DetNet Working Group G. Mirsky
Internet-Draft Ericsson
Intended status: Informational M. Chen
Expires: 23 November 2023 Huawei
D. Black
Dell EMC
22 May 2023
Operations, Administration and Maintenance (OAM) for Deterministic
Networks (DetNet) with IP Data Plane
draft-ietf-detnet-ip-oam-07
Abstract
This document defines the principles for using Operations,
Administration, and Maintenance protocols and mechanisms in the
Deterministic Networking networks with the IP data plane.
Status of This Memo
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Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Keywords . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Active OAM for DetNet Networks with the IP Data Plane . . . . 4
3.1. Mapping Active OAM and IP DetNet flows . . . . . . . . . 4
3.2. Active OAM Using IP-in-UDP Encapsulation . . . . . . . . 5
3.3. Active OAM Using DetNet-in-UDP Encapsulation . . . . . . 5
3.4. Active OAM Using GRE-in-UDP Encapsulation . . . . . . . . 6
4. Active OAM for DetNet IP Interworking with OAM of non-IP DetNet
domains . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informational References . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
[RFC8655] introduces and explains Deterministic Networks (DetNet)
architecture.
Operations, Administration and Maintenance (OAM) protocols are used
to detect, localize defects in the network, and monitor network
performance. Some OAM functions, e.g., failure detection, work in
the network proactively, while others, e.g., defect localization,
usually performed on-demand. These tasks achieved by a combination
of active and hybrid, as defined in [RFC7799], OAM methods.
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[I-D.ietf-detnet-oam-framework] lists the functional requirements
toward OAM for DetNet domain. The list can further be used for gap
analysis of available OAM tools to identify possible enhancements of
existing or whether new OAM tools are required to support proactive
and on-demand path monitoring and service validation. Also, the
document defines the OAM use principals for the DetNet networks with
the IP data plane.
2. Conventions used in this document
2.1. Terminology
The term "DetNet OAM" used in this document interchangeably with
longer version "set of OAM protocols, methods and tools for
Deterministic Networks".
DetNet Deterministic Networks
DiffServ Differentiated Services
OAM: Operations, Administration, and Maintenance
PREF Packet Replication and Elimination Function
POF Packet Ordering Function
RDI Remote Defect Indication
ICMP Internet Control Message Protocol
ACH Associated Channel Header
Underlay Network or Underlay Layer: The network that provides
connectivity between the DetNet nodes. MPLS network providing LSP
connectivity between DetNet nodes is an example of the underlay
layer.
DetNet Node - a node that is an actor in the DetNet domain. DetNet
domain edge node and node that performs PREF within the domain are
examples of DetNet node.
2.2. Keywords
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.
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3. Active OAM for DetNet Networks with the IP Data Plane
OAM protocols and mechanisms act within the data plane of the
particular networking layer. And thus it is critical that the data
plane encapsulation supports OAM mechanisms in such a way that DetNet
OAM packets are in-band with a DetNet flow being monitored, i.e.,
DetNet OAM test packets follow precisely the same path as DetNet data
plane traffic both for unidirectional and bi-directional DetNet
paths.
The DetNet data plane encapsulation in a transport network with IP
encapsulations specified in Section 6 of [RFC8939]. For the IP
underlay network, DetNet flows are identified by the ordered match to
the provisioned information set that, among other elements, includes
the IP protocol, source port number, destination port number. Active
IP OAM protocols like Bidirectional Forwarding Detection (BFD)
[RFC5880] or Simple Two-way Active Measurement Protocol (STAMP)
[RFC8762], use UDP transport and the well-known UDP port numbers as
the destination port. Thus a DetNet node MUST be able to associate
an IP DetNet flow with the particular test session to ensure that
test packets experience the same treatment as the DetNet flow
packets. For example, that can be achieved with a 3-tuple
(destination and source IP addresses in combination with DSCP value)
used to identify the IP DetNet flow. In such a scenario, an IP OAM
session between the same pair of IP nodes would share the network
treatment with the monitored IP DetNet flow regardless of whether
ICMP, BFD, or STAMP protocol is used.
Most of on-demand failure detection and localization in IP networks
is being done by using the Internet Control Message Protocol (ICMP)
Echo Request, Echo Reply and the set of defined error messages, e.g.,
Destination Unreachable, with the more detailed information provided
through code points. [RFC0792] and [RFC4443] define the ICMP for
IPv4 and IPv6 networks, respectively. Because ICMP is another IP
protocol like, for example, UDP, a DetNet node MUST able to associate
an ICMP packet generated by the specified IP DetNet node and
addressed to the another IP DetnNet node with an IP DetNet flow
between this pair of endpoints.
3.1. Mapping Active OAM and IP DetNet flows
IP OAM protocols are used to detect failures (e.g., BFD [RFC5880])
and performance degradation (e.g., STAMP [RFC8762]) that affect an IP
DetNet flow. When the UDP destination port number used by the OAM
protocol is one of the assigned by IANA, then the UDP source port can
be used to achieve co-routedness of OAM, and the monitored IP DetNet
flow in the multipath environments, e.g., Link Aggregation Group or
Equal Cost Multipath. (That also applies to encapsulation techniques
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described in Section 3.2 and Section 3.3.) To ensure the accuracy of
OAM results in detecting failures and monitoring the performance of
IP DetNet, it is essential that test packets not only traverse the
same path as the monitored IP DetNet flow but also receive the same
treatment by the nodes, e.g., shaping, filtering, policing, and
availability of the pre-allocated resources, as experienced by the IP
DetNet packet. That correlation between the particular IP OAM
protocol session and the monitored IP DetNet flow can be achieved
using the DetNet YANG model [I-D.ietf-detnet-yang]. Each IP OAM
protocol session is presented as DetNet Application with related
service and forwarding sub-layers. The forwarding sub-layer of the
IP OAM session is identical to the forwarding sub-layer of the
monitored IP DetNet flow, except for information in the grouping ip-
header, defined in [I-D.ietf-detnet-yang].
3.2. Active OAM Using IP-in-UDP Encapsulation
As described above, IP active OAM is realized through several
protocols. Some protocols use UDP transport, while ICMP is a
network-layer protocol. The amount of operational work mapping IP
OAM protocols to the monitored DetNet flow can be reduced by using an
IP/UDP tunnel to carry IP test packets. Then, to ensure that OAM
packets traverse the same set of nodes and links, the IP/UDP tunnel
MUST be mapped to the monitored DetNet flow. Note that the DetNet
domain for the test packet is seen as a single IP link in such a
case. As a result, transit DetNet IP nodes cannot be traced using
the usual traceroute procedure, and a modification of the traceroute
may be required.
3.3. Active OAM Using DetNet-in-UDP Encapsulation
Active OAM in IP DetNet can be realized using DetNet-in-UDP
encapsulation. Using DetNet-in-UDP tunnel between IP DetNet nodes
ensures that active OAM test packets are fate-sharing with the
monitored IP DetNet flow packets. As a result, a test packet shares
the tunnel with the IP DetNet flow and shares the fate, statistically
speaking, of the IP DetNet flow being monitored.
[I-D.ietf-detnet-mpls-over-ip-preof] describes how DetNet with MPLS
over UDP/IP data plane [RFC9025] can be used to support Packet
Replication, Elimination, and Ordering Functions to potentially lower
packet loss, improve the probability of on-time packet delivery and
ensure in-order packet delivery in IP DetNet's service sub-layer. To
ensure that an active OAM test packet follows the path of the
monitored DetNet flow in the DetNet service sub-layer the
encapsulation shown in Figure 1 is used.
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+---------------------------------+
| |
| DetNet App-Flow |
| (original IP) Packet |
| |
+---------------------------------+ <--\
| DetNet ACH | |
+---------------------------------+ +--> PREOF capable
| Service-ID (S-Label) | | DetNet IP data
+---------------------------------+ | plane encapsulation
| UDP Header | |
+---------------------------------+ |
| IP Header | |
+---------------------------------+ <--/
| Data-Link |
+---------------------------------+
| Physical |
+---------------------------------+
Figure 1: DetNet Associated Channel Header Format
where DetNet ACH is the DetNet Associated Channel Header defined in
[I-D.ietf-detnet-mpls-oam].
3.4. Active OAM Using GRE-in-UDP Encapsulation
[RFC8086] has defined the method of encapsulating GRE (Generic
Routing Encapsulation) headers in UDP. GRE-in-UDP encapsulation can
be used for IP DetNet OAM as it eases the task of mapping an OAM test
session to a particular IP DetNet flow that is identified by N-tuple.
Matching a GRE-in-UDP tunnel to the monitored IP DetNet flow enables
the use of Y.1731/G.8013 [ITU-T.1731] as a comprehensive toolset of
OAM. The Protocol Type field in GRE header MUST be set to 0x8902
assigned by IANA to IEEE 802.1ag Connectivity Fault Management (CFM)
Protocol / ITU-T Recommendation Y.1731. Y.1731/G.8013 supports
necessary for IP DetNet OAM functions, i.e., continuity check, one-
way packet loss and packet delay measurement.
4. Active OAM for DetNet IP Interworking with OAM of non-IP DetNet
domains
A domain in which IP data plane provides DetNet service could be used
in conjunction with a TSN and a DetNet domain with MPLS data plane to
deliver end-to-end service. In such scenarios, the ability to detect
defects and monitor performance using OAM is essential.
[I-D.ietf-detnet-mpls-oam] identified two OAM interworking models -
peering and tunneling. Interworking between DetNet domains with IP
and MPLS data planes analyzed in Section 6.2 of
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[I-D.ietf-detnet-mpls-oam]. Also, requirements and recommendations
for OAM interworking between a DetNet domain with MPLS data plane and
OAM of a TSN equally apply to a DetNet domain with an IP data plane.
5. IANA Considerations
This document does not have any requests for IANA allocation. This
section can be deleted before the publication of the draft.
6. Security Considerations
This document describes the applicability of the existing Fault
Management and Performance Monitoring IP OAM protocols, and does not
raise any security concerns or issues in addition to ones common to
networking or already documented for the referenced DetNet and OAM
protocols.
7. Acknowledgment
TBA
8. References
8.1. Normative References
[I-D.ietf-detnet-mpls-oam]
Mirsky, G., Chen, M., and B. Varga, "Operations,
Administration and Maintenance (OAM) for Deterministic
Networks (DetNet) with MPLS Data Plane", Work in Progress,
Internet-Draft, draft-ietf-detnet-mpls-oam-12, 20 April
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
detnet-mpls-oam-12>.
[I-D.ietf-detnet-yang]
Geng, X., Ryoo, Y., Fedyk, D., Rahman, R., and Z. Li,
"Deterministic Networking (DetNet) YANG Model", Work in
Progress, Internet-Draft, draft-ietf-detnet-yang-17, 4
October 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-detnet-yang-17>.
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, DOI 10.17487/RFC0792, September 1981,
<https://www.rfc-editor.org/info/rfc792>.
[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>.
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[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", STD 89,
RFC 4443, DOI 10.17487/RFC4443, March 2006,
<https://www.rfc-editor.org/info/rfc4443>.
[RFC8086] Yong, L., Ed., Crabbe, E., Xu, X., and T. Herbert, "GRE-
in-UDP Encapsulation", RFC 8086, DOI 10.17487/RFC8086,
March 2017, <https://www.rfc-editor.org/info/rfc8086>.
[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>.
[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane:
IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
<https://www.rfc-editor.org/info/rfc8939>.
[RFC9025] Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane:
MPLS over UDP/IP", RFC 9025, DOI 10.17487/RFC9025, April
2021, <https://www.rfc-editor.org/info/rfc9025>.
8.2. Informational References
[I-D.ietf-detnet-mpls-over-ip-preof]
Varga, B., Farkas, J., and A. G. Malis, "Deterministic
Networking (DetNet): DetNet PREOF via MPLS over UDP/IP",
Work in Progress, Internet-Draft, draft-ietf-detnet-mpls-
over-ip-preof-03, 26 April 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
mpls-over-ip-preof-03>.
[I-D.ietf-detnet-oam-framework]
Mirsky, G., Theoleyre, F., Papadopoulos, G. Z., Bernardos,
C. J., Varga, B., and J. Farkas, "Framework of Operations,
Administration and Maintenance (OAM) for Deterministic
Networking (DetNet)", Work in Progress, Internet-Draft,
draft-ietf-detnet-oam-framework-08, 1 February 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
oam-framework-08>.
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[ITU-T.1731]
ITU-T, "Operations, administration and maintenance (OAM)
functions and mechanisms for Ethernet-based networks",
ITU-T G.8013/Y.1731, August 2015.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.
[RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple
Two-Way Active Measurement Protocol", RFC 8762,
DOI 10.17487/RFC8762, March 2020,
<https://www.rfc-editor.org/info/rfc8762>.
Authors' Addresses
Greg Mirsky
Ericsson
Email: gregimirsky@gmail.com
Mach(Guoyi) Chen
Huawei
Email: mach.chen@huawei.com
David Black
Dell EMC
176 South Street
Hopkinton, MA, 01748
United States of America
Email: david.black@dell.com
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