Hi Yingzhen,
thank you for your thoughtful suggestions that helped alot in improving the document. I like shorter sentences; they make text clearer. Both text updates accepted and are in the working version (attached).
Best regards,
Greg
On Wed, Feb 14, 2024 at 8:39 AM Yingzhen Qu <yingzhen.ietf@xxxxxxxxx> wrote:
Hi Greg,Thanks for the reply. Please see my answers below inline.Thanks,YingzhenOn Tue, Feb 13, 2024 at 9:48 PM Greg Mirsky <gregimirsky@xxxxxxxxx> wrote:Hi Yingzhen,thank you for your kind words in support of this work; much appreciated. Please find my notes below tagged GIM>>.Regards,GregOn Tue, Feb 13, 2024 at 8:09 PM Yingzhen Qu via Datatracker <noreply@xxxxxxxx> wrote:Reviewer: Yingzhen Qu
Review result: Ready
I've reviewed version 10, and this is a follow up review.
Thanks to the authors for working on this document and addressing my comments.
The document readability has improved a lot from my last review of version -10,
and I believe it is ready for publication.
There are a couple of nits for the authors to consider.
The line numbers are generated using idnits.
160 is being done by using the Internet Control Message Protocol (ICMP)
nits: there should be a "." in the end.GIM>> It seems like the long sentence may confuse a reader:Most of on-demand failure detection and localization in IP networksis 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 providedthrough code points.The intention is to note that Echo Request/Reply that are the mechanism used in ICMP are the common method for on-demand failure detection and localization, i.e., of ping and traceroute. Would a slight re-wording make it clearer:NEW TEXT:Most of on-demand failure detection and localization in IP networksis being done by using the Internet Control Message Protocol's (ICMP)Echo Request, Echo Reply, and the set of defined error messages, e.g.,Destination Unreachable, with the more detailed information providedthrough code points.WDYT?[Yingzhen]: Now I see I did break the long sentence wrong. Fortunately the message of the sentence was still delivered correctly. Here is my suggestion:In IP networks, the majority of on-demand failure detection and localization is achieved through the use of the Internet Control Message Protocol (ICMP), utilizing Echo Request and Echo Reply messages, along with a set of defined error messages such as Destination Unreachable, which provide detailed information through assigned code points.
166 traffic between DetNet nodes with IP DetNet traffic, e.g., ensure
167 that such ICMP traffic uses the DetNet IP data plane in each node,
nits: somehow this sentence doesn't read well to me. "uses the DetNet IP
data plane" is not very clear to me, I think you're trying to say ICMP traffic
should go through the same path/interface as DetNet traffic, for example,
there is ECMP between two DetNet nodes.GIM>> Thank you for pointing this to me. You are correct, the intention is to stress the importance of ensuring that ICMP packets traverse the same set of nodes and interfaces and receieve the same QoS treatment as the monitored DetNet IP flow. I propose the following update:OLD TEXT:In order to use ICMP for thesepurposes with DetNet, DetNet nodes must be able to associate ICMPtraffic between DetNet nodes with IP DetNet traffic, e.g., ensurethat such ICMP traffic uses the DetNet IP data plane in each node,otherwise ICMP may be unable to detect and localize failures that arespecific to the DetNet IP data plane.NEW TEXT:In order to use ICMPfor these purposes with DetNet, DetNet nodes must be able toassociate ICMP traffic between DetNet nodes with IP DetNet traffic,i.e., ensure that such ICMP traffic traverses the same interfaces andreceives the same QoS treatment as the monitored DetNet IP flow;otherwise, ICMP may be unable to detect and localize failures thatare specific to the DetNet IP data plane.What are your thoughts? Is the text more clear now?[Yingzhen]: The new text is definitely more clear. Here is my suggestion, and it's up to you to decide whether to use it or not.To utilize ICMP effectively for these purposes within DetNet, DetNet nodes must establish the association of ICMP traffic between DetNet nodes with IP DetNet traffic. This entails ensuring that such ICMP traffic traverses the same interfaces and receives identical QoS treatment as the monitored DetNet IP flow. Failure to do so may result in ICMP being unable to detect and localize failures specific to the DetNet IP data plane.
DetNet Working Group G. Mirsky
Internet-Draft Ericsson
Intended status: Informational M. Chen
Expires: 17 August 2024 Huawei
D. Black
Dell EMC
14 February 2024
Operations, Administration, and Maintenance (OAM) for Deterministic
Networks (DetNet) with IP Data Plane
draft-ietf-detnet-ip-oam-13
Abstract
This document discusses the use of existing IP Operations,
Administration, and Maintenance protocols and mechanisms in
Deterministic Networking networks that use the IP data plane.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 17 August 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
3. Active OAM for DetNet Networks with the IP Data Plane . . . . 3
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. The Application of Y.1731/G.8013 Using GRE-in-UDP
Encapsulation . . . . . . . . . . . . . . . . . . . . . . 6
4. Active OAM for DetNet IP Interworking with OAM of non-IP DetNet
domains . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. 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 and localize defects in the network as well as to monitor
network performance. Some OAM functions (e.g., failure detection),
work in the network proactively, while others (e.g., defect
localization) are usually performed on-demand. These tasks are
achieved by a combination of active and hybrid OAM methods, as
defined in [RFC7799].
[I-D.ietf-detnet-oam-framework] lists the OAM functional requirements
for DetNet, and defines the principles for OAM use within DetNet
networks utilizing the IP data plane. The functional requirements
can be compared against current OAM tools to identify gaps and
potential enhancements required to enable proactive and on-demand
path monitoring and service validation.
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This document discusses the use of existing IP OAM protocols and
mechanisms in DetNet networks that use 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
OAM: Operations, Administration, and Maintenance
ICMP: Internet Control Message Protocol
Underlay Network or Underlay Layer: The network that provides
connectivity between DetNet nodes. MPLS networks providing LSP
connectivity between DetNet nodes are an example of the DetNet IP
network underlay layer.
DetNet Node: a node that is an actor in the DetNet domain. DetNet
domain edge nodes and nodes that perform the Packet Replication and
Elimination Function within the domain are examples of a DetNet node.
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. Thus, it is critical that the data
plane encapsulation supports OAM mechanisms and enables them to be
configured so that DetNet OAM packets follow the same path
(unidirectional or bidirectional) through the network and receive the
same forwarding treatment in the DetNet forwarding sub-layer as the
DetNet flow being monitored.
The DetNet data plane encapsulation in a transport network with IP
encapsulations is 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. For BFD, the UDP destination port is specific
to the BFD variant, e.g., Multihop BFD uses port 4784 [RFC5883].
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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, in a
network where path selection and DetNet functionality are based on
3-tuples (destination and source IP addresses in combination with the
Differentiated Services Code Point value) that association can be
achieved by having the OAM traffic use the same 3-tuple as the
monitored 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.
In IP networks, the majority of on-demand failure detection and
localization is achieved through the use of the Internet Control
Message Protocol (ICMP), utilizing Echo Request and Echo Reply
messages, along with a set of defined error messages such as
Destination Unreachable, which provide detailed information through
assigned code points. [RFC0792] and [RFC4443] define the ICMP for
IPv4 and IPv6 networks, respectively. To utilize ICMP effectively
for these purposes within DetNet, DetNet nodes must establish the
association of ICMP traffic between DetNet nodes with IP DetNet
traffic. This entails ensuring that such ICMP traffic traverses the
same interfaces and receives identical QoS treatment as the monitored
DetNet IP flow. Failure to do so may result in ICMP being unable to
detect and localize failures specific to the DetNet IP data plane.
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. It is essential to ensure that specially constructed
OAM packets traverse the same set of nodes and links and receive the
same network QoS treatment as the monitored data flow, e.g., a DetNet
flow, for making active OAM useful. When the UDP destination port
number used by the OAM protocol is assigned by IANA, then judicious
selection of the UDP source port may be able to achieve co-routedness
of OAM with the monitored IP DetNet flow in multipath environments,
e.g., Link Aggregation Group or Equal Cost Multipath, via use of a
UDP source port value that results in the OAM traffic and the
monitored IP DetNet flow hashing to the same path based on the packet
header hashes used for path selection. This does assume that
forwarding equipment along the multipath makes consistent hashing
decisions, which might not always be true in a heterogeneous
environment. (That also applies to encapsulation techniques
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
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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
session and the monitored IP DetNet flow can be achieved by using
DetNet provisioning information (e.g., [I-D.ietf-detnet-yang]). Each
IP OAM protocol session is presented as a 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, active IP 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 ([RFC2003]). 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 follow the same path through the
network as the monitored IP DetNet flow packets and receive the same
forwarding treatment in the DetNet forwarding sub-layer (see
Section 4.1.2 of [RFC8655]) as 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].
PREOF - Packet Replication, Elimination, and Ordering Functions if
DetNet service sub-layer defined in [RFC8655].
3.4. The Application of Y.1731/G.8013 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 the
necessary functions required for IP DetNet OAM, i.e., continuity
check, one-way packet loss and packet delay measurement.
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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 4.2 of
[I-D.ietf-detnet-mpls-oam]. In addition, OAM interworking
requirements and recommendations that apply between a DetNet Domain
with the MPLS dataplane and an adjacent TSN network also apply
between a DetNet domain with the IP dataplane and an adjacent TSN
network.
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. It does not
raise any security concerns or issues in addition to ones common to
networking or already documented in [RFC0792], [RFC4443], [RFC5880],
and [RFC8762] for the referenced DetNet and OAM protocols.
7. References
7.1. 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-15, 12 January
2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
detnet-mpls-oam-15>.
[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-19, 25
January 2024, <https://datatracker.ietf.org/doc/html/
draft-ietf-detnet-yang-19>.
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[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, DOI 10.17487/RFC0792, September 1981,
<https://www.rfc-editor.org/info/rfc792>.
[RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003,
DOI 10.17487/RFC2003, October 1996,
<https://www.rfc-editor.org/info/rfc2003>.
[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>.
[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>.
7.2. 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-09, 8 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
mpls-over-ip-preof-09>.
[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,
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draft-ietf-detnet-oam-framework-11, 8 January 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
oam-framework-11>.
[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>.
[RFC5883] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for Multihop Paths", RFC 5883, DOI 10.17487/RFC5883,
June 2010, <https://www.rfc-editor.org/info/rfc5883>.
[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@xxxxxxxxx
Mach(Guoyi) Chen
Huawei
Email: mach.chen@xxxxxxxxxx
David Black
Dell EMC
176 South Street
Hopkinton, MA, 01748
United States of America
Email: david.black@xxxxxxxx
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