DetNet B. Varga Internet-Draft J. Farkas Intended status: Informational Ericsson Expires: December 8, 2021 June 6, 2021 Deterministic Networking (DetNet): OAM Functions for The Service Sub- Layer draft-varga-detnet-service-sub-layer-oam-00 Abstract Operation, Administration, and Maintenance (OAM) tools are essential for a deterministic network. The DetNet architecture [RFC8655] has defined two sub-layers: (1) DetNet service sub-layer and (2) DetNet forwarding sub-layer. OAM mechanisms exist for the DetNet forwarding sub-layer, nonetheless, OAM for the service sub-layer requires a new mechanism. This draft introduces OAM related procedures for the DetNet service sub-layer functions. 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. 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Code Components extracted from this document must Varga & Farkas Expires December 8, 2021 [Page 1] Internet-Draft DetNet Service-Sub-layer OAM June 2021 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Terms Used in This Document . . . . . . . . . . . . . . . 3 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3 2.3. Requirements Language . . . . . . . . . . . . . . . . . . 3 3. Requirements on OAM for DetNet Service Sub-layer . . . . . . 4 4. DetNet PING . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 4 4.2. OAM processing at the DetNet service sub-layer . . . . . 5 4.2.1. Relay node with PRF . . . . . . . . . . . . . . . . . 5 4.2.2. Relay node with PEF . . . . . . . . . . . . . . . . . 6 4.2.3. Relay node with POF . . . . . . . . . . . . . . . . . 6 4.2.4. Relay node without PREOF . . . . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. Normative References . . . . . . . . . . . . . . . . . . 8 7.2. Informative References . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction The DetNet Working Group has defined two sub-layers: (1) DetNet service sub-layer, at which a DetNet service (e.g., service protection) is provided and (2) DetNet forwarding sub-layer, which optionally provides resource allocation for DetNet flows over paths provided by the underlying network. In [RFC8655] new DetNet-specific functions have been defined for the DetNet service sub-layer, namely PREOF (a collective name for Packet Replication, Elimination, and Ordering Functions). Framework of Operations, Administration and Maintenance (OAM) for Deterministic Networking (DetNet) is described in [I-D.ietf-detnet-oam-framework]. OAM for the DetNet MPLS data plane is described in [I-D.ietf-detnet-mpls-oam] and OAM for the DetNet IP data plane is described in [I-D.ietf-detnet-mpls-oam]. This draft has been submitted as an individual contribution to OAM discussions, in particular, to kick-off Working Group discussions on introducing OAM functions for the DetNet service sub-layer. It is also up to the Working Group discussions to which draft parts of this contribution may go, if any. Varga & Farkas Expires December 8, 2021 [Page 2] Internet-Draft DetNet Service-Sub-layer OAM June 2021 The OAM functions for the DetNet service sub-layer allow, for example, to recognize/discover DetNet relay nodes, to get information about their configuration, and to check their operation or status. The approach described in this draft introduces a new OAM shim layer to achieve OAM for the DetNet service sub-layer. In the rest of the draft, this approach is referred to as "DetNet PING", which is an in- band OAM approach, i.e., the OAM packets follow precisely the same path as the data packets of the corresponding DetNet flow(s) The OAM packets provide DetNet service sub-layer specific information, like: o Identity of a DetNet service sub-layer node. o Discover Ingress/Egress flow specific configuration of a DetNet service sub-layer node. o Detect the status of the flow specific service sub-layer function. DetNet PING is applicable both to IP and MPLS DetNet data planes. 2. Terminology 2.1. Terms Used in This Document This document uses the terminology established in the DetNet architecture [RFC8655], and the reader is assumed to be familiar with that document and its terminology. 2.2. Abbreviations The following abbreviations are used in this document: DetNet Deterministic Networking. PEF Packet Elimination Function. POF Packet Ordering Function. PREOF Packet Replication, Elimination and Ordering Functions. PRF Packet Replication Function. 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 Varga & Farkas Expires December 8, 2021 [Page 3] Internet-Draft DetNet Service-Sub-layer OAM June 2021 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Requirements on OAM for DetNet Service Sub-layer The requirements on OAM for a DetNet relay node are: 1. to provide OAM functions for the DetNet service sub-layer. 2. to discover DetNet relay nodes in a DetNet network. 3. to collect DetNet service sub-layer specific (e.g., configuration/operation/status) information from DetNet relay nodes. 4. to work for both DetNet data planes: (1) MPLS and (2) IP. 4. DetNet PING 4.1. Overview The "DetNet PING" approach uses two types of OAM packets: (1) DetNet- Echo-Request and (2) DetNet-Echo-Reply. Their encapsulation is identical to that of the corresponding DetNet data flow, so they follow precisely the same path as the packets of the corresponding DetNet data flow. They target DetNet service sub-layer entities, so they may not be recognized as OAM packet by entities not implementing DetNet service sub-layer for a packet flow (e.g., transit nodes). Other entities treat them as packets belonging to the corresponding DetNet data flow. The following relay node roles can be distinguished: 1. DetNet PING originator node, 2. Intermediate DetNet service sub-layer node, 3. DetNet PING targeted node. An originator node sends (generates) DetNet-Echo-Request packet(s). DetNet-Echo-Request packet contains an OAM specific "PINGSeqNum", what can be used by the DetNet service sub-layer of relay nodes. Note that "PINGSeqNum" is originator specific. An intermediate DetNet service sub-layer node executes DetNet flow specific service sub-layer functionality. Packet processing may be done in an OAM specific manner (see details in in Section 4.2). Varga & Farkas Expires December 8, 2021 [Page 4] Internet-Draft DetNet Service-Sub-layer OAM June 2021 A targeted node answers with DetNet-Echo-Reply packet for each DetNet-Echo-Request. DetNet-Echo-Reply packet provides DetNet service sub-layer specific information on (i) identities of DetNet service sub-layer node (e.g., Node-ID, local Flow-ID), (ii) ingress/ egress flow related configuration (e.g., in/out member flow specific information (including forwarding sub-layer specifics)), and (iii) status of service sub-layer function (e.g., local PxF-ID, Action- Type=x, operational status, value of key state variable(s), function related counters). 4.2. OAM processing at the DetNet service sub-layer Detailed OAM packet processing rules of various DetNet relay nodes are described in the next sections. 4.2.1. Relay node with PRF A DetNet relay node with PRF processes DetNet OAM packets in a stateless manner. If the relay node with PRF is the target of a DetNet-Echo-Request packet, then the DetNet-Echo-Request packet MUST NOT be further forwarded and an DetNet-Echo-Reply packet MUST be generated. If the relay node with PRF is not the target of a DetNet-Echo-Request packet, then the DetNet-Echo-Request packet MUST be sent over all DetNet flow specific member flow paths (i.e., it is replicated). A DetNet-Echo-Reply packet MUST contain the following information: o Identities related to the DetNet service sub-layer node (e.g., Node-ID, local Flow-ID), o Ingress/Egress flow related configuration (e.g., in/out member flow specific information (including forwarding sub-layer specifics)), o Status of service sub-layer function (e.g., local PRF-ID, Action- Type=Replication, operational status, value of the flow related key state variable (e.g., "GenSeqNum" in [IEEE8021CB]). A DetNet-Echo-Reply packet MAY contain the following information: o PRF function related local counters. Varga & Farkas Expires December 8, 2021 [Page 5] Internet-Draft DetNet Service-Sub-layer OAM June 2021 4.2.2. Relay node with PEF A DetNet relay node with PEF processes DetNet OAM packets in a stateful manner. If the relay node with PEF is the target of DetNet-Echo-Request packet, then the DetNet-Echo-Request packet MUST NOT be further forwarded and an DetNet-Echo-Reply packet MUST be generated. If the relay node with PEF is not the target of DetNet-Echo-Request packet, then elimination MUST be executed on the DetNet-Echo-Request packet(s) using the OAM specific "PINGSeqNum" in the packet. So only a single DetNet-Echo-Request packet is forwarded and all further replicas (having the same originator's sequence number) MUST be discarded. Note, that PEF MAY use a simplified elimination algorithm for DetNet- Echo-Request packets (e.g., "MatchRecoveryAlgorithm" in [IEEE8021CB]) as OAM is a slow protocol. A DetNet-Echo-Reply packet MUST contain the following information: o Identities related to the DetNet service sub-layer node (e.g., Node-ID, local Flow-ID), o Ingress/Egress flow related configuration (e.g., in/out member flow specific information (including forwarding sub-layer specifics)) , o Status of service sub-layer function (e.g., local PEF-ID, Action- Type=Elimination, operational status, value of the flow related key state variable (e.g., "RecovSeqNum" in [IEEE8021CB]). A DetNet-Echo-Reply packet MAY contain the following information: o PEF function related local counters. 4.2.3. Relay node with POF A DetNet relay node with POF processes DetNet OAM packets in a stateless manner. If the relay node with POF is the target of DetNet-Echo-Request packet, then the DetNet-Echo-Request packet MUST NOT be further forwarded and a DetNet-Echo-Reply packet MUST be generated. If the relay node with POF is not the target of DetNet-Echo-Request packet, then the DetNet-Echo-Request packet(s) MUST be forwarded without any POF specific action. Varga & Farkas Expires December 8, 2021 [Page 6] Internet-Draft DetNet Service-Sub-layer OAM June 2021 A DetNet-Echo-Reply packet MUST contain the following information: o Identities of the DetNet service sub-layer node (e.g., Node-ID, local Flow-ID), o Ingress/Egress flow related configuration (e.g., in/out member flow specific information (including forwarding sub-layer specifics)) , o Status of service sub-layer function (e.g., local POF-ID, Action- Type=Ordering, operational status, value of the flow related key state variable (e.g., "POFLastSent" in [I-D.varga-detnet-pof]). A DetNet-Echo-Reply packet MAY contain the following information: o POF function related local counters. 4.2.4. Relay node without PREOF A DetNet relay node without PREOF processes DetNet OAM packets in a stateless manner. If the relay node without PREOF is the target of DetNet-Echo-Request packet, then the DetNet-Echo-Request packet MUST NOT be further forwarded and an DetNet-Echo-Reply packet MUST be generated. If the relay node without PREOF is not the target of DetNet-Echo-Request packet, then the DetNet-Echo-Request packet(s) MUST be forwarded (as any data packets of the related DetNet flow). DetNet-Echo-Reply packet MUST contain the following information: o Identities of the DetNet service sub-layer node (e.g., Node-ID, local Flow-ID), o Ingress/Egress flow related configuration (e.g., in/out member flow specific information (including forwarding sub-layer specifics)) . 5. Security Considerations Tbd. 6. IANA Considerations Tbd. Varga & Farkas Expires December 8, 2021 [Page 7] Internet-Draft DetNet Service-Sub-layer OAM June 2021 7. References 7.1. 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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, "Deterministic Networking Architecture", RFC 8655, DOI 10.17487/RFC8655, October 2019, . 7.2. Informative References [I-D.ietf-detnet-ip-oam] Mirsky, G., Chen, M., and D. Black, "Operations, Administration and Maintenance (OAM) for Deterministic Networks (DetNet) with IP Data Plane", draft-ietf-detnet- ip-oam-02 (work in progress), March 2021. [I-D.ietf-detnet-mpls-oam] Mirsky, G. and M. Chen, "Operations, Administration and Maintenance (OAM) for Deterministic Networks (DetNet) with MPLS Data Plane", draft-ietf-detnet-mpls-oam-03 (work in progress), March 2021. [I-D.ietf-detnet-oam-framework] Mirsky, G., Theoleyre, F., Papadopoulos, G. Z., and C. J. Bernardos, "Framework of Operations, Administration and Maintenance (OAM) for Deterministic Networking (DetNet)", draft-ietf-detnet-oam-framework-01 (work in progress), May 2021. [I-D.varga-detnet-pof] Varga, B., Farkas, J., Kehrer, S., and T. Heer, "Deterministic Networking (DetNet): Packet Ordering Function", draft-varga-detnet-pof-00 (work in progress), April 2021. Varga & Farkas Expires December 8, 2021 [Page 8] Internet-Draft DetNet Service-Sub-layer OAM June 2021 [IEEE8021CB] IEEE, "IEEE Standard for Local and metropolitan area networks -- Frame Replication and Elimination for Reliability", DOI 10.1109/IEEESTD.2017.8091139, October 2017, . Authors' Addresses Balazs Varga Ericsson Magyar Tudosok krt. 11. Budapest 1117 Hungary Email: balazs.a.varga@ericsson.com Janos Farkas Ericsson Magyar Tudosok krt. 11. Budapest 1117 Hungary Email: janos.farkas@ericsson.com Varga & Farkas Expires December 8, 2021 [Page 9]