Reliable and Available Wireless Architecture
draft-ietf-raw-architecture-04
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| Authors | Pascal Thubert , Georgios Z. Papadopoulos | ||
| Last updated | 2022-03-04 | ||
| Replaces | draft-pthubert-raw-architecture | ||
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draft-ietf-raw-architecture-04
RAW P. Thubert, Ed.
Internet-Draft Cisco Systems
Intended status: Informational G.Z. Papadopoulos
Expires: 5 September 2022 IMT Atlantique
4 March 2022
Reliable and Available Wireless Architecture
draft-ietf-raw-architecture-04
Abstract
Reliable and Available Wireless (RAW) provides for high reliability
and availability for IP connectivity over a wireless medium. The
wireless medium presents significant challenges to achieve
deterministic properties such as low packet error rate, bounded
consecutive losses, and bounded latency. This document defines the
RAW Architecture following an OODA loop that involves OAM, PCE, PSE
and PAREO functions. It builds on the DetNet Architecture and
discusses specific challenges and technology considerations needed to
deliver DetNet service utilizing scheduled wireless segments and
other media, e.g., frequency/time-sharing physical media resources
with stochastic traffic.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on 5 September 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The RAW problem . . . . . . . . . . . . . . . . . . . . . . . 6
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . 6
2.1.2. Link and Direction . . . . . . . . . . . . . . . . . 7
2.1.3. Path and Tracks . . . . . . . . . . . . . . . . . . . 8
2.1.4. Deterministic Networking . . . . . . . . . . . . . . 10
2.1.5. Reliability and Availability . . . . . . . . . . . . 11
2.1.6. OAM variations . . . . . . . . . . . . . . . . . . . 12
2.2. Reliability and Availability . . . . . . . . . . . . . . 13
2.2.1. High Availability Engineering Principles . . . . . . 13
2.2.2. Applying Reliability Concepts to Networking . . . . . 16
2.2.3. Wireless Effects Affecting Reliability . . . . . . . 16
2.3. Routing Time Scale vs. Forwarding Time Scale . . . . . . 18
3. The RAW Conceptual Model . . . . . . . . . . . . . . . . . . 20
4. The OODA Loop . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1. Observe: The RAW OAM . . . . . . . . . . . . . . . . . . 23
4.2. Orient: The Path Computation Engine . . . . . . . . . . . 24
4.3. Decide: The Path Selection Engine . . . . . . . . . . . . 24
4.4. Act: The PAREO Functions . . . . . . . . . . . . . . . . 26
4.4.1. Packet Replication . . . . . . . . . . . . . . . . . 27
4.4.2. Packet Elimination . . . . . . . . . . . . . . . . . 28
4.4.3. Promiscuous Overhearing . . . . . . . . . . . . . . . 28
4.4.4. Constructive Interference . . . . . . . . . . . . . . 29
5. Security Considerations . . . . . . . . . . . . . . . . . . . 29
5.1. Layer-2 encryption . . . . . . . . . . . . . . . . . . . 29
5.2. Forced Access . . . . . . . . . . . . . . . . . . . . . . 29
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 30
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
9.1. Normative References . . . . . . . . . . . . . . . . . . 30
9.2. Informative References . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 33
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1. Introduction
Deterministic Networking is an attempt to emulate the properties of a
serial link over a switched fabric, by providing a bounded latency
and eliminating congestion loss, even when co-existing with best-
effort traffic. It is getting traction in various industries
including professional A/V, manufacturing, online gaming, and
smartgrid automation, enabling cost and performance optimizations
(e.g., vs. loads of P2P cables).
Bringing determinism in a packet network means eliminating the
statistical effects of multiplexing that result in probabilistic
jitter and loss. This can be approached with a tight control of the
physical resources to maintain the amount of traffic within a
budgeted volume of data per unit of time that fits the physical
capabilities of the underlying network, and the use of time-shared
resources (bandwidth and buffers) per circuit, and/or by shaping and/
or scheduling the packets at every hop.
This innovation was initially introduced on wired networks, with IEEE
802.1 Time Sensitive networking (TSN) - for Ethernet LANs - and IETF
DetNet. But the wired and the wireless media are fundamentally
different at the physical level and in the possible abstractions that
can be built for IPv6 [IPoWIRELESS]. Nevertheless, deterministic
capabilities are required in a number of wireless use cases as well
[RAW-USE-CASES]. With new scheduled radios such as TSCH and OFDMA
[RAW-TECHNOS] being developped to provide determinism over wireless
links at the lower layers, providing DetNet capabilities is now
becoming possible.
Wireless networks operate on a shared medium where uncontrolled
interference, including the self-induced multipath fading cause
random transmission losses. Fixed and mobile obstacles and
reflectors may block or alter the signal, causing transient and
unpredictable variations of the throughput and packet delivery ratio
(PDR) of a wireless link. This adds new dimensions to the
statistical effects that affect the quality and reliability of the
link. Multiple links and transmissions must be used, and the
challenge is to provide enough diversity and redundancy to ensure the
timely packet delivery while preserving energy and optimizing the use
of the shared spectrum.
Reliable and Available Wireless (RAW) takes up the challenge of
providing highly available and reliable end-to-end performances in a
network with scheduled wireless segments. To defeat those additional
causes of transmission delay and loss in wireless transmission, RAW
requires and leverages deterministic layer-2 capabilities. Operating
at the layer-3, RAW can further increase diversity in the spatial,
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time, code, and frequency domains by enabling multiple link-layer
wired and wireless technologies in parallel or sequentially, for a
higher resilience and a wider applicability. RAW can also provide
homogeneous services to critical applications beyond the boundaries
of a single subnetwork, e.g., controlling the use of diverse radio
access technologies to optimize the end-to-end application
experience.
While the generic "Deterministic Networking Problem Statement"
[RFC8557] applies to both the wired and the wireless media, the
methods to achieve RAW must extend those used to support time-
sensitive networking over wires, as a RAW solution has to address
less consistent transmissions, energy conservation and shared
spectrum efficiency.
RAW provides DetNet elements that are specialized for IPv6 flows
[IPv6] over selected deterministic radios technologies [RAW-TECHNOS].
Conceptually, RAW is agnostic to the radio layer underneath though
the capability to schedule transmissions is assumed. How the PHY is
programmed to do so, and whether the radio is single-hop or meshed,
are unknown at the IP layer and not part of the RAW abstraction.
Nevertheless, cross-layer optimizations may take place to ensure
proper link awareness (think, link quality) and packet handling
(think, scheduling).
The "Deterministic Networking Architecture" [RFC8655] is composed of
three planes: the Application (User) Plane, the Controller Plane, and
the Network Plane. The DetNet Network Plane is composed of a DetNet
service sublayer that focuses on flow protection (e.g., using
redundancy) and can be fully operated at layer-3, and a DetNet
forwarding sublayer that associates the flows to the paths, ensures
the availability of the necessary resources, and leverages layer-2
functionalities for timely delivery to the next Detnet system.
The RAW Architecture extends the DetNet Network Plane, to accommodate
one or multiple hops of homogeneous or heterogeneous wired and
wireless technologies. RAW adds reactivity to the DetNet service
sublayer to compensate the dynamics for the radio links in terms of
lossiness and bandwidth. This may apply for instance to mesh
networks as illustrated in Figure 3, or diverse radio access networks
as illustrated in Figure 5.
RAW and DetNet route application flows that require a special
treatment along the paths that will provide that treatment. This may
be seen as a form of Path Aware Networking and may be subject to
impediments documented in [RFC9049].
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The establishment of a path is not in-scope for RAW. It may be the
product of a centralized Controller Plane as described for DetNet.
As opposed to wired networks, the action of installing a path over a
set of wireless links may be very slow relative to the speed at which
the radio conditions vary, and it makes sense in the wireless case to
provide redundant forwarding solutions along a complex path (see
Section 2.1.3) and to leave it to the Network Plane to select which
of those forwarding solutions are to be used for a given packet based
on the current conditions.
RAW distinguishes the longer time scale at which routes are computed
from the the shorter forwarding time scale where per-packet decisions
are made. RAW operates within the Network Plane at the forwarding
time scale on one DetNet flow over a complex path delineated by a
Track (see Section 2.1.3.2). The Track is preestablished and
installed by means outside of the scope of RAW; it may be strict or
loose depending on whether each or just a subset of the hops are
observed and controlled by RAW.
The RAW Architecture is based on an abstract OODA Loop (Observe,
Orient, Decide, Act). The generic concept involves:
1. Network Plane measurement protocols for Operations,
Administration and Maintenance (OAM) to Observe some or all hops
along a Track as well as the end-to-end packet delivery
2. Controller plane elements to reports the links statistics to a
Path computation Element (PCE) in a centralized controller that
computes and installs the Tracks and provides meta data to Orient
the routing decision
3. A Runtime distributed Path Selection Engine (PSE) that Decides
which subTrack to use for the next packet(s) that are routed
along the Track
4. Packet (hybrid) ARQ, Replication, Elimination and Ordering
Dataplane actions that operate at the DetNet Service Layer to
increase the reliability of the end-to-end transmissions. The
RAW architecture also covers in-situ signalling when the decision
is Acted by a node that down the Track from the PSE.
The overall OODA Loop optimizes the use of redundancy to achieve the
required reliability and availability Service Level Agreement (SLA)
while minimizing the use of constrained resources such as spectrum
and battery.
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This document presents the RAW problem and associated terminology in
Section 2, and elaborates in Section 4 on the OODA loop based on the
RAW conceptual model presented in Section 3.
2. The RAW problem
2.1. Terminology
RAW reuses terminology defined for DetNet in the "Deterministic
Networking Architecture" [RFC8655], e.g., PREOF for Packet
Replication, Elimination and Ordering Functions.
RAW also reuses terminology defined for 6TiSCH in [6TiSCH-ARCHI] such
as the term Track. A Track associates a complex path with PAREO and
shaping operations. The concept is agnostic to the underlaying
technology and applies but is not limited to any fully or partially
wireless mesh. RAW specifies strict and loose Tracks depending on
whether the path is fully controlled by RAW or traverses an opaque
network where RAW cannot observe and control the individual hops.
RAW uses the following terminology and acronyms:
2.1.1. Acronyms
2.1.1.1. ARQ
Automatic Repeat Request, enabling an acknowledged transmission and
retries. ARQ is a typical model at Layer-2 on a wireless medium.
ARQ is typically implemented hop-by-hop and not end-to-end in
wireless networks. Else, it introduces excessive indetermination in
latency, but a limited number of retries within a bounded time may be
used within end-to-end constraints.
2.1.1.2. OAM
OAM stands for Operations, Administration, and Maintenance, and
covers the processes, activities, tools, and standards involved with
operating, administering, managing and maintaining any system. This
document uses the terms Operations, Administration, and Maintenance,
in conformance with the 'Guidelines for the Use of the "OAM" Acronym
in the IETF' [RFC6291] and the system observed by the RAW OAM is the
Track.
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2.1.1.3. OODA
Observe, Orient, Decide, Act. The OODA Loop is a conceptual cyclic
model developed by USAF Colonel John Boyd, and that is applicable in
multiple domains where agility can provide benefits against brute
force.
2.1.1.4. PAREO
Packet (hybrid) ARQ, Replication, Elimination and Ordering. PAREO is
a superset Of DetNet's PREOF that includes radio-specific techniques
such as short range broadcast, MUMIMO, PHY rate and other Modulation
Coding Scheme (MCS) adaptation, constructive interference and
overhearing, which can be leveraged separately or combined to
increase the reliability.
2.1.2. Link and Direction
2.1.2.1. Flapping
In the context of RAW, a link flaps when the reliability of the
wireless connectivity drops abruptly for a short period of time,
typically of a subsecond to seconds duration.
2.1.2.2. Uplink
Connection from end-devices to a data communication equipment. In
the context of wireless, uplink refers to the connection between a
station (STA) and a controller (AP) or a User Equipment (UE) to a
Base Station (BS) such as a 3GPP 5G gNodeB (gNb).
2.1.2.3. Downlink
The reverse direction from uplink.
2.1.2.4. Downstream
Following the direction of the flow data path along a Track.
2.1.2.5. Upstream
Against the direction of the flow data path along a Track.
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2.1.3. Path and Tracks
2.1.3.1. Path
Quoting section 1.1.3 of [INT-ARCHI]:
| At a given moment, all the IP datagrams from a particular source
| host to a particular destination host will typically traverse the
| same sequence of gateways. We use the term "path" for this
| sequence. Note that a path is uni-directional; it is not unusual
| to have different paths in the two directions between a given host
| pair.
Section 2 of [I-D.irtf-panrg-path-properties] points to a longer,
more modern definition of path, which begins as follows:
| A sequence of adjacent path elements over which a packet can be
| transmitted, starting and ending with a node. A path is
| unidirectional. Paths are time-dependent, i.e., the sequence of
| path elements over which packets are sent from one node to another
| may change. A path is defined between two nodes.
It follows that the general acceptance of a path is a linear sequence
of nodes, as opposed to a multi-dimensional graph, defined by the
experience of the packet that went from a node A to a node B.
With DetNet and RAW, a packet may be duplicated, fragmented and
network-coded, and the various byproducts may travel different paths
that are not necessarily end-to-end between A and B; we refer to that
experience as a complex path. The complex path does not fit the
traditional description of a path, and is subject to change from a
packet to the next. This is why we introduce below the term of a
Track as the overall topology where the possible complex paths are
all contained.
In the context of this document, a path is observed by following one
copy or one fragment of a packet that conserves its uniqueness and
integrity. For instance, if C replicates to E and F and D eliminates
on the way from A to B, a packet from A to B experiences 2 paths,
A->C->E->D->B and A->C->F->D->B.
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2.1.3.2. Track
A networking graph that can be followed to transport packets with
equivalent treatment; as opposed to the definition of a path above, a
Track represents not an experience but a potential, is not
necessarily a linear sequence, and is not necessarily fully traversed
(flooded) by all packets of a flow. It may contain multiple paths
that may overlap, fork and rejoin, for instance to enable the RAW
PAREO operations.
+---------+
| IoT G/W |
+---------+
EGR <=== Elimination at Egress
| |
/------/ \-------\ Wired backbone
| |
+--|--+ +--|--+
| | | Backbone | | | Backbone
| | | Router | | | Router
+--|--+ +--|--+
| |
o \ o / Track branch
o o o---o---o o o o o
\ o / o o o
o o \ / o low power lossy network
\/ o o o
o IN <=== Replication at Track Ingress
|
o <- source device
Figure 1: Example IoT Track to an IoT gateway with 1+1 redundancy
In DetNet [RFC8655] terms, a Track has the following properties:
* A Track is a layer-3 abstraction built upon P2P IP links between
routers. A router may form multiple P2P IP links over a single
radio interface.
* A Track has one Ingress and one Egress nodes, which operate as
DetNet Edge nodes.
* A Track is reversible, meaning that packets can be routed against
the flow of data packets, e.g., to carry OAM measurements or
control messages back to the Ingress.
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* The vertices of the Track are DetNet Relay nodes that operate at
the DetNet Service sublayer and provide the PAREO functions.
* The topological edges of the graph are serial sequences of DetNet
Transit nodes that operate at the DetNet Forwarding sublayer.
2.1.3.3. SubTrack
A Track within a Track. The RAW PSE selects a subTrack on a per-
packet or a per-collection of packets basis to provide the desired
reliability for the transported flows.
2.1.3.4. Segment
A serial path formed by a topological edge of a Track. East-West
Segments are oriented from Ingress (East) to Egress (West). North/
South Segments can be bidirectional; to avoid loops, measures must be
taken to ensure that a given packet flows either Northwards or
Southwards along a bidirectional Segment, but never bounces back.
2.1.4. Deterministic Networking
This document reuses the terminology in section 2 of [RFC8557] and
section 4.1.2 of [RFC8655] for deterministic networking and
deterministic networks.
2.1.4.1. Flow
A collection of consecutive IP packets defined by the upper layers
and signaled by the same 5 or 6-tuple, see section 5.1 of [RFC8939].
Packets of the same flow must be placed on the same Track to receive
an equivalent treatment from Ingress to Egress within the Track.
Multiple flows may be transported along the same Track. The subTrack
that is selected for the flow may change over time under the control
of the PSE.
2.1.4.2. Deterministic Flow Identifier (L2)
A tuple identified by a stream_handle, and provided by a bridge, in
accordance with IEEE 802.1CB. The tuple comprises at least src MAC,
dst MAC, VLAN ID, and L2 priority. Continuous streams are
characterized by bandwidth and max packet size; scheduled streams are
characterized by a repeating pattern of timed transmissions.
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2.1.4.3. Deterministic Flow Identifier (L3)
See section 3.3 of [DetNet-DP]. The classical IP 5-tuple that
identifies a flow comprises the src IP, dst IP, src port, dest port,
and the upper layer protocol (ULP). DetNet uses a 6-tuple where the
extra field is the DSCP field in the packet. The IPv6 flow label is
not used for that purpose.
2.1.4.4. TSN
TSN stands for Time Sensitive Networking and denotes the efforts at
IEEE 802 for deterministic networking, originally for use on
Ethernet. Wireless TSN (WTSN) denotes extensions of the TSN work on
wireless media such as the selected RAW technologies [RAW-TECHNOS].
2.1.5. Reliability and Availability
In the context of the RAW work, Reliability and Availability are
defined as follows:
2.1.5.1. Service Level Agreement
In the context of RAW, an SLA (service level agreement) is a contract
between a provider, the network, and a client, the application flow,
about measurable metrics such as latency boundaries, consecutive
losses, and packet delivery ratio (PDR).
2.1.5.2. Service Level Objective
A service level objective (SLO) is one term in the SLA, for which
specific network setting and operations are implemented. For
instance, a dynamic tuning of the packet redundancy will address an
SLO of consecutive losses in a row by augmenting the chances of
delivery of a packet that follows a loss.
2.1.5.3. Service Level Indicator
A service level indicator (SLI) measures the compliance of an SLO to
the terms of the contrast. It can be for instance the statistics of
individual losses and losses in a row as time series.).
2.1.5.4. Reliability
Reliability is a measure of the probability that an item will perform
its intended function for a specified interval under stated
conditions (SLA). RAW expresses reliability in terms of Mean Time
Between Failure (MTBF) and Maximum Consecutive Failures (MCF). More
in [NASA].).
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2.1.5.5. Available
That is exempt of unscheduled outage or derivation from the terms of
the SLA. A basic expectation for a RAW network is that the flow is
maintained in the face of any single breakage or flapping.
2.1.5.6. Availability
Availability is a measure of the relative amount of time where a RAW
Network operates in stated condition (SLA), expressed as
(uptime)/(uptime+downtime). Because a serial wireless path may not
be good enough to provide the required reliability, and even 2
parallel paths may not be over a longer period of time, the RAW
availability implies a journey that is a lot more complex than
following a serial path.
2.1.6. OAM variations
2.1.6.1. Active OAM
See [RFC7799]. In the context of RAW, Active OAM is used to observe
a particular Track, subTrack, or Segment of a Track regardless of
whether it is used for traffic at that time.
2.1.6.2. In-Band OAM
An active OAM packet is considered in-band for the monitored Track
when it traverses the same set of links and interfaces and if the OAM
packet receives the same QoS and PAREO treatment as the packets of
the data flows that are injected in the Track.
2.1.6.3. Out-of-Band OAM
Out-of-band OAM is an active OAM whose path is not topologically
congruent to the Track, or its test packets receive a QoS and/or
PAREO treatment that is different from that of the packets of the
data flows that are injected in the Track, or both.
2.1.6.4. Limited OAM
An active OAM packet is a Limited OAM packet when it observes the RAW
operation over a node, a segment, or a subTrack of the Track, though
not from Ingress to Egress. It is injected in the datapath and
extracted from the datapath around the particular function or
subnetwork (e.g., around a relay providing a service layer
replication point) that is being tested.
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2.1.6.5. Upstream OAM
An upstream OAM packet is an Out-of-Band OAM packet that traverses
the Track from egress to ingress on the reverse direction, to capture
and report OAM measurements upstream. The collection may capture all
information along the whole Track, or it may only learn select data
across all, or only a particular subTrack, or Segment of a Track.
2.1.6.6. Residence Time
A residence time (RT) is defined as the time period between the
reception of a packet starts and the transmission of the packet
begins. In the context of RAW, RT is useful for a transit node, not
ingress or egress.
2.1.6.7. Additional References
[DetNet-OAM] provides additional terminology related to OAM in the
context of DetNet and by extension of RAW, whereas [RFC7799] defines
the Active, Passive, and Hybrid OAM methods.
2.2. Reliability and Availability
2.2.1. High Availability Engineering Principles
The reliability criteria of a critical system pervades through its
elements, and if the system comprises a data network then the data
network is also subject to the inherited reliability and availability
criteria. It is only natural to consider the art of high
availability engineering and apply it to wireless communications in
the context of RAW.
There are three principles [pillars] of high availability
engineering:
1. elimination of single points of failure
2. reliable crossover
3. prompt detection of failures as they occur.
These principles are common to all high availability systems, not
just ones with Internet technology at the center. Examples of both
non-Internet and Internet are included.
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2.2.1.1. Elimination of Single Points of Failure
Physical and logical components in a system happen to fail, either as
the effect of wear and tear, when used beyond acceptable limits, or
due to a software bug. It is necessary to decouple component failure
from system failure to avoid the latter. This allows failed
components to be restored while the rest of the system continues to
function.
IP Routers leverage routing protocols to compute alternate routes in
case of a failure. There is a rather open-ended issue over alternate
routes -- for example, when links are cabled through the same
conduit, they form a shared risk link group (SRLG), and will share
the same fate if the bundle is cut. The same effect can happen with
virtual links that end up in a same physical transport through the
games of encapsulation. In a same fashion, an interferer or an
obstacle may affect multiple wireless transmissions at the same time,
even between different sets of peers.
Intermediate network Nodes such as routers, switches and APs, wire
bundles and the air medium itself can become single points of
failure. For High Availability, it is thus required to use
physically link- and Node-disjoint paths; in the wireless space, it
is also required to use the highest possible degree of diversity
(time, space, code, frequency, channel width) in the transmissions
over the air to combat the additional causes of transmission loss.
From an economics standpoint, executing this principle properly
generally increases capitalization expense because of the redundant
equipment. In a constrained network where the waste of energy and
bandwidth should be minimized, an excessive use of redundant links
must be avoided; for RAW this means that the extra bandwidth must be
used wisely and with parcimony.
2.2.1.2. Reliable Crossover
Having a backup equipment has a limited value unless it can be
reliably switched into use within the down-time parameters. IP
Routers execute reliable crossover continuously because the routers
will use any alternate routes that are available [RFC0791]. This is
due to the stateless nature of IP datagrams and the dissociation of
the datagrams from the forwarding routes they take. The "IP Fast
Reroute Framework" [FRR] analyzes mechanisms for fast failure
detection and path repair for IP Fast-Reroute, and discusses the case
of multiple failures and SRLG. Examples of FRR techniques include
Remote Loop-Free Alternate [RLFA-FRR] and backup label-switched path
(LSP) tunnels for the local repair of LSP tunnels using RSVP-TE
[RFC4090].
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Deterministic flows, on the contrary, are attached to specific paths
where dedicated resources are reserved for each flow. This is why
each DetNet path must inherently provide sufficient redundancy to
provide the guaranteed SLA at all times. The DetNet PREOF typically
leverages 1+1 redundancy whereby a packet is sent twice, over non-
congruent paths. This avoids the gap during the fast reroute
operation, but doubles the traffic in the network.
In the case of RAW, the expectation is that multiple transient faults
may happen in overlapping time windows, in which case the 1+1
redundancy with delayed reestablishment of the second path will not
provide the required guarantees. The Data Plane must be configured
with a sufficient degree of redundancy to select an alternate
redundant path immediately upon a fault, without the need for a slow
intervention from the controller plane.
2.2.1.3. Prompt Notification of Failures
The execution of the two above principles is likely to render a
system where the user will rarely see a failure. But someone needs
to in order to direct maintenance.
There are many reasons for system monitoring (FCAPS for fault,
configuration, accounting, performance, security is a handy mental
checklist) but fault monitoring is sufficient reason.
"An Architecture for Describing Simple Network Management Protocol
(SNMP) Management Frameworks" [STD 62] describes how to use SNMP to
observe and correct long-term faults.
"Overview and Principles of Internet Traffic Engineering" [TE]
discusses the importance of measurement for network protection, and
provides abstract an method for network survivability with the
analysis of a traffic matrix as observed by SNMP, probing techniques,
FTP, IGP link state advertisements, and more.
Those measurements are needed in the context of RAW to inform the
controller and make the long term reactive decision to rebuild a
complex path based on statistical and aggregated information. RAW
itself operates in the Network Plane at a faster time scale with live
information on speed, state, etc... This live information can be
obtained directly from the lower layer, e.g., using L2 triggers, read
from a protocol such as the Dynamic Link Exchange Protocol (DLEP)
[DLEP], or transported over multiple hops using OAM and reverse OAM,
as illustrated in Figure 6.
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2.2.2. Applying Reliability Concepts to Networking
The terms Reliability and Availability are defined for use in RAW in
Section 2.1 and the reader is invited to read [NASA] for more details
on the general definition of Reliability. Practically speaking a
number of nines is often used to indicate the reliability of a data
link, e.g., 5 nines indicate a Packet Delivery Ratio (PDR) of
99.999%.
This number is typical in a wired environment where the loss is due
to a random event such as a solar particle that affects the
transmission of a particular frame, but does not affect the previous
or next frame, nor frames transmitted on other links. Note that the
QoS requirements in RAW may include a bounded latency, and a packet
that arrives too late is a fault and not considered as delivered.
For a periodic networking pattern such as an automation control loop,
this number is proportional to the Mean Time Between Failures (MTBF).
When a single fault can have dramatic consequences, the MTBF
expresses the chances that the unwanted fault event occurs. In data
networks, this is rarely the case. Packet loss cannot never be fully
avoided and the systems are built to resist to one loss, e.g., using
redundancy with Retries (HARQ) or Packet Replication and Elimination
(PRE), or, in a typical control loop, by linear interpolation from
the previous measurements.
But the linear interpolation method cannot resist multiple
consecutive losses, and a high MTBF is desired as a guarantee that
this will not happen, IOW that the number of losses-in-a-row can be
bounded. In that case, what is really desired is a Maximum
Consecutive Failures (MCF). If the number of losses in a row passes
the MCF, the control loop has to abort and the system, e.g., the
production line, may need to enter an emergency stop condition.
Engineers that build automated processes may use the network
reliability expressed in nines or as an MTBF as a proxy to indicate
an MCF, e.g., as described in section 7.4 of the "Deterministic
Networking Use Cases" [RFC8578].
2.2.3. Wireless Effects Affecting Reliability
In contrast with wired networks, errors in transmission are the
predominant source of packet loss in wireless networks.
The root cause for the loss may be of multiple origins, calling for
the use of different forms of diversity:
Multipath Fading A destructive interference by a reflection of the
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original signal.
A radio signal may be received directly (line-of-sight) and/or as
a reflection on a physical structure (echo). The reflections take
a longer path and are delayed by the extra distance divided by the
speed of light in the medium. Depending on the frequency, the
echo lands with a different phase which may add up to
(constructive interference) or cancel the direct signal
(destructive interference).
The affected frequencies depend on the relative position of the
sender, the receiver, and all the reflecting objects in the
environment. A given hop will suffer from multipath fading for
multiple packets in a row till a physical movement changes the
reflection patterns.
Co-channel Interference Energy in the spectrum used for the
transmission confuses the receiver.
The wireless medium itself is a Shared Risk Link Group (SRLG) for
nearby users of the same spectrum, as an interference may affect
multiple co-channel transmissions between different peers within
the interference domain of the interferer, possibly even when they
use different technologies.
Obstacle in Fresnel Zone The optimal transmission happens when the
Fresnel Zone between the sender and the receiver is free of
obstacles.
As long as a physical object (e.g., a metallic trolley between
peers) that affects the transmission is not removed, the quality
of the link is affected.
In an environment that is rich of metallic structures and mobile
objects, a single radio link will provide a fuzzy service, meaning
that it cannot be trusted to transport the traffic reliably over a
long period of time.
Transmission losses are typically not independent, and their nature
and duration are unpredictable; as long as a physical object (e.g., a
metallic trolley between peers) that affects the transmission is not
removed, or as long as the interferer (e.g., a radar) keeps
transmitting, a continuous stream of packets will be affected.
The key technique to combat those unpredictable losses is diversity.
Different forms of diversity are necessary to combat different causes
of loss and the use of diversity must be maximized to optimize the
PDR.
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A single packet may be sent at different times (time diversity) over
diverse paths (spatial diversity) that rely on diverse radio channels
(frequency diversity) and diverse PHY technologies, e.g., narrowband
vs. spread spectrum, or diverse codes. Using time diversity will
defeat short-term interferences; spatial diversity combats very local
causes such as multipath fading; narrowband and spread spectrum are
relatively innocuous to one another and can be used for diversity in
the presence of the other.
2.3. Routing Time Scale vs. Forwarding Time Scale
With DetNet, the Controller Plane Function that handles the routing
computation and maintenance (the PCE) can be centralized and can
reside outside the network. In a wireless mesh, the path to the PCE
can be expensive and slow, possibly going across the whole mesh and
back. Reaching to the PCE can also be slow in regards to the speed
of events that affect the forwarding operation at the radio layer.
Due to that cost and latency, the Controller Plane is not expected to
be sensitive/reactive to transient changes. The abstraction of a
link at the routing level is expected to use statistical metrics that
aggregate the behavior of a link over long periods of time, and
represent its properties as shades of gray as opposed to numerical
values such as a link quality indicator, or a boolean value for
either up or down.
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+----------------+
| Controller |
| [PCE] |
+----------------+
^
|
Slow
|
_-._-._-._-._-._-. | ._-._-._-._-._-._-._-._-._-._-._-._-
_-._-._-._-._-._-._-. | _-._-._-._-._-._-._-._-._-._-._-._-
|
Expensive
|
.... | .......
.... . | . .......
.... v ...
.. A-------B-------C---D ..
... / \ / \ ..
. I ----M-------N--***-- E ..
.. \ / / ...
.. P--***--Q-----M---R ....
.. ....
. <----- Fast -------> ....
....... ....
.................
*** = flapping at this time
Figure 2: Time Scales
In the case of wireless, the changes that affect the forwarding
decision can happen frequently and often for short durations, e.g., a
mobile object moves between a transmitter and a receiver, and will
cancel the line of sight transmission for a few seconds, or a radar
measures the depth of a pool and interferes on a particular channel
for a split second.
There is thus a desire to separate the long term computation of the
route and the short term forwarding decision. In that model, the
routing operation computes a complex Track that enables multiple Non-
Equal Cost Multi-Path (N-ECMP) forwarding solutions, and leaves it to
the Data Plane to make the per-packet decision of which of these
possibilities should be used.
In the wired world, and more specifically in the context of Traffic
Engineering (TE), an alternate path can be used upon the detection of
a failure in the main path, e.g., using OAM in MPLS-TP or BFD over a
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collection of SD-WAN tunnels. RAW formalizes a forwarding time scale
that is an order(s) of magnitude shorter than the controller plane
routing time scale, and separates the protocols and metrics that are
used at both scales. Routing can operate on long term statistics
such as delivery ratio over minutes to hours, but as a first
approximation can ignore flapping. On the other hand, the RAW
forwarding decision is made at the scale of the packet rate, and uses
information that must be pertinent at the present time for the
current transmission(s).
3. The RAW Conceptual Model
RAW inherits the conceptual model described in section 4 of the
DetNet Architecture [RFC8655]. RAW extends the DetNet service layer
to provide additional agility against transmission loss.
A RAW Network Plane may be strict or loose, depending on whether RAW
observes and takes actions on all hops or not. For instance, the
packets between two wireless entities may be relayed over a wired
infrastructure such as a Wi-Fi extended service set (ESS) or a 5G
Core; in that case, RAW observes and controls the transmission over
the wireless first and last hops, as well as end-to-end metrics such
as latency, jitter, and delivery ratio. This operation is loose
since the structure and properties of the wired infrastructure are
ignored, and may be either controlled by other means such as DetNet/
TSN, or neglected in the face of the wireless hops.
A Controller Plane Function (CPF) called the Path Computation Element
(PCE) [RFC4655] interacts with RAW Nodes over a Southbound API. The
RAW Nodes are DetNet relays that are capable of additional diversity
mechanisms and measurement functions related to the radio interface,
in particular the PAREO diversity mechanisms.
The PCE defines a complex Track between an Ingress End System and an
Egress End System, and indicates to the RAW Nodes where the PAREO
operations may be actionned in the Network Plane. The Track may be
expressed loosely to enable traversing a non-RAW subnetwork. In that
case, the expectation is that the non-RAW subnetwork can be neglected
in the RAW computation, that is, considered infinitely fast, reliable
and/or available in comparison with the links between RAW nodes.
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CPF CPF CPF CPF
Southbound API
_-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-
_-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-
RAW --/ RAW --/ RAW --/ RAW
/-- Node /-- Node /-- Node /-- Node --/
Ingress --/ / / /-- Egress
End / / .. . End
Node ---/ / / .. .. . /-- Node
/-- RAW --/ RAW ( non-RAW ) -- RAW --/
Node /-- Node --- ( Nodes ) Node
... .
--/ wireless wired
/-- link --- link
Figure 3: RAW Nodes
The Link-Layer metrics are reported to the PCE in a time-aggregated,
e.g., statistical fashion. Example Link-Layer metrics include
typical Link bandwidth (the medium speed depends dynamically on the
PHY mode), number of flows (bandwidth that can be reserved for a
flomw depends on the number and size of flows sharing the spectrum)
and average and mean squared deviation of availability and
reliability figures such as Packet Delivery Ratio (PDR) over long
periods of time.
Based on those metrics, the PCE installs the Track with enough
redundant forwarding solutions to ensure that the Network Plane can
reliably deliver the packets within a System Level Agreement (SLA)
associated to the flows that it transports. The SLA defines end-to-
end reliability and availability requirements, where reliability may
be expressed as a successful delivery in order and within a bounded
delay of at least one copy of a packet.
Depending on the use case and the SLA, the Track may comprise non-RAW
segments, either interleaved inside the Track, or all the way to the
Egress End Node (e.g., a server in the Internet). RAW observes the
Lower-Layer Links between RAW nodes (typically, radio links) and the
end-to-end Network Layer operation to decide at all times which of
the PAREO diversity schemes is actioned by which RAW Nodes.
Once a Track is established, per-segment and end-to-end reliability
and availability statistics are periodically reported to the PCE to
assure that the SLA can be met or have it recompute the Track if not.
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4. The OODA Loop
The RAW Architecture is structured as an OODA Loop (Observe, Orient,
Decide, Act). It involves:
1. Network Plane measurement protocols for Operations,
Administration and Maintenance (OAM) to Observe some or all hops
along a Track as well as the end-to-end packet delivery, more in
Section 4.1;
2. Controller plane elements to report the links statistics to a
Path computation Element (PCE) in a centralized controller that
computes and installs the Tracks and provides meta data to Orient
the routing decision, more in Section 4.2;
3. A Runtime distributed Path Selection Engine (PSE) thar Decides
which subTrack to use for the next packet(s) that are routed
along the Track, more in Section 4.3;
4. Packet (hybrid) ARQ, Replication, Elimination and Ordering
Dataplane actions that operate at the DetNet Service Layer to
increase the reliability of the end-to-end transmission. The RAW
architecture also covers in-situ signalling when the decision is
Acted by a node that down the Track from the PSE, more in
Section 4.4.
+-------> Orient (PCE) --------+
| link stats, |
| pre-trained model |
| ... |
| v
Observe (OAM) Decide (PSE)
^ |
| |
| |
+-------- Act (PAREO) <--------+
At DetNet
Service sublayer
Figure 4: The RAW OODA Loop
The overall OODA Loop optimizes the use of redundancy to achieve the
required reliability and availability Service Level Agreement (SLA)
while minimizing the use of constrained resources such as spectrum
and battery.
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4.1. Observe: The RAW OAM
RAW In-situ OAM operation in the Network Plane may observe either a
full Track or subTracks that are being used at this time. As packets
may be load balanced, replicated, eliminated, and / or fragmented for
Network Coding (NC) forward error correction (FEC), the RAW In-situ
operation needs to be able to signal which operation occured to an
individual packet.
Active RAW OAM may be needed to observe the unused segments and
evaluate the desirability of a rerouting decision.
Finally, the RAW Service Layer Assurance may observe the individual
PAREO operation of a relay node to ensure that it is conforming; this
might require injecting an OAM packet at an upstream point inside the
Track and extracting that packet at another point downstream before
it reaches the egress.
This observation feeds the RAW PSE that makes the decision on which
PAREO function is actioned at which RAW Node, for one a small
continuous series of packets.
... ..
RAN 1 ----- ... .. ...
/ . .. ....
+-------+ / . .. .... +------+
|Ingress|- . ..... |Egress|
| End |------ RAN 2 -- . Internet ....---| End |
|System |- .. ..... |System|
+-------+ \ . ...... +------+
\ ... ... .....
RAN n -------- ... .....
<------------------> <-------------------->
Observed by OAM Opaque to OAM
Figure 5: Observed Links in Radio Access Protection
In the case of a End-to-End Protection in a Wireless Mesh, the Track
is strict and congruent with the path so all links are observed.
Conversely, in the case of Radio Access Protection illustrated in
Figure 5, the Track is Loose and only the first hop is observed; the
rest of the path is abstracted and considered infinitely reliable.
The loss if a packet is attributed to the first hop Radio Access
Network (RAN), even if a particular loss effectively happens farther
down the path. In that case, RAW enables technology diversity (e.g.
Wi-Fi and 5G) which in turn improves the diversity in spectrum usage.
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The Links that are not observed by OAM are opaque to it, meaning that
the OAM information is carried across and possibly echoed as data,
but there is no information capture in intermediate nodes. In the
example above, the Internet is opaque and not controlled by RAW;
still the RAW OAM measures the end-to-end latency and delivery ratio
for packets sent via each if RAN 1, RAN 2 and RAN 3, and determines
whether a packet should be sent over either or a collection of those
access links.
4.2. Orient: The Path Computation Engine
RAW separates the long time scale at which a Track is elaborated and
installed, from the short time scale at which the forwarding decision
is taken for one or a few packets (see in Section 2.3) that will
experience the same path until the network conditions evolve and
another patyh is selected within the same Track.
The Track computation is out of scope, but RAW expects that the
Controller plane protocol that installs the Track also provides
related knowledge in the form of meta data about the links, segments
and possible subTracks. That meta data can be a pre-digested
statistical model, and may include prediction of future flaps and
packet loss, as well as recommended actions when that happens.
The meta data may include:
* Pre-Determined subTracks to match predictable error profiles
* Pre-Trained models
* Link Quality Statistics and their projected evolution
The Track is installed with measurable objectives that are computed
by the PCE to achieve the RAW SLA. The objectives can be expressed
as any of maximum number of packet lost in a row, bounded latency,
maximal jitter, maximum number of interleaved out of order packets,
average number of copies received at the elimination point, and
maximal delay between the first and the last received copy of the
same packet.
4.3. Decide: The Path Selection Engine
The RAW OODA Loop operates at the path selection time scale to
provide agility vs. the brute force approach of flooding the whole
Track. The OODA Loop controls, within the redundant solutions that
are proposed by the PCE, which will be used for each packet to
provide a Reliable and Available service while minimizing the waste
of constrained resources.
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To that effect, RAW defines the Path Selection Engine (PSE) that is
the counterpart of the PCE to perform rapid local adjustments of the
forwarding tables within the diversity that the PCE has selected for
the Track. The PSE enables to exploit the richer forwarding
capabilities with PAREO and scheduled transmissions at a faster time
scale over the smaller domain that is the Track, in either a loose or
a strict fashion.
Compared to the PCE, the PSE operates on metrics that evolve faster,
but that need to be advertised at a fast rate but only locally,
within the Track. The forwarding decision may also change rapidly,
but with a scope that is also contained within the Track, with no
visibility to the other Tracks and flows in the network. This is as
opposed to the PCE that must observe the whole network and optimize
all the Tracks globally, which can only be done at a slow pace and
using long-term statistical metrics, as presented in Table 1.
+===============+========================+===================+
| | PCE (Not in Scope) | PSE (In Scope) |
+===============+========================+===================+
| Operation | Centralized | Source-Routed or |
| | | Distributed |
+---------------+------------------------+-------------------+
| Communication | Slow, expensive | Fast, local |
+---------------+------------------------+-------------------+
| Time Scale | hours and above | seconds and below |
+---------------+------------------------+-------------------+
| Network Size | Large, many Tracks to | Small, within one |
| | optimize globally | Track |
+---------------+------------------------+-------------------+
| Considered | Averaged, Statistical, | Instant values / |
| Metrics | Shade of grey | boolean condition |
+---------------+------------------------+-------------------+
Table 1: PCE vs. PSE
The PSE sits in the DetNet Service sub-Layer of Edge and Relay Nodes.
On the one hand, it operates on the packet flow, learning the Track
and path selection information from the packet, possibly making local
decision and retagging the packet to indicate so. On the other hand,
the PSE interacts with the lower layers and with its peers to obtain
up-to-date information about its radio links and the quality of the
overall Track, respectively, as illustrated in Figure 6.
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|
packet | going
down the | stack
+==========v==========+=====================+=====================+
| (iOAM + iCTRL) | (L2 Triggers, DLEP) | (oOAM) |
+==========v==========+=====================+=====================+
| Learn from Learn from |
| packet tagging Maintain end-to-end |
+----------v----------+ Forwarding OAM packets |
| Forwarding decision < State +---------^-----------|
+----------v----------+ | Enrich or |
+ Retag Packet | Learn abstracted > Regenerate |
| and Forward | metrics about Links | OAM packets |
+..........v..........+..........^..........+.........^.v.........+
| Lower layers |
+..........v.....................^....................^.v.........+
frame | sent Frame | L2 Ack oOAM | | packet
over | wireless In | In | | and out
v | | v
Figure 6: PSE
4.4. Act: The PAREO Functions
RAW may control whether and how to use packet replication and
elimination (PRE), fragmentation, and network coding, and how the
lower layers performs Automatic Repeat reQuest (ARQ), Hybrid ARQ
(HARQ) that includes Forward Error Correction (FEC), and other
wireless-specific techniques such as overhearing and constructive
interferences, in order to increase the reliabiility and availability
of the end-to-end transmission.
Collectively, those function are called PAREO for Packet (hybrid)
ARQ, Replication, Elimination and Ordering. By tuning dynamically
the use of PAREO functions, RAW avoids the waste of critical
resources such as spectrum and energy while providing that the
guaranteed SLA, e.g., by adding redundancy only when a spike of loss
is observed.
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In a nutshell, PAREO establishes several paths in a network to
provide redundancy and parallel transmissions to bound the end-to-end
delay to traverse the network. Optionally, promiscuous listening
between paths is possible, such that the Nodes on one path may
overhear transmissions along the other path. Considering the
scenario shown in Figure 7, many different paths are possible to
traverse the network from ingress to egress. A simple way to benefit
from this topology could be to use the two independent paths via
Nodes A, C, E and via B, D, F. But more complex paths are possible
by interleaving transmissions from the lower level of the path to the
upper level.
(A) -- (C) -- (E)
/ \
Ingress = | | | = Egress
\ /
(B) -- (D) -- (F)
Figure 7: A Ladder Shape with Two Parallel Paths
PAREO may also take advantage of the shared properties of the
wireless medium to compensate for the potential loss that is incurred
with radio transmissions.
For instance, when the source sends to Node A, Node B may listen
promiscuously and get a second chance to receive the frame without an
additional transmission. Note that B would not have to listen if it
already received that particular frame at an earlier timeslot in a
dedicated transmission towards B.
The PAREO model can be implemented in both centralized and
distributed scheduling approaches. In the centralized approach, a
Path Computation Element (PCE) scheduler calculates a Track and
schedules the communication. In the distributed approach, the Track
is computed within the network, and signaled in the packets, e.g.,
using BIER-TE, Segment Routing, or a Source Routing Header.
4.4.1. Packet Replication
By employing a Packet Replication procedure, a Node forwards a copy
of each data packet to more than one successor. To do so, each Node
(i.e., Ingress and intermediate Node) sends the data packet multiple
times as separate unicast transmissions. For instance, in Figure 8,
the Ingress Node is transmitting the packet to both successors, nodes
A and B, at two different times.
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===> (A) => (C) => (E) ===
// \\// \\// \\
Ingress //\\ //\\ Egress
\\ // \\ // \\ //
===> (B) => (D) => (F) ===
Figure 8: Packet Replication
An example schedule is shown in Table 2. This way, the transmission
leverages with the time and spatial forms of diversity.
+=========+======+======+======+======+======+======+======+
| Channel | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
+=========+======+======+======+======+======+======+======+
| 0 | S->A | S->B | B->C | B->D | C->F | E->R | F->R |
+---------+------+------+------+------+------+------+------+
| 1 | | A->C | A->D | C->E | D->E | D->F | |
+---------+------+------+------+------+------+------+------+
Table 2: Packet Replication: Sample schedule
4.4.2. Packet Elimination
The replication operation increases the traffic load in the network,
due to packet duplications. This may occur at several stages inside
the Track, and to avoid an explosion of the number of copies, a
Packet Elimination procedure must be applied as well. To this aim,
once a Node receives the first copy of a data packet, it discards the
subsequent copies.
The logical functions of Replication and Elimination may be
collocated in an intermediate Node, the Node first eliminating the
redundant copies and then sending the packet exactly once to each of
the selected successors.
4.4.3. Promiscuous Overhearing
Considering that the wireless medium is broadcast by nature, any
neighbor of a transmitter may overhear a transmission. By employing
the Promiscuous Overhearing operation, the next hops have additional
opportunities to capture the data packets. In Figure 9, when Node A
is transmitting to its DP (Node C), the AP (Node D) and its sibling
(Node B) may decode this data packet as well. As a result, by
employing corellated paths, a Node may have multiple opportunities to
receive a given data packet.
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===> (A) ====> (C) ====> (E) ====
// ^ | \\ \\
Ingress | | \\ Egress
\\ | v \\ //
===> (B) ====> (D) ====> (F) ====
Figure 9: Unicast with Overhearing
Variations on the same idea such as link-layer anycast and multicast
may also be used to reach more than one next-hop with a single frame.
4.4.4. Constructive Interference
Constructive Interference can be seen as the reverse of Promiscuous
Overhearing, and refers to the case where two senders transmit the
exact same signal in a fashion that the emitted symbols add up at the
receiver and permit a reception that would not be possible with a
single sender at the same PHY mode and the same power level.
Constructive Interference was proposed on 5G, Wi-Fi7 and even tested
on IEEE Std 802.14.5. The hard piece is to synchronize the senders
to the point that the signals are emitted at slightly different time
to offset the difference of propagation delay that corresponds to the
difference of distance of the transmitters to the receiver at the
speed of light to the point that the symbols are superposed long
enough to be recognizable.
5. Security Considerations
RAW uses all forms of diversity including radio technology and
physical path to increase the reliability and availability in the
face of unpredictable conditions. While this is not done
specifically to defeat an attacker, the amount of diversity used in
RAW makes an attack harder to achieve.
5.1. Layer-2 encryption
Radio networks typically encrypt at the MAC layer to protect the
transmission. If the encryption is per pair of peers, then certain
RAW operations like promiscuous overhearing become impossible.
5.2. Forced Access
RAW will typically select the cheapest collection of links that
matches the requested SLA, for instance, leverage free WI-Fi vs. paid
3GPP access. By defeating the cheap connectivity (e.g., PHY-layer
interference) the attacker can force an End System to use the paid
access and increase the cost of the transmission for the user.
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6. IANA Considerations
This document has no IANA actions.
7. Contributors
The editor wishes to thank:
Xavi Vilajosana: Wireless Networks Research Lab, Universitat Oberta
de Catalunya
Remous-Aris Koutsiamanis: IMT Atlantique
Nicolas Montavont: IMT Atlantique
Rex Buddenberg: Individual contributor
Greg Mirsky: ZTE
for their contributions to the text and ideas exposed in this
document.
8. Acknowledgments
TBD
9. References
9.1. Normative References
[6TiSCH-ARCHI]
Thubert, P., Ed., "An Architecture for IPv6 over the Time-
Slotted Channel Hopping Mode of IEEE 802.15.4 (6TiSCH)",
RFC 9030, DOI 10.17487/RFC9030, May 2021,
<https://www.rfc-editor.org/info/rfc9030>.
[INT-ARCHI]
Braden, R., Ed., "Requirements for Internet Hosts -
Communication Layers", STD 3, RFC 1122,
DOI 10.17487/RFC1122, October 1989,
<https://www.rfc-editor.org/info/rfc1122>.
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[RAW-TECHNOS]
Thubert, P., Cavalcanti, D., Vilajosana, X., Schmitt, C.,
and J. Farkas, "Reliable and Available Wireless
Technologies", Work in Progress, Internet-Draft, draft-
ietf-raw-technologies-05, 2 February 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-raw-
technologies-05>.
[RAW-USE-CASES]
Bernardos, C. J., Papadopoulos, G. Z., Thubert, P., and F.
Theoleyre, "RAW use-cases", Work in Progress, Internet-
Draft, draft-ietf-raw-use-cases-05, 23 February 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-raw-use-
cases-05>.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[RFC6291] Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
D., and S. Mansfield, "Guidelines for the Use of the "OAM"
Acronym in the IETF", BCP 161, RFC 6291,
DOI 10.17487/RFC6291, June 2011,
<https://www.rfc-editor.org/info/rfc6291>.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.
[RFC8578] Grossman, E., Ed., "Deterministic Networking Use Cases",
RFC 8578, DOI 10.17487/RFC8578, May 2019,
<https://www.rfc-editor.org/info/rfc8578>.
[IPv6] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC8557] Finn, N. and P. Thubert, "Deterministic Networking Problem
Statement", RFC 8557, DOI 10.17487/RFC8557, May 2019,
<https://www.rfc-editor.org/info/rfc8557>.
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>.
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[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane:
IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
<https://www.rfc-editor.org/info/rfc8939>.
[RFC9049] Dawkins, S., Ed., "Path Aware Networking: Obstacles to
Deployment (A Bestiary of Roads Not Taken)", RFC 9049,
DOI 10.17487/RFC9049, June 2021,
<https://www.rfc-editor.org/info/rfc9049>.
9.2. Informative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
[TE] Awduche, D., Chiu, A., Elwalid, A., Widjaja, I., and X.
Xiao, "Overview and Principles of Internet Traffic
Engineering", RFC 3272, DOI 10.17487/RFC3272, May 2002,
<https://www.rfc-editor.org/info/rfc3272>.
[STD 62] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
DOI 10.17487/RFC3411, December 2002,
<https://www.rfc-editor.org/info/rfc3411>.
[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
DOI 10.17487/RFC4090, May 2005,
<https://www.rfc-editor.org/info/rfc4090>.
[FRR] Shand, M. and S. Bryant, "IP Fast Reroute Framework",
RFC 5714, DOI 10.17487/RFC5714, January 2010,
<https://www.rfc-editor.org/info/rfc5714>.
[RLFA-FRR] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N.
So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
RFC 7490, DOI 10.17487/RFC7490, April 2015,
<https://www.rfc-editor.org/info/rfc7490>.
[DetNet-DP]
Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane
Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020,
<https://www.rfc-editor.org/info/rfc8938>.
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[DLEP] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B.
Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175,
DOI 10.17487/RFC8175, June 2017,
<https://www.rfc-editor.org/info/rfc8175>.
[I-D.irtf-panrg-path-properties]
Enghardt, T. and C. Kraehenbuehl, "A Vocabulary of Path
Properties", Work in Progress, Internet-Draft, draft-irtf-
panrg-path-properties-04, 25 October 2021,
<https://datatracker.ietf.org/doc/html/draft-irtf-panrg-
path-properties-04>.
[IPoWIRELESS]
Thubert, P., "IPv6 Neighbor Discovery on Wireless
Networks", Work in Progress, Internet-Draft, draft-
thubert-6man-ipv6-over-wireless-11, 15 December 2021,
<https://datatracker.ietf.org/doc/html/draft-thubert-6man-
ipv6-over-wireless-11>.
[DetNet-OAM]
Mirsky, G., Theoleyre, F., Papadopoulos, G. Z., Bernardos,
C. J., Varga, B., and J. Farkas, "Framework of Operations,
Administration and Maintenance (OAM) for Deterministic
Networking (DetNet)", Work in Progress, Internet-Draft,
draft-ietf-detnet-oam-framework-05, 14 October 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
oam-framework-05>.
[NASA] Adams, T., "RELIABILITY: Definition & Quantitative
Illustration", <https://kscddms.ksc.nasa.gov/Reliability/
Documents/150814-3bWhatIsReliability.pdf>.
Authors' Addresses
Pascal Thubert (editor)
Cisco Systems, Inc
Building D
45 Allee des Ormes - BP1200
06254 MOUGINS - Sophia Antipolis
France
Phone: +33 497 23 26 34
Email: pthubert@cisco.com
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Georgios Z. Papadopoulos
IMT Atlantique
Office B00 - 114A
2 Rue de la Chataigneraie
35510 Cesson-Sevigne - Rennes
France
Phone: +33 299 12 70 04
Email: georgios.papadopoulos@imt-atlantique.fr
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