rfc9037.original   rfc9037.txt 
DetNet B. Varga, Ed. Internet Engineering Task Force (IETF) B. Varga, Ed.
Internet-Draft J. Farkas Request for Comments: 9037 J. Farkas
Intended status: Informational Ericsson Category: Informational Ericsson
Expires: August 23, 2021 A. Malis ISSN: 2070-1721 A. Malis
Malis Consulting Malis Consulting
S. Bryant S. Bryant
Futurewei Technologies Futurewei Technologies
February 19, 2021 June 2021
DetNet Data Plane: MPLS over IEEE 802.1 Time-Sensitive Networking (TSN) Deterministic Networking (DetNet) Data Plane: MPLS over IEEE 802.1 Time-
draft-ietf-detnet-mpls-over-tsn-07 Sensitive Networking (TSN)
Abstract Abstract
This document specifies the Deterministic Networking MPLS data plane This document specifies the Deterministic Networking (DetNet) MPLS
when operating over an IEEE 802.1 Time-Sensitive Networking (TSN) data plane when operating over an IEEE 802.1 Time-Sensitive
sub-network. This document does not define new procedures or Networking (TSN) sub-network. This document does not define new
processes. Whenever this document makes statements or procedures or processes. Whenever this document makes statements or
recommendations, these are taken from normative text in the recommendations, they are taken from normative text in the referenced
referenced RFCs. RFCs.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for informational purposes.
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approved by the IESG are candidates for any level of Internet
Standard; see Section 2 of RFC 7841.
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and how to provide feedback on it may be obtained at
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology
2.1. Terms Used in This Document . . . . . . . . . . . . . . . 3 2.1. Terms Used in This Document
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Abbreviations
3. DetNet MPLS Data Plane Overview . . . . . . . . . . . . . . . 3 3. DetNet MPLS Data Plane Overview
4. DetNet MPLS Operation Over IEEE 802.1 TSN Sub-Networks . . . 4 4. DetNet MPLS Operation over IEEE 802.1 TSN Sub-networks
4.1. Functions for DetNet Flow to TSN Stream Mapping . . . . . 6 4.1. Functions for DetNet Flow to TSN Stream Mapping
4.2. TSN requirements of MPLS DetNet nodes . . . . . . . . . . 6 4.2. TSN Requirements of MPLS DetNet Nodes
4.3. Service protection within the TSN sub-network . . . . . . 8 4.3. Service Protection within the TSN Sub-network
4.4. Aggregation during DetNet flow to TSN Stream mapping . . 8 4.4. Aggregation during DetNet Flow to TSN Stream Mapping
5. Management and Control Implications . . . . . . . . . . . . . 8 5. Management and Control Implications
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 6. Security Considerations
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 7. IANA Considerations
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 8. References
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1. Normative References
9.1. Normative References . . . . . . . . . . . . . . . . . . 11 8.2. Informative References
9.2. Informative References . . . . . . . . . . . . . . . . . 11 Acknowledgements
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses
1. Introduction 1. Introduction
Deterministic Networking (DetNet) is a service that can be offered by Deterministic Networking (DetNet) is a service that can be offered by
a network to DetNet flows. DetNet provides these flows with low a network to DetNet flows. DetNet provides these flows with low
packet loss rate and assured maximum end-to-end delivery latency. packet loss rate and assured maximum end-to-end delivery latency.
General background and concepts of DetNet can be found in [RFC8655]. General background and concepts of DetNet can be found in [RFC8655].
The DetNet Architecture decomposes the DetNet related data plane The DetNet architecture decomposes DetNet-related data plane
functions into two sub-layers: a service sub-layer and a forwarding functions into two sub-layers: a service sub-layer and a forwarding
sub-layer. The service sub-layer is used to provide DetNet service sub-layer. The service sub-layer is used to provide DetNet service
protection and reordering. The forwarding sub-layer is used to protection and reordering. The forwarding sub-layer is used to
provide congestion protection (low loss, assured latency, and limited provide congestion protection (low loss, assured latency, and limited
reordering) leveraging MPLS Traffic Engineering mechanisms. reordering) leveraging MPLS Traffic Engineering mechanisms.
[RFC8964] specifies the DetNet data plane operation for MPLS-based [RFC8964] specifies the DetNet data plane operation for an MPLS-based
Packet Switched Network (PSN). MPLS encapsulated DetNet flows can be PSN. MPLS-encapsulated DetNet flows can be carried over network
carried over network technologies that can provide the DetNet technologies that can provide the DetNet-required level of service.
required level of service. This document focuses on the scenario This document focuses on the scenario where MPLS (DetNet) nodes are
where MPLS (DetNet) nodes are interconnected by a IEEE 802.1 TSN sub- interconnected by an IEEE 802.1 TSN sub-network. There is close
network. There is close cooperation between the IETF DetNet WG and cooperation between the IETF DetNet Working Group and the IEEE 802.1
the IEEE 802.1 TSN TG. Time-Sensitive Networking Task Group (TSN TG).
2. Terminology 2. Terminology
2.1. Terms Used in This Document 2.1. Terms Used in This Document
This document uses the terminology established in the DetNet This document uses the terminology established in the DetNet
architecture [RFC8655] and [RFC8964]. TSN specific terms are defined architecture [RFC8655] [RFC8964]. TSN-specific terms are defined in
in the TSN TG of IEEE 802.1 Working Group. The reader is assumed to the TSN TG of the IEEE 802.1 Working Group. The reader is assumed to
be familiar with these documents and their terminology. be familiar with these documents and their terminology.
2.2. Abbreviations 2.2. Abbreviations
The following abbreviations are used in this document: The following abbreviations are used in this document:
A-Label Aggregation label, a special case of an S-Label. A-Label Aggregation label; a special case of an S-Label.
d-CW DetNet Control Word. d-CW DetNet Control Word
DetNet Deterministic Networking. DetNet Deterministic Networking
F-Label Forwarding label that identifies the LSP used by a F-Label Forwarding label that identifies the LSP used by a
DetNet flow. DetNet flow.
FRER Frame Replication and Elimination for Redundancy (TSN FRER Frame Replication and Elimination for Redundancy (TSN
function). function)
L2 Layer 2. L2 Layer 2
L3 Layer 3. L3 Layer 3
MPLS Multiprotocol Label Switching. LSP Label Switched Path
PREOF Packet Replication, Elimination and Ordering Functions. MPLS Multiprotocol Label Switching
PSN Packet Switched Network. PREOF Packet Replication, Elimination, and Ordering Functions
PW PseudoWire. PSN Packet Switched Network
RSVP-TE Resource Reservation Protocol - Traffic Engineering. PW Pseudowire
S-Label Service label. RSVP-TE Resource Reservation Protocol - Traffic Engineering
TSN Time-Sensitive Network. S-Label Service label
TSN Time-Sensitive Networking
3. DetNet MPLS Data Plane Overview 3. DetNet MPLS Data Plane Overview
The basic approach defined in [RFC8964] supports the DetNet service The basic approach defined in [RFC8964] supports the DetNet service
sub-layer based on existing pseudowire (PW) encapsulations and sub-layer based on existing PW encapsulations and mechanisms and
mechanisms, and supports the DetNet forwarding sub-layer based on supports the DetNet forwarding sub-layer based on existing MPLS
existing MPLS Traffic Engineering encapsulations and mechanisms. Traffic Engineering encapsulations and mechanisms.
A node operating on a DetNet flow in the Detnet service sub-layer, A node operates on a DetNet flow in the DetNet service sub-layer,
i.e. a node processing a DetNet packet which has the S-Label as top i.e., a node processing a DetNet packet that has the service label
of stack uses the local context associated with that service label (S-Label) as the top of stack uses the local context associated with
(S-Label), for example a received forwarding label (F-Label), to that S-Label, for example, a received forwarding label (F-Label), to
determine what local DetNet operation(s) are applied to that packet. determine what local DetNet operation(s) is applied to that packet.
An S-Label may be unique when taken from the platform label space An S-Label may be unique when taken from the platform label space
[RFC3031], which would enable correct DetNet flow identification [RFC3031], which would enable correct DetNet flow identification
regardless of which input interface or LSP the packet arrives on. regardless of which input interface or LSP the packet arrives on.
The service sub-layer functions (i.e., PREOF) use a DetNet control The service sub-layer functions (i.e., PREOF) use a d-CW.
word (d-CW).
The DetNet MPLS data plane builds on MPLS Traffic Engineering The DetNet MPLS data plane builds on MPLS Traffic Engineering
encapsulations and mechanisms to provide a forwarding sub-layer that encapsulations and mechanisms to provide a forwarding sub-layer that
is responsible for providing resource allocation and explicit routes. is responsible for providing resource allocation and explicit routes.
The forwarding sub-layer is supported by one or more F-Labels. The forwarding sub-layer is supported by one or more F-Labels.
DetNet edge/relay nodes are DetNet service sub-layer aware, DetNet edge/relay nodes are DetNet service sub-layer-aware,
understand the particular needs of DetNet flows and provide both understand the particular needs of DetNet flows, and provide both
DetNet service and forwarding sub-layer functions. They add, remove DetNet service and forwarding sub-layer functions. They add, remove,
and process d-CWs, S-Labels and F-labels as needed. MPLS DetNet and process d-CWs, S-Labels, and F-Labels as needed. MPLS DetNet
nodes and transit nodes include DetNet forwarding sub-layer nodes and transit nodes include DetNet forwarding sub-layer
functions, notably support for explicit routes, and resources functions, notable support for explicit routes, and resource
allocation to eliminate (or reduce) congestion loss and jitter. allocation to eliminate (or reduce) congestion loss and jitter.
Unlike other DetNet node types, transit nodes provide no service sub- Unlike other DetNet node types, transit nodes provide no service sub-
layer processing. layer processing.
MPLS (DetNet) nodes and transit nodes interconnected by a TSN sub- MPLS (DetNet) nodes and transit nodes interconnected by a TSN sub-
network are the primary focus of this document. The mapping of network are the primary focus of this document. The mapping of
DetNet MPLS flows to TSN streams and TSN protection mechanisms are DetNet MPLS flows to TSN Streams and TSN protection mechanisms are
covered in Section 4. covered in Section 4.
4. DetNet MPLS Operation Over IEEE 802.1 TSN Sub-Networks 4. DetNet MPLS Operation over IEEE 802.1 TSN Sub-networks
The DetNet WG collaborates with IEEE 802.1 TSN in order to define a The DetNet WG collaborates with IEEE 802.1 TSN in order to define a
common architecture for both Layer 2 and Layer 3, that maintains common architecture for both Layer 2 and Layer 3 that maintains
consistency across diverse networks. Both DetNet MPLS and TSN use consistency across diverse networks. Both DetNet MPLS and TSN use
the same techniques to provide their deterministic service: the same techniques to provide their deterministic service:
o Service protection. * Service protection
o Resource allocation. * Resource allocation
o Explicit routes. * Explicit routes
As described in the DetNet architecture [RFC8655] a sub-network As described in the DetNet architecture [RFC8655], from the MPLS
provides from MPLS perspective a single hop connection between MPLS perspective, a sub-network provides a single-hop connection between
(DetNet) nodes. Functions used for resource allocation and explicit MPLS (DetNet) nodes. Functions used for resource allocation and
routes are treated as domain internal functions and do not require explicit routes are treated as domain internal functions and do not
function interworking across the DetNet MPLS network and the TSN sub- require function interworking across the DetNet MPLS network and the
network. TSN sub-network.
In the case of the service protection function due to the In the case of the service protection function, due to the
similarities of the DetNet PREOF and TSN FRER functions some level of similarities of the DetNet PREOF and TSN FRER functions, some level
interworking is possible. However, such interworking is out-of-scope of interworking is possible. However, such interworking is out of
in this document and left for further study. scope of this document and left for further study.
Figure 1 illustrates a scenario, where two MPLS (DetNet) nodes are Figure 1 illustrates a scenario where two MPLS (DetNet) nodes are
interconnected by a TSN sub-network. Node-1 is single homed and interconnected by a TSN sub-network. Node-1 is single-homed, and
Node-2 is dual-homed to the TSN sub-network. Node-2 is dual-homed to the TSN sub-network.
MPLS (DetNet) MPLS (DetNet) MPLS (DetNet) MPLS (DetNet)
Node-1 Node-2 Node-1 Node-2
+----------+ +----------+ +----------+ +----------+
<--| Service* |-- DetNet flow ---| Service* |--> <--| Service* |-- DetNet flow ---| Service* |-->
+----------+ +----------+ +----------+ +----------+
|Forwarding| |Forwarding| |Forwarding| |Forwarding|
+--------.-+ <-TSN Str-> +-.-----.--+ +--------.-+ <-TSN Str-> +-.-----.--+
\ ,-------. / / \ ,-------. / /
+----[ TSN-Sub ]---+ / +----[ TSN Sub-]---+ /
[ Network ]--------+ [ network ]--------+
`-------' `-------'
<---------------- DetNet MPLS ---------------> <---------------- DetNet MPLS --------------->
Note: * no service sub-layer required for transit nodes Note: * no service sub-layer required for transit nodes
Figure 1: DetNet Enabled MPLS Network Over a TSN Sub-Network Figure 1: DetNet-Enabled MPLS Network over a TSN Sub-network
At the time of this writing, the Time-Sensitive Networking (TSN) Task At the time of this writing, the TSN TG of the IEEE 802.1 Working
Group of the IEEE 802.1 Working Group have defined (and are defining) Group have defined (and are defining) a number of amendments to
a number of amendments to [IEEE8021Q] that provide zero congestion [IEEE8021Q] that provide zero congestion loss and bounded latency in
loss and bounded latency in bridged networks. Furthermore bridged networks. Furthermore, [IEEE8021CB] defines frame
[IEEE8021CB] defines frame replication and elimination functions for replication and elimination functions for reliability that should
reliability that should prove both compatible with and useful to, prove both compatible with and useful to DetNet networks. All these
DetNet networks. All these functions have to identify flows those functions have to identify flows that require TSN treatment (i.e.,
require TSN treatment (i.e., applying TSN functions during applying TSN functions during forwarding).
forwarding).
TSN capabilities of the TSN sub-network are made available for MPLS TSN capabilities of the TSN sub-network are made available for MPLS
(DetNet) flows via the protocol interworking function defined in (DetNet) flows via the protocol interworking function defined in
Annex C.5 of [IEEE8021CB]. For example, applied on the TSN edge port Annex C.5 of [IEEE8021CB]. For example, when applied on the TSN edge
it can convert an ingress unicast MPLS (DetNet) flow to use a port, it can convert an ingress unicast MPLS (DetNet) flow to use a
specific Layer-2 multicast destination MAC address and a VLAN, in specific Layer 2 multicast destination Media Access Control (MAC)
order to direct the packet through a specific path inside the bridged address and a VLAN, in order to direct the packet through a specific
network. A similar interworking function pair at the other end of path inside the bridged network. A similar interworking function
the TSN sub-network would restore the packet to its original Layer-2 pair at the other end of the TSN sub-network would restore the packet
destination MAC address and VLAN. to its original Layer 2 destination MAC address and VLAN.
Placement of TSN functions depends on the TSN capabilities of the The placement of TSN functions depends on the TSN capabilities of the
nodes along the path. MPLS (DetNet) Nodes may or may not support TSN nodes along the path. MPLS (DetNet) nodes may or may not support TSN
functions. For a given TSN Stream (i.e., DetNet flow) an MPLS functions. For a given TSN Stream (i.e., DetNet flow), an MPLS
(DetNet) node is treated as a Talker or a Listener inside the TSN (DetNet) node is treated as a Talker or a Listener inside the TSN
sub-network. sub-network.
4.1. Functions for DetNet Flow to TSN Stream Mapping 4.1. Functions for DetNet Flow to TSN Stream Mapping
Mapping of a DetNet MPLS flow to a TSN Stream is provided via the Mapping of a DetNet MPLS flow to a TSN Stream is provided via the
combination of a passive and an active stream identification function combination of a passive and an active Stream identification function
that operate at the frame level. The passive stream identification that operate at the frame level. The passive Stream identification
function is used to catch the MPLS label(s) of a DetNet MPLS flow and function is used to catch the MPLS label(s) of a DetNet MPLS flow,
the active stream identification function is used to modify the and the active Stream identification function is used to modify the
Ethernet header according to the ID of the mapped TSN Stream. Ethernet header according to the ID of the mapped TSN Stream.
Clause 6.8 of [IEEEP8021CBdb] defines a Mask-and-Match Stream Clause 6.8 of [IEEEP8021CBdb] defines a Mask-and-Match Stream
identification function that can be used as a passive function for identification function that can be used as a passive function for
MPLS DetNet flows. MPLS DetNet flows.
Clause 6.6 of [IEEE8021CB] defines an Active Destination MAC and VLAN Clause 6.6 of [IEEE8021CB] defines an Active Destination MAC and a
Stream identification function, what can replace some Ethernet header VLAN Stream identification function that can replace some Ethernet
fields namely (1) the destination MAC-address, (2) the VLAN-ID and header fields, namely (1) the destination MAC address, (2) the VLAN-
(3) priority parameters with alternate values. Replacement is ID, and (3) priority parameters with alternate values. Replacement
provided for the frame passed down the stack from the upper layers or is provided for the frame that is passed either down the stack from
up the stack from the lower layers. the upper layers or up the stack from the lower layers.
Active Destination MAC and VLAN Stream identification can be used Active Destination MAC and VLAN Stream identification can be used
within a Talker to set flow identity or a Listener to recover the within a Talker to set flow identity or a Listener to recover the
original addressing information. It can be used also in a TSN bridge original addressing information. It can also be used in a TSN bridge
that is providing translation as a proxy service for an End System. that is providing translation as a proxy service for an end system.
4.2. TSN requirements of MPLS DetNet nodes 4.2. TSN Requirements of MPLS DetNet Nodes
This section covers required behavior of a TSN-aware MPLS (DetNet) This section covers required behavior of a TSN-aware MPLS (DetNet)
node using a TSN sub-network. The implementation of TSN packet node using a TSN sub-network. The implementation of TSN packet-
processing functions must be compliant with the relevant IEEE 802.1 processing functions must be compliant with the relevant IEEE 802.1
standards. standards.
From the TSN sub-network perspective MPLS (DetNet) nodes are treated From the TSN sub-network perspective, MPLS (DetNet) nodes are treated
as Talker or Listener, that may be (1) TSN-unaware or (2) TSN-aware. as a Talker or Listener, which may be (1) TSN-unaware or (2) TSN-
aware.
In cases of TSN-unaware MPLS DetNet nodes the TSN relay nodes within In cases of TSN-unaware MPLS DetNet nodes, the TSN relay nodes within
the TSN sub-network must modify the Ethernet encapsulation of the the TSN sub-network must modify the Ethernet encapsulation of the
DetNet MPLS flow (e.g., MAC translation, VLAN-ID setting, Sequence DetNet MPLS flow (e.g., MAC translation, VLAN-ID setting, sequence
number addition, etc.) to allow proper TSN specific handling inside number addition, etc.) to allow proper TSN-specific handling inside
the sub-network. There are no requirements defined for TSN-unaware the sub-network. There are no requirements defined for TSN-unaware
MPLS DetNet nodes in this document. MPLS DetNet nodes in this document.
MPLS (DetNet) nodes being TSN-aware can be treated as a combination MPLS (DetNet) nodes that are TSN-aware can be treated as a
of a TSN-unaware Talker/Listener and a TSN-Relay, as shown in combination of a TSN-unaware Talker/Listener and a TSN-Relay, as
Figure 2. In such cases the MPLS (DetNet) node must provide the TSN shown in Figure 2. In such cases, the MPLS (DetNet) node must
sub-network specific Ethernet encapsulation over the link(s) towards provide the TSN sub-network-specific Ethernet encapsulation over the
the sub-network. link(s) towards the sub-network.
MPLS (DetNet) MPLS (DetNet)
Node Node
<----------------------------------> <---------------------------------->
+----------+ +----------+
<--| Service* |-- DetNet flow ------------------ <--| Service* |-- DetNet flow ------------------
+----------+ +----------+
|Forwarding| |Forwarding|
+----------+ +---------------+ +----------+ +---------------+
skipping to change at page 7, line 43 skipping to change at line 325
Talker / TSN-Bridge Talker / TSN-Bridge
Listener Relay Listener Relay
<----- TSN Sub-network ----- <----- TSN Sub-network -----
<------- TSN-aware Tlk/Lstn -------> <------- TSN-aware Tlk/Lstn ------->
Note: * no service sub-layer required for transit nodes Note: * no service sub-layer required for transit nodes
Figure 2: MPLS (DetNet) Node with TSN Functions Figure 2: MPLS (DetNet) Node with TSN Functions
A TSN-aware MPLS (DetNet) node implementation must support the Stream A TSN-aware MPLS (DetNet) node implementation must support the Stream
Identification TSN component for recognizing flows. identification TSN component for recognizing flows.
A Stream identification component must be able to instantiate the A Stream identification component must be able to instantiate the
following functions (1) Active Destination MAC and VLAN Stream following functions: (1) Active Destination MAC and VLAN Stream
identification function, (2) Mask-and-Match Stream identification identification function, (2) Mask-and-Match Stream identification
function and (3) the related managed objects in Clause 9 of function, and (3) the related managed objects in Clause 9 of
[IEEE8021CB] and [IEEEP8021CBdb]. [IEEE8021CB] and [IEEEP8021CBdb].
A TSN-aware MPLS (DetNet) node implementation must support the A TSN-aware MPLS (DetNet) node implementation must support the
Sequencing function and the Sequence encode/decode function as Sequencing function and the Sequence encode/decode function as
defined in Clause 7.4 and 7.6 of [IEEE8021CB] in order for FRER to be defined in Clauses 7.4 and 7.6 of [IEEE8021CB] in order for FRER to
used inside the TSN sub-network. be used inside the TSN sub-network.
The Sequence encode/decode function must support the Redundancy tag The Sequence encode/decode function must support the Redundancy tag
(R-TAG) format as per Clause 7.8 of [IEEE8021CB]. (R-TAG) format as per Clause 7.8 of [IEEE8021CB].
A TSN-aware MPLS (DetNet) node implementation must support the Stream A TSN-aware MPLS (DetNet) node implementation must support the Stream
splitting function and the Individual recovery function as defined in splitting function and the Individual recovery function as defined in
Clause 7.7 and 7.5 of [IEEE8021CB] in order for that node to be a Clauses 7.5 and 7.7 of [IEEE8021CB] in order for that node to be a
replication or elimination point for FRER. replication or elimination point for FRER.
4.3. Service protection within the TSN sub-network 4.3. Service Protection within the TSN Sub-network
TSN Streams supporting DetNet flows may use Frame Replication and TSN Streams supporting DetNet flows may use FRER as defined in Clause
Elimination for Redundancy (FRER) as defined in Clause 8. of 8 of [IEEE8021CB] based on the loss service requirements of the TSN
[IEEE8021CB] based on the loss service requirements of the TSN
Stream, which is derived from the DetNet service requirements of the Stream, which is derived from the DetNet service requirements of the
DetNet mapped flow. The specific operation of FRER is not modified DetNet mapped flow. The specific operation of FRER is not modified
by the use of DetNet and follows [IEEE8021CB]. by the use of DetNet and follows [IEEE8021CB].
FRER function and the provided service recovery is available only FRER function and the provided service recovery is available only
within the TSN sub-network as the TSN Stream-ID and the TSN sequence within the TSN sub-network as the TSN Stream-ID and the TSN sequence
number are not valid outside the sub-network. An MPLS (DetNet) node number are not valid outside the sub-network. An MPLS (DetNet) node
represents a L3 border and as such it terminates all related represents an L3 border, and as such, it terminates all related
information elements encoded in the L2 frames. information elements encoded in the L2 frames.
As the Stream-ID and the TSN sequence number are paired with the As the Stream-ID and the TSN sequence number are paired with similar
similar MPLS flow parameters, FRER can be combined with PREOF MPLS flow parameters, FRER can be combined with PREOF functions.
functions. Such service protection interworking scenarios may Such service protection interworking scenarios may require moving
require to move sequence number fields among TSN (L2) and PW (MPLS) sequence number fields among TSN (L2) and PW (MPLS) encapsulations,
encapsulations and they are left for further study. and they are left for further study.
4.4. Aggregation during DetNet flow to TSN Stream mapping 4.4. Aggregation during DetNet Flow to TSN Stream Mapping
Implementation of this document shall use management and control Implementation of this document shall use management and control
information to map a DetNet flow to a TSN Stream. N:1 mapping information to map a DetNet flow to a TSN Stream. N:1 mapping
(aggregating DetNet flows in a single TSN Stream) shall be supported. (aggregating DetNet flows in a single TSN Stream) shall be supported.
The management or control function that provisions flow mapping shall The management or control function that provisions flow mapping shall
ensure that adequate resources are allocated and configured to ensure that adequate resources are allocated and configured to
provide proper service requirements of the mapped flows. provide proper service requirements of the mapped flows.
5. Management and Control Implications 5. Management and Control Implications
DetNet flow and TSN Stream mapping related information are required Information related to DetNet flow and TSN Stream mapping is required
only for TSN-aware MPLS (DetNet) nodes. From the Data Plane only for TSN-aware MPLS (DetNet) nodes. From the data plane
perspective there is no practical difference based on the origin of perspective, there is no practical difference based on the origin of
flow mapping related information (management plane or control plane). flow-mapping-related information (management plane or control plane).
The following summarizes the set of information that is needed to The following summarizes the set of information that is needed to
configure DetNet MPLS over TSN: configure DetNet MPLS over TSN:
o DetNet MPLS related configuration information according to the * DetNet MPLS-related configuration information according to the
DetNet role of the DetNet MPLS node, as per [RFC8964]. DetNet role of the DetNet MPLS node, as per [RFC8964].
o TSN related configuration information according to the TSN role of * TSN-related configuration information according to the TSN role of
the DetNet MPLS node, as per [IEEE8021Q], [IEEE8021CB] and the DetNet MPLS node, as per [IEEE8021Q], [IEEE8021CB], and
[IEEEP8021CBdb]. [IEEEP8021CBdb].
o Mapping between DetNet MPLS flow(s) (label information: A-labels, * Mapping between a DetNet MPLS flow(s) (label information:
S-labels and F-labels as defined in [RFC8964]) and TSN Stream(s) A-Labels, S-Labels, and F-Labels as defined in [RFC8964]) and a
(as stream identification information defined in [IEEEP8021CBdb]). TSN Stream(s) (as Stream identification information defined in
Note, that managed objects for TSN Stream identification can be [IEEEP8021CBdb]). Note that managed objects for TSN Stream
found in [IEEEP8021CBcv]. identification can be found in [IEEEP8021CBcv].
This information must be provisioned per DetNet flow. This information must be provisioned per DetNet flow.
Mappings between DetNet and TSN management and control planes are out Mappings between DetNet and TSN management and control planes are out
of scope of the document. Some of the challenges are highlighted of scope of this document. Some of the challenges are highlighted
below. below.
TSN-aware MPLS DetNet nodes are members of both the DetNet domain and TSN-aware MPLS DetNet nodes are members of both the DetNet domain and
the TSN sub-network. Within the TSN sub-network the TSN-aware MPLS the TSN sub-network. Within the TSN sub-network, the TSN-aware MPLS
(DetNet) node has a TSN-aware Talker/Listener role, so TSN specific (DetNet) node has a TSN-aware Talker/Listener role, so TSN-specific
management and control plane functionalities must be implemented. management and control plane functionalities must be implemented.
There are many similarities in the management plane techniques used There are many similarities in the management plane techniques used
in DetNet and TSN, but that is not the case for the control plane in DetNet and TSN, but that is not the case for the control plane
protocols. For example, RSVP-TE and MSRP (Multiple Stream protocols. For example, RSVP-TE and the Multiple Stream Registration
Registration Protocol) behaves differently. Therefore management and Protocol (MSRP) behave differently. Therefore, management and
control plane design is an important aspect of scenarios, where control plane design are important aspects of scenarios where mapping
mapping between DetNet and TSN is required. between DetNet and TSN is required.
In order to use a TSN sub-network between DetNet nodes, DetNet In order to use a TSN sub-network between DetNet nodes, DetNet-
specific information must be converted to TSN sub-network specific specific information must be converted to information specific to the
ones. DetNet flow ID and flow related parameters/requirements must TSN sub-network. DetNet flow ID and flow-related parameters/
be converted to a TSN Stream ID and stream related parameters/ requirements must be converted to a TSN Stream ID and stream-related
requirements. Note that, as the TSN sub-network is just a portion of parameters/requirements. Note that, as the TSN sub-network is just a
the end-2-end DetNet path (i.e., a single hop from MPLS perspective), portion of the end-to-end DetNet path (i.e., a single hop from the
some parameters (e.g., delay) may differ significantly. Other MPLS perspective), some parameters (e.g., delay) may differ
parameters (like bandwidth) also may have to be tuned due to the L2 significantly. Other parameters (like bandwidth) also may have to be
encapsulation used within the TSN sub-network. tuned due to the L2 encapsulation used within the TSN sub-network.
In some cases it may be challenging to determine some TSN Stream In some cases, it may be challenging to determine some TSN-Stream-
related information. For example, on a TSN-aware MPLS (DetNet) node related information. For example, on a TSN-aware MPLS (DetNet) node
that acts as a Talker, it is quite obvious which DetNet node is the that acts as a Talker, it is quite obvious which DetNet node is the
Listener of the mapped TSN stream (i.e., the MPLS Next-Hop). However Listener of the mapped TSN Stream (i.e., the MPLS next hop).
it may be not trivial to locate the point/interface where that However, it may be not trivial to locate the point/interface where
Listener is connected to the TSN sub-network. Such attributes may that Listener is connected to the TSN sub-network. Such attributes
require interaction between control and management plane functions may require interaction between control and management plane
and between DetNet and TSN domains. functions and between DetNet and TSN domains.
Mapping between DetNet flow identifiers and TSN Stream identifiers, Mapping between DetNet flow identifiers and TSN Stream identifiers,
if not provided explicitly, can be done by a TSN-aware MPLS (DetNet) if not provided explicitly, can be done by a TSN-aware MPLS (DetNet)
node locally based on information provided for configuration of the node locally based on information provided for configuration of the
TSN Stream identification functions (Mask-and-match Stream TSN Stream identification functions (Mask-and-Match Stream
identification and Active Stream identification function). identification and active Stream identification).
Triggering the setup/modification of a TSN Stream in the TSN sub- Triggering the setup/modification of a TSN Stream in the TSN sub-
network is an example where management and/or control plane network is an example where management and/or control plane
interactions are required between the DetNet and TSN sub-network. interactions are required between the DetNet and TSN sub-network.
TSN-unaware MPLS (DetNet) nodes make such a triggering even more TSN-unaware MPLS (DetNet) nodes make such a triggering even more
complicated as they are fully unaware of the sub-network and run complicated as they are fully unaware of the sub-network and run
independently. independently.
Configuration of TSN specific functions (e.g., FRER) inside the TSN Configuration of TSN-specific functions (e.g., FRER) inside the TSN
sub-network is a TSN domain specific decision and may not be visible sub-network is a TSN-domain-specific decision and may not be visible
in the DetNet domain. Service protection interworking scenarios are in the DetNet domain. Service protection interworking scenarios are
left for further study. left for further study.
6. Security Considerations 6. Security Considerations
Security considerations for DetNet are described in detail in Security considerations for DetNet are described in detail in
[I-D.ietf-detnet-security]. General security considerations are [DETNET-SECURITY]. General security considerations are described in
described in [RFC8655]. DetNet MPLS data plane specific [RFC8655]. Considerations specific to the DetNet MPLS data plane are
considerations are summarized in [RFC8964]. This section considers summarized in [RFC8964]. This section considers exclusively security
exclusively security considerations which are specific to the DetNet considerations that are specific to the DetNet MPLS over TSN sub-
MPLS over TSN sub-network scenario. network scenario.
The sub-network between DetNet nodes needs to be subject to The sub-network between DetNet nodes needs to be subject to
appropriate confidentiality. Additionally, knowledge of what DetNet/ appropriate confidentiality. Additionally, knowledge of what DetNet/
TSN services are provided by a sub-network may supply information TSN services are provided by a sub-network may supply information
that can be used in a variety of security attacks. The ability to that can be used in a variety of security attacks. The ability to
modify information exchanges between connected DetNet nodes may modify information exchanges between connected DetNet nodes may
result in bogus operations. Therefore, it is important that the result in bogus operations. Therefore, it is important that the
interface between DetNet nodes and TSN sub-network are subject to interface between DetNet nodes and the TSN sub-network are subject to
authorization, authentication, and encryption. authorization, authentication, and encryption.
The TSN sub-network operates at Layer-2 so various security The TSN sub-network operates at Layer 2, so various security
mechanisms defined by IEEE can be used to secure the connection mechanisms defined by IEEE can be used to secure the connection
between the DetNet nodes (e.g., encryption may be provided using between the DetNet nodes (e.g., encryption may be provided using
MACSec [IEEE802.1AE-2018]). MACsec [IEEE802.1AE-2018]).
7. IANA Considerations 7. IANA Considerations
This document makes no IANA requests. This document has no IANA actions.
8. Acknowledgements
The authors wish to thank Norman Finn, Lou Berger, Craig Gunther,
Christophe Mangin and Jouni Korhonen for their various contributions
to this work.
9. References 8. References
9.1. Normative References 8.1. Normative References
[IEEE8021CB] [IEEE8021CB]
IEEE 802.1, "Standard for Local and metropolitan area IEEE, "IEEE Standard for Local and metropolitan area
networks - Frame Replication and Elimination for networks--Frame Replication and Elimination for
Reliability (IEEE Std 802.1CB-2017)", 2017, Reliability", IEEE Std 802.1CB-2017,
<http://standards.ieee.org/about/get/>. DOI 10.1109/IEEESTD.2017.8091139, October 2017,
<https://ieeexplore.ieee.org/document/8091139>.
[IEEEP8021CBdb] [IEEEP8021CBdb]
Mangin, C., "Extended Stream identification functions", IEEE, "Draft Standard for Local and metropolitan area
IEEE P802.1CBdb /D1.0 P802.1CBdb, September 2020, networks -— Frame Replication and Elimination for
<http://www.ieee802.org/1/files/private/db-drafts/d1/802- Reliability -— Amendment: Extended Stream Identification
1CBdb-d1-0.pdf>. Functions", IEEE P802.1CBdb / D1.3, April 2021,
<https://1.ieee802.org/tsn/802-1cbdb/>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001, DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>. <https://www.rfc-editor.org/info/rfc3031>.
[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>.
[RFC8964] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant, [RFC8964] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant,
S., and J. Korhonen, "Deterministic Networking (DetNet) S., and J. Korhonen, "Deterministic Networking (DetNet)
Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January
2021, <https://www.rfc-editor.org/info/rfc8964>. 2021, <https://www.rfc-editor.org/info/rfc8964>.
9.2. Informative References 8.2. Informative References
[I-D.ietf-detnet-security] [DETNET-SECURITY]
Grossman, E., Mizrahi, T., and A. Hacker, "Deterministic Grossman, E., Mizrahi, T., and A. J. Hacker,
Networking (DetNet) Security Considerations", draft-ietf- "Deterministic Networking (DetNet) Security
detnet-security-13 (work in progress), December 2020. Considerations", Work in Progress, Internet-Draft, draft-
ietf-detnet-security-16, 2 March 2021,
<https://tools.ietf.org/html/draft-ietf-detnet-security-
16>.
[IEEE802.1AE-2018] [IEEE802.1AE-2018]
IEEE Standards Association, "IEEE Std 802.1AE-2018 MAC IEEE, "IEEE Standard for Local and metropolitan area
Security (MACsec)", 2018, networks-Media Access Control (MAC) Security", IEEE Std
<https://ieeexplore.ieee.org/document/8585421>. 802.1AE-2018, DOI 10.1109/IEEESTD.2018.8585421, December
2018, <https://ieeexplore.ieee.org/document/8585421>.
[IEEE8021Q] [IEEE8021Q]
IEEE 802.1, "Standard for Local and metropolitan area IEEE, "IEEE Standard for Local and metropolitan area
networks--Bridges and Bridged Networks (IEEE Std 802.1Q- networks--Bridges and Bridged Networks", IEEE Std 802.1Q-
2018)", 2018, <http://standards.ieee.org/about/get/>. 2018, DOI 10.1109/IEEESTD.2018.8403927, July 2018,
<https://ieeexplore.ieee.org/document/8403927/>.
[IEEEP8021CBcv] [IEEEP8021CBcv]
Kehrer, S., "FRER YANG Data Model and Management IEEE 802.1, "Draft Standard for Local and metropolitan
Information Base Module", IEEE P802.1CBcv area networks -- Frame Replication and Elimination for
/D0.4 P802.1CBcv, August 2020, Reliability -- Amendment: Information Model, YANG Data
<https://www.ieee802.org/1/files/private/cv-drafts/d0/802- Model and Management Information Base Module", IEEE
1CBcv-d0-4.pdf>. P802.1CBcv, Draft 1.1, February 2021,
<https://1.ieee802.org/tsn/802-1cbcv/>.
Acknowledgements
The authors wish to thank Norman Finn, Lou Berger, Craig Gunther,
Christophe Mangin, and Jouni Korhonen for their various contributions
to this work.
Authors' Addresses Authors' Addresses
Balazs Varga (editor) Balázs Varga (editor)
Ericsson Ericsson
Budapest
Magyar Tudosok krt. 11. Magyar Tudosok krt. 11.
Budapest 1117 1117
Hungary Hungary
Email: balazs.a.varga@ericsson.com Email: balazs.a.varga@ericsson.com
Janos Farkas János Farkas
Ericsson Ericsson
Budapest
Magyar Tudosok krt. 11. Magyar Tudosok krt. 11.
Budapest 1117 1117
Hungary Hungary
Email: janos.farkas@ericsson.com Email: janos.farkas@ericsson.com
Andrew G. Malis Andrew G. Malis
Malis Consulting Malis Consulting
Email: agmalis@gmail.com Email: agmalis@gmail.com
Stewart Bryant Stewart Bryant
Futurewei Technologies Futurewei Technologies
Email: stewart.bryant@gmail.com Email: sb@stewartbryant.com
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