draft-ietf-detnet-tsn-vpn-over-mpls-07.txt   rfc9024.txt 
DetNet B. Varga, Ed. Internet Engineering Task Force (IETF) B. Varga, Ed.
Internet-Draft J. Farkas Request for Comments: 9024 J. Farkas
Intended status: Standards Track Ericsson Category: Standards Track Ericsson
Expires: August 23, 2021 A. Malis ISSN: 2070-1721 A. Malis
Malis Consulting Malis Consulting
S. Bryant S. Bryant
Futurewei Technologies Futurewei Technologies
D. Fedyk D. Fedyk
LabN Consulting, L.L.C. LabN Consulting, L.L.C.
February 19, 2021 June 2021
DetNet Data Plane: IEEE 802.1 Time Sensitive Networking over MPLS Deterministic Networking (DetNet) Data Plane: IEEE 802.1 Time-Sensitive
draft-ietf-detnet-tsn-vpn-over-mpls-07 Networking over MPLS
Abstract Abstract
This document specifies the Deterministic Networking data plane when This document specifies the Deterministic Networking data plane when
TSN networks are interconnected over a DetNet MPLS Network. Time-Sensitive Networking (TSN) networks are interconnected over a
DetNet MPLS network.
Status of This Memo Status of This Memo
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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
2.3. Requirements Language . . . . . . . . . . . . . . . . . . 4 2.3. Requirements Language
3. IEEE 802.1 TSN Over DetNet MPLS Data Plane Scenario . . . . . 4 3. IEEE 802.1 TSN over DetNet MPLS Data Plane Scenario
4. DetNet MPLS Data Plane . . . . . . . . . . . . . . . . . . . 6 4. DetNet MPLS Data Plane
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Overview
4.2. TSN over DetNet MPLS Encapsulation . . . . . . . . . . . 7 4.2. TSN over DetNet MPLS Encapsulation
5. TSN over MPLS Data Plane Procedures . . . . . . . . . . . . . 8 5. TSN over MPLS Data Plane Procedures
5.1. Edge Node TSN Procedures . . . . . . . . . . . . . . . . 8 5.1. Edge Node TSN Procedures
5.2. Edge Node DetNet Service Proxy Procedures . . . . . . . . 9 5.2. Edge Node DetNet Service Proxy Procedures
5.3. Edge Node DetNet Service and Forwarding Sub-Layer 5.3. Edge Node DetNet Service and Forwarding Sub-Layer
Procedures . . . . . . . . . . . . . . . . . . . . . . . 10 Procedures
6. Controller Plane (Management and Control) Considerations . . 11 6. Controller Plane (Management and Control) Considerations
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 8. IANA Considerations
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 9. References
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1. Normative References
10.1. Normative References . . . . . . . . . . . . . . . . . . 13 9.2. Informative References
10.2. Informative References . . . . . . . . . . . . . . . . . 14 Acknowledgements
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses
1. Introduction 1. Introduction
The Time-Sensitive Networking Task Group (TSN TG) within IEEE 802.1 The Time-Sensitive Networking Task Group (TSN TG) within the IEEE
Working Group deals with deterministic services through IEEE 802 802.1 Working Group deals with deterministic services through IEEE
networks. Deterministic Networking (DetNet) defined by IETF is a 802 networks. Deterministic Networking (DetNet) defined by the IETF
service that can be offered by a L3 network to DetNet flows. General is a service that can be offered by an L3 network to DetNet flows.
background and concepts of DetNet can be found in [RFC8655]. General background and concepts of DetNet can be found in [RFC8655].
This document specifies the use of a DetNet MPLS network to This document specifies the use of a DetNet MPLS network to
interconnect TSN nodes/network segments. DetNet MPLS data plane is interconnect TSN nodes/network segments. The DetNet MPLS data plane
defined in [RFC8964]. is defined in [RFC8964].
2. Terminology 2. Terminology
2.1. Terms Used in This Document 2.1. Terms Used in This Document
This document uses the terminology and concepts established in the This document uses the terminology and concepts established in the
DetNet architecture [RFC8655] and [RFC8938], and [RFC8964]. TSN DetNet architecture [RFC8655] [RFC8938] [RFC8964]. TSN-specific
specific terms are defined in the TSN TG of IEEE 802.1 Working Group. terms are defined in the TSN TG of the IEEE 802.1 Working Group. The
The reader is assumed to be familiar with these documents and their reader is assumed to be familiar with these documents and their
terminology. terminology.
2.2. Abbreviations 2.2. Abbreviations
The following abbreviations are used in this document: The following abbreviations are used in this document:
AC Attachment Circuit. AC Attachment Circuit
CE Customer Edge equipment. CE Customer Edge equipment
d-CW DetNet Control Word. d-CW DetNet Control Word
DetNet Deterministic Networking. DetNet Deterministic Networking
DF DetNet Flow. DF 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
L2VPN Layer 2 Virtual Private Network. L2VPN Layer 2 Virtual Private Network
L3 Layer 3. L3 Layer 3
LSR Label Switching Router. LSP Label Switched Path
MPLS Multiprotocol Label Switching. LSR Label Switching Router
MPLS-TE Multiprotocol Label Switching - Traffic Engineering. MPLS Multiprotocol Label Switching
NSP Native Service Processing. MPLS-TE Multiprotocol Label Switching - Traffic Engineering
OAM Operations, Administration, and Maintenance. NSP Native Service Processing
PE Provider Edge. OAM Operations, Administration, and Maintenance
PREOF Packet Replication, Elimination and Ordering Functions. PE Provider Edge
PW PseudoWire. PREOF Packet Replication, Elimination and Ordering Functions
S-PE Switching Provider Edge. PW Pseudowire
T-PE Terminating Provider Edge. S-PE Switching Provider Edge
TSN Time-Sensitive Network. T-PE Terminating Provider Edge
TSN Time-Sensitive Network
2.3. Requirements Language 2.3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. IEEE 802.1 TSN Over DetNet MPLS Data Plane Scenario 3. IEEE 802.1 TSN over DetNet MPLS Data Plane Scenario
Figure 1 shows IEEE 802.1 TSN end stations operating over a TSN aware Figure 1 shows IEEE 802.1 TSN end stations operating over a TSN-aware
DetNet service running over an MPLS network. DetNet Edge Nodes sit DetNet service running over an MPLS network. DetNet edge nodes sit
at the boundary of a DetNet domain. They are responsible for mapping at the boundary of a DetNet domain. They are responsible for mapping
non-DetNet aware L2 traffic to DetNet services. They also support non-DetNet-aware L2 traffic to DetNet services. They also support
the imposition and disposition of the required DetNet encapsulation. the imposition and disposition of the required DetNet encapsulation.
These are functionally similar to pseudowire (PW) Terminating These are functionally similar to PW T-PE nodes, which use MPLS-TE
Provider Edge (T-PE) nodes which use MPLS-TE LSPs. In this example LSPs. In this example, TSN Streams are simple applications over
TSN Streams are simple applications over DetNet flows. The specific DetNet flows. The specifics of this operation are discussed later in
of this operation are discussed later in this document. this document.
TSN Edge Transit Edge TSN TSN Edge Transit Edge TSN
End System Node Node Node End System End System Node Node Node End System
(T-PE) (LSR) (T-PE) (T-PE) (LSR) (T-PE)
+----------+ +----------+ +----------+ +----------+
| TSN | <---------End to End TSN Service----------> | TSN | | TSN | <-------- End-to-End TSN Service ---------> | TSN |
| Applic. | | Applic. | | Applic. | | Applic. |
+----------+ +.........+ +.........+ +----------+ +----------+ +.........+ +.........+ +----------+
| | | \S-Proxy: :S-Proxy/ | | | | | | \S-Proxy: :S-Proxy/ | | |
| TSN | | +.+---+<-- DetNet flow -->+---+ | | | TSN | | TSN | | +.+---+<-- DetNet flow -->+---+ | | | TSN |
| | |TSN| |Svc| |Svc| |TSN| | | | | |TSN| |Svc| |Svc| |TSN| | |
+----------+ +---+ +---+ +----------+ +---+ +---+ +----------+ +----------+ +---+ +---+ +----------+ +---+ +---+ +----------+
| L2 | | L2| |Fwd| |Forwarding| |Fwd| |L2 | | L2 | | L2 | | L2| |Fwd| |Forwarding| |Fwd| |L2 | | L2 |
+------.---+ +-.-+ +-.-+ +---.----.-+ +--.+ +-.-+ +---.------+ +------.---+ +-.-+ +-.-+ +---.----.-+ +--.+ +-.-+ +---.------+
: Link : / ,-----. \ : Link : / ,-----. \ : Link : / ,-----. \ : Link : / ,-----. \
+........+ +-[ Sub ]-+ +........+ +-[ TSN ]-+ +........+ +-[ Sub- ]-+ +........+ +-[ TSN ]-+
[Network] [Network] [Network] [Network]
`-----' `-----' `-----' `-----'
|<------ DetNet MPLS ------>| |<------ DetNet MPLS ------>|
|<---------------------- TSN --------------------->| |<---------------------- TSN --------------------->|
Figure 1: A TSN over DetNet MPLS Enabled Network Figure 1: A TSN over DetNet MPLS-Enabled Network
In this example, edge nodes provide a service proxy function that In this example, edge nodes provide a service proxy function that
"associates" the DetNet flows and native flows (i.e., TSN Streams) at "associates" the DetNet flows and native flows (i.e., TSN Streams) at
the edge of the DetNet domain. TSN streams are treated as App-flows the edge of the DetNet domain. TSN Streams are treated as App-flows
for DetNet. The whole DetNet domain behaves as a TSN relay node for for DetNet. The whole DetNet domain behaves as a TSN relay node for
the TSN streams. The service proxy behaves as a port of that TSN the TSN Streams. The service proxy behaves as a port of that TSN
relay node. relay node.
Figure 2 illustrates how DetNet can provide services for IEEE 802.1 Figure 2 illustrates how DetNet can provide services for IEEE 802.1
TSN end systems, CE1 and CE2, over a DetNet enabled MPLS network. TSN end systems, CE1 and CE2, over a DetNet-enabled MPLS network.
Edge nodes, E1 and E2, insert and remove required DetNet data plane Edge nodes E1 and E2 insert and remove the required DetNet data plane
encapsulation. The 'X' in the edge nodes and relay node, R1, encapsulation. The 'X' in the edge nodes and relay node, R1,
represent a potential DetNet compound flow packet replication and represent a potential DetNet compound flow packet replication and
elimination point. This conceptually parallels L2VPN services, and elimination point. This conceptually parallels L2VPN services and
could leverage existing related solutions as discussed below. could leverage existing related solutions as discussed below.
TSN |<------- End to End DetNet Service ------>| TSN TSN |<------- End-to-End DetNet Service ------>| TSN
Service | Transit Transit | Service Service | Transit Transit | Service
TSN (AC) | |<-Tnl->| |<-Tnl->| | (AC) TSN TSN (AC) | |<-Tnl->| |<-Tnl->| | (AC) TSN
End | V V 1 V V 2 V V | End End | V V 1 V V 2 V V | End
System | +--------+ +--------+ +--------+ | System System | +--------+ +--------+ +--------+ | System
+---+ | | E1 |=======| R1 |=======| E2 | | +---+ +---+ | | E1 |=======| R1 |=======| E2 | | +---+
| |--|----|._X_....|..DF1..|.._ _...|..DF3..|...._X_.|---|---| | | |--|----|._X_....|..DF1..|.._ _...|..DF3..|...._X_.|---|---| |
|CE1| | | \ | | X | | / | | |CE2| |CE1| | | \ | | X | | / | | |CE2|
| | | \_.|..DF2..|._/ \_..|..DF4..|._/ | | | | | | \_.|..DF2..|._/ \_..|..DF4..|._/ | | |
+---+ | |=======| |=======| | +---+ +---+ | |=======| |=======| | +---+
^ +--------+ +--------+ +--------+ ^ ^ +--------+ +--------+ +--------+ ^
| Edge Node Relay Node Edge Node | | Edge Node Relay Node Edge Node |
| (T-PE) (S-PE) (T-PE) | | (T-PE) (S-PE) (T-PE) |
| | | |
|<- TSN -> <------- TSN Over DetNet MPLS -------> <- TSN ->| |<- TSN -> <------- TSN over DetNet MPLS -------> <- TSN ->|
| | | |
|<-------- Time Sensitive Networking (TSN) Service ------->| |<-------- Time-Sensitive Networking (TSN) Service ------->|
X = Service protection X = Service protection
DFx = DetNet member flow x over a TE LSP DFx = DetNet member flow x over a TE LSP
AC = Attachment Circuit AC = Attachment Circuit
Tnl = Tunnel Tnl = Tunnel
Figure 2: IEEE 802.1TSN Over DetNet Figure 2: IEEE 802.1TSN over DetNet
4. DetNet MPLS Data Plane 4. DetNet MPLS Data Plane
4.1. Overview 4.1. 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 operating 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 S-Label as top
of stack uses the local context associated with that S-Label, for of stack, uses the local context associated with that S-Label. For
example a received F-Label, to determine what local DetNet example, a received F-Label can be used to determine what local
operation(s) are applied to that packet. An S-Label may be unique DetNet operation(s) is applied to that packet. An S-Label may be
when taken from the platform label space [RFC3031], which would unique when taken from the platform label space [RFC3031], which
enable correct DetNet flow identification regardless of which input would enable correct DetNet flow identification regardless of which
interface or LSP the packet arrives on. The service sub-layer input interface or LSP the packet arrives on. The service sub-layer
functions (i.e., PREOF) use a DetNet control word (d-CW). functions (i.e., PREOF) use a DetNet control 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 forwarding The forwarding sub-layer is supported by one or more forwarding
labels (F-Labels). labels (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
functions, notably, support for explicit routes and resource -- notably, support for explicit routes and resource allocation to
allocation to eliminate (or reduce) congestion loss and jitter. eliminate (or reduce) congestion loss and jitter. Unlike other
Unlike other DetNet node types, transit nodes provide no service sub- DetNet node types, transit nodes provide no service sub-layer
layer processing. processing.
4.2. TSN over DetNet MPLS Encapsulation 4.2. TSN over DetNet MPLS Encapsulation
The basic encapsulation approach is to treat a TSN Stream as an App- The basic encapsulation approach is to treat a TSN Stream as an App-
flow from the DetNet MPLS perspective. The corresponding example flow from the DetNet MPLS perspective. The corresponding example is
shown in Figure 3. Note, that three example flows are shown in the shown in Figure 3. Note that three example flows are shown in the
figure. figure.
/-> +------+ +------+ +------+ TSN ^ ^ /-> +------+ +------+ +------+ TSN ^ ^
MPLS | | X | | X | | X |<- Appli : : MPLS | | X | | X | | X |<- Appli : :
App-Flow <-+ +------+ +------+ +------+ cation : :(1) App-Flow <-+ +------+ +------+ +------+ cation : :(1)
| |TSN-L2| |TSN-L2| |TSN-L2| : v | |TSN-L2| |TSN-L2| |TSN-L2| : v
\-> +---+======+--+======+--+======+-----+ : \-> +---+======+--+======+--+======+-----+ :
| d-CW | | d-CW | | d-CW | : | d-CW | | d-CW | | d-CW | :
DetNet-MPLS +------+ +------+ +------+ :(2) DetNet-MPLS +------+ +------+ +------+ :(2)
|Labels| |Labels| |Labels| v |Labels| |Labels| |Labels| v
skipping to change at page 8, line 5 skipping to change at line 297
(2) DetNet MPLS Flow (2) DetNet MPLS Flow
Figure 3: Examples of TSN over MPLS Encapsulation Formats Figure 3: Examples of TSN over MPLS Encapsulation Formats
In the figure, "Application" indicates the application payload In the figure, "Application" indicates the application payload
carried by the TSN network. "MPLS App-Flow" indicates that the TSN carried by the TSN network. "MPLS App-Flow" indicates that the TSN
Stream is the payload from the perspective of the DetNet MPLS data Stream is the payload from the perspective of the DetNet MPLS data
plane defined in [RFC8964]. A single DetNet MPLS flow can aggregate plane defined in [RFC8964]. A single DetNet MPLS flow can aggregate
multiple TSN Streams. multiple TSN Streams.
Note: In order to avoid fragmentation (see section 5.3 of [RFC3985]), | Note: Network fragmentation for DetNet is not supported and
the network operator has to make sure that all the DetNet | MUST be avoided. The reason for this is that network
encapsulation overhead plus the TSN App-flow do not exceed the DetNet | fragmentation is not consistent with the packet delivery times
network's MTU. | needed for DetNet. Therefore, when IP is used as the sub-
| network, IPv6 fragmentation MUST NOT be used, and IPv4 packets
| MUST be sent with the DF bit set. This means that the network
| operator MUST ensure that all the DetNet encapsulation overhead
| plus the maximum TSN App-flow frame size does not exceed the
| DetNet network's MTU.
5. TSN over MPLS Data Plane Procedures 5. TSN over MPLS Data Plane Procedures
The description of Edge Nodes procedures and functions for TSN over The description of edge node procedures and functions for TSN over
DetNet MPLS scenarios follows the concepts from [RFC3985], and covers DetNet MPLS scenarios follows the concepts from [RFC3985] and covers
the Edge Nodes components shown in Figure 1. In this section the the edge node components shown in Figure 1. In this section, the
following procedures of DetNet Edge Nodes are described: following procedures of DetNet edge nodes are described:
o TSN related (Section 5.1) * TSN related (Section 5.1)
o DetNet Service Proxy (Section 5.2) * DetNet Service Proxy (Section 5.2)
o DetNet service and forwarding sub-layer (Section 5.3) * DetNet service and forwarding sub-layer (Section 5.3)
The sub-sections describe procedures for forwarding packets by DetNet The subsections describe procedures for forwarding packets by DetNet
Edge nodes, where such packets are received from either directly edge nodes, where such packets are received from either directly
connected CEs (TSN nodes) or some other DetNet Edge nodes. connected CEs (TSN nodes) or some other DetNet edge nodes.
5.1. Edge Node TSN Procedures 5.1. Edge Node TSN Procedures
The Time-Sensitive Networking (TSN) Task Group of the IEEE 802.1 The TSN TG of the IEEE 802.1 Working Group has defined (and is
Working Group have defined (and are defining) a number of amendments defining) a number of amendments to [IEEE8021Q] that provide zero
to [IEEE8021Q] that provide zero congestion loss and bounded latency congestion loss and bounded latency in bridged networks.
in bridged networks. [IEEE8021CB] defines packet replication and [IEEE8021CB] defines packet replication and elimination functions for
elimination functions for a TSN network. a TSN network.
The implementation of TSN entity (i.e., TSN packet processing The implementation of a TSN entity (i.e., TSN packet processing
functions) must be compliant with the relevant IEEE 802.1 standards. functions) must be compliant with the relevant IEEE 802.1 standards.
TSN specific functions are executed on the data received by the TSN-specific functions are executed on the data received by the
DetNet Edge Node from the connected CE before being forwarded to DetNet edge node from the connected CE before being forwarded to
connected CE(s) or presented to the DetNet Service Proxy function for connected CE(s) or presented to the DetNet service proxy function for
transmission across the DetNet domain. TSN specific functions are transmission across the DetNet domain. TSN-specific functions are
also executed on the data received from a DetNet PW by a PE before also executed on the data received from a DetNet PW by a PE before
the data is output on the Attachment Circuit(s) (AC). the data is output on the AC(s).
TSN packet processing function(s) of Edge Nodes (T-PE) are belonging The TSN packet processing function(s) of edge nodes (T-PE) belongs to
to the native service processing (NSP) [RFC3985] block. This is the NSP [RFC3985] block. This is similar to other functionalities
similar to other functionalities being defined by standard bodies being defined by standards bodies other than the IETF (for example,
other than the IETF (for example in case of Ethernet: stripping, in the case of Ethernet, stripping, overwriting, or adding VLAN tags,
overwriting or adding VLAN tags, etc.). Depending on the TSN role of etc.). Depending on the TSN role of the edge node in the end-to-end
the Edge Node in the end-to-end TSN service selected TSN functions TSN service, selected TSN functions are supported.
are supported.
When a PE receives a packet from a CE, on a given AC with DetNet When a PE receives a packet from a CE on a given AC with DetNet
service, it first checks via Stream Identification (see Clause 6. of service, it first checks via Stream identification (see Clause 6 of
[IEEE8021CB] and [IEEEP8021CBdb]) whether the packet belongs to a [IEEE8021CB] and [IEEEP8021CBdb]) whether the packet belongs to a
configured TSN Stream (i.e., App-flow from DetNet perspective). If configured TSN Stream (i.e., App-flow from the DetNet perspective).
no Stream ID is matched and no other (VPN) service is configured for If no Stream ID is matched and no other (VPN) service is configured
the AC, then the packet MUST be dropped. If there is a matching TSN for the AC, then the packet MUST be dropped. If there is a matching
Stream, then the Stream ID specific TSN functions are executed (e.g., TSN Stream, then the Stream-ID-specific TSN functions are executed
ingress policing, header field manipulation in case of active Stream (e.g., ingress policing, header field manipulation in the case of
Identification, FRER, etc.). Source MAC lookup may also be used for active Stream identification, FRER, etc.). Source Media Access
local MAC address learning. Control (MAC) lookup may also be used for local MAC address learning.
If the PE decides to forward the packet, the packet MUST be forwarded If the PE decides to forward the packet, the packet MUST be forwarded
according to the TSN Stream specific configuration to connected CE(s) according to the TSN-Stream-specific configuration to connected CE(s)
(in case of local bridging) and/or to the DetNet Service Proxy (in (in case of local bridging) and/or to the DetNet service proxy (in
case of forwarding to remote CE(s)). If there are no TSN Stream case of forwarding to remote CE(s)). If there are no TSN-Stream-
specific forwarding configurations, the PE MUST flood the packet to specific forwarding configurations, the PE MUST flood the packet to
other locally attached CE(s) and to the DetNet Service Proxy. If the other locally attached CE(s) and to the DetNet service proxy. If the
administrative policy on the PE does not allow flooding, the PE MUST administrative policy on the PE does not allow flooding, the PE MUST
drop the packet. drop the packet.
When a TSN entity of the PE receives a packet from the DetNet Service When a TSN entity of the PE receives a packet from the DetNet service
Proxy, it first checks via Stream Identification (see Clause 6. of proxy, it first checks via Stream identification (see Clause 6 of
[IEEE8021CB] and [IEEEP8021CBdb]) whether the packet belongs to a [IEEE8021CB] and [IEEEP8021CBdb]) whether the packet belongs to a
configured TSN Stream. If no Stream ID is matched, then the packet configured TSN Stream. If no Stream ID is matched, then the packet
is dropped. If there is a matching TSN Stream, then the Stream ID is dropped. If there is a matching TSN Stream, then the Stream-ID-
specific TSN functions are executed (e.g., header field manipulation specific TSN functions are executed (e.g., header field manipulation
in case of active Stream Identification, FRER, etc.). Source MAC in case of active Stream identification, FRER, etc.). Source MAC
lookup may also be used for local MAC address learning. lookup may also be used for local MAC address learning.
If the PE decides to forward the packet, the packet is forwarded If the PE decides to forward the packet, the packet is forwarded
according to the TSN Stream specific configuration to connected according to the TSN-Stream-specific configuration to connected
CE(s). If there are no TSN Stream specific forwarding CE(s). If there are no TSN-Stream-specific forwarding
configurations, the PE floods the packet to locally attached CE(s). configurations, the PE floods the packet to locally attached CE(s).
If the administrative policy on the PE does not allow flooding, the If the administrative policy on the PE does not allow flooding, the
PE drops the packet. PE drops the packet.
Implementations of this document SHALL use management and control Implementations of this document SHALL use management and control
information to ensure TSN specific functions of the Edge Node information to ensure TSN-specific functions of the edge node
according to the expectations of the connected TSN network. according to the expectations of the connected TSN network.
5.2. Edge Node DetNet Service Proxy Procedures 5.2. Edge Node DetNet Service Proxy Procedures
The Service Proxy function maps between App-flows and DetNet flows. The service proxy function maps between App-flows and DetNet flows.
The DetNet Edge Node TSN entity MUST support the TSN Stream The DetNet edge node TSN entity MUST support the TSN Stream
identification functions and the related managed objects as defined identification functions (as defined in Clause 6 of [IEEE8021CB] and
in Clause 6. and Clause 9. of [IEEE8021CB] and [IEEEP8021CBdb] to [IEEEP8021CBdb]) and the related managed objects (as defined in
recognize the App-flow related packets. The Service Proxy presents Clause 9 of [IEEE8021CB] and [IEEEP8021CBdb]) to recognize the
TSN Streams as an App-flow to a DetNet Flow. packets related to App-flow. The service proxy presents TSN Streams
as an App-flow to a DetNet flow.
When a DetNet Service Proxy receives a packet from the TSN Entity it When a DetNet service proxy receives a packet from the TSN entity, it
MUST check whether such an App-flow is present in its mapping table. MUST check whether such an App-flow is present in its mapping table.
If present it associates the internal DetNet flow-ID to the packet If present, it associates the internal DetNet flow ID to the packet
and MUST forward it to the DetNet Service and Forwarding sub-layers. and MUST forward it to the DetNet service and forwarding sub-layers.
If no match is found it MUST drop the packet. If no match is found, it MUST drop the packet.
When a DetNet Service Proxy receives a packet from the DetNet Service When a DetNet service proxy receives a packet from the DetNet service
and Forwarding sub-layers it MUST be forwarded to the Edge Node TSN and forwarding sub-layers, it MUST be forwarded to the edge node TSN
Entity. entity.
Implementations of this document SHALL use management and control Implementations of this document SHALL use management and control
information to map a TSN Stream to a DetNet flow. N:1 mapping information to map a TSN Stream to a DetNet flow. N:1 mapping
(aggregating multiple TSN Streams in a single DetNet flow) SHALL be (aggregating multiple TSN Streams in a single DetNet flow) SHALL be
supported. The management or control function that provisions flow supported. The management or control function that provisions flow
mapping SHALL ensure that adequate resources are allocated and mapping SHALL ensure that adequate resources are allocated and
configured to fulfil the service requirements of the mapped flows. configured to fulfill the service requirements of the mapped flows.
Due to the (intentional) similarities of the DetNet PREOF and TSN Due to the (intentional) similarities of the DetNet PREOF and TSN
FRER functions service protection function interworking is possible FRER functions, service protection function interworking is possible
between the TSN and the DetNet domains. Such service protection between the TSN and the DetNet domains. Such service protection
interworking scenarios might require to copy sequence number fields interworking scenarios might require copying of sequence number
from TSN (L2) to PW (MPLS) encapsulation. However, such interworking fields from TSN (L2) to PW (MPLS) encapsulation. However, such
is out-of-scope in this document and left for further study. interworking is out of scope in this document and is left for further
study.
5.3. Edge Node DetNet Service and Forwarding Sub-Layer Procedures 5.3. Edge Node DetNet Service and Forwarding Sub-Layer Procedures
In the design of [RFC8964] an MPLS service label (the S-Label), In the design presented in [RFC8964], an MPLS service label (the
similar to a pseudowire (PW) label [RFC3985], is used to identify S-Label), similar to a PW label [RFC3985], is used to identify both
both the DetNet flow identity and the payload MPLS payload type. The the DetNet flow identity and the MPLS payload type. The DetNet
DetNet sequence number is carried in the DetNet Control word (d-CW) sequence number is carried in the d-CW, which carries the Data/OAM
which carries the Data/OAM discriminator as well. In [RFC8964] two discriminator as well. In [RFC8964], two sequence number sizes are
sequence number sizes are supported: a 16 bit sequence number and a supported: a 16-bit sequence number and a 28-bit sequence number.
28 bit sequence number.
PREOF functions and the provided service recovery is available only PREOF functions and the provided service recovery are available only
within the DetNet domain as the DetNet flow-ID and the DetNet within the DetNet domain as the DetNet flow ID and the DetNet
sequence number are not valid outside the DetNet network. MPLS sequence number are not valid outside the DetNet network. MPLS
(DetNet) Edge nodes terminate all related information elements (DetNet) edge nodes terminate all related information elements
encoded in the MPLS labels. encoded in the MPLS labels.
When a PE receives a packet from the Service Proxy function it MUST When a PE receives a packet from the service proxy function, it MUST
handle the packet as defined in [RFC8964]. handle the packet as defined in [RFC8964].
When a PE receives an MPLS packet from a remote PE, then, after When a PE receives an MPLS packet from a remote PE, then, after
processing the MPLS label stack, if the top MPLS label ends up being processing the MPLS label stack, if the top MPLS label ends up being
a DetNet S-label that was advertised by this node, then the PE MUST a DetNet S-Label that was advertised by this node, then the PE MUST
forward the packet according to the configured DetNet Service and forward the packet according to the configured DetNet service and
Forwarding sub-layer rules to other PE nodes or via the Detnet forwarding sub-layer rules to other PE nodes or via the DetNet
Service Proxy function towards locally connected CE(s). service proxy function towards locally connected CE(s).
For further details on DetNet Service and Forwarding sub-layers see For further details on DetNet service and forwarding sub-layers, see
[RFC8964]. [RFC8964].
6. Controller Plane (Management and Control) Considerations 6. Controller Plane (Management and Control) Considerations
TSN Stream(s) to DetNet flow mapping related information are required Information related to TSN Stream(s) to DetNet flow mapping is
only for the service proxy function of MPLS (DetNet) Edge nodes. required only for the service proxy function of MPLS (DetNet) edge
From the Data Plane perspective there is no practical difference nodes. From the data plane perspective, there is no practical
based on the origin of flow mapping related information (management difference based on the origin of flow-mapping-related information
plane or control plane). (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 TSN over DetNet MPLS: configure TSN over DetNet MPLS:
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 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 App-Flow identification information to map received TSN Stream(s) * App-flow identification information to map received TSN Stream(s)
to the DetNet flow. Parameters of TSN stream identification are to the DetNet flow. Parameters of TSN Stream identification are
defined in [IEEE8021CB] and [IEEEP8021CBdb]. defined in [IEEE8021CB] and [IEEEP8021CBdb].
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 challanges are highligthed of scope of the document. Some of the challenges are highlighted
below. below.
MPLS DetNet Edge nodes are member of both the DetNet domain and the MPLS DetNet edge nodes are a member of both the DetNet domain and the
connected TSN network. From the TSN network perspective the MPLS connected TSN network. From the TSN network perspective, the MPLS
(DetNet) Edge node has a "TSN relay node" role, so TSN specific (DetNet) edge node has a "TSN relay node" 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 behaves differently. protocols. For example, RSVP-TE and MSRP behave differently.
Therefore management and control plane design is an important aspect Therefore, management and control plane design is an important aspect
of scenarios, where mapping between DetNet and TSN is required. of scenarios where mapping between DetNet and TSN is required.
Note that, as the DetNet network is just a portion of the end to end Note that as the DetNet network is just a portion of the end-to-end
TSN path (i.e., single hop from Ethernet perspective), some TSN path (i.e., single hop from the Ethernet perspective), some
parameters (e.g., delay) may differ significantly. Since there is no parameters (e.g., delay) may differ significantly. Since there is no
interworking function the bandwidth of DetNet network is assumed to interworking function, the bandwidth of the DetNet network is assumed
be set large enough to handle all TSN Flows it will support. At the to be set large enough to handle all TSN flows it will support. At
egress of the Detnet Domain the MPLS headers are stripped and the TSN the egress of the DetNet domain, the MPLS headers are stripped, and
flow continues on as a normal TSN flow. the TSN flow continues on as a normal TSN flow.
In order to use a DetNet network to interconnect TSN segments, TSN In order to use a DetNet network to interconnect TSN segments, TSN-
specific information must be converted to DetNet domain specific specific information must be converted to DetNet-domain-specific
ones. TSN Stream ID(s) and stream(s) related parameters/requirements information. TSN Stream ID(s) and stream-related parameters/
must be converted to a DetNet flow-ID and flow related parameters/ requirements must be converted to a DetNet flow ID and flow-related
requirements. parameters/requirements.
In some case it may be challenging to determine some egress node In some cases, it may be challenging to determine some information
related information. For example, it may be not trivial to locate related to the egress-node. For example, it may be not trivial to
the egress point/interface of a TSN Stream with a multicast locate the egress point/interface of a TSN Stream with a multicast
destination MAC address. Such scenarios may require interaction destination MAC address. Such scenarios may require interaction
between control and management plane functions and between DetNet and between control and management plane functions and between DetNet and
TSN domains. 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 the service proxy function if not provided explicitly, can be done by the service proxy function
of an MPLS (DetNet) Edge node locally based on information provided of an MPLS (DetNet) edge node locally based on information provided
for configuration of the TSN Stream identification functions (e.g., for the configuration of the TSN Stream identification functions
Mask-and-Match Stream identification). (e.g., Mask-and-Match Stream identification).
Triggering the setup/modification of a DetNet flow in the DetNet Triggering the setup/modification of a DetNet flow in the DetNet
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 the TSN network. interactions are required between the DetNet and the TSN network.
Configuration of TSN specific functions (e.g., FRER) inside the TSN Configuration of TSN-specific functions (e.g., FRER) inside the TSN
network is a TSN domain specific decision and may not be visible in network is a TSN-domain-specific decision and may not be visible in
the DetNet domain. Service protection interworking scenarios are the DetNet domain. Service protection interworking scenarios are
left for further study. left for further study.
7. Security Considerations 7. 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-SEC]. General security considerations are described in
described in [RFC8655]. [RFC8655].
DetNet MPLS data plane specific considerations are summarized and Considerations specific to the DetNet MPLS data plane are summarized
described in [RFC8964] including any application flow types. This and described in [RFC8964], including any application flow types.
document focuses on the scenario where TSN Streams are the This document focuses on a scenario where TSN Streams are the
application flows for DetNet and it is already covered by those application flows for DetNet, which is already covered by those
DetNet MPLS data plane security considerations. DetNet MPLS data plane security considerations.
8. IANA Considerations 8. IANA Considerations
This document makes no IANA requests. This document has no IANA actions.
9. Acknowledgements
The authors wish to thank Norman Finn, Lou Berger, Craig Gunther,
Christophe Mangin and Jouni Korhonen for their various contributions
to this work.
10. References 9. References
10.1. Normative References 9.1. Normative References
[IEEE8021CB] [IEEE8021CB]
IEEE 802.1, "Standard for Local and metropolitan area IEEE, "Standard for Local and metropolitan area networks
networks - Frame Replication and Elimination for -- Frame Replication and Elimination for Reliability",
Reliability (IEEE Std 802.1CB-2017)", 2017, IEEE 802.1CB-2017, DOI 10.1109/IEEESTD.2017.8091139,
<http://standards.ieee.org/about/get/>. 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>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[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>.
skipping to change at page 14, line 15 skipping to change at line 589
[RFC8938] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S. [RFC8938] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane Bryant, "Deterministic Networking (DetNet) Data Plane
Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020, Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020,
<https://www.rfc-editor.org/info/rfc8938>. <https://www.rfc-editor.org/info/rfc8938>.
[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>.
10.2. Informative References 9.2. Informative References
[I-D.ietf-detnet-security] [DETNET-SEC]
Grossman, E., Mizrahi, T., and A. Hacker, "Deterministic Grossman, E., Ed., Mizrahi, T., and A. 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>.
[IEEE8021Q] [IEEE8021Q]
IEEE 802.1, "Standard for Local and metropolitan area IEEE, "Standard for Local and Metropolitan Area Networks--
networks--Bridges and Bridged Networks (IEEE Std 802.1Q- Bridges and Bridged Networks", IEEE Std. 802.1Q-2018,
2018)", 2018, <http://standards.ieee.org/about/get/>. DOI 10.1109/IEEESTD.2018.8403927, July 2018,
<https://ieeexplore.ieee.org/document/8403927>.
[RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation [RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation
Edge-to-Edge (PWE3) Architecture", RFC 3985, Edge-to-Edge (PWE3) Architecture", RFC 3985,
DOI 10.17487/RFC3985, March 2005, DOI 10.17487/RFC3985, March 2005,
<https://www.rfc-editor.org/info/rfc3985>. <https://www.rfc-editor.org/info/rfc3985>.
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
Don Fedyk Don Fedyk
LabN Consulting, L.L.C. LabN Consulting, L.L.C.
Email: dfedyk@labn.net Email: dfedyk@labn.net
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