IPPM Working Group X. Min Internet-Draft G. Mirsky Intended status: Standards Track ZTE Corp. Expires: July 24, 2021 L. Bo China Telecom January 20, 2021 Echo Request/Reply for Enabled In-situ OAM Capabilities draft-xiao-ippm-ioam-conf-state-08 Abstract This document describes an extension to the echo request/reply mechanisms used in IPv6, MPLS and SFC environments, which can be used within an IOAM domain, allowing the IOAM encapsulating node to acquire the enabled IOAM capabilities of each IOAM transit node and/ or IOAM decapsulating node. 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 July 24, 2021. Copyright Notice Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (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 Simplified BSD License text as described in Section 4.e of Min, et al. Expires July 24, 2021 [Page 1] Internet-Draft Ping Enabled IOAM Capabilities January 2021 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4 3. IOAM Capabilities Formats . . . . . . . . . . . . . . . . . . 5 3.1. IOAM Capabilities Query TLV in the Echo Request . . . . . 5 3.2. IOAM Capabilities Response TLV in the Echo Reply . . . . 6 3.2.1. IOAM Pre-allocated Tracing Capabilities sub-TLV . . . 7 3.2.2. IOAM Incremental Tracing Capabilities sub-TLV . . . . 8 3.2.3. IOAM Proof of Transit Capabilities sub-TLV . . . . . 9 3.2.4. IOAM Edge-to-Edge Capabilities sub-TLV . . . . . . . 10 3.2.5. IOAM DEX Capabilities sub-TLV . . . . . . . . . . . . 11 3.2.6. IOAM End-of-Domain sub-TLV . . . . . . . . . . . . . 12 4. Operational Guide . . . . . . . . . . . . . . . . . . . . . . 13 5. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 6.1. IOAM SoR Capability Registry . . . . . . . . . . . . . . 14 6.2. IOAM TSF+TSL Capability Registry . . . . . . . . . . . . 15 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 8.1. Normative References . . . . . . . . . . . . . . . . . . 16 8.2. Informative References . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 1. Introduction The Data Fields for In-situ OAM (IOAM) [I-D.ietf-ippm-ioam-data] defines data fields that record OAM information within the packet while the packet traverses a particular network domain, which is called an IOAM domain. IOAM can be used to complement OAM mechanisms based on, e.g., ICMP or other types of probe packets, and IOAM mechanisms can be leveraged where mechanisms using, e.g., ICMP do not apply or do not offer the desired results. As specified in [I-D.ietf-ippm-ioam-data], within the IOAM-domain, the IOAM data may be updated by network nodes that the packet traverses. The device which adds an IOAM data container to the packet to capture IOAM data is called the "IOAM encapsulating node". In contrast, the device which removes the IOAM data container is referred to as the "IOAM decapsulating node". Nodes within the domain that are aware of IOAM data and read and/or write or process the IOAM data are called "IOAM transit nodes". Both the IOAM Min, et al. Expires July 24, 2021 [Page 2] Internet-Draft Ping Enabled IOAM Capabilities January 2021 encapsulating node and the decapsulating node are referred to as domain edge devices, which can be hosts or network devices. In order to add the correct IOAM data container to the packet, the IOAM encapsulating node needs to know the enabled IOAM capabilities at the IOAM transit nodes and/or the IOAM decapsulating node as a whole, e.g., how many IOAM transit nodes will add tracing data, and what kinds of data fields will be added. A centralized controller could be used in some IOAM deployments. The IOAM encapsulating node can acquire these IOAM capabilities info from the centralized controller, through, e.g., Netconf/Yang, PCEP, or BGP. In the IOAM deployment scenario where there is no centralized controller, Netconf/Yang or IGP may be used for the IOAM encapsulating node to acquire these IOAM capabilities info, however, whether Netconf/Yang or IGP has some limitations as follows. o When Netconf/Yang is used in this scenario, each IOAM encapsulating node (including the host when it takes the role of an IOAM encapsulating node) needs to implement a Netconf Client, each IOAM transit node and IOAM decapsulating node (including the host when it takes the role of an IOAM decapsulating node) needs to implement a Netconf Server, the complexity can be an issue. Furthermore, each IOAM encapsulating node needs to establish Netconf Connection with each IOAM transit node and IOAM decapsulating node, the scalability can be an issue. o When IGP is used in this scenario, the IGP domain and an IOAM domain don't always have the same coverage. For example, when the IOAM encapsulating node or the IOAM decapsulating node is a host, the availability can be an issue. Furthermore, it might be too challenging to reflect IOAM capabilities at the IOAM transit node and/or the IOAM decapsulating node if these are controlled by a local policy depending on the identity of the IOAM encapsulating node. This document describes an extension to the echo request/reply mechanisms used in IPv6, MPLS and SFC environments, which can be used within an IOAM domain where no Centralized Controller exists, allowing the IOAM encapsulating node to acquire the enabled IOAM capabilities of each IOAM transit node and/or IOAM decapsulating node. The following documents contain references to the echo request/reply mechanisms used in IPv6, MPLS and SFC environments: o [RFC4443] ("Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification"), [RFC4884] Min, et al. Expires July 24, 2021 [Page 3] Internet-Draft Ping Enabled IOAM Capabilities January 2021 ("Extended ICMP to Support Multi-Part Messages") and [RFC8335] ("PROBE: A Utility for Probing Interfaces") o [RFC8029] ("Detecting Multiprotocol Label Switched (MPLS) Data- Plane Failures") o [I-D.ietf-sfc-multi-layer-oam] ("Active OAM for Service Function Chains in Networks") This feature described in this document is assumedly applied to explicit path (strict or loose), because the precondition for this feature to work is that the echo request reaches each IOAM transit node as live traffic traverses. 2. Conventions 2.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2.2. Abbreviations BGP: Border Gateway Protocol E2E: Edge to Edge ICMP: Internet Control Message Protocol IGP: Interior Gateway Protocol IOAM: In-situ Operations, Administration, and Maintenance LSP: Label Switched Path MPLS: Multi-Protocol Label Switching MBZ: Must Be Zero MTU: Maximum Transmission Unit NTP: Network Time Protocol OAM: Operations, Administration, and Maintenance Min, et al. Expires July 24, 2021 [Page 4] Internet-Draft Ping Enabled IOAM Capabilities January 2021 PCEP: Path Computation Element (PCE) Communication Protocol POSIX: Portable Operating System Interface POT: Proof of Transit PTP: Precision Time Protocol SFC: Service Function Chain TTL: Time to Live 3. IOAM Capabilities Formats 3.1. IOAM Capabilities Query TLV in the Echo Request In echo request IOAM Capabilities Query uses TLV (Type-Length-Value tuple) which have the following format: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = IOAM Capabilities Query| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . List of Namespace-IDs . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: IOAM Capabilities Query TLV in the Echo Request When this TLV is present in the echo request sent by an IOAM encapsulating node, it means that the IOAM encapsulating node requests the receiving node to reply with its enabled IOAM capabilities. If there is no IOAM capability to be reported by the receiving node, then this TLV SHOULD be ignored by the receiving node, which means the receiving node SHOULD send echo reply without IOAM capabilities or no echo reply, in the light of whether the echo request includes other TLV than IOAM Capabilities Query TLV. List of Namespace-IDs MAY be included in this TLV of the echo request. In that case, the IOAM encapsulating node requests only the IOAM capabilities that match one of the Namespace-IDs. The Namespace-ID has the same definition as what's specified in [I-D.ietf-ippm-ioam-data]. Type is set to the value that identifies it as an IOAM Capabilities Query TLV. Min, et al. Expires July 24, 2021 [Page 5] Internet-Draft Ping Enabled IOAM Capabilities January 2021 Length is the length of the TLV's Value field in octets, including a List of Namespace-IDs. Value field of this TLV is zero-padded to align to a 4-octet boundary. 3.2. IOAM Capabilities Response TLV in the Echo Reply In echo reply IOAM Capabilities Response uses TLV which have the following format: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = IOAM Capabilities Resp | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . List of Sub-TLVs . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: IOAM Capabilities Response TLV in the Echo Reply When this TLV is present in the echo reply sent by an IOAM transit node and/or an IOAM decapsulating node, it means that the IOAM function is enabled at this node, and this TLV contains the enabled IOAM capabilities of the sender. A list of Sub-TLVs which contains the IOAM capabilities SHOULD be included in this TLV of the echo reply. Note that the IOAM encapsulating node or the IOAM decapsulating node can also be an IOAM transit node. Type is set to the value that identifies it as an IOAM Capabilities Response TLV. Length is the length of the TLV's Value field in octets, including a List of Sub-TLVs. Value field of this TLV or any Sub-TLV is zero-padded to align to a 4-octet boundary. Based on the data fields for IOAM, specified in [I-D.ietf-ippm-ioam-data] and [I-D.ietf-ippm-ioam-direct-export], six kinds of Sub-TLVs are defined in this document. The same type of the sub-TLV MAY be in the IOAM Capabilities Response TLV more than once only if with a different Namespace-ID. Note that the IOAM encapsulating node may receive both IOAM Pre-allocated Tracing Capabilities sub-TLV and IOAM Incremental Tracing Capabilities sub- TLV in the process of traceroute, which means both pre-allocated tracing node and incremental tracing node are on the same path, or some node supports both pre-allocated tracing and incremental Min, et al. Expires July 24, 2021 [Page 6] Internet-Draft Ping Enabled IOAM Capabilities January 2021 tracing, the behavior of the IOAM encapsulating node in this scenario is outside the scope of this document. 3.2.1. IOAM Pre-allocated Tracing Capabilities sub-TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sub-type = Pre-allocated trace | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | Egress_MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress_if_id (short or wide format) ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: IOAM Pre-allocated Tracing Capabilities Sub-TLV When this sub-TLV is present in the IOAM Capabilities Response TLV, it means that the sending node is an IOAM transit node and IOAM tracing function is enabled at this IOAM transit node. Sub-type is set to the value that identifies it as an IOAM Pre- allocated Tracing Capabilities sub-TLV. Length is the length of the sub-TLV's Value field in octets. If Egress_if_id is in the short format, which is 16 bits long, it MUST be set to 10. If Egress_if_id is in the wide format, which is 32 bits long, it MUST be set to 12. IOAM-Trace-Type field has the same definition as what's specified in section 5.4 of [I-D.ietf-ippm-ioam-data]. Reserved field is reserved for future use and MUST be set to zero. Namespace-ID field has the same definition as what's specified in section 5.3 of [I-D.ietf-ippm-ioam-data], it should be one of the Namespace-IDs listed in the IOAM Capabilities Query TLV of echo request. Egress_MTU field has 16 bits and specifies the MTU of the egress direction out of which the sending node would forward the received echo request, it should be the MTU of the egress interface or the MTU between the sending node and the downstream IOAM transit node. Min, et al. Expires July 24, 2021 [Page 7] Internet-Draft Ping Enabled IOAM Capabilities January 2021 Egress_if_id field has 16 bits (in short format) or 32 bits (in wide format) and specifies the identifier of the egress interface out of which the sending node would forward the received echo request. 3.2.2. IOAM Incremental Tracing Capabilities sub-TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-type = Incremental trace | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | Egress_MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress_if_id (short or wide format) ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: IOAM Incremental Tracing Capabilities Sub-TLV When this sub-TLV is present in the IOAM Capabilities Response TLV, it means that the sending node is an IOAM transit node and IOAM tracing function is enabled at this IOAM transit node. Sub-type is set to the value that identifies it as an IOAM Incremental Tracing Capabilities sub-TLV. Length is the length of the sub-TLV's Value field in octets. If Egress_if_id is in the short format, which is 16 bits long, it MUST be set to 10. If Egress_if_id is in the wide format, which is 32 bits long, it MUST be set to 12. IOAM-Trace-Type field has the same definition as what's specified in section 5.4 of [I-D.ietf-ippm-ioam-data]. Reserved field is reserved for future use and MUST be set to zero. Namespace-ID field has the same definition as what's specified in section 5.3 of [I-D.ietf-ippm-ioam-data], it should be one of the Namespace-IDs listed in the IOAM Capabilities Query TLV of echo request. Egress_MTU field has 16 bits and specifies the MTU of the egress direction out of which the sending node would forward the received echo request, it should be the MTU of the egress interface or the MTU between the sending node and the downstream IOAM transit node. Min, et al. Expires July 24, 2021 [Page 8] Internet-Draft Ping Enabled IOAM Capabilities January 2021 Egress_if_id field has 16 bits (in short format) or 32 bits (in wide format) and specifies the identifier of the egress interface out of which the sending node would forward the received echo request. 3.2.3. IOAM Proof of Transit Capabilities sub-TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-type = POT Capabilities | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | IOAM-POT-Type |P|SoR|Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: IOAM Proof of Transit Capabilities Sub-TLV When this sub-TLV is present in the IOAM Capabilities Response TLV, it means that the sending node is an IOAM transit node and IOAM proof of transit function is enabled at this IOAM transit node. Sub-type is set to the value that identifies it as an IOAM Proof of Transit Capabilities sub-TLV. Length is the length of the sub-TLV's Value field in octets and MUST be set to 4. Namespace-ID field has the same definition as what's specified in section 5.3 of [I-D.ietf-ippm-ioam-data], it should be one of the Namespace-IDs listed in the IOAM Capabilities Query TLV of echo request. IOAM-POT-Type field and P bit have the same definition as what's specified in section 5.5 of [I-D.ietf-ippm-ioam-data]. If the IOAM encapsulating node receives IOAM-POT-Type and/or P bit values from an IOAM transit node that are different from its own, then the IOAM encapsulating node MAY choose to abandon the proof of transit function or to select one kind of IOAM-POT-Type and P bit, it's based on the policy applied to the IOAM encapsulating node. SoR field has two bits, which means the size of "Random" and "Cumulative" data that are specified in section 5.5 of [I-D.ietf-ippm-ioam-data]. This document defines SoR as follow: 0b00 means 64-bit "Random" and 64-bit "Cumulative" data. 0b01~0b11: Reserved for future standardization Reserved field is reserved for future use and MUST be set to zero. Min, et al. Expires July 24, 2021 [Page 9] Internet-Draft Ping Enabled IOAM Capabilities January 2021 3.2.4. IOAM Edge-to-Edge Capabilities sub-TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-type = E2E Capabilities | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | IOAM-E2E-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |TSF|TSL| Reserved | MBZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6: IOAM Edge-to-Edge Capabilities Sub-TLV When this sub-TLV is present in the IOAM Capabilities Response TLV, it means that the sending node is an IOAM decapsulating node and IOAM edge-to-edge function is enabled at this IOAM decapsulating node. That is to say, if the IOAM encapsulating node receives this sub-TLV, the IOAM encapsulating node can determine that the node which sends this sub-TLV is an IOAM decapsulating node. Sub-type is set to the value that identifies it as an IOAM Edge-to- Edge Capabilities sub-TLV. Length is the length of the sub-TLV's Value field in octets and MUST be set to 8. Namespace-ID field has the same definition as what's specified in section 5.3 of [I-D.ietf-ippm-ioam-data], it should be one of the Namespace-IDs listed in the IOAM Capabilities Query TLV of echo request. IOAM-E2E-Type field has the same definition as what's specified in section 5.6 of [I-D.ietf-ippm-ioam-data]. TSF field specifies the timestamp format used by the sending node. This document defines TSF as follow: 0b00: PTP timestamp format 0b01: NTP timestamp format 0b10: POSIX timestamp format 0b11: Reserved for future standardization TSL field specifies the timestamp length used by the sending node. This document defines TSL as follow. Min, et al. Expires July 24, 2021 [Page 10] Internet-Draft Ping Enabled IOAM Capabilities January 2021 When the TSF field is set to 0b00, which indicates the PTP timestamp format, the values of the TSL field are interpreted as follows: 0b00: 64-bit PTPv1 timestamp as defined in IEEE1588-2008 [IEEE1588v2] 0b01: 80-bit PTPv2 timestamp as defined in IEEE1588-2008 [IEEE1588v2] 0b10~0b11: Reserved for future standardization When the TSF field is set to 0b01, which indicates the NTP timestamp format, the values of the TSL field are interpreted as follows: 0b00: 32-bit NTP timestamp as defined in NTPv4 [RFC5905] 0b01: 64-bit NTP timestamp as defined in NTPv4 [RFC5905] 0b10: 128-bit NTP timestamp as defined in NTPv4 [RFC5905] 0b11: Reserved for future standardization When the TSF field is set to 0b10 or 0b11, the TSL field would be ignored. Reserved field is reserved for future use and MUST be set to zero. 3.2.5. IOAM DEX Capabilities sub-TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-type = DEX Capabilities | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7: IOAM DEX Capabilities Sub-TLV When this sub-TLV is present in the IOAM Capabilities Response TLV, it means that the sending node is an IOAM transit node and the IOAM DEX function is enabled at this IOAM transit node. Min, et al. Expires July 24, 2021 [Page 11] Internet-Draft Ping Enabled IOAM Capabilities January 2021 Sub-type is set to the value that identifies it as an IOAM DEX Capabilities sub-TLV. Length is the length of the sub-TLV's Value field in octets and MUST be set to 8. IOAM-Trace-Type field has the same definition as what's specified in section 3.2 of [I-D.ietf-ippm-ioam-direct-export]. Namespace-ID field has the same definition as what's specified in section 3.2 of [I-D.ietf-ippm-ioam-direct-export], it should be one of the Namespace-IDs listed in the IOAM Capabilities Query TLV of echo request. Reserved field is reserved for future use and MUST be set to zero. 3.2.6. IOAM End-of-Domain sub-TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-type = End of Domain | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | MBZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 8: IOAM End of Domain Sub-TLV When this sub-TLV is present in the IOAM Capabilities Response TLV, it means that the sending node is an IOAM decapsulating node. That is to say, if the IOAM encapsulating node receives this sub-TLV, the IOAM encapsulating node can determine that the node which sends this sub-TLV is an IOAM decapsulating node. When the IOAM Edge-to-Edge Capabilities sub-TLV is present in the IOAM Capabilities Response TLV sent by the IOAM decapsulating node, the IOAM End-of-Domain sub-TLV doesn't need to be present in the same IOAM Capabilities Response TLV, otherwise the End-of-Domain sub-TLV MUST be present in the IOAM Capabilities Response TLV sent by the IOAM decapsulating node. Both the IOAM Edge-to-Edge Capabilities sub-TLV and the IOAM End-of-Domain sub-TLV can be used to indicate that the sending node is an IOAM decapsulating node. It's recommended to include only the IOAM Edge- to-Edge Capabilities sub-TLV if IOAM edge-to-edge function is enabled at this IOAM decapsulating node. Sub-type is set to the value that identifies it as an IOAM End of Domain sub-TLV. Min, et al. Expires July 24, 2021 [Page 12] Internet-Draft Ping Enabled IOAM Capabilities January 2021 Length is the length of the sub-TLV's Value field in octets and MUST be set to 4. Namespace-ID field has the same definition as what's specified in section 5.3 of [I-D.ietf-ippm-ioam-data], it should be one of the Namespace-IDs listed in the IOAM Capabilities Query TLV of echo request. 4. Operational Guide Once the IOAM encapsulating node is triggered to acquire the enabled IOAM capabilities of each IOAM transit node and/or IOAM decapsulating node, the IOAM encapsulating node will send echo requests that include the IOAM Capabilities Query TLV. First with TTL equal to 1 to reach the nearest node, which may be an IOAM transit node or not. Then with TTL equal to 2 to reach the second nearest node, which also may be an IOAM transit node or not. And further, increasing by 1 the TTL every time the IOAM encapsulating node sends a new echo request, until the IOAM encapsulating node receives an echo reply sent by the IOAM decapsulating node, which should contain the IOAM Capabilities Response TLV including the IOAM Edge-to-Edge Capabilities sub-TLV or the IOAM End-of-Domain sub-TLV. Alternatively, if the IOAM encapsulating node knows exactly all the IOAM transit nodes and/or IOAM decapsulating node beforehand, once the IOAM encapsulating node is triggered to acquire the enabled IOAM capabilities, it can send an echo request to each IOAM transit node and/or IOAM decapsulating node directly, without TTL expiration. The IOAM encapsulating node may be triggered by the device administrator, the network management system, the network controller, or even the live user traffic. The specific triggering mechanisms are outside the scope of this document. Each IOAM transit node and/or IOAM decapsulating node that receives an echo request containing the IOAM Capabilities Query TLV will send an echo reply to the IOAM encapsulating node, and within the echo reply, there should be an IOAM Capabilities Response TLV containing one or more sub-TLVs. The IOAM Capabilities Query TLV contained in the echo request would be ignored by the receiving node that is unaware of IOAM. 5. Security Considerations Queries and responses about the state of an IOAM domain should be processed only from a trusted source. An unauthorized query MUST be discarded by an implementation that supports this specification. Similarly, unsolicited echo response with the IOAM Capabilities TLV MUST be discarded. Authentication of echo request/reply that Min, et al. Expires July 24, 2021 [Page 13] Internet-Draft Ping Enabled IOAM Capabilities January 2021 includes the IOAM Capabilities TLV is one of methods of the integrity protection. Implementations could also provide a means of filtering based on the source address of the received echo request/reply. The integrity protection for IOAM capabilities information collection can also be achieved using mechanisms in the underlay data plane. For example, if the underlay is an IPv6 network, IP Authentication Header [RFC4302] or IP Encapsulating Security Payload Header [RFC4303] can be used to provide integrity protection. Information about the state of the IOAM domain collected in the IAOM Capabilities TLV is confidential. An implementation can use secure transport to provide privacy protection. For example, if the underlay is an IPv6 network, confidentiality can be achieved using the IP Encapsulating Security Payload Header [RFC4303]. 6. IANA Considerations This document requests the following IANA Actions. IANA is requested to create a registry group named "In-Situ OAM (IOAM) Capabilities Parameters". This group will include the following registries: o IOAM SoR Capability o IOAM TSF+TSL Capability New registries in this group can be created via RFC Required process as per [RFC8126]. The subsequent sub-sections detail the registries herein contained. Considering the TLVs/sub-TLVs defined in this document would be carried in different kinds of Echo Request/Reply message, such as ICMPv6 or LSP Ping, it is intended that the registries for Type and sub-Type would be requested in subsequent documents. 6.1. IOAM SoR Capability Registry This registry defines 4 code points for the IOAM SoR Capability field for identifying the size of "Random" and "Cumulative" data as explained in section 5.5 of [I-D.ietf-ippm-ioam-data]. The following code points are defined in this draft: SoR Description ---- ----------- 0b00 64-bit "Random" and 64-bit "Cumulative" data Min, et al. Expires July 24, 2021 [Page 14] Internet-Draft Ping Enabled IOAM Capabilities January 2021 0b01 - 0b11 are available for assignment via RFC Required process as per [RFC8126]. 6.2. IOAM TSF+TSL Capability Registry This registry defines 3 code points for the IOAM TSF Capability field for identifying the timestamp format as explained in section 6 of [I-D.ietf-ippm-ioam-data]. o When the code point for the IOAM TSF Capability field equals 0b00 which means PTP timestamp format, this registry defines 2 code points for the IOAM TSL Capability field for identifying the timestamp length. o When the code point for the IOAM TSF Capability field equals 0b01 which means NTP timestamp format, this registry defines 3 code points for the IOAM TSL Capability field for identifying the timestamp length. The following code points are defined in this draft: TSF TSL Description ---- ---- ----------- 0b00 PTP Timestamp Format 0b00 64-bit PTPv1 timestamp 0b01 80-bit PTPv2 timestamp 0b01 NTP Timestamp Format 0b00 32-bit NTP timestamp 0b01 64-bit NTP timestamp 0b10 128-bit NTP timestamp 0b10 POSIX Timestamp Format Unassigned code points of TSF+TSL are available for assignment via RFC Required process as per [RFC8126]. 7. Acknowledgements The authors would like to acknowledge Tianran Zhou, Dhruv Dhody, Frank Brockners and Cheng Li for their careful review and helpful comments. The authors appreciate the f2f discussion with Frank Brockners on this document. The authors would like to acknowledge Tommy Pauly and Ian Swett for their good suggestion and guidance. Min, et al. Expires July 24, 2021 [Page 15] Internet-Draft Ping Enabled IOAM Capabilities January 2021 8. References 8.1. Normative References [I-D.ietf-ippm-ioam-data] Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields for In-situ OAM", draft-ietf-ippm-ioam-data-11 (work in progress), November 2020. [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", draft-ietf-ippm-ioam-direct- export-02 (work in progress), November 2020. [IEEE1588v2] Institute of Electrical and Electronics Engineers, "IEEE Std 1588-2008 - IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", IEEE Std 1588-2008, 2008, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, "Network Time Protocol Version 4: Protocol and Algorithms Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010, . [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 8.2. Informative References [I-D.ietf-sfc-multi-layer-oam] Mirsky, G., Meng, W., Khasnabish, B., and C. Wang, "Active OAM for Service Function Chains in Networks", draft-ietf- sfc-multi-layer-oam-07 (work in progress), December 2020. Min, et al. Expires July 24, 2021 [Page 16] Internet-Draft Ping Enabled IOAM Capabilities January 2021 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, DOI 10.17487/RFC4302, December 2005, . [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", RFC 4303, DOI 10.17487/RFC4303, December 2005, . [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, . [RFC4884] Bonica, R., Gan, D., Tappan, D., and C. Pignataro, "Extended ICMP to Support Multi-Part Messages", RFC 4884, DOI 10.17487/RFC4884, April 2007, . [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., Aldrin, S., and M. Chen, "Detecting Multiprotocol Label Switched (MPLS) Data-Plane Failures", RFC 8029, DOI 10.17487/RFC8029, March 2017, . [RFC8335] Bonica, R., Thomas, R., Linkova, J., Lenart, C., and M. Boucadair, "PROBE: A Utility for Probing Interfaces", RFC 8335, DOI 10.17487/RFC8335, February 2018, . Authors' Addresses Xiao Min ZTE Corp. Nanjing China Phone: +86 25 88013062 Email: xiao.min2@zte.com.cn Greg Mirsky ZTE Corp. USA Email: gregimirsky@gmail.com Min, et al. Expires July 24, 2021 [Page 17] Internet-Draft Ping Enabled IOAM Capabilities January 2021 Lei Bo China Telecom Beijing China Phone: +86 10 50902903 Email: leibo@chinatelecom.cn Min, et al. Expires July 24, 2021 [Page 18]