draft-ietf-detnet-oam-framework-00.txt   draft-ietf-detnet-oam-framework-01.txt 
DetNet G. Mirsky DetNet G. Mirsky
Internet-Draft ZTE Corp. Internet-Draft ZTE Corp.
Intended status: Standards Track F. Theoleyre Intended status: Informational F. Theoleyre
Expires: 27 October 2021 CNRS Expires: 20 November 2021 CNRS
G.Z. Papadopoulos G.Z. Papadopoulos
IMT Atlantique IMT Atlantique
CJ. Bernardos CJ. Bernardos
UC3M UC3M
25 April 2021 19 May 2021
Framework of Operations, Administration and Maintenance (OAM) for Framework of Operations, Administration and Maintenance (OAM) for
Deterministic Networking (DetNet) Deterministic Networking (DetNet)
draft-ietf-detnet-oam-framework-00 draft-ietf-detnet-oam-framework-01
Abstract Abstract
Deterministic Networking (DetNet), as defined in RFC 8655, is aimed Deterministic Networking (DetNet), as defined in RFC 8655, is aimed
to provide a bounded end-to-end latency on top of the network to provide a bounded end-to-end latency on top of the network
infrastructure, comprising both Layer 2 bridged and Layer 3 routed infrastructure, comprising both Layer 2 bridged and Layer 3 routed
segments. This document's primary purpose is to detail the specific segments. This document's primary purpose is to detail the specific
requirements of the Operation, Administration, and Maintenance (OAM) requirements of the Operation, Administration, and Maintenance (OAM)
recommended to maintain a deterministic network. With the recommended to maintain a deterministic network. With the
implementation of the OAM framework in DetNet, an operator will have implementation of the OAM framework in DetNet, an operator will have
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 27 October 2021. This Internet-Draft will expire on 20 November 2021.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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extracted from this document must include Simplified BSD License text extracted from this document must include Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License. provided without warranty as described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.3. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Role of OAM in DetNet . . . . . . . . . . . . . . . . . . . . 5 2. Role of OAM in DetNet . . . . . . . . . . . . . . . . . . . . 4
3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Information Collection . . . . . . . . . . . . . . . . . 5 3.1. Information Collection . . . . . . . . . . . . . . . . . 5
3.2. Continuity Check . . . . . . . . . . . . . . . . . . . . 6 3.2. Continuity Check . . . . . . . . . . . . . . . . . . . . 6
3.3. Connectivity Verification . . . . . . . . . . . . . . . . 6 3.3. Connectivity Verification . . . . . . . . . . . . . . . . 6
3.4. Route Tracing . . . . . . . . . . . . . . . . . . . . . . 6 3.4. Route Tracing . . . . . . . . . . . . . . . . . . . . . . 6
3.5. Fault Verification/detection . . . . . . . . . . . . . . 6 3.5. Fault Verification/detection . . . . . . . . . . . . . . 6
3.6. Fault Isolation/identification . . . . . . . . . . . . . 7 3.6. Fault Localization and Characterization . . . . . . . . . 7
3.7. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . 7 3.7. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . 7
4. Administration . . . . . . . . . . . . . . . . . . . . . . . 7 4. Administration . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Collection of metrics . . . . . . . . . . . . . . . . . . 8 4.1. Collection of metrics . . . . . . . . . . . . . . . . . . 8
4.2. Worst-case metrics . . . . . . . . . . . . . . . . . . . 8 4.2. Worst-case metrics . . . . . . . . . . . . . . . . . . . 8
5. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. Replication / Elimination . . . . . . . . . . . . . . . . 8 5.1. Replication / Elimination . . . . . . . . . . . . . . . . 9
5.2. Resource Reservation . . . . . . . . . . . . . . . . . . 9 5.2. Resource Reservation . . . . . . . . . . . . . . . . . . 9
5.3. Soft transition after reconfiguration . . . . . . . . . . 9 5.3. Soft transition after reconfiguration . . . . . . . . . . 10
6. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 9 6. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
10.1. Normative References . . . . . . . . . . . . . . . . . . 11 10.1. Normative References . . . . . . . . . . . . . . . . . . 12
10.2. Informative References . . . . . . . . . . . . . . . . . 11 10.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
Deterministic Networking (DetNet) [RFC8655] has proposed to provide a Deterministic Networking (DetNet) [RFC8655] has proposed to provide a
bounded end-to-end latency on top of the network infrastructure, bounded end-to-end latency on top of the network infrastructure,
comprising both Layer 2 bridged and Layer 3 routed segments. Their comprising both Layer 2 bridged and Layer 3 routed segments. That
work encompasses the data plane, OAM, time synchronization, work encompasses the data plane, OAM, time synchronization,
management, control, and security aspects. management, control, and security aspects.
Operations, Administration, and Maintenance (OAM) Tools are of Operations, Administration, and Maintenance (OAM) Tools are of
primary importance for IP networks [RFC7276]. DetNet OAM should primary importance for IP networks [RFC7276]. DetNet OAM should
provide a toolset for fault detection, localization, and performance provide a toolset for fault detection, localization, and performance
measurement. measurement.
This document's primary purpose is to detail the specific This document's primary purpose is to detail the specific
requirements of the OAM features recommended to maintain a requirements of the OAM features recommended to maintain a
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loss ratio, assigned to each data flow. loss ratio, assigned to each data flow.
This document lists the functional requirements toward OAM for DetNet This document lists the functional requirements toward OAM for DetNet
domain. The list can further be used for gap analysis of available domain. The list can further be used for gap analysis of available
OAM tools to identify possible enhancements of existing or whether OAM tools to identify possible enhancements of existing or whether
new OAM tools are required to support proactive and on-demand path new OAM tools are required to support proactive and on-demand path
monitoring and service validation. monitoring and service validation.
1.1. Terminology 1.1. Terminology
The following terms are used througout this document as defined The following terms are used throughout this document as defined
below: below:
* OAM entity: a data flow to be monitored for defects and/or its * OAM entity: a data flow to be monitored for defects and/or its
performance metrics measured. performance metrics measured.
* Maintenance End Point (MEP): OAM systems traversed by a data flow * Maintenance End Point (MEP): OAM systems traversed by a data flow
when entering/exiting the network. In DetNet, it corresponds with when entering/exiting the network. In DetNet, it corresponds with
the source and destination of a data flow. OAM messages can be the source and destination of a data flow. OAM messages can be
exchanged between two MEPs. exchanged between two MEPs.
* Maintenance Intermediate endPoint (MIP): an OAM system along the * Maintenance Intermediate endPoint (MIP): an OAM system along the
flow; a MIP MAY respond to an OAM message generated by the MEP. flow; a MIP MAY respond to an OAM message generated by the MEP.
* Control and management plane: the control and management planes * Control and management plane: the control and management planes
are used to configure and control the network (long-term). are used to configure and control the network (long-term).
Relative to a data flow, the control and/or management plane can Relative to a data flow, the control and/or management plane can
be out-of-band. be out-of-band.
* Active measurement methods (as defined in [RFC7799]) modify a * Active measurement methods (as defined in [RFC7799]) modify a
normal data flow by inserting novel fields, injecting specially normal data flow by inserting novel fields, injecting specially
constructed test packets [RFC2544]). It is critical for the constructed test packets [RFC2544]).
quality of information obtained using an active method that
generated test packets are in-band with the monitored data flow.
In other words, a test packet is required to cross the same
network nodes and links and receive the same Quality of Service
(QoS) treatment as a data packet.
* Passive measurement methods [RFC7799] infer information by * Passive measurement methods [RFC7799] infer information by
observing unmodified existing flows. observing unmodified existing flows.
* Hybrid measurement methods [RFC7799] is the combination of * Hybrid measurement methods [RFC7799] is the combination of
elements of both active and passive measurement methods. elements of both active and passive measurement methods.
1.2. Acronyms 1.2. Acronyms
OAM: Operations, Administration, and Maintenance OAM: Operations, Administration, and Maintenance
DetNet: Deterministic Networking DetNet: Deterministic Networking
SLO: Service Level Objective SLO: Service Level Objective
QoS: Quality of Service
SNMP: Simple Network Management Protocol SNMP: Simple Network Management Protocol
SDN: Software Defined Network SDN: Software Defined Network
<TODO> we need here an exhaustive list, to be completed after the <TODO> we need here an exhaustive list, to be completed after the
document has evolved. document has evolved.
1.3. Requirements Language 1.3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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2. Role of OAM in DetNet 2. Role of OAM in DetNet
DetNet networks expect to provide communications with predictable low DetNet networks expect to provide communications with predictable low
packet delay and packet loss. Most critical applications will define packet delay and packet loss. Most critical applications will define
an SLO to be required for the data flows it generates. an SLO to be required for the data flows it generates.
To respect strict guarantees, DetNet can use an orchestrator able to To respect strict guarantees, DetNet can use an orchestrator able to
monitor and maintain the network. Typically, a Software-Defined monitor and maintain the network. Typically, a Software-Defined
Network (SDN) controller places DetNet flows in the deployed network Network (SDN) controller places DetNet flows in the deployed network
based on their the SLO. Thus, resources have to be provisioned a based on their SLO. Thus, resources have to be provisioned a priori
priori for the regular operation of the network. OAM represents the for the regular operation of the network. Because OAM is an
essential elements of the network operation and necessary for OAM essential element of the network operation, resources, necessary for
resources that need to be accounted for to maintain the network OAM, need to be accounted for in addition to DetNet flows.
operational.
Fault-tolerance also assumes that multiple paths could be provisioned Fault-tolerance also assumes that multiple paths could be provisioned
so that an end-to-end circuit is maintained by adapting to the so that an end-to-end circuit is maintained by adapting to the
existing conditions. The central controller/orchestrator typically existing conditions. The central controller/orchestrator typically
controls the Packet Replication, Elimination, and Ordering Functions controls the Packet Replication, Elimination, and Ordering Functions
(PREOF) on a node. OAM is expected to support monitoring and (PREOF) on a node. OAM is expected to support monitoring and
troubleshooting PREOF on a particular node and within the domain. troubleshooting PREOF on a particular node and within the domain.
Note that PREOF can also be controlled by a set of distributed Note that PREOF can also be controlled by a set of distributed
controllers, in those scenarios where DetNet solutions involve more controllers, in those scenarios where DetNet solutions involve more
than one single central controller. than one single central controller.
3. Operation 3. Operation
OAM features will enable DetNet with robust operation both for OAM features will enable DetNet with robust operation both for
forwarding and routing purposes. forwarding and routing purposes.
It is worth noting that the test and data packets MUST follow the
same path, i.e., the connectivity verification has to be conducted
in-band without impacting the data traffic. Test packets MUST share
fate with the monitored data traffic without introducing congestion
in normal network conditions.
3.1. Information Collection 3.1. Information Collection
Information about the state of the network can be collected using Information about the state of the network can be collected using
several mechanisms. Some protocols, e.g., Simple Network Management several mechanisms. Some protocols, e.g., Simple Network Management
Protocol (SNMP), send queries. Others, e.g., YANG-based data models, Protocol (SNMP), send queries. Others, e.g., YANG-based data models,
generate notifications based on the publish-subscribe method. In generate notifications based on the publish-subscribe method. In
either way, information about the state of the network being either way, information is collected and sent to the controller.
collected and sent to the controller.
Also, we can characterize methods of transporting OAM information Also, we can characterize methods of transporting OAM information
relative to the path of data. For instance, OAM information may be relative to the path of data. For instance, OAM information may be
transported out-of-band or in-band with the data flow. transported in-band or out-of-band with the data flow. In case of
the former, the telemetry information uses resources allocated for
the monitored DetNet flow. If an in-band method of transporting
telemetry is used, the amount of generated information needs to be
carefully analyzed, and additional resources must be reserved.
[I-D.ietf-ippm-ioam-data] defines the in-band transport mechanism
where telemetry information is collected in the data packet on which
information is generated. Two tracing methods are described - end-
to-end, i.e., from the ingress and egress nodes, and hop-by-hop,
i.e., like end-to-end with additional information from transit nodes.
[I-D.ietf-ippm-ioam-direct-export] and
[I-D.mirsky-ippm-hybrid-two-step] are examples of out-of-band
telemetry transport. In the former case, information is transported
by each node traversed by the data packet of the monitored DetNet
flow in a specially constructed packet. In the latter, information
is collected in a sequence of follow-up packets that traverse the
same path as the data packet of the monitored DetNet flow. In both
methods, transport of the telemetry can avoid using resources
allocated for the DetNet domain.
3.2. Continuity Check 3.2. Continuity Check
Continuity check is used to monitor the continuity of a path, i.e., Continuity check is used to monitor the continuity of a path, i.e.,
that there exists a way to deliver the packets between two endpoints that there exists a way to deliver the packets between two endpoints
A and B. A and B.
3.3. Connectivity Verification 3.3. Connectivity Verification
In addition to the Continuity Check, DetNet solutions have to verify In addition to the Continuity Check, DetNet solutions have to verify
the connectivity. This verification considers additional the connectivity. This verification considers additional
constraints, i.e., the absence of misconnection. constraints, i.e., the absence of misconnection. The misconnection
error state is entered after several consecutive test packets from
In particular, resources have to be reserved for a given flow, so other DetNet flows are received. The definition of the conditions of
they are booked for use without being impacted by other flows. entry and exit for misconnection error state is outside the scope of
Similarly, the destination does not receive packets from different this document.
flows through its interface.
It is worth noting that the test and data packets MUST follow the
same path, i.e., the connectivity verification has to be conducted
in-band without impacting the data traffic. Test packets MUST share
fate with the monitored data traffic without introducing congestion
in normal network conditions.
3.4. Route Tracing 3.4. Route Tracing
Ping and traceroute are two ubiquitous tools that help localize and Ping and traceroute are two ubiquitous tools that help localize and
characterize a failure in the network. They help to identify a characterize a failure in the network. They help to identify a
subset of the list of routers in the route. However, to be subset of the list of routers in the route. However, to be
predictable, resources are reserved per flow in DetNet. Thus, DetNet predictable, resources are reserved per flow in DetNet. Thus, DetNet
needs to define route tracing tools able to track the route for a needs to define route tracing tools able to track the route for a
specific flow. specific flow. Also, tracing can be used for the discovery of the
Path Maximum Transmission Unit or location of elements of PREOF for
the particular route in the DetNet domain.
DetNet with IP data plane is NOT RECOMMENDED to use multiple paths or DetNet with IP data plane is NOT RECOMMENDED to use multiple paths or
links, i.e., Equal-Cost Multipath (ECMP) [RFC8939]. As the result, links, i.e., Equal-Cost Multipath (ECMP) [RFC8939]. As the result,
OAM in IP ECMP environment is outside the scope of this document. OAM in IP ECMP environment is outside the scope of this document.
3.5. Fault Verification/detection 3.5. Fault Verification/detection
DetNet expects to operate fault-tolerant networks. Thus, mechanisms DetNet expects to operate fault-tolerant networks. Thus, mechanisms
able to detect faults before they impact the network performance are able to detect faults before they impact the network performance are
needed. needed.
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has deviated from its expected behavior. While the network must has deviated from its expected behavior. While the network must
report an alarm, the cause may not be identified precisely. For report an alarm, the cause may not be identified precisely. For
instance, the end-to-end reliability has decreased significantly, or instance, the end-to-end reliability has decreased significantly, or
a buffer overflow occurs. a buffer overflow occurs.
DetNet OAM mechanisms SHOULD allow a fault detection in real time. DetNet OAM mechanisms SHOULD allow a fault detection in real time.
They MAY, when possible, predict faults based on current network They MAY, when possible, predict faults based on current network
conditions. They MAY also identify and report the cause of the conditions. They MAY also identify and report the cause of the
actual/predicted network failure. actual/predicted network failure.
3.6. Fault Isolation/identification 3.6. Fault Localization and Characterization
The network has isolated and identified the cause of the fault. For An ability to localize the network defect and provide its
instance, the replication process behaves not as expected to a characterization are necessary elements of network operation.
specific intermediary router.
Fault localization, a process of deducing the location of a
network failure from a set of observed failure indications, might
be achieved, for example, by tracing the route of the DetNet flow
in which the network failure was detected. Another method of
fault localization can correlate reports of failures from a set of
interleaving sessions monitoring path continuity.
Fault characterization is a process of identifying the root cause
of the problem. For instance, misconfiguration or malfunction of
PREOF elements can be the cause of erroneous packet replication or
extra packets being flooded in the DetNet domain.
3.7. Use of Hybrid OAM in DetNet 3.7. Use of Hybrid OAM in DetNet
Hybrid OAM methods are used in performance monitoring and defined in Hybrid OAM methods are used in performance monitoring and defined in
[RFC7799] as: [RFC7799] as:
Hybrid Methods are Methods of Measurement that use a combination Hybrid Methods are Methods of Measurement that use a combination
of Active Methods and Passive Methods. of Active Methods and Passive Methods.
A hybrid measurement method may produce metrics as close to passive, A hybrid measurement method may produce metrics as close to passive,
but it still alters something in a data packet even if that is the but it still alters something in a data packet even if that is the
value of a designated field in the packet encapsulation. One example value of a designated field in the packet encapsulation. One example
of such a hybrid measurement method is the Alternate Marking method of such a hybrid measurement method is the Alternate Marking method
(AMM) described in [RFC8321]. One of the advantages of the use of (AMM) described in [RFC8321]. As with all on-path telemetry methods,
AMM in a DetNet domain with the IP data plane is that the marking is AMM in a DetNet domain with the IP data plane is natively in-band in
applied to a data flow, thus ensuring that measured metrics are respect to the monitored DetNet flow. Because the marking is applied
directly applicable to the DetNet flow. to a data flow, measured metrics are directly applicable to the
DetNet flow. AMM minimizes the additional load on the DetNet domain
by using nodal collection and computation of performance metrics in
combination with optionally using out-of-band telemetry collection
for further network analysis.
4. Administration 4. Administration
The network SHOULD expose a collection of metrics to support an The network SHOULD expose a collection of metrics to support an
operator making proper decisions, including: operator making proper decisions, including:
* Queuing Delay: the time elapsed between a packet enqueued and its * Queuing Delay: the time elapsed between a packet enqueued and its
transmission to the next hop. transmission to the next hop.
* Buffer occupancy: the number of packets present in the buffer, for * Buffer occupancy: the number of packets present in the buffer, for
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DetNet aims to enable real-time communications on top of a DetNet aims to enable real-time communications on top of a
heterogeneous multi-hop architecture. To make correct decisions, the heterogeneous multi-hop architecture. To make correct decisions, the
controller needs to know the distribution of packet losses/delays for controller needs to know the distribution of packet losses/delays for
each flow, and each hop of the paths. In other words, the average each flow, and each hop of the paths. In other words, the average
end-to-end statistics are not enough. The collected information must end-to-end statistics are not enough. The collected information must
be sufficient to allow the controller to predict the worst-case. be sufficient to allow the controller to predict the worst-case.
5. Maintenance 5. Maintenance
DetNet needs to implement a self-healing and self-optimization In the face of events that impact the network operation (e.g., link
approach. The controller MUST be able to continuously retrieve the up/down, node crash/reboot, flows starting and ending), the DetNet
state of the network, to evaluate conditions and trends about the Controller need to perform repair and re-optimization actions in
relevance of a reconfiguration, quantifying: order to permanently ensure the SLO of all active flows with minimal
waste of resources The controller MUST be able to continuously
retrieve the state of the network, to evaluate conditions and trends
about the relevance of a reconfiguration, quantifying:
the cost of the sub-optimality: resources may not be used the cost of the sub-optimality: resources may not be used
optimally (e.g., a better path exists). optimally (e.g., a better path exists).
the reconfiguration cost: the controller needs to trigger some the reconfiguration cost: the controller needs to trigger some
reconfigurations. For this transient period, resources may be reconfigurations. For this transient period, resources may be
twice reserved, and control packets have to be transmitted. twice reserved, and control packets have to be transmitted.
Thus, reconfiguration may only be triggered if the gain is Thus, reconfiguration may only be triggered if the gain is
significant. significant.
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// \\// \\// \\ // \\// \\// \\
source (S) //\\ //\\ (R) (root) source (S) //\\ //\\ (R) (root)
\\ // \\ // \\ // \\ // \\ // \\ //
===> (B) => (D) => (F) === ===> (B) => (D) => (F) ===
Figure 1: Packet Replication: S transmits twice the same data Figure 1: Packet Replication: S transmits twice the same data
packet, to DP(A) and AP (B). packet, to DP(A) and AP (B).
5.2. Resource Reservation 5.2. Resource Reservation
Because the QoS criteria associated with a path may degrade, the Because the quality of service criteria associated with a path may
network has to provision additional resources along the path. We degrade, the network has to provision additional resources along the
need to provide mechanisms to patch the network configuration. path. We need to provide mechanisms to patch the network
configuration.
5.3. Soft transition after reconfiguration 5.3. Soft transition after reconfiguration
Since DetNet expects to support real-time flows, DetNet OAM MUST Since DetNet expects to support real-time flows, DetNet OAM MUST
support soft-reconfiguration, where the novel resources are reserved support soft-reconfiguration, where the novel resources are reserved
before the ancient ones are released. Some mechanisms have to be before the ancient ones are released. Some mechanisms have to be
proposed so that packets are forwarded through the novel track only proposed so that packets are forwarded through the novel track only
when the resources are ready to be used, while maintaining the global when the resources are ready to be used, while maintaining the global
state consistent (no packet reordering, duplication, etc.) state consistent (no packet reordering, duplication, etc.)
6. Requirements 6. Requirements
This section lists requirements for OAM in DetNet domain with MPLS This section lists requirements for OAM in DetNet domain:
data plane:
1. It MUST be possible to initiate DetNet OAM session from any 1. It MUST be possible to initiate DetNet OAM session from any
DetNet node towards another DetNet node(s) within given domain. DetNet node towards another DetNet node(s) within given domain.
2. It SHOULD be possible to initialize DetNet OAM session from a 2. It MUST be possible to initialize DetNet OAM session from a
centralized controller. centralized controller.
3. DetNet OAM MUST support proactive and on-demand OAM monitoring 3. DetNet OAM MUST support proactive and on-demand OAM monitoring
and measurement methods. and measurement methods.
4. DetNet OAM packets MUST be in-band, i.e., follow precisely the 4. DetNet OAM packets MUST be in-band, i.e., follow precisely the
same path as DetNet data plane traffic. same path as DetNet data plane traffic.
5. DetNet OAM MUST support unidirectional OAM methods, continuity 5. DetNet OAM MUST support unidirectional OAM methods, continuity
check, connectivity verification, and performance measurement. check, connectivity verification, and performance measurement.
skipping to change at page 10, line 17 skipping to change at page 10, line 45
forward direction and out-of-bound notification in the reverse forward direction and out-of-bound notification in the reverse
direction, i.e., from egress to ingress end point of the OAM direction, i.e., from egress to ingress end point of the OAM
test session. test session.
7. DetNet OAM MUST support proactive monitoring of a DetNet node 7. DetNet OAM MUST support proactive monitoring of a DetNet node
availability in the given DetNet domain. availability in the given DetNet domain.
8. DetNet OAM MUST support Path Maximum Transmission Unit 8. DetNet OAM MUST support Path Maximum Transmission Unit
discovery. discovery.
9. DetNet OAM MUST support Remote Defect Indication (RDI) 9. DetNet OAM MUST support the discovery of PREOF along a route in
the given DetNet domain.
10. DetNet OAM MUST support Remote Defect Indication (RDI)
notification to the DetNet node performing continuity checking. notification to the DetNet node performing continuity checking.
10. DetNet OAM MUST support performance measurement methods. 11. DetNet OAM MUST support performance measurement methods.
11. DetNet OAM MAY support hybrid performance measurement methods. 12. DetNet OAM MAY support hybrid performance measurement methods.
12. DetNet OAM MUST support unidirectional performance measurement 13. DetNet OAM MUST support unidirectional performance measurement
methods. Calculated performance metrics MUST include but are methods. Calculated performance metrics MUST include but are
not limited to throughput, packet loss, delay and delay not limited to throughput, packet loss, delay and delay
variation metrics. [RFC6374] provides excellent details on variation metrics. [RFC6374] provides detailed information on
performance measurement and performance metrics. performance measurement and performance metrics.
13. DetNet OAM MUST support defect notification mechanism, like 14. DetNet OAM MUST support defect notification mechanism, like
Alarm Indication Signal. Any DetNet node in the given DetNet Alarm Indication Signal. Any DetNet node in the given DetNet
domain MAY originate a defect notification addressed to any domain MAY originate a defect notification addressed to any
subset of nodes within the domain. subset of nodes within the domain.
14. DetNet OAM MUST support methods to enable survivability of the 15. DetNet OAM MUST support methods to enable survivability of the
DetNet domain. These recovery methods MAY use protection DetNet domain. These recovery methods MAY use protection
switching and restoration. switching and restoration.
15. DetNet OAM MUST support the discovery of Packet Replication, 16. DetNet OAM MUST support the discovery of Packet Replication,
Elimination, and Order preservation sub-functions locations in Elimination, and Order preservation sub-functions locations in
the domain. the domain.
16. DetNet OAM MUST support testing of Packet Replication, 17. DetNet OAM MUST support testing of Packet Replication,
Elimination, and Order preservation sub-functions in the domain. Elimination, and Order preservation sub-functions in the domain.
17. DetNet OAM MUST support monitoring any sub-set of paths 18. DetNet OAM MUST support monitoring levels of resources allocated
for the particular DetNet flow. Such resources include but not
limited to buffer utilization, scheduler transmission calendar.
19. DetNet OAM MUST support monitoring any sub-set of paths
traversed through the DetNet domain by the DetNet flow. traversed through the DetNet domain by the DetNet flow.
7. IANA Considerations 7. IANA Considerations
This document has no actionable requirements for IANA. This section This document has no actionable requirements for IANA. This section
can be removed before the publication. can be removed before the publication.
8. Security Considerations 8. Security Considerations
This document lists the OAM requirements for a DetNet domain and does This document lists the OAM requirements for a DetNet domain and does
not raise any security concerns or issues in addition to ones common not raise any security concerns or issues in addition to ones common
to networking and those specific to a DetNet discussed in to networking and those specific to a DetNet discussed in
[I-D.ietf-detnet-security]. [I-D.ietf-detnet-security].
9. Acknowledgments 9. Acknowledgments
TBD The authors express their appreciation and gratitude to Pascal
Thubert for the review, insightful questions, and helpful comments.
10. References 10. References
10.1. Normative References 10.1. Normative References
[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>.
skipping to change at page 11, line 39 skipping to change at page 12, line 28
10.2. Informative References 10.2. Informative References
[I-D.ietf-detnet-security] [I-D.ietf-detnet-security]
Grossman, E., Mizrahi, T., and A. J. Hacker, Grossman, E., Mizrahi, T., and A. J. Hacker,
"Deterministic Networking (DetNet) Security "Deterministic Networking (DetNet) Security
Considerations", Work in Progress, Internet-Draft, draft- Considerations", Work in Progress, Internet-Draft, draft-
ietf-detnet-security-16, 2 March 2021, ietf-detnet-security-16, 2 March 2021,
<https://tools.ietf.org/html/draft-ietf-detnet-security- <https://tools.ietf.org/html/draft-ietf-detnet-security-
16>. 16>.
[I-D.ietf-ippm-ioam-data]
Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields
for In-situ OAM", Work in Progress, Internet-Draft, draft-
ietf-ippm-ioam-data-12, 21 February 2021,
<https://tools.ietf.org/html/draft-ietf-ippm-ioam-data-
12>.
[I-D.ietf-ippm-ioam-direct-export]
Song, H., Gafni, B., Zhou, T., Li, Z., Brockners, F.,
Bhandari, S., Sivakolundu, R., and T. Mizrahi, "In-situ
OAM Direct Exporting", Work in Progress, Internet-Draft,
draft-ietf-ippm-ioam-direct-export-03, 17 February 2021,
<https://tools.ietf.org/html/draft-ietf-ippm-ioam-direct-
export-03>.
[I-D.mirsky-ippm-hybrid-two-step]
Mirsky, G., Lingqiang, W., Zhui, G., and H. Song, "Hybrid
Two-Step Performance Measurement Method", Work in
Progress, Internet-Draft, draft-mirsky-ippm-hybrid-two-
step-10, 17 May 2021, <https://tools.ietf.org/html/draft-
mirsky-ippm-hybrid-two-step-10>.
[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for [RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544, Network Interconnect Devices", RFC 2544,
DOI 10.17487/RFC2544, March 1999, DOI 10.17487/RFC2544, March 1999,
<https://www.rfc-editor.org/info/rfc2544>. <https://www.rfc-editor.org/info/rfc2544>.
[RFC6291] Andersson, L., van Helvoort, H., Bonica, R., Romascanu, [RFC6291] Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
D., and S. Mansfield, "Guidelines for the Use of the "OAM" D., and S. Mansfield, "Guidelines for the Use of the "OAM"
Acronym in the IETF", BCP 161, RFC 6291, Acronym in the IETF", BCP 161, RFC 6291,
DOI 10.17487/RFC6291, June 2011, DOI 10.17487/RFC6291, June 2011,
<https://www.rfc-editor.org/info/rfc6291>. <https://www.rfc-editor.org/info/rfc6291>.
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