predetermined path
along a predefined schedule to be delivered at the exact due time. along a predefined schedule to be delivered at the exact due time.
In a real and imperfect world, a Deterministic Network must highly In a real and imperfect world, a Deterministic Network must highly
predictable, which is a combination of reliability and availability. predictable, which is a combination of reliability and availability.
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networking standards and recommended practices for local, networking standards and recommended practices for local,
metropolitan, and other area networks, using an open and accredited metropolitan, and other area networks, using an open and accredited
process, and advocates them on a global basis. The most widely used process, and advocates them on a global basis. The most widely used
standards are for Ethernet, Bridging and Virtual Bridged LANs standards are for Ethernet, Bridging and Virtual Bridged LANs
Wireless LAN, Wireless PAN, Wireless MAN, Wireless Coexistence, Media Wireless LAN, Wireless PAN, Wireless MAN, Wireless Coexistence, Media
Independent Handover Services, and Wireless RAN. An individual Independent Handover Services, and Wireless RAN. An individual
Working Group provides the focus for each area. Standards produced Working Group provides the focus for each area. Standards produced
by the IEEE 802 SC are freely available from the IEEE GET Program by the IEEE 802 SC are freely available from the IEEE GET Program
after they have been published in PDF for six months. after they have been published in PDF for six months.
The IEEE 802.11 LAN standards define the underlying MAC and PHY The IEEE 802.11 Wireless LAN (WLAN) standards define the underlying
layers for the Wi-Fi technology. Wi-Fi/802.11 is one of the most MAC and PHY layers for the Wi-Fi technology. Wi-Fi/802.11 is one of
successful wireless technologies, supporting many application the most successful wireless technologies, supporting many
domains. While previous 802.11 generations, such as 802.11n and application domains. While previous 802.11 generations, such as
802.11ac, have focused mainly on improving peak throughput, more 802.11n and 802.11ac, have focused mainly on improving peak
recent generations are also considering other performance vectors, throughput, more recent generations are also considering other
such as efficiency enhancements for dense environments in 802.11ax, performance vectors, such as efficiency enhancements for dense
and latency and support for Time-Sensitive Networking (TSN) environments in 802.11ax, latency, reliability and enhancements
capabilities in 802.11be. supporting Time-Sensitive Networking (TSN) capabilities in P802.11be.
IEEE 802.11 already supports some 802.1 TSN standards and it is IEEE std 802.11-2012 introduced support for TSN time synchronization
undergoing efforts to support for other 802.1 TSN capabilities based on IEEE 802.1AS over 802.11 Timing Measurement protocol. IEEE
required to address the use cases that require time synchronization 802.11-2016 extended the 802.1AS operation over 802.11 Fine Timing
and timeliness (bounded latency) guarantees with high reliability and Measurement (FTM), as well as the Stream Reservation Protocol (IEEE
availability. The IEEE 802.11 working group has been working in 802.1Qat). 802.11 WLANs can also be part of a 802.1Q bridged networks
collaboration with the IEEE 802.1 group for several years extending with enhancements enabled by the 802.11ak amendment. Traffic
802.1 features over 802.11. As with any wireless media, 802.11 classification based on 802.1Q VLAN tags is also supported in 802.11.
imposes new constraints and restrictions to TSN-grade QoS, and Other 802.1 TSN capabilities such as 802.1Qbv and 802.1CB, which are
tradeoffs between latency and reliability guarantees must be media agnostic, can already operate over 802.11. The IEEE Std.
considered as well as managed deployment requirements. An overview 802.11ax-2021 adds new scheduling capabilities that can enhance the
of 802.1 TSN capabilities and their extensions to 802.11 are timeliness performance in the 802.11 MAC and achieve lower bounded
discussed in [Cavalcanti_2019]. latency. The IEEE 802.11be is undergoing efforts to enhance the
support for 802.1 TSN capabilities especially related to worst-case
latency, reliability and availability. The IEEE 802.11 working group
has been working in collaboration with the IEEE 802.1 working group
for several years extending some 802.1 features over 802.11. As with
any wireless media, 802.11 imposes new constraints and restrictions
to TSN-grade QoS, and tradeoffs between latency and reliability
guarantees must be considered as well as managed deployment
requirements. An overview of 802.1 TSN capabilities and challenges
for their extensions to 802.11 are discussed in [Cavalcanti_2019].
Wi-Fi Alliance (WFA) is the worldwide network of companies that Wi-Fi Alliance (WFA) is the worldwide network of companies that
drives global Wi-Fi adoption and evolution through thought drives global Wi-Fi adoption and evolution through thought
leadership, spectrum advocacy, and industry-wide collaboration. The leadership, spectrum advocacy, and industry-wide collaboration. The
WFA work helps ensure that Wi-Fi devices and networks provide users WFA work helps ensure that Wi-Fi devices and networks provide users
the interoperability, security, and reliability they have come to the interoperability, security, and reliability they have come to
expect. expect.
The following [IEEE Std. 802.11] specifications/certifications are The following [IEEE Std. 802.11] specifications/certifications are
relevant in the context of reliable and available wireless services relevant in the context of reliable and available wireless services
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4.2. 802.11ax High Efficiency (HE) 4.2. 802.11ax High Efficiency (HE)
4.2.1. General Characteristics 4.2.1. General Characteristics
The next generation Wi-Fi (Wi-Fi 6) is based on the IEEE802.11ax The next generation Wi-Fi (Wi-Fi 6) is based on the IEEE802.11ax
amendment [IEEE Std. 802.11ax], which includes new capabilities to amendment [IEEE Std. 802.11ax], which includes new capabilities to
increase efficiency, control and reduce latency. Some of the new increase efficiency, control and reduce latency. Some of the new
features include higher order 1024-QAM modulation, support for uplink features include higher order 1024-QAM modulation, support for uplink
multi-user MIMO, OFDMA, trigger-based access and Target Wake time multi-user MIMO, OFDMA, trigger-based access and Target Wake time
(TWT) for enhanced power savings. The OFDMA mode and trigger-based (TWT) for enhanced power savings. The OFDMA mode and trigger-based
access enable scheduled operation, which is a key capability required access enable the AP, after acquiring the channel for a given
to support deterministic latency and reliability for time-sensitive duration, to schedule multi-user transmissions, which is a key
flows. 802.11ax can operate in up to 160 MHz channels and it includes capability required to increase latency predictability and and
support for operation in the new 6 GHz band, which is expected to be reliability for time-sensitive flows. 802.11ax can operate in up to
open to unlicensed use by the FCC and other regulatory agencies 160 MHz channels and it includes support for operation in the new 6
worldwide. GHz band, which is expected to be open to unlicensed use by the FCC
and other regulatory agencies worldwide.
4.2.1.1. Multi-User OFDMA and Trigger-based Scheduled Access 4.2.1.1. Multi-User OFDMA and Trigger-based Scheduled Access
802.11ax introduced a new orthogonal frequency-division multiple 802.11ax introduced a new orthogonal frequency-division multiple
access (OFDMA) mode in which multiple users can be scheduled across access (OFDMA) mode in which multiple users can be scheduled across
the frequency domain. In this mode, the Access Point (AP) can the frequency domain. In this mode, the Access Point (AP) can
initiate multi-user (MU) Uplink (UL) transmissions in the same PHY initiate multi-user (MU) Uplink (UL) transmissions in the same PHY
Protocol Data Unit (PPDU) by sending a trigger frame. This Protocol Data Unit (PPDU) by sending a trigger frame. This
centralized scheduling capability gives the AP much more control of centralized scheduling capability gives the AP much more control of
the channel, and it can remove contention between devices for uplink the channel in its Basic Service Set (BSS) and it can remove
transmissions, therefore reducing the randomness caused by CSMA-based contention between associated stations for uplink transmissions,
access between stations. The AP can also transmit simultaneously to therefore reducing the randomness caused by CSMA-based access between
multiple users in the downlink direction by using a Downlink (DL) MU stations within the same BSS. The AP can also transmit
OFDMA PPDU. In order to initiate a contention free Transmission simultaneously to multiple users in the downlink direction by using a
Opportunity (TXOP) using the OFDMA mode, the AP still follows the Downlink (DL) MU OFDMA PPDU. In order to initiate a contention free
typical listen before talk procedure to acquire the medium, which Transmission Opportunity (TXOP) using the OFDMA mode, the AP still
ensures interoperability and compliance with unlicensed band access follows the typical listen before talk procedure to acquire the
rules. However, 802.11ax also includes a multi-user Enhanced medium, which ensures interoperability and compliance with unlicensed
Distributed Channel Access (MU-EDCA) capability, which allows the AP band access rules. However, 802.11ax also includes a multi-user
to get higher channel access priority. Enhanced Distributed Channel Access (MU-EDCA) capability, which
allows the AP to get higher channel access priority than other
devices in its BSS.
4.2.1.2. Improved PHY Robustness 4.2.1.2. Improved PHY Robustness
The 802.11ax PHY can operate with 0.8, 1.6 or 3.2 microsecond guard The 802.11ax PHY can operate with 0.8, 1.6 or 3.2 microsecond guard
interval (GI). The larger GI options provide better protection interval (GI). The larger GI options provide better protection
against multipath, which is expected to be a challenge in industrial against multipath, which is expected to be a challenge in industrial
environments. The possibility to operate with smaller resource units environments. The possibility to operate with smaller resource units
(e.g. 2 MHz) enabled by OFDMA also helps reduce noise power and (e.g. 2 MHz) enabled by OFDMA also helps reduce noise power and
improve SNR, leading to better packet error rate (PER) performance. improve SNR, leading to better packet error rate (PER) performance.
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The 802.11ax specification [IEEE Std. 802.11ax] includes support for The 802.11ax specification [IEEE Std. 802.11ax] includes support for
operation in the new 6 GHz band. Given the amount of new spectrum operation in the new 6 GHz band. Given the amount of new spectrum
available as well as the fact that no legacy 802.11 device (prior available as well as the fact that no legacy 802.11 device (prior
802.11ax) will be able to operate in this new band, 802.11ax 802.11ax) will be able to operate in this new band, 802.11ax
operation in this new band can be even more efficient. operation in this new band can be even more efficient.
4.2.2. Applicability to deterministic flows 4.2.2. Applicability to deterministic flows
TSN capabilities, as defined by the IEEE 802.1 TSN standards, provide TSN capabilities, as defined by the IEEE 802.1 TSN standards, provide
the underlying mechanism for supporting deterministic flows in a the underlying mechanism for supporting deterministic flows in a
Local Area Network (LAN). The 802.11 working group has already Local Area Network (LAN). The 802.11 working group has incorporated
incorporated support for several TSN capabilities, so that time- support for absolute time synchronization to extend the TSN 802.1AS
sensitive flow can experience precise time synchronization and protocol so that time-sensitive flow can experience precise time
timeliness when operating over 802.11 links. TSN capabilities synchronization when operating over 802.11 links. As IEEE 802.11 and
supported over 802.11 (which also extends to 802.11ax), include: IEEE 802.1 TSN are both based on the IEEE 802 architecture, 802.11
devices can directly implement TSN capabilities without the need for
a gateway/translation protocol. Basic features required for
operation in a 802.1Q LAN are already enabled for 802.11. Some TSN
capabilities, such as 802.1Qbv, can already operate over the existing
802.11 MAC SAP [SUR2021]. Nevertheless, the IEEE 802.11 MAC/PHY
requires further extensions to improve the operation of IEEE 802.1
TSN features and achieve better performance metrics [CAL1287].
TSN capabilities supported over 802.11 (which also extends to
802.11ax), include:
1. 802.1AS based Time Synchronization (other time synchronization 1. 802.1AS based Time Synchronization (other time synchronization
techniques may also be used) techniques may also be used)
2. Interoperating with IEEE802.1Q bridges 2. Interoperating with IEEE802.1Q bridges as per IEEE 802.11ak
3. Time-sensitive Traffic Stream identification 3. Time-sensitive Traffic Stream Identification and Classification
The exiting 802.11 TSN capabilities listed above, and the 802.11ax The exiting 802.11 TSN capabilities listed above, and the 802.11ax
OFDMA and scheduled access provide a new set of tools to better OFDMA and AP-controlled access within a BSS provide a new set of
server time-sensitive flows. However, it is important to understand tools to better serve time-sensitive flows. However, it is important
the tradeoffs and constraints associated with such capabilities, as to understand the tradeoffs and constraints associated with such
well as redundancy and diversity mechanisms that can be used to capabilities, as well as redundancy and diversity mechanisms that can
provide more predictable and reliable performance. be used to provide more predictable and reliable performance.
4.2.2.1. 802.11 Managed network operation and admission control 4.2.2.1. 802.11 Managed network operation and admission control
Time-sensitive applications and TSN standards are expected to operate Time-sensitive applications and TSN standards are expected to operate
under a managed network (e.g. industrial/enterprise network). Thus, under a managed network (e.g. industrial/enterprise network). Thus,
the Wi-Fi operation must also be carefully managed and integrated the Wi-Fi operation must also be carefully managed and integrated
with the overall TSN management framework, as defined in the with the overall TSN management framework, as defined in the
[IEEE8021Qcc] specification. [IEEE8021Qcc] specification.
Some of the random-access latency and interference from legacy/ Some of the random-access latency and interference from legacy/
unmanaged devices can be minimized under a centralized management unmanaged devices can be minimized under a centralized management
mode as defined in [IEEE8021Qcc], in which admission control mode as defined in [IEEE8021Qcc].
procedures are enforced.
Existing traffic stream identification, configuration and admission Existing traffic stream identification, configuration and admission
control procedures defined in [IEEE Std. 802.11] QoS mechanism can be control procedures defined in [IEEE Std. 802.11] QoS mechanism can be
re-used. However, given the high degree of determinism required by re-used. However, given the high degree of determinism required by
many time-sensitive applications, additional capabilities to manage many time-sensitive applications, additional capabilities to manage
interference and legacy devices within tight time-constraints need to interference and legacy devices within tight time-constraints need to
be explored. be explored.
4.2.2.2. Scheduling for bounded latency and diversity 4.2.2.2. Scheduling for bounded latency and diversity
As discussed earlier, the [IEEE Std. 802.11ax] OFDMA mode introduces As discussed earlier, the [IEEE Std. 802.11ax] OFDMA mode introduces
the possibility of assigning different RUs (frequency resources) to the possibility of assigning different RUs (frequency resources) to
users within a PPDU. Several RU sizes are defined in the users within a PPDU. Several RU sizes are defined in the
specification (26, 52, 106, 242, 484, 996 subcarriers). In addition, specification (26, 52, 106, 242, 484, 996 subcarriers). In addition,
the AP can also decide on MCS and grouping of users within a given the AP can also decide on MCS and grouping of users within a given
OFMDA PPDU. Such flexibility can be leveraged to support time- OFMDA PPDU. Such flexibility can be leveraged to support time-
sensitive applications with bounded latency, especially in a managed sensitive applications with bounded latency, especially in a managed
network where stations can be configured to operate under the control network where stations can be configured to operate under the control
of the AP. of the AP, in a controlled environment (which contains only devices
operating on the unlicensed band installed by the facility owner and
where unexpected interference from other systems and/or radio access
technologies only sporadically happens), or in a deployment where
channel/link redundancy is used to minimize the impact of unmanaged
devices/interference.
As shown in [Cavalcanti_2019], it is possible to achieve latencies in When the network in lightly loaded, it is possible to achieve
the order of 1msec with high reliability in an interference free latencies under 1 msec when Wi-Fi is operated in contention-based
environment. Obviously, there are latency, reliability and capacity (i.e., without OFDMA) mode. It is also has been shown that it is
tradeoffs to be considered. For instance, smaller Resource Units possible to achieve 1 msec latencies in controlled environment with
(RU)s result in longer transmission durations, which may impact the higher efficiency when multi-user transmissions are used (enabled by
minimal latency that can be achieved, but the contention latency and OFDMA operation) [Cavalcanti_2019]. Obviously, there are latency,
randomness elimination due to multi-user transmission is a major reliability and capacity tradeoffs to be considered. For instance,
benefit of the OFDMA mode. smaller Resource Units (RU)s result in longer transmission durations,
which may impact the minimal latency that can be achieved, but the
contention latency and randomness elimination in an interference-free
environment due to multi-user transmission is a major benefit of the
OFDMA mode.
The flexibility to dynamically assign RUs to each transmission also The flexibility to dynamically assign RUs to each transmission also
enables the AP to provide frequency diversity, which can help enables the AP to provide frequency diversity, which can help
increase reliability. increase reliability.
4.3. 802.11be Extreme High Throughput (EHT) 4.3. 802.11be Extreme High Throughput (EHT)
4.3.1. General Characteristics 4.3.1. General Characteristics
The [IEEE 802.11be WIP]is the next major 802.11 amendment (after The ongoing [IEEE 802.11be WIP] project is the next major 802.11
[IEEE Std. 802.11ax]) for operation in the 2.4, 5 and 6 GHz bands. amendment (after [IEEE Std. 802.11ax-2021]) for operation in the 2.4,
802.11be is expected to include new PHY and MAC features and it is 5 and 6 GHz bands. 802.11be is expected to include new PHY and MAC
targeting extremely high throughput (at least 30 Gbps), as well as features and it is targeting extremely high throughput (at least 30
enhancements to worst case latency and jitter. It is also expected Gbps), as well as enhancements to worst case latency and jitter. It
to improve the integration with 802.1 TSN to support time-sensitive is also expected to improve the integration with 802.1 TSN to support
applications over Ethernet and Wireless LANs. time-sensitive applications over Ethernet and Wireless LANs.
The 802.11be Task Group started its operation in May 2019, therefore, The 802.11be Task Group started its operation in May 2019, therefore,
detailed information about specific features is not yet available. detailed information about specific features is not yet available.
Only high level candidate features have been discussed so far, Only high level candidate features have been discussed so far,
including: including:
1. 320MHz bandwidth and more efficient utilization of non-contiguous 1. 320MHz bandwidth and more efficient utilization of non-contiguous
spectrum. spectrum.
2. Multi-band/multi-channel aggregation and operation. 2. Multi-band/multi-channel aggregation and operation.
skipping to change at page 13, line 33 skipping to change at page 13, line 50
The high data rates achievable with 802.11ad and 802.11ay can The high data rates achievable with 802.11ad and 802.11ay can
significantly reduce latency down to microsecond levels. Limited significantly reduce latency down to microsecond levels. Limited
interference from legacy and other unlicensed devices in 60 GHz is interference from legacy and other unlicensed devices in 60 GHz is
also a benefit. However, directionality and short range typical in also a benefit. However, directionality and short range typical in
mmWave operation impose new challenges such as the overhead required mmWave operation impose new challenges such as the overhead required
for beam training and blockage issues, which impact both latency and for beam training and blockage issues, which impact both latency and
reliability. Therefore, it is important to understand the use case reliability. Therefore, it is important to understand the use case
and deployment conditions in order to properly apply and configure and deployment conditions in order to properly apply and configure
802.11ad/ay networks for time sensitive applications. 802.11ad/ay networks for time sensitive applications.
The 802.11ad standard include a scheduled access mode in which The 802.11ad standard includes a scheduled access mode in which the
stations can be allocated contention-free service periods by a central controller, after contending and reserving the channel for a
central controller. This scheduling capability is also available in dedicated period, can allocate to stations contention-free service
802.11ay, and it is one of the mechanisms that can be used to provide periods. This scheduling capability is also available in 802.11ay,
bounded latency to time-sensitive data flows. An analysis of the and it is one of the mechanisms that can be used to provide bounded
theoretical latency bounds that can be achieved with 802.11ad service latency to time-sensitive data flows in interference-free scenarios.
periods is provided in [Cavalcanti_2019]. An analysis of the theoretical latency bounds that can be achieved
with 802.11ad service periods is provided in [Cavalcanti_2019].
5. IEEE 802.15.4 5. IEEE 802.15.4
5.1. Provenance and Documents 5.1. Provenance and Documents
The IEEE802.15.4 Task Group has been driving the development of low- The IEEE802.15.4 Task Group has been driving the development of low-
power low-cost radio technology. The IEEE802.15.4 physical layer has power low-cost radio technology. The IEEE802.15.4 physical layer has
been designed to support demanding low-power scenarios targeting the been designed to support demanding low-power scenarios targeting the
use of unlicensed bands, both the 2.4 GHz and sub GHz Industrial, use of unlicensed bands, both the 2.4 GHz and sub GHz Industrial,
Scientific and Medical (ISM) bands. This has imposed requirements in Scientific and Medical (ISM) bands. This has imposed requirements in
skipping to change at page 55, line 25 skipping to change at page 56, line 25
This specification does not require IANA action. This specification does not require IANA action.
9. Security Considerations 9. Security Considerations
Most RAW technologies integrate some authentication or encryption Most RAW technologies integrate some authentication or encryption
mechanisms that were defined outside the IETF. mechanisms that were defined outside the IETF.
10. Contributors 10. Contributors
This document aggregates articles from authors specialized in each
technologies. Beyond the main authors listed in the front page, the
following contributors proposed additional text and refinement that
improved the documertn greatly!
Georgios Z. Papadopoulos: Contributed to the TSCH section. Georgios Z. Papadopoulos: Contributed to the TSCH section.
Nils M&#228;urer: Contributed to the LDACS section. Nils M&#228;urer: Contributed to the LDACS section.
Thomas Gr&#228;upl: Contributed to the LDACS section. Thomas Gr&#228;upl: Contributed to the LDACS section.
Janos Farkas, Torsten Dudda, Alexey Shapin, and Sara Sandberg: Contr Janos Farkas, Torsten Dudda, Alexey Shapin, and Sara Sandberg: Contr
ibuted to the 5G section. ibuted to the 5G section.
Rocco Di Taranto: Contributed to the Wi-Fi section
11. Acknowledgments 11. Acknowledgments
Many thanks to the participants of the RAW WG where a lot of the work Many thanks to the participants of the RAW WG where a lot of the work
discussed here happened. discussed here happened.
12. Normative References 12. Normative References
[RFC8480] Wang, Q., Ed., Vilajosana, X., and T. Watteyne, "6TiSCH [RFC8480] Wang, Q., Ed., Vilajosana, X., and T. Watteyne, "6TiSCH
Operation Sublayer (6top) Protocol (6P)", RFC 8480, Operation Sublayer (6top) Protocol (6P)", RFC 8480,
DOI 10.17487/RFC8480, November 2018, DOI 10.17487/RFC8480, November 2018,
skipping to change at page 56, line 24 skipping to change at page 57, line 29
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655, "Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019, DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>. <https://www.rfc-editor.org/info/rfc8655>.
[RFC9030] Thubert, P., Ed., "An Architecture for IPv6 over the Time- [RFC9030] Thubert, P., Ed., "An Architecture for IPv6 over the Time-
Slotted Channel Hopping Mode of IEEE 802.15.4 (6TiSCH)", Slotted Channel Hopping Mode of IEEE 802.15.4 (6TiSCH)",
RFC 9030, DOI 10.17487/RFC9030, May 2021, RFC 9030, DOI 10.17487/RFC9030, May 2021,
<https://www.rfc-editor.org/info/rfc9030>. <https://www.rfc-editor.org/info/rfc9030>.
[RFC9033] Chang, T., Ed., Vucinic, M., Vilajosana, X., Duquennoy, [RFC9033] Chang, T., Ed., Vučinić, M., Vilajosana, X., Duquennoy,
S., and D. Dujovne, "6TiSCH Minimal Scheduling Function S., and D. Dujovne, "6TiSCH Minimal Scheduling Function
(MSF)", RFC 9033, DOI 10.17487/RFC9033, May 2021, (MSF)", RFC 9033, DOI 10.17487/RFC9033, May 2021,
<https://www.rfc-editor.org/info/rfc9033>. <https://www.rfc-editor.org/info/rfc9033>.
13. Informative References 13. Informative References
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550, Low-Power and Lossy Networks", RFC 6550,
skipping to change at page 57, line 18 skipping to change at page 58, line 24
DOI 10.17487/RFC7276, June 2014, DOI 10.17487/RFC7276, June 2014,
<https://www.rfc-editor.org/info/rfc7276>. <https://www.rfc-editor.org/info/rfc7276>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279, Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017, DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>. <https://www.rfc-editor.org/info/rfc8279>.
[I-D.pthubert-raw-architecture] [I-D.pthubert-raw-architecture]
Thubert, P., Papadopoulos, G. Z., and R. Buddenberg, Thubert, P., Papadopoulos, G. Z., and L. Berger, "Reliable
"Reliable and Available Wireless Architecture/Framework", and Available Wireless Architecture/Framework", Work in
Work in Progress, Internet-Draft, draft-pthubert-raw- Progress, Internet-Draft, draft-pthubert-raw-architecture-
architecture-05, 15 November 2020, 09, 7 July 2021, <https://datatracker.ietf.org/doc/html/
<https://tools.ietf.org/html/draft-pthubert-raw- draft-pthubert-raw-architecture-09>.
architecture-05>.
[I-D.ietf-roll-nsa-extension] [I-D.ietf-roll-nsa-extension]
Koutsiamanis, R., Papadopoulos, G., Montavont, N., and P. Koutsiamanis, R., Papadopoulos, G., Montavont, N., and P.
Thubert, "Common Ancestor Objective Function and Parent Thubert, "Common Ancestor Objective Function and Parent
Set DAG Metric Container Extension", Work in Progress, Set DAG Metric Container Extension", Work in Progress,
Internet-Draft, draft-ietf-roll-nsa-extension-10, 29 Internet-Draft, draft-ietf-roll-nsa-extension-10, 29
October 2020, <https://tools.ietf.org/html/draft-ietf- October 2020, <https://datatracker.ietf.org/doc/html/
roll-nsa-extension-10>. draft-ietf-roll-nsa-extension-10>.
[I-D.papadopoulos-paw-pre-reqs] [I-D.papadopoulos-paw-pre-reqs]
Papadopoulos, G., Koutsiamanis, R., Montavont, N., and P. Papadopoulos, G., Koutsiamanis, R., Montavont, N., and P.
Thubert, "Exploiting Packet Replication and Elimination in Thubert, "Exploiting Packet Replication and Elimination in
Complex Tracks in LLNs", Work in Progress, Internet-Draft, Complex Tracks in LLNs", Work in Progress, Internet-Draft,
draft-papadopoulos-paw-pre-reqs-01, 25 March 2019, draft-papadopoulos-paw-pre-reqs-01, 25 March 2019,
<https://tools.ietf.org/html/draft-papadopoulos-paw-pre- <https://datatracker.ietf.org/doc/html/draft-papadopoulos-
reqs-01>. paw-pre-reqs-01>.
[I-D.thubert-bier-replication-elimination] [I-D.thubert-bier-replication-elimination]
Thubert, P., Eckert, T., Brodard, Z., and H. Jiang, "BIER- Thubert, P., Eckert, T., Brodard, Z., and H. Jiang, "BIER-
TE extensions for Packet Replication and Elimination TE extensions for Packet Replication and Elimination
Function (PREF) and OAM", Work in Progress, Internet- Function (PREF) and OAM", Work in Progress, Internet-
Draft, draft-thubert-bier-replication-elimination-03, 3 Draft, draft-thubert-bier-replication-elimination-03, 3
March 2018, <https://tools.ietf.org/html/draft-thubert- March 2018, <https://datatracker.ietf.org/doc/html/draft-
bier-replication-elimination-03>. thubert-bier-replication-elimination-03>.
[I-D.thubert-6lo-bier-dispatch] [I-D.thubert-6lo-bier-dispatch]
Thubert, P., Brodard, Z., Jiang, H., and G. Texier, "A Thubert, P., Brodard, Z., Jiang, H., and G. Texier, "A
6loRH for BitStrings", Work in Progress, Internet-Draft, 6loRH for BitStrings", Work in Progress, Internet-Draft,
draft-thubert-6lo-bier-dispatch-06, 28 January 2019, draft-thubert-6lo-bier-dispatch-06, 28 January 2019,
<https://tools.ietf.org/html/draft-thubert-6lo-bier- <https://datatracker.ietf.org/doc/html/draft-thubert-6lo-
dispatch-06>. bier-dispatch-06>.
[I-D.ietf-bier-te-arch] [I-D.ietf-bier-te-arch]
Eckert, T., Cauchie, G., and M. Menth, "Tree Engineering Eckert, T., Cauchie, G., and M. Menth, "Tree Engineering
for Bit Index Explicit Replication (BIER-TE)", Work in for Bit Index Explicit Replication (BIER-TE)", Work in
Progress, Internet-Draft, draft-ietf-bier-te-arch-09, 30 Progress, Internet-Draft, draft-ietf-bier-te-arch-10, 9
October 2020, July 2021, <https://datatracker.ietf.org/doc/html/draft-
<https://tools.ietf.org/html/draft-ietf-bier-te-arch-09>. ietf-bier-te-arch-10>.
[I-D.ietf-6tisch-coap] [I-D.ietf-6tisch-coap]
Sudhaakar, R. S. and P. Zand, "6TiSCH Resource Management Sudhaakar, R. S. and P. Zand, "6TiSCH Resource Management
and Interaction using CoAP", Work in Progress, Internet- and Interaction using CoAP", Work in Progress, Internet-
Draft, draft-ietf-6tisch-coap-03, 9 March 2015, Draft, draft-ietf-6tisch-coap-03, 9 March 2015,
<https://tools.ietf.org/html/draft-ietf-6tisch-coap-03>. <https://datatracker.ietf.org/doc/html/draft-ietf-6tisch-
coap-03>.
[I-D.svshah-tsvwg-deterministic-forwarding] [I-D.svshah-tsvwg-deterministic-forwarding]
Shah, S. and P. Thubert, "Deterministic Forwarding PHB", Shah, S. and P. Thubert, "Deterministic Forwarding PHB",
Work in Progress, Internet-Draft, draft-svshah-tsvwg- Work in Progress, Internet-Draft, draft-svshah-tsvwg-
deterministic-forwarding-04, 30 August 2015, deterministic-forwarding-04, 30 August 2015,
<https://tools.ietf.org/html/draft-svshah-tsvwg- <https://datatracker.ietf.org/doc/html/draft-svshah-tsvwg-
deterministic-forwarding-04>. deterministic-forwarding-04>.
[IEEE Std. 802.15.4] [IEEE Std. 802.15.4]
IEEE standard for Information Technology, "IEEE Std. IEEE standard for Information Technology, "IEEE Std.
802.15.4, Part. 15.4: Wireless Medium Access Control (MAC) 802.15.4, Part. 15.4: Wireless Medium Access Control (MAC)
and Physical Layer (PHY) Specifications for Low-Rate and Physical Layer (PHY) Specifications for Low-Rate
Wireless Personal Area Networks". Wireless Personal Area Networks".
[IEEE Std. 802.11] [IEEE Std. 802.11]
"IEEE Standard 802.11 - IEEE Standard for Information "IEEE Standard 802.11 - IEEE Standard for Information
skipping to change at page 62, line 15 skipping to change at page 63, line 15
[TS38300] "3GPP TS 38.300, NR Overall description", [TS38300] "3GPP TS 38.300, NR Overall description",
<https://portal.3gpp.org/desktopmodules/Specifications/ <https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3191>. SpecificationDetails.aspx?specificationId=3191>.
[IMT2020] "ITU towards IMT for 2020 and beyond", [IMT2020] "ITU towards IMT for 2020 and beyond",
<https://www.itu.int/en/ITU-R/study-groups/rsg5/rwp5d/imt- <https://www.itu.int/en/ITU-R/study-groups/rsg5/rwp5d/imt-
2020/Pages/default.aspx>. 2020/Pages/default.aspx>.
[I-D.ietf-detnet-ip-over-tsn] [I-D.ietf-detnet-ip-over-tsn]
Varga, B., Farkas, J., Malis, A. G., and S. Bryant, Varga, B., Farkas, J., Malis, A. G., and S. Bryant,
"DetNet Data Plane: IP over IEEE 802.1 Time Sensitive "Deterministic Networking (DetNet) Data Plane: IP over
Networking (TSN)", Work in Progress, Internet-Draft, IEEE 802.1 Time-Sensitive Networking (TSN)", Work in
draft-ietf-detnet-ip-over-tsn-07, 19 February 2021, Progress, Internet-Draft, draft-ietf-detnet-ip-over-tsn-
<https://tools.ietf.org/html/draft-ietf-detnet-ip-over- 07, 19 February 2021,
tsn-07>. <https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
ip-over-tsn-07>.
[IEEE802.1TSN] [IEEE802.1TSN]
IEEE 802.1, "Time-Sensitive Networking (TSN) Task Group", IEEE 802.1, "Time-Sensitive Networking (TSN) Task Group",
<http://www.ieee802.org/1/pages/tsn.html>. <http://www.ieee802.org/1/pages/tsn.html>.
[IEEE802.1AS] [IEEE802.1AS]
IEEE, "IEEE Standard for Local and metropolitan area IEEE, "IEEE Standard for Local and metropolitan area
networks -- Timing and Synchronization for Time-Sensitive networks -- Timing and Synchronization for Time-Sensitive
Applications", IEEE 802.1AS-2020, Applications", IEEE 802.1AS-2020,
<https://standards.ieee.org/content/ieee-standards/en/ <https://standards.ieee.org/content/ieee-standards/en/
skipping to change at page 64, line 42 skipping to change at page 65, line 42
[EHA11] Ehammer, M. and T. Graeupl, "AeroMACS - An Airport [EHA11] Ehammer, M. and T. Graeupl, "AeroMACS - An Airport
Communications System", IEEE 30th Digital Avionics Systems Communications System", IEEE 30th Digital Avionics Systems
Conference (DACS), pp. 1-16, New York, NY, USA , September Conference (DACS), pp. 1-16, New York, NY, USA , September
2011. 2011.
[SCH14] Schnell, M., Epple, U., Shutin, D., and N. [SCH14] Schnell, M., Epple, U., Shutin, D., and N.
Schneckenburger, "LDACS: Future Aeronautical Schneckenburger, "LDACS: Future Aeronautical
Communications for Air- Traffic Management", IEEE Communications for Air- Traffic Management", IEEE
Communications Magazine, 52(5), 104-110 , 2017. Communications Magazine, 52(5), 104-110 , 2017.
[CAL1287] Cavalcanti, D., Venkatesan, G., Cariou, L., and C.
Vordeiro, "TSN support in 802.11 and potential extensions
for TGbe", 2019,
<https://mentor.ieee.org/802.11/dcn/19/11-19-1287>.
[SUR2021] Sudhakaran, S., Montgomery, K., Kashef, M., Cavalcanti,
D., and R. Candell, "Wireless Time Sensitive Networking
for Industrial Collaborative Robotic Workcells", 17th IEEE
International Conference on Factory Communication Systems
(WFCS) , 2021,
<https://ieeexplore.ieee.org/abstract/document/9483447>.
Authors' Addresses Authors' Addresses
Pascal Thubert (editor) Pascal Thubert (editor)
Cisco Systems, Inc Cisco Systems, Inc
Building D Building D
45 Allee des Ormes - BP1200 45 Allee des Ormes - BP1200
06254 MOUGINS - Sophia Antipolis 06254 MOUGINS - Sophia Antipolis
France France
Phone: +33 497 23 26 34 Phone: +33 497 23 26 34
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