Internet Engineering Task Force (IETF) B. Varga, Ed.
Request for Comments: 8964 J. Farkas
Category: Standards Track Ericsson
ISSN: 2070-1721 L. Berger
LabN Consulting, L.L.C.
A. Malis
Malis Consulting
S. Bryant
Futurewei Technologies
J. Korhonen
December 2020
January 2021
Deterministic Networking (DetNet) Data Plane: MPLS
Abstract
This document specifies the Deterministic Networking (DetNet) data
plane when operating over an MPLS Packet Switched Network. It
leverages existing pseudowire (PW) encapsulations and MPLS Traffic
Engineering (MPLS-TE) encapsulations and mechanisms. This document
builds on the DetNet architecture and data plane framework.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8964.
Copyright Notice
Copyright (c) 2020 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction
2. Terminology
2.1. Terms Used in This Document
2.2. Abbreviations
2.3. Requirements Language
3. Overview of the DetNet MPLS Data Plane
3.1. Layers of DetNet Data Plane
3.2. DetNet MPLS Data Plane Scenarios
4. MPLS-Based DetNet Data Plane Solution
4.1. DetNet over MPLS Encapsulation Components
4.2. MPLS Data Plane Encapsulation
4.2.1. DetNet Control Word and DetNet Sequence Number
4.2.2. S-Labels
4.2.3. F-Labels
4.3. OAM Indication
4.4. Flow Aggregation
4.4.1. Aggregation via LSP Hierarchy
4.4.2. Aggregating DetNet Flows as a New DetNet Flow
4.5. Service Sub-Layer Considerations
4.5.1. Edge Node Processing
4.5.2. Relay Node Processing
4.6. Forwarding Sub-Layer Considerations
4.6.1. Class of Service
4.6.2. Quality of Service
5. Management and Control Information Summary
5.1. Service Sub-Layer Information Summary
5.1.1. Service Aggregation Information Summary
5.2. Forwarding Sub-Layer Information Summary
6. Security Considerations
7. IANA Considerations
8. References
8.1. Normative References
8.2. Informative References
Acknowledgements
Contributors
Authors' Addresses
1. Introduction
Deterministic Networking (DetNet) is a service that can be offered by
a network to DetNet flows. DetNet provides a capability for the
delivery of data flows with extremely low packet loss rates and
bounded end-to-end delivery latency. General background and concepts
of DetNet can be found in the DetNet architecture [RFC8655].
The purpose of this document is to describe the use of the MPLS data
plane to establish and support DetNet flows. The DetNet architecture
models the DetNet-related data plane functions as being decomposed
into two sub-layers: a service sub-layer and a forwarding sub-layer.
The service sub-layer is used to provide DetNet service functions,
such as protection and reordering. At the DetNet data plane, a new
set of functions (Packet Replication, Elimination and Ordering
Functions (PREOF)) provide the tasks specific to the service sub-
layer. The forwarding sub-layer is used to provide forwarding
assurance (low loss, assured latency, and limited out-of-order
delivery). The use of the functionalities of the DetNet service sub-
layer and the DetNet forwarding sub-layer require careful design and
control by the Controller Plane in addition to the DetNet-specific
use of MPLS encapsulation as specified by this document.
This document specifies the DetNet data plane operation and the on-
wire encapsulation of DetNet flows over an MPLS-based Packet Switched
Network (PSN) using the service reference model. MPLS encapsulation
already provides a solid foundation of building blocks to enable the
DetNet service and forwarding sub-layer functions. MPLS-encapsulated
DetNet can be carried over a variety of different network
technologies that can provide the level of service required for
DetNet. However, the specific details of how DetNet MPLS is carried
over different network technologies are out of scope for this
document.
MPLS-encapsulated DetNet flows can carry different types of traffic.
The details of the types of traffic that are carried in DetNet are
also out of scope for this document. An example of IP using DetNet
MPLS sub-networks can be found in [RFC8939]. DetNet MPLS may use an
associated controller and Operations, Administration, and Maintenance
(OAM) functions that are defined outside of this document.
Background information common to all data planes for DetNet can be
found in the DetNet data plane framework [RFC8938].
2. Terminology
2.1. Terms Used in This Document
This document uses the terminology established in the DetNet
architecture [RFC8655] and the DetNet data plane framework [RFC8938].
The reader is assumed to be familiar with these documents, any
terminology defined therein, and basic MPLS-related terminologies in
[RFC3031].
The following terminology is introduced in this document:
F-Label A DetNet "forwarding" label that identifies the Label
Switched Path (LSP) used to forward a DetNet flow
across an MPLS PSN, i.e., a hop-by-hop label used
between Label Switching Routers (LSRs).
S-Label A DetNet "service" label that is used between DetNet
nodes that implement the DetNet service sub-layer
functions. An S-Label is used to identify a DetNet
flow at the DetNet service sub-layer at a receiving
DetNet node.
A-Label A special case of an S-Label, whose aggregation
properties are known only at the aggregation and
deaggregation end points.
d-CW A DetNet Control Word (d-CW) that is used for
sequencing information of a DetNet flow at the DetNet
service sub-layer.
2.2. Abbreviations
The following abbreviations are used in this document:
CoS Class of Service
CW Control Word
DetNet Deterministic Networking
LSR Label Switching Router
MPLS Multiprotocol Label Switching
MPLS-TE Multiprotocol Label Switching Traffic Engineering
MPLS-TP Multiprotocol Label Switching Transport Profile
OAM Operations, Administration, and Maintenance
PE Provider Edge
PEF Packet Elimination Function
PRF Packet Replication Function
PREOF Packet Replication, Elimination and Ordering Functions
POF Packet Ordering Function
PSN Packet Switched Network
PW Pseudowire
QoS Quality of Service
S-PE Switching Provider Edge
T-PE Terminating Provider Edge
TSN Time-Sensitive Networking
2.3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Overview of the DetNet MPLS Data Plane
3.1. Layers of DetNet Data Plane
MPLS provides a wide range of capabilities that can be utilized by
DetNet. A straight-forward approach utilizing MPLS for a DetNet
service sub-layer is based on the existing pseudowire (PW)
encapsulations and utilizes existing MPLS-TE encapsulations and
mechanisms. Background on PWs can be found in [RFC3985], [RFC3032],
and [RFC3031]. Background on MPLS-TE can be found in [RFC3272] and
[RFC3209].
DetNet MPLS
.
Bottom of Stack .
(inner label) +------------+
| Service | d-CW, S-Label (A-Label)
+------------+
| Forwarding | F-Label(s)
+------------+
Top of Stack .
(outer label) .
Figure 1: DetNet Adaptation to MPLS Data Plane
The DetNet MPLS data plane representation is illustrated in Figure 1.
The service sub-layer includes a DetNet Control Word (d-CW) and an
identifying service label (S-Label). The DetNet Control Word (d-CW)
conforms to the Generic PW MPLS Control Word (PWMCW) defined in
[RFC4385]. An aggregation label (A-Label) is a special case of
S-Label used for aggregation.
A node operating on a received DetNet flow at the DetNet service sub-
layer uses the local context associated with a received S-Label,
i.e., a received F-Label, to determine which local DetNet
operation(s) are applied to that packet. An S-Label may be taken
from the platform label space [RFC3031], making it unique and
enabling DetNet flow identification regardless of which input
interface or LSP the packet arrives on. It is important to note that
S-Label values are driven by the receiver, not the sender.
The DetNet forwarding sub-layer is supported by zero or more
forwarding labels (F-Labels). MPLS-TE encapsulations and mechanisms
can be utilized to provide a forwarding sub-layer that is responsible
for providing resource allocation and explicit routes.
3.2. DetNet MPLS Data Plane Scenarios
DetNet MPLS Relay Transit Relay DetNet MPLS
End System Node Node Node End System
(T-PE) (S-PE) (LSR) (S-PE) (T-PE)
+----------+ +----------+
| Appl. |<------------ End-to-End Service ----------->| Appl. |
+----------+ +---------+ +---------+ +----------+
| Service |<--| Service |-- DetNet flow --| Service |-->| Service |
+----------+ +---------+ +----------+ +---------+ +----------+
|Forwarding| |Fwd| |Fwd| |Forwarding| |Fwd| |Fwd| |Forwarding|
+-------.--+ +-.-+ +-.-+ +----.---.-+ +-.-+ +-.-+ +---.------+
: Link : / ,-----. \ : Link : / ,-----. \
+........+ +-[ Sub- ]-+ +......+ +-[ Sub- ]-+
[Network] [Network]
`-----' `-----'
|<- LSP -->| |<-------- LSP -----------| |<--- LSP -->|
|<----------------- DetNet MPLS --------------------->|
Figure 2: A DetNet MPLS Network
Figure 2 illustrates a hypothetical DetNet MPLS-only network composed
of DetNet-aware MPLS-enabled end systems operating over a DetNet-
aware MPLS network. In this figure, the relay nodes are PE devices
that define the MPLS LSP boundaries, and the transit nodes are LSRs.
DetNet end systems and relay nodes understand the particular needs of
DetNet flows and provide both DetNet service and forwarding sub-layer
functions. In the case of MPLS, DetNet service-aware nodes add,
remove, and process d-CWs, S-Labels, and F-Labels as needed. DetNet
MPLS nodes provide functionality analogous to T-PEs when they sit at
the edge of an MPLS domain and S-PEs when they are in the middle of
an MPLS domain; see [RFC6073].
In a DetNet MPLS network, transit nodes may be DetNet-service-aware
or DetNet-unaware MPLS Label Switching Routers (LSRs). In this
latter case, such LSRs would be unaware of the special requirements
of the DetNet service sub-layer but would still provide traffic
engineering functions and the QoS capabilities needed to ensure that
the (TE) LSPs meet the service requirements of the carried DetNet
flows.
The application of DetNet using MPLS supports a number of control and
management plane types. These types support certain MPLS data plane
deployments. For example, RSVP-TE, MPLS-TP, or MPLS Segment Routing
(when extended to support resource allocation) are all valid MPLS
deployment cases.
Figure 3 illustrates how an end-to-end MPLS-based DetNet service is
provided in more detail. In this figure, the Customer Edge (CE1 and
CE2) are able to send and receive MPLS-encapsulated DetNet flows, and
R1, R2, and R3 are relay nodes in the middle of a DetNet network.
The 'X' in the end systems and relay nodes represents potential
DetNet compound flow packet replication and elimination points. In
this example, service protection is supported utilizing at least two
DetNet member flows and TE LSPs. For a unidirectional flow, R1
supports PRF, and R3 supports PEF and POF. Note that the relay nodes
may change the underlying forwarding sub-layer, for example,
tunneling MPLS over IEEE 802.1 TSN [DetNet-MPLS-over-TSN] or simply
over interconnected network links.
DetNet DetNet
DetNet Service Transit Transit Service DetNet
MPLS | |<-Tnl->| |<-Tnl->| | MPLS
End | V 1 V V 2 V | End
System | +--------+ +--------+ +--------+ | System
+---+ | | R1 |=======| R2 |=======| R3 | | +---+
| X...DFa...|._X_....|..DF1..|.__ ___.|..DF3..|...._X_.|.DFa..|.X |
|CE1|========| \ | | X | | / |======|CE2|
| | | | \_.|..DF2..|._/ \__.|..DF4..|._/ | | | |
+---+ | |=======| |=======| | +---+
^ +--------+ +--------+ +--------+ ^
| Relay Node Relay Node Relay Node |
| (S-PE) (S-PE) (S-PE) |
| |
|<---------------------- DetNet MPLS --------------------->|
| |
|<--------------- End-to-End DetNet Service -------------->|
-------------------------- Data Flow ------------------------->
Figure 3: MPLS-Based Native DetNet
X - Optional service protection (none, PRF, PREOF, PEF/POF)
DFx - DetNet member flow x over a TE LSP
4. MPLS-Based DetNet Data Plane Solution
4.1. DetNet over MPLS Encapsulation Components
To carry DetNet over MPLS, the following is required:
1. A method of identifying the MPLS payload type.
2. A method of identifying the DetNet flow(s) to the processing
element.
3. A method of distinguishing DetNet OAM packets from DetNet data
packets.
4. A method of carrying the DetNet sequence number.
5. A suitable LSP to deliver the packet to the egress PE.
6. A method of carrying queuing and forwarding indication.
In this design, an MPLS service label (the S-Label) is similar to a
pseudowire (PW) label [RFC3985] and is used to identify both the
DetNet flow identity and the MPLS payload type satisfying (1) and (2)
in the list above. OAM traffic discrimination happens through the
use of the Associated Channel method described in [RFC4385]. The
DetNet sequence number is carried in the DetNet Control Word, which
also carries the Data/OAM discriminator. To simplify implementation
and to maximize interoperability, two sequence number sizes are
supported: a 16-bit sequence number and a 28-bit sequence number.
The 16-bit sequence number is needed to support some types of legacy
clients. The 28-bit sequence number is used in situations where it
is necessary to ensure that, in high-speed networks, the sequence
number space does not wrap whilst packets are in flight.
The LSP used to forward the DetNet packet is not restricted regarding
any method used for establishing that LSP (for example, MPLS-LDP,
MPLS-TE, MPLS-TP [RFC5921], MPLS Segment Routing [RFC8660], etc.).
The F-Label(s) and the S-Label may be used alone or together to
indicate the required queue processing as well as the forwarding
parameters. Note that the possible use of Penultimate Hop Popping
(PHP) means that the S-Label may be the only label received at the
terminating DetNet service.
4.2. MPLS Data Plane Encapsulation
Figure 4 illustrates a DetNet data plane MPLS encapsulation. The
MPLS-based encapsulation of the DetNet flows is well suited for the
scenarios described in [RFC8938]. Furthermore, an end-to-end DetNet
service, i.e., native DetNet deployment (see Section 3.2), is also
possible if DetNet end systems are capable of initiating and
terminating MPLS-encapsulated packets.
The MPLS-based DetNet data plane encapsulation consists of:
* A DetNet Control Word (d-CW) containing sequencing information for
packet replication and duplicate elimination purposes, and the OAM
indicator.
* A DetNet service label (S-Label) that identifies a DetNet flow at
the receiving DetNet service sub-layer processing node.
* Zero or more DetNet MPLS forwarding label(s) (F-Label) used to
direct the packet along the Label Switched Path (LSP) to the next
DetNet service sub-layer processing node along the path. When PHP
is in use, there may be no F-Label in the protocol stack on the
final hop.
* The necessary data-link encapsulation is then applied prior to
transmission over the physical media.
DetNet MPLS-based encapsulation
+---------------------------------+
| |
| DetNet App-Flow |
| Payload Packet |
| |
+---------------------------------+ <--\
| DetNet Control Word | |
+---------------------------------+ +--> DetNet data plane
| S-Label | | MPLS encapsulation
+---------------------------------+ |
| [ F-Label(s) ] | |
+---------------------------------+ <--/
| Data-Link |
+---------------------------------+
| Physical |
+---------------------------------+
Figure 4: Encapsulation of a DetNet App-Flow in an MPLS PSN
4.2.1. DetNet Control Word and DetNet Sequence Number
A DetNet Control Word (d-CW) conforms to the Generic PW MPLS Control
Word (PWMCW) defined in [RFC4385]. The d-CW formatted as shown in
Figure 5 MUST be present in all DetNet packets containing App-flow
data. This format of the d-CW was created in order to (1) allow
larger sequence number space to avoid sequence number rollover
frequency in some applications and (2) allow sequence numbering
systems that include the value zero as a valid sequence number, which
simplifies implementation.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: DetNet Control Word
(bits 0 to 3)
Per [RFC4385], MUST be set to zero (0).
Sequence Number (bits 4 to 31)
An unsigned value implementing the DetNet sequence number. The
sequence number space is a circular one with no restriction on the
initial value.
A separate sequence number space MUST be maintained by the node that
adds the d-CW for each DetNet App-flow, i.e., DetNet service. The
following Sequence Number field lengths MUST be supported:
* 0 bits
* 16 bits
* 28 bits
The sequence number length MUST be provisioned on a per-DetNet-
service basis via configuration, i.e., via the Controller Plane
described in [RFC8938].
A 0-bit Sequence Number field length indicates that there is no
DetNet sequence number used for the flow. When the length is zero,
the Sequence Number field MUST be set to zero (0) on all packets sent
for the flow.
When the Sequence Number field length is 16 or 28 bits for a flow,
the sequence number MUST be incremented by one for each new App-flow
packet sent. When the field length is 16 bits, d-CW bits 4 to 15
MUST be set to zero (0). The values carried in this field can wrap,
and it is important to note that zero (0) is a valid field value.
For example, where the sequence number size is 16 bits, the sequence
will contain: 65535, 0, 1, where zero (0) is an ordinary sequence
number.
It is important to note that this document differs from [RFC4448],
where a sequence number of zero (0) is used to indicate that the
sequence number check algorithm is not used.
The sequence number is optionally used during receive processing, as
described below in Sections 4.2.2.2 and 4.2.2.3.
4.2.2. S-Labels
A DetNet flow at the DetNet service sub-layer is identified by an
S-Label. MPLS-aware DetNet end systems and edge nodes, which are by
definition MPLS ingress and egress nodes, MUST add (push) and remove
(pop) a DetNet service-specific d-CW and S-Label. Relay nodes MAY
swap S-Label values when processing a DetNet flow, i.e., incoming and
outgoing S-Labels of a DetNet flow can be different.
S-Label values MUST be provisioned per DetNet service via
configuration, i.e., via the Controller Plane described in [RFC8938].
Note that S-Labels provide identification at the downstream DetNet
service sub-layer receiver, not the sender. As such, S-Labels MUST
be allocated by the entity that controls the service sub-layer
receiving a node's label space and MAY be allocated from the platform
label space [RFC3031]. Because S-Labels are local to each node,
rather than being a global identifier within a domain, they must be
advertised to their upstream DetNet service-aware peer nodes (i.e., a
DetNet MPLS end system or a DetNet relay or edge node) and
interpreted in the context of their received F-Label(s). In some
PREOF topologies, the node performing replication will be sending to
multiple nodes performing PEF or POF and may need to send different
S-Label values for the different member flows for the same DetNet
service.
An S-Label will normally be at the bottom of the label stack once the
last F-Label is removed, immediately preceding the d-CW. To support
OAM at the service sub-layer level, an OAM Associated Channel Header
(ACH) [RFC4385] together with a Generic Associated Channel Label
(GAL) [RFC5586] MAY be used in place of a d-CW.
Similarly, an Entropy Label Indicator (ELI) and Entropy Label (EL)
[RFC6790] MAY be carried below the S-Label in the label stack in
networks where DetNet flows would otherwise receive ECMP treatment.
When ELs are used, the same EL value SHOULD be used for all of the
packets sent using a specific S-Label to force the flow to follow the
same path. However, as outlined in [RFC8938], the use of ECMP for
DetNet flows is NOT RECOMMENDED. ECMP MAY be used for non-DetNet
flows within a DetNet domain.
When receiving a DetNet MPLS packet, an implementation MUST identify
the DetNet service associated with the incoming packet based on the
S-Label. When a node is using platform labels for S-Labels, no
additional information is needed, as the S-Label uniquely identifies
the DetNet service. In the case where platform labels are not used,
zero or more F-Labels proceeding the S-Label MUST be used together
with the S-Label to uniquely identify the DetNet service associated
with a received packet. The incoming interface MAY also be used
together with any present F-Label(s) and the S-Label to uniquely
identify an incoming DetNet service, for example, in the case where
PHP is used. Note that the choice to use the platform label space
for an S-Label or an S-Label plus one or more F-Labels to identify
DetNet services is a local implementation choice, with one caveat.
When one or more F-Labels, or the incoming interface, is needed
together with an S-Label to uniquely identify a service, the
Controller Plane must ensure that incoming DetNet MPLS packets arrive
with the needed information (F-Label(s) and/or the incoming
interface) and provision the needed information. The provisioned
information MUST then be used to identify incoming DetNet service
based on the combination of S-Label and F-Label(s) or the incoming
interface.
The use of platform labels for S-Labels matches other pseudowire
encapsulations for consistency, but there is no hard requirement in
this regard.
Implementation details of PREOF are out of scope for this document.
[IEEE802.1CB-2017] defines equivalent replication and elimination-
specific aspects, which can be applied to PRF and PEF.
4.2.2.1. Packet Replication Function Processing
The Packet Replication Function (PRF) MAY be supported by an
implementation for outgoing DetNet flows. The use of the PRF for a
particular DetNet service MUST be provisioned via configuration,
i.e., via the Controller Plane described in [RFC8938]. When
replication is configured, the same App-flow data will be sent over
multiple outgoing DetNet member flows using forwarding sub-layer
LSPs. An S-Label value MUST be configured per outgoing member flow.
The same d-CW field value MUST be used on all outgoing member flows
for each replicated MPLS packet.
4.2.2.2. Packet Elimination Function Processing
Implementations MAY support the Packet Elimination Function (PEF) for
received DetNet MPLS flows. When supported, use of the PEF for a
particular DetNet service MUST be provisioned via configuration,
i.e., via the Controller Plane described in [RFC8938].
After a DetNet service is identified for a received DetNet MPLS
packet, as described above, if PEF is configured for that DetNet
service, duplicate (replicated) instances of a particular sequence
number MUST be discarded. The specific mechanisms used for an
implementation to identify which received packets are duplicates and
which are new is an implementation choice. Note that, per
Section 4.2.1, the Sequence Number field length may be 16 or 28 bits,
and the field value can wrap. PEF MUST NOT be used with DetNet flows
configured with a d-CW Sequence Number field length of 0 bits.
An implementation MAY constrain the maximum number of sequence
numbers that are tracked on either a platform-wide or per-flow basis.
Some implementations MAY support the provisioning of the maximum
number of sequence numbers that are tracked on either a platform-wide
or per-flow basis.
4.2.2.3. Packet Ordering Function Processing
A function that is related to in-order delivery is the Packet
Ordering Function (POF). Implementations MAY support POF. When
supported, use of the POF for a particular DetNet service MUST be
provisioned via configuration, i.e., via the Controller Plane
described by [RFC8938]. Implementations MAY require that PEF and POF
be used in combination. There is no requirement related to the order
of execution of the PEF and POF in an implementation.
After a DetNet service is identified for a received DetNet MPLS
packet, as described above, if POF is configured for that DetNet
service, packets MUST be processed in the order indicated in the
received d-CW Sequence Number field, which may not be in the order
the packets are received. As defined in Section 4.2.1, the Sequence
Number field length may be 16 or 28 bits, the sequence number is
incremented by one (1) for each new MPLS packet sent for a particular
DetNet service, and the field value can wrap. The specific
mechanisms used for an implementation to identify the order of
received packets is an implementation choice.
An implementation MAY constrain the maximum number of out-of-order
packets that can be processed on either a platform-wide or per-flow
basis. The number of out-of-order packets that can be processed also
impacts the latency of a flow.
The latency impact on the system resources needed to support a
specific DetNet flow will need to be evaluated by the Controller
Plane based on that flow's traffic specification. An example traffic
specification that can be used with MPLS-TE can be found in
[RFC2212].
DetNet implementations can use flow-specific requirements (e.g.,
maximum number of out-of-order packets and maximum latency of the
flow) for configuration of POF-related buffers. POF implementation
details are out of scope for this document, and POF configuration
parameters are implementation specific. The Controller Plane
identifies and sets the POF configuration parameters.
4.2.3. F-Labels
F-Labels support the DetNet forwarding sub-layer. F-Labels are used
to provide LSP-based connectivity between DetNet service sub-layer
processing nodes.
4.2.3.1. Service Sub-Layer-Related Processing
DetNet MPLS end systems, edge nodes, and relay nodes may operate at
the DetNet service sub-layer with understanding of DetNet services
and their requirements. As mentioned earlier, when operating at this
layer, such nodes can push, pop, or swap (pop then push) S-Labels.
In all cases, the F-Label(s) used for a DetNet service are always
replaced, and the following procedures apply.
When sending a DetNet flow, zero or more F-Labels MAY be pushed on
top of an S-Label by the node pushing an S-Label. The F-Label(s) to
be pushed when sending a particular DetNet service MUST be
provisioned per outgoing S-Label via configuration, i.e., via the
Controller Plane discussed in [RFC8938]. F-Label(s) can also provide
context for an S-Label. To allow for the omission of F-Label(s), an
implementation SHOULD also allow an outgoing interface to be
configured per S-Label.
Note that when PRF is supported, the same App-flow data will be sent
over multiple outgoing DetNet member flows using forwarding sub-layer
LSPs. This means that an implementation may be sending different
sets of F-Labels per DetNet member flow, each with a different
S-Label.
When a single set of F-Labels is provisioned for a particular
outgoing S-Label, that set of F-Labels MUST be pushed after the
S-Label is pushed. The outgoing packet is then forwarded, as
described below in Section 4.2.3.2. When a single outgoing interface
is provisioned, the outgoing packet is then forwarded, as described
below in Section 4.2.3.2.
When multiple sets of outgoing F-Labels or interfaces are provisioned
for a particular DetNet service (i.e., for PRF), a copy of the
outgoing packet, including the pushed member flow-specific S-Label,
MUST be made per F-Label set and outgoing interface. Each set of
provisioned F-Labels are then pushed onto a copy of the packet. Each
copy is then forwarded, as described below in Section 4.2.3.2.
As described in the previous section, when receiving a DetNet MPLS
flow, an implementation identifies the DetNet service associated with
the incoming packet based on the S-Label. When a node is using
platform labels for S-Labels, any F-Labels can be popped, and the
S-Label uniquely identifies the DetNet service. In the case where
platform labels are not used, incoming F-Label(s) and, optionally,
the incoming interface MUST also be provisioned for a DetNet service.
4.2.3.2. Common F-Label Processing
All DetNet-aware MPLS nodes process F-Labels as needed to meet the
service requirements of the DetNet flow or flows carried in the LSPs
represented by the F-Labels. This includes normal push, pop, and
swap operations. Such processing is essentially the same type of
processing provided for TE LSPs, although the specific service
parameters, or traffic specification, can differ. When the DetNet
service parameters of the DetNet flow or flows carried in an LSP
represented by an F-Label can be met by an existing TE mechanism, the
forwarding sub-layer processing node MAY be a DetNet-unaware, i.e.,
standard, MPLS LSR. Such TE LSPs may provide LSP forwarding service
as defined in, but not limited, to the following: [RFC3209],
[RFC3270], [RFC3272], [RFC3473], [RFC4875], [RFC5440], and [RFC8306].
More specifically, as mentioned above, the DetNet forwarding sub-
layer provides explicit routes and allocated resources, and F-Labels
are used to map to each. Explicit routes are supported based on the
topmost (outermost) F-Label that is pushed or swapped and the LSP
that corresponds to this label. This topmost (outgoing) label MUST
be associated with a provisioned outgoing interface and, for non-
point-to-point outgoing interfaces, a next-hop LSR. Note that this
information MUST be provisioned via configuration or the Controller
Plane. In the previously mentioned special case where there are no
added F-Labels and the outgoing interface is not a point-to-point
interface, the outgoing interface MUST also be associated with a
next-hop LSR.
Resources may be allocated in a hierarchical fashion per each LSP
that is represented by each F-Label. Each LSP MAY be provisioned
with a service parameter that dictates the specific traffic treatment
to be received by the traffic carried over that LSP. Implementations
of this document MUST ensure that traffic carried over each LSP
represented by one or more F-Labels receives the traffic treatment
provisioned for that LSP. Typical mechanisms used to provide
different treatment to different flows include the allocation of
system resources (such as queues and buffers) and provisioning of
related parameters (such as shaping and policing) that may be found
in implementations of the Resource ReSerVation Protocol (RSVP)
[RFC2205] and RSVP-TE [RFC3209] [RFC3473]. Support can also be
provided via an underlying network technology, such as IEEE 802.1 TSN
[DetNet-MPLS-over-TSN]. The specific mechanisms selected by a DetNet
node to ensure DetNet service delivery requirements are met for
supported DetNet flows is outside the scope of this document.
Packets that are marked in a way that do not correspond to allocated
resources, e.g., lack a provisioned F-Label, can disrupt the QoS
offered to properly reserved DetNet flows by using resources
allocated to the reserved flows. Therefore, the network nodes of a
DetNet network:
* MUST defend the DetNet QoS by discarding or remarking (to an
allocated DetNet flow or noncompeting non-DetNet flow) packets
received that are not associated with a completed resource
allocation.
* MUST NOT use a DetNet allocated resource, e.g., a queue or shaper
reserved for DetNet flows, for any packet that does match the
corresponding DetNet flow.
* MUST ensure a QoS flow does not exceed its allocated resources or
provisioned service level.
* MUST ensure a CoS flow or service class does not impact the
service delivered to other flows. This requirement is similar to
the requirement for MPLS LSRs that CoS LSPs do not impact the
resources allocated to TE LSPs, e.g., via [RFC3473].
Subsequent sections provide additional considerations related to CoS
(Section 4.6.1), QoS (Section 4.6.2), and aggregation (Section 4.4).
4.3. OAM Indication
OAM follows the procedures set out in [RFC5085] with the restriction
that only Virtual Circuit Connectivity Verification (VCCV) type 1 is
supported.
As shown in Figure 3 of [RFC5085], when the first nibble of the d-CW
is 0x0, the payload following the d-CW is normal user data. However,
when the first nibble of the d-CW is 0x1, the payload that follows
the d-CW is an OAM payload with the OAM type indicated by the value
in the d-CW Channel Type field.
The reader is referred to [RFC5085] for a more detailed description
of the Associated Channel mechanism and to the DetNet work on OAM
[DetNet-MPLS-OAM] for more information about DetNet OAM.
Additional considerations on DetNet-specific OAM are subjects for
further study.
4.4. Flow Aggregation
The ability to aggregate individual flows and their associated
resource control into a larger aggregate is an important technique
for improving scaling of control in the data, management, and control
planes. The DetNet data plane allows for the aggregation of DetNet
flows to improved scaling. There are two methods of supporting flow
aggregation covered in this section.
The resource control and management aspects of aggregation (including
the configuration of queuing, shaping, and policing) are the
responsibility of the DetNet Controller Plane and are out of scope
for this document. It is also the responsibility of the Controller
Plane to ensure that consistent aggregation methods are used.
4.4.1. Aggregation via LSP Hierarchy
DetNet flows forwarded via MPLS can leverage MPLS-TE's existing
support for hierarchical LSPs (H-LSPs); see [RFC4206]. H-LSPs are
typically used to aggregate control and resources; they may also be
used to provide OAM or protection for the aggregated LSPs. Arbitrary
levels of aggregation naturally fall out of the definition for
hierarchy and the MPLS label stack [RFC3032]. DetNet nodes that
support aggregation (LSP hierarchy) map one or more LSPs (labels)
into and from an H-LSP. Both carried LSPs and H-LSPs may or may not
use the Traffic Class (TC) field, i.e., L-LSPs (Label-Only-Inferred-
PSC LSPs) or E-LSPs (EXP-Inferred-PSC LSPs [RFC3270], which were
renamed to "Explicitly TC-encoded-PSC LSPs" in Section 2.2 of
[RFC5462]). Such nodes will need to ensure that individual LSPs and
H-LSPs receive the traffic treatment required to ensure the required
DetNet service is preserved.
Additional details of the traffic control capabilities needed at a
DetNet-aware node may be covered in the new service definitions
mentioned above or in separate future documents. Controller Plane
mechanisms will also need to ensure that the service required on the
aggregate flow are provided, which may include the discarding or
remarking mentioned in the previous sections.
4.4.2. Aggregating DetNet Flows as a New DetNet Flow
An aggregate can be built by layering DetNet flows, including both
their S-Label and (when present) F-Labels, as shown below:
+---------------------------------+
| |
| DetNet Flow |
| Payload Packet |
| |
+---------------------------------+ <--\
| DetNet Control Word | |
+=================================+ |
| S-Label | |
+---------------------------------+ |
| [ F-Label(s) ] | +----DetNet data plane
+---------------------------------+ |
| DetNet Control Word | |
+=================================+ |
| A-Label | |
+---------------------------------+ |
| F-Label(s) | <--/
+---------------------------------+
| Data-Link |
+---------------------------------+
| Physical |
+---------------------------------+
Figure 6: DetNet Aggregation as a New DetNet Flow
Both the aggregation label, which is referred to as an A-Label, and
the individual flow's S-Label have their MPLS S bit set indicating
the bottom of stack, and the d-CW allows the PREOF to work. An
A-Label is a special case of an S-Label, whose properties are known
only at the aggregation and deaggregation end points.
It is a property of the A-Label that what follows is a d-CW followed
by an MPLS label stack. A relay node processing the A-Label would
not know the underlying payload type, and the A-Label would be
processed as a normal S-Label. This would only be known to a node
that was a peer of the node imposing the S-Label. However, there is
no real need for it to know the payload type during aggregation
processing.
As in the previous section, nodes supporting this type of aggregation
will need to ensure that individual and aggregated flows receive the
traffic treatment required to ensure the required DetNet service is
preserved. Also, it is the Controller Plane's responsibility to
ensure that the service required on the aggregate flow is properly
provisioned.
4.5. Service Sub-Layer Considerations
The internal procedures for edge and relay nodes related to PREOF are
implementation specific. The order of a packet elimination or
replication is out of scope for this specification.
It is important that the DetNet layer is configured such that a
DetNet node never receives its own replicated packets. If it were to
receive such packets, the replication function would make the loop
more destructive of bandwidth than a conventional unicast loop.
Ultimately, the TTL in the S-Label will cause the packet to die
during a transient loop, but given the sensitivity of applications to
packet latency, the impact on the DetNet application would be severe.
To avoid the problem of a transient forwarding loop, changes to an
LSP supporting DetNet MUST be loop-free.
4.5.1. Edge Node Processing
A DetNet edge node operates in the DetNet forwarding sub-layer and
service sub-layer. An edge node is responsible for matching incoming
packets to the service they require and encapsulating them
accordingly. An edge node may perform PRF, PEF, and/or POF. Details
on encapsulation can be found in Section 4.2; details on PRF can be
found in Section 4.2.2.1; details on PEF can be found in
Section 4.2.2.2; and details on POF can be found in Section 4.2.2.3.
4.5.2. Relay Node Processing
A DetNet relay node operates in the DetNet forwarding sub-layer and
service sub-layer. For DetNet using MPLS, forwarding-related
processing is performed on the F-Label. This processing is done
within an extended forwarder function. Whether an incoming DetNet
flow receives DetNet-specific processing depends on how the
forwarding is programmed. Some relay nodes may be DetNet service
aware for certain DetNet services, while, for other DetNet services,
these nodes may perform as unmodified LSRs that only understand how
to switch MPLS-TE LSPs, i.e., as a transit node; see Section 4.4.
Again, this is entirely up to how the forwarding has been programmed.
During the elimination and replication process, the sequence number
of an incoming DetNet packet MUST be preserved and carried in the
corresponding outgoing DetNet packet. For example, a relay node that
performs both PEF and PRF first performs PEF on incoming packets to
create a compound flow. It then performs PRF and copies the App-flow
data and the d-CW into packets for each outgoing DetNet member flow.
The internal design of a relay node is out of scope for this
document. However, the reader's attention is drawn to the need to
make any PREOF state available to the packet processor(s) dealing
with packets to which PREOF must be applied and to maintain that
state in such a way that it is available to the packet processor
operation on the next packet in the DetNet flow (which may be a
duplicate, a late packet, or the next packet in sequence).
4.6. Forwarding Sub-Layer Considerations
4.6.1. Class of Service
Class of Service (CoS) and Quality of Service (QoS) are terms that
are often used interchangeably and confused with each other. In the
context of DetNet, CoS is used to refer to mechanisms that provide
traffic-forwarding treatment based on non-flow-specific traffic
classification, and QoS is used to refer to mechanisms that provide
traffic-forwarding treatment based on DetNet flow-specific traffic
classification. Examples of existing network-level CoS mechanisms
include Differentiated Services (Diffserv), which is enabled by the
IP header Differentiated Services Code Point (DSCP) field [RFC2474]
and MPLS label Traffic Class field [RFC5462] and at Layer 2 by IEEE
802.1p Priority Code Point (PCP).
CoS for DetNet flows carried in PWs and MPLS is provided using the
existing MPLS Differentiated Services (Diffserv) architecture
[RFC3270]. Both E-LSP and L-LSP MPLS Diffserv modes MAY be used to
support DetNet flows. The Traffic Class field (formerly the EXP
field) of an MPLS label follows the definition of [RFC5462] and
[RFC3270]. The Uniform, Pipe, and Short Pipe Diffserv tunneling and
TTL processing models are described in [RFC3270] and [RFC3443] and
MAY be used for MPLS LSPs supporting DetNet flows. MPLS Explicit
Congestion Notification (ECN) MAY also be used, as defined in ECN
[RFC5129] and updated by [RFC5462].
4.6.2. Quality of Service
In addition to explicit routes and packet replication and elimination
(described in Section 4 above), DetNet provides zero congestion loss
and bounded latency and jitter. As described in [RFC8655], there are
different mechanisms that may be used separately or in combination to
deliver a zero congestion loss service. This includes QoS mechanisms
at the MPLS layer, which may be combined with the mechanisms defined
by the underlying network layer, such as IEEE 802.1 TSN.
QoS mechanisms for flow-specific traffic treatment typically include
a guarantee/agreement for the service and allocation of resources to
support the service. Example QoS mechanisms include discrete
resource allocation, admission control, flow identification and
isolation, and sometimes path control, traffic protection, shaping,
policing, and remarking. Example protocols that support QoS control
include the Resource ReSerVation Protocol (RSVP) [RFC2205] and RSVP-
TE [RFC3209] [RFC3473]. The existing MPLS mechanisms defined to
support CoS [RFC3270] can also be used to reserve resources for
specific traffic classes.
A baseline set of QoS capabilities for DetNet flows carried in PWs
and MPLS can be provided by MPLS-TE [RFC3209] [RFC3473]. TE LSPs can
also support explicit routes (path pinning). Current service
definitions for packet TE LSPs can be found in "Specification of the
Controlled-Load Network Element Service" [RFC2211], "Specification of
Guaranteed Quality of Service" [RFC2212], and "Ethernet Traffic
Parameters" [RFC6003]. Additional service definitions are expected
in future documents to support the full range of DetNet services. In
all cases, the existing label-based marking mechanisms defined for TE
LSPs and even E-LSPs are used to support the identification of flows
requiring DetNet QoS.
5. Management and Control Information Summary
The specific information needed for the processing of each DetNet
service depends on the DetNet node type and the functions being
provided on the node. This section summarizes this information based
on the DetNet sub-layer and if the DetNet traffic is being sent or
received. All DetNet node types are DetNet forwarding sub-layer
aware, while all but transit nodes are service sub-layer aware. This
is shown in Figure 2.
Much like other MPLS labels, there are a number of alternatives
available for DetNet S-Label and F-Label advertisement to an upstream
peer node. These include distributed signaling protocols (such as
RSVP-TE), centralized label distribution via a controller that
manages both the sender and the receiver using the Network
Configuration Protocol (NETCONF) and YANG, BGP, the Path Computation
Element Communication Protocol (PCEP), etc., and hybrid combinations
of the two. The details of the Controller Plane solution required
for the label distribution and the management of the label number
space are out of scope for this document. Particular DetNet
considerations and requirements are discussed in [RFC8938].
Conformance language is not used in the summary, since it applies to
future mechanisms, such as those that may be provided in signaling
and YANG models, e.g., [DetNet-YANG].
5.1. Service Sub-Layer Information Summary
The following summarizes the information that is needed (on a per-
service basis) on nodes that are service sub-layer aware and transmit
DetNet MPLS traffic:
* App-flow identification information, e.g., IP information as
defined in [DetNet-IP-over-MPLS]. Note that this information is
not needed on DetNet relay nodes.
* The sequence number length to be used for the service. Valid
values include 0, 16, and 28 bits. 0 bits cannot be used when PEF
or POF is configured for the service.
* If PRF is to be provided for the service.
* The outgoing S-Label for each of the service's outgoing DetNet
(member) flows.
* The forwarding sub-layer information associated with the output of
the service sub-layer. Note that when PRF is provisioned, this
information is per DetNet member flow. Logically, the forwarding
sub-layer information is a pointer to further details of
transmission of DetNet flows at the forwarding sub-layer.
The following summarizes the information that is needed (on a per-
service basis) on nodes that are service sub-layer aware and receive
DetNet MPLS traffic:
* The forwarding sub-layer information associated with the input of
the service sub-layer. Note that when PEF is provisioned, this
information is per DetNet member flow. Logically, the forwarding
sub-layer information is a pointer to further details of the
reception of DetNet flows at the forwarding sub-layer or A-Label.
* The incoming S-Label for the service.
* If PEF or POF is to be provided for the service.
* The sequence number length to be used for the service. Valid
values included 0, 16, and 28 bits. 0 bits cannot be used when PEF
or POF are configured for the service.
* App-flow identification information, e.g., IP information as
defined in [DetNet-IP-over-MPLS]. Note that this information is
not needed on DetNet relay nodes.
5.1.1. Service Aggregation Information Summary
Nodes performing aggregation using A-Labels, per Section 4.4.2,
require the additional information summarized in this section.
The following summarizes the additional information that is needed on
a node that sends aggregated flows using A-Labels:
* The S-Labels or F-Labels that are to be carried over each
aggregated service.
* The A-Label associated with each aggregated service.
* The other S-Label information summarized above.
On the receiving node, the A-Label provides the forwarding context of
an incoming interface or an F-Label and is used in subsequent service
or forwarding sub-layer receive processing, as appropriate. The
related additional configuration that may be provided is discussed
elsewhere in this section.
5.2. Forwarding Sub-Layer Information Summary
The following summarizes the information that is needed (on a per-
forwarding-sub-layer-flow basis) on nodes that are forwarding sub-
layer aware and send DetNet MPLS traffic:
* The outgoing F-Label stack to be pushed. The stack may include
H-LSP labels.
* The traffic parameters associated with a specific label in the
stack. Note that there may be multiple sets of traffic parameters
associated with specific labels in the stack, e.g., when H-LSPs
are used.
* Outgoing interface and, for unicast traffic, the next-hop
information.
* Sub-network-specific parameters on a technology-specific basis.
For example, see [DetNet-MPLS-over-TSN].
The following summarizes the information that is needed (on a per-
forwarding-sub-layer-flow basis) on nodes that are forwarding sub-
layer aware and receive DetNet MPLS traffic:
* The incoming interface. For some implementations and deployment
scenarios, this information may not be needed.
* The incoming F-Label stack to be popped. The stack may include
H-LSP labels.
* How the incoming forwarding sub-layer flow is to be handled, i.e.,
forwarded as a transit node or provided to the service sub-layer.
It is the responsibility of the DetNet Controller Plane to properly
provision both flow identification information and the flow-specific
resources needed to provide the traffic treatment needed to meet each
flow's service requirements. This applies for aggregated and
individual flows.
6. Security Considerations
Detailed security considerations for DetNet are cataloged in
[DetNet-Security], and more general security considerations are
described in [RFC8655]. This section exclusively considers security
considerations that are specific to the DetNet MPLS data plane. The
considerations raised related to MPLS networks in general in
[RFC5920] are equally applicable to the DetNet MPLS data plane.
Security aspects that are unique to DetNet are those whose aim is to
protect the support of specific QoS aspects of DetNet, which are
primarily to deliver data flows with extremely low packet loss rates
and bounded end-to-end delivery latency. Achieving such loss rates
and bounded latency may not be possible in the face of a highly
capable adversary, such as the one envisioned by the Internet Threat
Model of BCP 72 [RFC3552] that can arbitrarily drop or delay any or
all traffic. In order to present meaningful security considerations,
we consider a somewhat weaker attacker who does not control the
physical links of the DetNet domain but may have the ability to
control a network node within the boundary of the DetNet domain.
An additional consideration for the DetNet data plane is to maintain
integrity of data and delivery of the associated DetNet service
traversing the DetNet network. Application flows can be protected
through whatever means are provided by the underlying technology.
For example, encryption may be used, such as that provided by IPsec
[RFC4301] for IP flows and/or by an underlying sub-network using
MACsec [IEEE802.1AE-2018] for IP over Ethernet (Layer 2) flows. MPLS
doesn't provide any native security services to account for
confidentiality and integrity.
From a data plane perspective, this document does not add or modify
any application header information.
At the management and control level, DetNet flows are identified on a
per-flow basis, which may provide Controller Plane attackers with
additional information about the data flows (when compared to
Controller Planes that do not include per-flow identification). This
is an inherent property of DetNet that has security implications that
should be considered when determining if DetNet is a suitable
technology for any given use case.
To provide uninterrupted availability of the DetNet service,
provisions can be made against DoS attacks and delay attacks. To
protect against DoS attacks, excess traffic due to malicious or
malfunctioning devices is prevented or mitigated through the use of
existing mechanisms, for example, by policing and shaping incoming
traffic. To prevent DetNet packets from having their delay
manipulated by an external entity, precautions need to be taken to
ensure that all devices on an LSP are those intended to be there by
the network operator and that they are well behaved. In addition to
physical security, technical methods, such as authentication and
authorization of network equipment and the instrumentation and
monitoring of the LSP packet delay, may be used. If a delay attack
is suspected, traffic may be moved to an alternate path, for example,
through changing the LSP or management of the PREOF configuration.
7. IANA Considerations
This document has no IANA actions.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2211] Wroclawski, J., "Specification of the Controlled-Load
Network Element Service", RFC 2211, DOI 10.17487/RFC2211,
September 1997, <https://www.rfc-editor.org/info/rfc2211>.
[RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212,
DOI 10.17487/RFC2212, September 1997,
<https://www.rfc-editor.org/info/rfc2212>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<https://www.rfc-editor.org/info/rfc3032>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<https://www.rfc-editor.org/info/rfc3209>.
[RFC3270] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
Protocol Label Switching (MPLS) Support of Differentiated
Services", RFC 3270, DOI 10.17487/RFC3270, May 2002,
<https://www.rfc-editor.org/info/rfc3270>.
[RFC3443] Agarwal, P. and B. Akyol, "Time To Live (TTL) Processing
in Multi-Protocol Label Switching (MPLS) Networks",
RFC 3443, DOI 10.17487/RFC3443, January 2003,
<https://www.rfc-editor.org/info/rfc3443>.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC3473, January 2003,
<https://www.rfc-editor.org/info/rfc3473>.
[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206,
DOI 10.17487/RFC4206, October 2005,
<https://www.rfc-editor.org/info/rfc4206>.
[RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for
Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385,
February 2006, <https://www.rfc-editor.org/info/rfc4385>.
[RFC5085] Nadeau, T., Ed. and C. Pignataro, Ed., "Pseudowire Virtual
Circuit Connectivity Verification (VCCV): A Control
Channel for Pseudowires", RFC 5085, DOI 10.17487/RFC5085,
December 2007, <https://www.rfc-editor.org/info/rfc5085>.
[RFC5129] Davie, B., Briscoe, B., and J. Tay, "Explicit Congestion
Marking in MPLS", RFC 5129, DOI 10.17487/RFC5129, January
2008, <https://www.rfc-editor.org/info/rfc5129>.
[RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching
(MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
Class" Field", RFC 5462, DOI 10.17487/RFC5462, February
2009, <https://www.rfc-editor.org/info/rfc5462>.
[RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed.,
"MPLS Generic Associated Channel", RFC 5586,
DOI 10.17487/RFC5586, June 2009,
<https://www.rfc-editor.org/info/rfc5586>.
[RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and
L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
RFC 6790, DOI 10.17487/RFC6790, November 2012,
<https://www.rfc-editor.org/info/rfc6790>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
[RFC8938] 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>.
8.2. Informative References
[DetNet-IP-over-MPLS]
Varga, B., Ed., Berger, L., Fedyk, D., Bryant, S., and J.
Korhonen, "DetNet Data Plane: IP over MPLS", Work in
Progress, Internet-Draft, draft-ietf-detnet-ip-over-mpls-
09, 11 October 2020, <https://tools.ietf.org/html/draft-
ietf-detnet-ip-over-mpls-09>.
[DetNet-MPLS-OAM]
Mirsky, G. and M. Chen, "Operations, Administration and
Maintenance (OAM) for Deterministic Networks (DetNet) with
MPLS Data Plane", Work in Progress, Internet-Draft, draft-
ietf-detnet-mpls-oam-01, 9 July 2020,
<https://tools.ietf.org/html/draft-ietf-detnet-mpls-oam-
01>.
[DetNet-MPLS-over-TSN]
Varga, B., Ed., Farkas, J., Malis, A., and S. Bryant,
"DetNet Data Plane: MPLS over IEEE 802.1 Time Sensitive
Networking (TSN)", Work in Progress, Internet-Draft,
draft-ietf-detnet-mpls-over-tsn-04, 2 November
draft-ietf-detnet-mpls-over-tsn-05, 13 December 2020,
<https://tools.ietf.org/html/draft-ietf-detnet-mpls-over-
tsn-04>.
tsn-05>.
[DetNet-Security]
Grossman, E., Ed., Mizrahi, T., and A. Hacker,
"Deterministic Networking (DetNet) Security
Considerations", Work in Progress, Internet-Draft, draft-
ietf-detnet-security-12, 2 October
ietf-detnet-security-13, 11 December 2020,
<https://tools.ietf.org/html/draft-ietf-detnet-security-
12>.
13>.
[DetNet-YANG]
Geng, X., Chen, M., Ryoo, Y., Fedyk, D., Rahman, R., and
Z. Li, "Deterministic Networking (DetNet) Configuration
YANG Model", Work in Progress, Internet-Draft, draft-ietf-
detnet-yang-09, 16 November 2020,
<https://tools.ietf.org/html/draft-ietf-detnet-yang-09>.
[IEEE802.1AE-2018]
IEEE, "IEEE Standard for Local and metropolitan area
networks-Media Access Control (MAC) Security", IEEE
802.1AE-2018, DOI 10.1109/IEEESTD.2018.8585421, December
2018, <https://ieeexplore.ieee.org/document/8585421>.
[IEEE802.1CB-2017]
IEEE, "IEEE Standard for Local and metropolitan area
networks-- Frame Replication and Elimination for
Reliability", IEEE 802.1CB-2017,
DOI 10.1109/IEEESTD.2017.8091139, October 2017,
<https://ieeexplore.ieee.org/document/8091139>.
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, DOI 10.17487/RFC2205,
September 1997, <https://www.rfc-editor.org/info/rfc2205>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>.
[RFC3272] 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>.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552,
DOI 10.17487/RFC3552, July 2003,
<https://www.rfc-editor.org/info/rfc3552>.
[RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation
Edge-to-Edge (PWE3) Architecture", RFC 3985,
DOI 10.17487/RFC3985, March 2005,
<https://www.rfc-editor.org/info/rfc3985>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC4448] Martini, L., Ed., Rosen, E., El-Aawar, N., and G. Heron,
"Encapsulation Methods for Transport of Ethernet over MPLS
Networks", RFC 4448, DOI 10.17487/RFC4448, April 2006,
<https://www.rfc-editor.org/info/rfc4448>.
[RFC4875] Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
Yasukawa, Ed., "Extensions to Resource Reservation
Protocol - Traffic Engineering (RSVP-TE) for Point-to-
Multipoint TE Label Switched Paths (LSPs)", RFC 4875,
DOI 10.17487/RFC4875, May 2007,
<https://www.rfc-editor.org/info/rfc4875>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<https://www.rfc-editor.org/info/rfc5920>.
[RFC5921] Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau,
L., and L. Berger, "A Framework for MPLS in Transport
Networks", RFC 5921, DOI 10.17487/RFC5921, July 2010,
<https://www.rfc-editor.org/info/rfc5921>.
[RFC6003] Papadimitriou, D., "Ethernet Traffic Parameters",
RFC 6003, DOI 10.17487/RFC6003, October 2010,
<https://www.rfc-editor.org/info/rfc6003>.
[RFC6073] Martini, L., Metz, C., Nadeau, T., Bocci, M., and M.
Aissaoui, "Segmented Pseudowire", RFC 6073,
DOI 10.17487/RFC6073, January 2011,
<https://www.rfc-editor.org/info/rfc6073>.
[RFC8306] Zhao, Q., Dhody, D., Ed., Palleti, R., and D. King,
"Extensions to the Path Computation Element Communication
Protocol (PCEP) for Point-to-Multipoint Traffic
Engineering Label Switched Paths", RFC 8306,
DOI 10.17487/RFC8306, November 2017,
<https://www.rfc-editor.org/info/rfc8306>.
[RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing with the MPLS Data Plane", RFC 8660,
DOI 10.17487/RFC8660, December 2019,
<https://www.rfc-editor.org/info/rfc8660>.
[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/rfc/rfc8939>.
<https://www.rfc-editor.org/info/rfc8939>.
Acknowledgements
The authors wish to thank Pat Thaler, Norman Finn, Loa Anderson,
David Black, Rodney Cummings, Ethan Grossman, Tal Mizrahi, David
Mozes, Craig Gunther, George Swallow, Yuanlong Jiang, Jeong-dong
Ryoo, and Carlos J. Bernardos for their various contributions to this
work.
Contributors
The editor of this document wishes to thank and acknowledge the
following person who contributed substantially to the content of this
document and should be considered a coauthor:
Don Fedyk
LabN Consulting, L.L.C.
Email: dfedyk@labn.net
Authors' Addresses
Balázs Varga (editor)
Ericsson
Budapest
Magyar Tudosok krt. 11.
1117
Hungary
Email: balazs.a.varga@ericsson.com
János Farkas
Ericsson
Budapest
Magyar Tudosok krt. 11.
1117
Hungary
Email: janos.farkas@ericsson.com
Lou Berger
LabN Consulting, L.L.C.
Email: lberger@labn.net
Andrew G. Malis
Malis Consulting
Email: agmalis@gmail.com
Stewart Bryant
Futurewei Technologies
Email: sb@stewartbryant.com
Jouni Korhonen
Email: jouni.nospam@gmail.com