ippm F. Brockners, Ed.Internet-Draft CiscoIntended status: Standards Track S. Bhandari, Ed.Expires: August 25, 2021 Thoughtspot T. Mizrahi, Ed. Huawei February 21, 2021Data Fields for In-situ OAMdraft-ietf-ippm-ioam-data-12Abstract In-situ Operations, Administration, and Maintenance (IOAM) records operational and telemetry information in the packet while the packet traverses a path between two points in the network. This document discusses the data fields and associated data types for in-situ OAM. In-situ OAM data fields can be encapsulated into a variety of protocols such as NSH, Segment Routing, Geneve, IPv6 (via extension header), or IPv4. In-situ OAM can be used to complement OAM mechanisms based on e.g. ICMP or other types of probe packets.Status of This Memo This Internet-Draft is submitted in full conformance with the provisions ofBCP 78 andBCP 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 athttps://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 August 25, 2021.Copyright Notice Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject toBCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date ofBrockners, et al. Expires August 25, 2021 [Page 1]
Internet-Draft In-situ OAM Data Fields February 2021 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 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.Table of Contents1. Introduction . . . . . . . . . . . . . . . . . . . . . . . .32. Contributors . . . . . . . . . . . . . . . . . . . . . . . .33. Conventions . . . . . . . . . . . . . . . . . . . . . . . . .44. Scope, Applicability, and Assumptions . . . . . . . . . . . .55. IOAM Data-Fields, Types, Nodes . . . . . . . . . . . . . . .65.1. IOAM Data-Fields and Option-Types . . . . . . . . . . . .65.2. IOAM-Domains and types of IOAM Nodes . . . . . . . . . .75.3. IOAM-Namespaces . . . . . . . . . . . . . . . . . . . . .85.4. IOAM Trace Option-Types . . . . . . . . . . . . . . . . .115.4.1. Pre-allocated and Incremental Trace Option-Types . .135.4.2. IOAM node data fields and associated formats . . . .175.4.2.1. Hop_Lim and node_id short format . . . . . . . .185.4.2.2. ingress_if_id and egress_if_id . . . . . . . . .185.4.2.3. timestamp seconds . . . . . . . . . . . . . . . .195.4.2.4. timestamp subseconds . . . . . . . . . . . . . .195.4.2.5. transit delay . . . . . . . . . . . . . . . . . .195.4.2.6. namespace specific data . . . . . . . . . . . . .205.4.2.7. queue depth . . . . . . . . . . . . . . . . . . .205.4.2.8. Checksum Complement . . . . . . . . . . . . . . .205.4.2.9. Hop_Lim and node_id wide . . . . . . . . . . . .215.4.2.10. ingress_if_id and egress_if_id wide . . . . . . .225.4.2.11. namespace specific data wide . . . . . . . . . .225.4.2.12. buffer occupancy . . . . . . . . . . . . . . . .225.4.2.13. Opaque State Snapshot . . . . . . . . . . . . . .235.4.3. Examples of IOAM node data . . . . . . . . . . . . .235.5. IOAM Proof of Transit Option-Type . . . . . . . . . . . .255.5.1. IOAM Proof of Transit Type 0 . . . . . . . . . . . .275.6. IOAM Edge-to-Edge Option-Type . . . . . . . . . . . . . .286. Timestamp Formats . . . . . . . . . . . . . . . . . . . . . .306.1. PTP Truncated Timestamp Format . . . . . . . . . . . . .306.2. NTP 64-bit Timestamp Format . . . . . . . . . . . . . . .326.3. POSIX-based Timestamp Format . . . . . . . . . . . . . .337. IOAM Data Export . . . . . . . . . . . . . . . . . . . . . .348. IANA Considerations . . . . . . . . . . . . . . . . . . . . .358.1. IOAM Option-Type Registry . . . . . . . . . . . . . . . .358.2. IOAM Trace-Type Registry . . . . . . . . . . . . . . . .368.3. IOAM Trace-Flags Registry . . . . . . . . . . . . . . . .368.4. IOAM POT-Type Registry . . . . . . . . . . . . . . . . .378.5. IOAM POT-Flags Registry . . . . . . . . . . . . . . . . .37Brockners, et al. Expires August 25, 2021 [Page 2]
Internet-Draft In-situ OAM Data Fields February 20218.6. IOAM E2E-Type Registry . . . . . . . . . . . . . . . . .378.7. IOAM Namespace-ID Registry . . . . . . . . . . . . . . .379. Management and Deployment Considerations . . . . . . . . . .3810. Security Considerations . . . . . . . . . . . . . . . . . . .3811. Acknowledgements . . . . . . . . . . . . . . . . . . . . . .4012. References . . . . . . . . . . . . . . . . . . . . . . . . .4012.1. Normative References . . . . . . . . . . . . . . . . . .4012.2. Informative References . . . . . . . . . . . . . . . . .41 Contributors' Addresses . . . . . . . . . . . . . . . . . . . . .43 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . .451. Introduction This document defines data fields for "in-situ" Operations, Administration, and Maintenance (IOAM). In-situ OAM records OAM information within the packet while the packet traverses a particular network domain. The term "in-situ" refers to the fact that the OAM data is added to the data packets rather than being sent within packets specifically dedicated to OAM. IOAM is to complement mechanisms such as Ping or Traceroute. In terms of "active" or "passive" OAM, "in-situ" OAM can be considered a hybrid OAM type. "In-situ" mechanisms do not require extra packets to be sent. IOAM adds information to the already available data packets and therefore cannot be considered passive. In terms of the classification given in [RFC7799] IOAM could be portrayed as Hybrid Type 1. IOAM mechanisms can be leveraged where mechanisms using e.g. ICMP do not apply or do not offer the desired results, such as proving that a certain traffic flow takes a pre-defined path, SLA verification for the live data traffic, detailed statistics on traffic distribution paths in networks that distribute traffic across multiple paths, or scenarios in which probe traffic is potentially handled differently from regular data traffic by the network devices. IOAM use cases and mechanisms have expanded as this document matured, resulting in additional flags and options that could trigger creation of additional packets dedicated to OAM. The term IOAM continues to be used for such mechanisms, in addition to the "in-situ" mechanisms that motivated this terminology.2. Contributors This document was the collective effort of several authors. The text and content were contributed by the editors and the co-authors listed below. The contact information of the co-authors appears at the end of this document. o Carlos PignataroBrockners, et al. Expires August 25, 2021 [Page 3]
Internet-Draft In-situ OAM Data Fields February 2021 o Mickey Spiegel o Barak Gafni o Jennifer Lemon o Hannes Gredler o John Leddy o Stephen Youell o David Mozes o Petr Lapukhov o Remy Chang o Daniel Bernier3. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. Abbreviations used in this document: E2E Edge to Edge Geneve: Generic Network Virtualization Encapsulation [I-D.ietf-nvo3-geneve] IOAM: In-situ Operations, Administration, and Maintenance MTU: Maximum Transmit Unit NSH: Network Service Header [RFC8300] OAM: Operations, Administration, and Maintenance PMTU Path MTU POT: Proof of Transit SFC: Service Function Chain SID: Segment IdentifierBrockners, et al. Expires August 25, 2021 [Page 4]
Internet-Draft In-situ OAM Data Fields February 2021 SR: Segment Routing VXLAN-GPE: Virtual eXtensible Local Area Network, Generic Protocol Extension [I-D.ietf-nvo3-vxlan-gpe]4. Scope, Applicability, and Assumptions IOAM deployment assumes a set of constraints, requirements, and guiding principles which are described in this section. Scope: This document defines the data fields and associated data types for in-situ OAM. The in-situ OAM data field can be encapsulated in a variety of protocols, including NSH, Segment Routing, Geneve, IPv6, or IPv4. Specification details for these different protocols are outside the scope of this document. It is expected that each such encapsulation will be defined in the relevant working group in the IETF. Deployment domain (or scope) of in-situ OAM deployment: IOAM is a network domain focused feature, with "network domain" being a set of network devices or entities within a single administration. For example, a network domain can include an enterprise campus using physical connections between devices or an overlay network using virtual connections / tunnels for connectivity between said devices. A network domain is defined by its perimeter or edge. Designers of protocol encapsulations for IOAM specify mechanisms to ensure that IOAM data stays within an IOAM domain. In addition, the operator of such a domain is expected to put provisions in place to ensure that IOAM data does not leak beyond the edge of an IOAM domain using,for example, packet filtering methods. The operator has to consider the potential operational impact of IOAM to mechanisms such as ECMP processing (e.g. load-balancing schemes based on packet length could be impacted by the increased packet size due to IOAM), path MTU (i.e. ensure that the MTU of all links within a domain is sufficiently large to support the increased packet size due to IOAM) and ICMP message handling (i.e. in case of IPv6, IOAM support for ICMPv6 Echo Request/Reply is desired which would translate into ICMPv6 extensions to enable IOAM-Data-Fields to be copied from an Echo Request message to an Echo Reply message). IOAM control points: IOAM-Data-Fields are added to or removed from the live user traffic by the devices which form the edge of a domain. Devices which form an IOAM-Domain can add, update or remove IOAM- Data-Fields. Edge devices of an IOAM-Domain can be hosts or network devices. Traffic-sets that IOAM is applied to: IOAM can be deployed on all or only on subsets of the live user traffic. Using IOAM on a selectedBrockners, et al. Expires August 25, 2021 [Page 5]
Internet-Draft In-situ OAM Data Fields February 2021 set of traffic (e.g., per interface, based on an access control list or flow specification defining a specific set of traffic, etc.) could be useful in deployments where the cost of processing IOAM-Data- Fields by encapsulating, transit, or decapsulating node(s) might be a concern from a performance or operational perspective. Thus limiting the amount of traffic IOAM is applied to could be beneficial in some deployments. Encapsulation independence: The definition of IOAM-Data-Fields is independent from the protocols the IOAM-Data-Fields are encapsulated into. IOAM-Data-Fields can be encapsulated into several encapsulating protocols. The specification of how IOAM-Data-Fields are encapsulated into "parent" protocols, like e.g., NSH or IPv6 is outside the scope of this document. Layering: If several encapsulation protocols (e.g., in case of tunneling) are stacked on top of each other, IOAM-Data-Fields could be present at multiple layers. The behavior follows the ships-in- the-night model, i.e. IOAM-Data-Fields in one layer are independent from IOAM-Data-Fields in another layer. Layering allows operators to instrument the protocol layer they want to measure. The different layers could, but do not have to, share the same IOAM encapsulation mechanisms. IOAM implementation: The definition of the IOAM-Data-Fields take the specifics of devices with hardware data planes and software data planes into account.5. IOAM Data-Fields, Types, Nodes This section details IOAM-related nomenclature and describes data types such as IOAM-Data-Fields, IOAM-Types, IOAM-Namespaces as well as the different types of IOAM nodes.5.1. IOAM Data-Fields and Option-Types An IOAM-Data-Field is a set of bits with a defined format and meaning, which can be stored at a certain place in a packet for the purpose of IOAM. To accommodate the different uses of IOAM, IOAM-Data-Fields fall into different categories. In IOAM these categories are referred to as IOAM-Option-Types. A common registry is maintained for IOAM-Option- Types, seeSection 8.1 for details. Corresponding to these IOAM- Option-Types, different IOAM-Data-Fields are defined. IOAM-Data- Fields can be encapsulated into a variety of protocols, such as NSH, Geneve, IPv6, etc. The definition of how IOAM-Data-Fields areBrockners, et al. Expires August 25, 2021 [Page 6]
Internet-Draft In-situ OAM Data Fields February 2021 encapsulated into other protocols is outside the scope of this document. This document defines four IOAM-Option-Types: o Pre-allocated Trace Option-Type o Incremental Trace Option-Type o Proof of Transit (POT) Option-Type o Edge-to-Edge (E2E) Option-Type5.2. IOAM-Domains and types of IOAM Nodes IOAM is expected to be deployed in a specific domain. The part of the network which employs IOAM is referred to as the "IOAM-Domain". One or more IOAM-Option-Types are added to a packet upon entering the IOAM-Domain and are removed from the packet when exiting the domain. Within the IOAM-Domain, the IOAM-Data-Fields MAY be updated by network nodes that the packet traverses. An IOAM-Domain consists of "IOAM encapsulating nodes", "IOAM decapsulating nodes" and "IOAM transit nodes". The role of a node (i.e. encapsulating, transit, decapsulating) is defined within an IOAM-Namespace (see below). A node can have different roles in different IOAM-Namespaces. A device which adds at least one IOAM-Option-Type to the packet is called the "IOAM encapsulating node", whereas a device which removes an IOAM-Option-Type is referred to as the "IOAM decapsulating node". Nodes within the domain which are aware of IOAM data and read and/or write or process the IOAM data are called "IOAM transit nodes". IOAM nodes which add or remove the IOAM-Data-Fields can also update the IOAM-Data-Fields at the same time. Or in other words, IOAM encapsulating or decapsulating nodes can also serve as IOAM transit nodes at the same time. Note that not every node in an IOAM domain needs to be an IOAM transit node. For example, a deployment might require that packets traverse a set of firewalls which support IOAM. In that case, only the set of firewall nodes would be IOAM transit nodes rather than all nodes. An "IOAM encapsulating node" incorporates one or more IOAM-Option- Types (from the list of IOAM-Types, seeSection 8.1) into packets that IOAM is enabled for. If IOAM is enabled for a selected subset of the traffic, the IOAM encapsulating node is responsible for applying the IOAM functionality to the selected subset. An "IOAM transit node" updates one or more of the IOAM-Data-Fields. If both the Pre-allocated and the Incremental Trace Option-Types areBrockners, et al. Expires August 25, 2021 [Page 7]
Internet-Draft In-situ OAM Data Fields February 2021 present in the packet, each IOAM transit node based on configuration and available implementation of IOAM populates IOAM trace data in either Pre-allocated or Incremental Trace Option-Type but not both. A transit node MUST ignore IOAM-Option-Types that it does not understand. A transit node MUST NOT add new IOAM-Option-Types to a packet, MUST NOT remove IOAM-Option-Types from a packet, and MUST NOT change the IOAM-Data-Fields of an IOAM Edge-to-Edge Option-Type. An "IOAM decapsulating node" removes IOAM-Option-Type(s) from packets. The role of an IOAM-encapsulating, IOAM-transit or IOAM-decapsulating node is always performed within a specific IOAM-Namespace. This means that an IOAM node which is e.g. an IOAM-decapsulating node for IOAM-Namespace "A" but not for IOAM-Namespace "B" will only remove the IOAM-Option-Types for IOAM-Namespace "A" from the packet. Note that this applies even for IOAM-Option-Types that the node does not understand, for example an IOAM-Option-Type other than the four described above, that is added in a future revision. An IOAM decapsulating node situated at the edge of an IOAM domain MUST remove all IOAM-Option-Types and associated encapsulation headers for all IOAM-Namespaces from the packet. IOAM-Namespaces allow for a namespace-specific definition and interpretation of IOAM-Data-Fields. An interface-id could for example point to a physical interface (e.g., to understand which physical interface of an aggregated link is used when receiving or transmitting a packet) whereas in another case it could refer to a logical interface (e.g., in case of tunnels). Please refer toSection 5.3 for details on IOAM-Namespaces.5.3. IOAM-Namespaces A subset or all of the IOAM-Option-Types and their corresponding IOAM-Data-Fields can be associated to an IOAM-Namespace. IOAM- Namespaces add further context to IOAM-Option-Types and associated IOAM-Data-Fields. Any IOAM-Namespace MUST interpret the IOAM-Option- Types and associated IOAM-Data-Fields per the definition in this document. IOAM-Namespaces group nodes to support different deployment approaches of IOAM (see a few example use-cases below) as well as resolve issues which can occur due to IOAM-Data-Fields not being globally unique (e.g. IOAM node identifiers do not have to be globally unique). IOAM-Data-Fields significance is always within a particular IOAM-Namespace. An IOAM-Namespace is identified by a 16-bit namespace identifier (Namespace-ID). IOAM-Namespace identifiers MUST be present andBrockners, et al. Expires August 25, 2021 [Page 8]
Internet-Draft In-situ OAM Data Fields February 2021 populated in all IOAM-Option-Types. The Namespace-ID value is divided into two sub-ranges: o An operator-assigned range from 0x0001 to 0x7FFF o An IANA-assigned range from 0x8000 to 0xFFFF The IANA-assigned range is intended to allow future extensions to have new and interoperable IOAM functionality, while the operator- assigned range is intended to be domain specific, and managed by the network operator. The Namespace-ID value of 0x0000 is the "Default- Namespace-ID". The Default-Namespace-ID indicates that no specific namespace is associated with the IOAM data fields in the packet. The Default-Namespace-ID MUST be supported by all nodes implementing IOAM. A use-case for the Default-Namespace-ID are deployments which do not leverage specific namespaces for some or all of their packets that carry IOAM data fields. Namespace identifiers allow devices which are IOAM capable to determine: o whether IOAM-Option-Type(s) need to be processed by a device: If the Namespace-ID contained in a packet does not match any Namespace-ID the node is configured to operate on, then the node MUST NOT change the contents of the IOAM-Data-Fields. o which IOAM-Option-Type needs to be processed/updated in case there are multiple IOAM-Option-Types present in the packet. Multiple IOAM-Option-Types can be present in a packet in case of overlapping IOAM-Domains or in case of a layered IOAM deployment. o whether IOAM-Option-Type(s) has to be removed from the packet, e.g. at a domain edge or domain boundary. IOAM-Namespaces support several different uses: o IOAM-Namespaces can be used by an operator to distinguish different operational domains. Devices at domain edges can filter on Namespace-IDs to provide for proper IOAM-Domain isolation. o IOAM-Namespaces provide additional context for IOAM-Data-Fields and thus ensure that IOAM-Data-Fields are unique and can be interpreted properly by management stations or network controllers. While, for example, the node identifier field (node_id, see below) does not need to be unique in a deployment (e.g. if an operator wishes to use different node identifiers for different IOAM layers, even within the same device; or node identifiers might not be unique for other organizational reasons,Brockners, et al. Expires August 25, 2021 [Page 9]
Internet-Draft In-situ OAM Data Fields February 2021 such as after a merger of two formerly separated organizations), the combination of node_id and Namespace-ID will always be unique. Similarly, IOAM-Namespaces can be used to define how certain IOAM- Data-Fields are interpreted: IOAM offers three different timestamp format options. The Namespace-ID can be used to determine the timestamp format. IOAM-Data-Fields (e.g. buffer occupancy) which do not have a unit associated are to be interpreted within the context of a IOAM-Namespace. o IOAM-Namespaces can be used to identify different sets of devices (e.g., different types of devices) in a deployment: If an operator desires to insert different IOAM-Data-Fields based on the device, the devices could be grouped into multiple IOAM-Namespaces. This could be due to the fact that the IOAM feature set differs between different sets of devices, or it could be for reasons of optimized space usage in the packet header. It could also stem from hardware or operational limitations on the size of the trace data that can be added and processed, preventing collection of a full trace for a flow. * Assigning different IOAM Namespace-IDs to different sets of nodes or network partitions and using the Namespace-ID as a selector at the IOAM encapsulating node, a full trace for a flow could be collected and constructed via partial traces in different packets of the same flow. Example: An operator could choose to group the devices of a domain into two IOAM- Namespaces, in a way that on average, only every second hop would be recorded by any device. To retrieve a full view of the deployment, the captured IOAM-Data-Fields of the two IOAM- Namespaces need to be correlated. * Assigning different IOAM Namespace-IDs to different sets of nodes or network partitions and using a separate instance of an IOAM-Option-Type for each Namespace-ID, a full trace for a flow could be collected and constructed via partial traces from each IOAM-Option-Type in each of the packets in the flow. Example: An operator could choose to group the devices of a domain into two IOAM-Namespaces, in a way that each IOAM-Namespace is represented by one of two IOAM-Option-Types in the packet. Each node would record data only for the IOAM-Namespace that it belongs to, ignoring the other IOAM-Option-Type with a IOAM- Namespace to which it doesn't belong. To retrieve a full view of the deployment, the captured IOAM-Data-Fields of the two IOAM-Namespaces need to be correlated.Brockners, et al. Expires August 25, 2021 [Page 10]
Internet-Draft In-situ OAM Data Fields February 20215.4. IOAM Trace Option-Types "IOAM tracing data" is expected to be collected at every IOAM transit node that a packet traverses to ensure visibility into the entire path a packet takes within an IOAM-Domain. I.e., in a typical deployment all nodes in an IOAM-Domain would participate in IOAM and thus be IOAM transit nodes, IOAM encapsulating or IOAM decapsulating nodes. If not all nodes within a domain support IOAM functionality as defined in this document, IOAM tracing information (i.e., node data, see below) will only be collected on those nodes which support IOAM functionality as defined in this document. Nodes which do not support IOAM functionality as defined in this document will forward the packet without any changes to the IOAM-Data-Fields. The maximum number of hops and the minimum path MTU of the IOAM domain is assumed to be known. An overflow indicator (O-bit) is defined as one of the ways to deal with situations where the PMTU was underestimated, i.e. where the number of hops which are IOAM capable exceeds the available space in the packet. To optimize hardware and software implementations, IOAM tracing is defined as two separate options. Any deployment MAY choose to configure and support one or both of the following options. Pre-allocated Trace-Option: This trace option is defined as a container of node data fields (see below) with pre-allocated space for each node to populate its information. This option is useful for implementations where it is efficient to allocate the space once and index into the array to populate the data during transit (e.g., software forwarders often fall into this class). The IOAM encapsulating node allocates space for Pre-allocated Trace Option- Type in the packet and sets corresponding fields in this IOAM- Option-Type. The IOAM encapsulating node allocates an array which is used to store operational data retrieved from every node while the packet traverses the domain. IOAM transit nodes update the content of the array, and possibly update the checksums of outer headers. A pointer which is part of the IOAM trace data, points to the next empty slot in the array. An IOAM transit node that updates the content of the pre-allocated option also updates the value of the pointer, which specifies where the next IOAM transit node fills in its data. The "node data list" array (see below) in the packet is populated iteratively as the packet traverses the network, starting with the last entry of the array, i.e., "node data list [n]" is the first entry to be populated, "node data list [n-1]" is the second one, etc. Incremental Trace-Option: This trace option is defined as a container of node data fields where each node allocates and pushes its node data immediately following the option header. This typeBrockners, et al. Expires August 25, 2021 [Page 11]
Internet-Draft In-situ OAM Data Fields February 2021 of trace recording is useful for some of the hardware implementations as it eliminates the need for the transit network elements to read the full array in the option and allows for arbitrarily long packets as the MTU allows. The IOAM encapsulating node allocates space for the Incremental Trace Option-Type. Based on operational state and configuration, the IOAM encapsulating node sets the fields in the Option-Type that control what IOAM-Data-Fields have to be collected and how large the node data list can grow. IOAM transit nodes push their node data to the node data list, decrease the remaining length available to subsequent nodes and adjust the lengths and possibly checksums in outer headers. A particular implementation of IOAM MAY choose to support only one of the two trace option types. In the event that both options are utilized at the same time, the Incremental Trace-Option MUST be placed before the Pre-allocated Trace-Option. Deployments which mix devices with either the Incremental Trace-Option or the Pre-allocated Trace-Option could result in both Option-Types being present in a packet. Given that the operator knows which equipment is deployed in a particular IOAM, the operator will decide by means of configuration which type(s) of trace options will be used for a particular domain. Every node data entry holds information for a particular IOAM transit node that is traversed by a packet. The IOAM decapsulating node removes the IOAM-Option-Type(s) and processes and/or exports the associated data. Like all IOAM-Data-Fields, the IOAM-Data-Fields of the IOAM-Trace-Option-Types are defined in the context of an IOAM- Namespace. IOAM tracing can collect the following types of information: o Identification of the IOAM node. An IOAM node identifier can match to a device identifier or a particular control point or subsystem within a device. o Identification of the interface that a packet was received on, i.e. ingress interface. o Identification of the interface that a packet was sent out on, i.e. egress interface. o Time of day when the packet was processed by the node as well as the transit delay. Different definitions of processing time are feasible and expected, though it is important that all devices of an in-situ OAM domain follow the same definition.Brockners, et al. Expires August 25, 2021 [Page 12]
Internet-Draft In-situ OAM Data Fields February 2021 o Generic data: Format-free information where syntax and semantic of the information is defined by the operator in a specific deployment. For a specific IOAM-Namespace, all IOAM nodes have to interpret the generic data the same way. Examples for generic IOAM data include geo-location information (location of the node at the time the packet was processed), buffer queue fill level or cache fill level at the time the packet was processed, or even a battery charge level. o Information to detect whether IOAM trace data was added at every hop or whether certain hops in the domain weren't IOAM transit nodes.5.4.1. Pre-allocated and Incremental Trace Option-Types The IOAM Pre-allocated Trace-Option and the IOAM Incremental Trace- Option have similar formats. Except where noted below, the internal formats and fields of the two trace options are identical. Both Trace-Options consist of a fixed size "trace option header" and a variable data space to store gathered data, the "node data list". An IOAM transit node (that is not an IOAM encapsulating node or IOAM decapsulating node) MUST NOT modify any of the fields in the fixed size "trace option header", other than "flags" and "RemainingLen", i.e. an IOAM transit node MUST NOT modify the Namespace-ID, NodeLen, IOAM-Trace-Type, or Reserved fields.Brockners, et al. Expires August 25, 2021 [Page 13]
Internet-Draft In-situ OAM Data Fields February 2021 Pre-allocated and incremental trace option headers: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID |NodeLen | Flags | RemainingLen| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The trace option data MUST be 4-octet aligned: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ | | | | node data list [0] | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ D | | a | node data list [1] | t | | a +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ... ~ S +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ p | | a | node data list [n-1] | c | | e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | node data list [n] | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ Namespace-ID: 16-bit identifier of an IOAM-Namespace. The Namespace-ID value of 0x0000 is defined as the "Default-Namespace- ID" (seeSection 5.3) and MUST be known to all the nodes implementing IOAM. For any other Namespace-ID value that does not match any Namespace-ID the node is configured to operate on, the node MUST NOT change the contents of the IOAM-Data-Fields. NodeLen: 5-bit unsigned integer. This field specifies the length of data added by each node in multiples of 4-octets, excluding the length of the "Opaque State Snapshot" field. If IOAM-Trace-Type bit 22 is not set, then NodeLen specifies the actual length added by each node. If IOAM-Trace-Type bit 22 isBrockners, et al. Expires August 25, 2021 [Page 14]
Internet-Draft In-situ OAM Data Fields February 2021 set, then the actual length added by a node would be (NodeLen + length of the "Opaque State Snapshot" field) in 4 octet units. For example, if 3 IOAM-Trace-Type bits are set and none of them are wide, then NodeLen would be 3. If 3 IOAM-Trace-Type bits are set and 2 of them are wide, then NodeLen would be 5. An IOAM encapsulating node MUST set NodeLen. A node receiving an IOAM Pre-allocated or Incremental Trace-Option relies on the NodeLen value, or it can ignore the NodeLen value and calculate the node length from the IOAM-Trace-Type bits (see below). Flags 4-bit field. Flags are allocated by IANA, as specified inSection 8.3. This document allocates a single flag as follows: Bit 0 "Overflow" (O-bit) (most significant bit). If there are not enough octets left to record node data, the network element MUST NOT add any fields and MUST set the overflow "O-bit" to "1" in the IOAM-Trace-Option header. This is useful for transit nodes to ignore further processing of the option. RemainingLen: 7-bit unsigned integer. This field specifies the data space in multiples of 4-octets remaining for recording the node data, before the node data list is considered to have overflowed. Given that the sender knows the path MTU (PMTU), the sender MAY set the initial value of RemainingLen according to the number of node data bytes allowed before exceeding the MTU. Subsequent nodes can carry out a simple comparison between RemainingLen and NodeLen, along with the length of the "Opaque State Snapshot" if applicable, to determine whether or not data can be added by this node. When node data is added, the node MUST decrease RemainingLen by the amount of data added. In the pre-allocated trace option, RemainingLen is used to derive the offset in data space to record the node data element. Specifically, the recording of the node data element would start from RemainingLen - NodeLen - sizeof(opaque snapshot) in 4 octet units. If RemainingLen in a pre-allocated trace option exceeds the length of the option, as specified in the preceding header, then the node MUST NOT add any fields. IOAM-Trace-Type: A 24-bit identifier which specifies which data types are used in this node data list. The IOAM-Trace-Type value is a bit field. The following bits are defined in this document, with details on each bit described in theSection 5.4.2. The order of packing the data fields in eachBrockners, et al. Expires August 25, 2021 [Page 15]
Internet-Draft In-situ OAM Data Fields February 2021 node data element follows the bit order of the IOAM-Trace-Type field, as follows: Bit 0 (Most significant bit) When set, indicates presence of Hop_Lim and node_id (short format) in the node data. Bit 1 When set, indicates presence of ingress_if_id and egress_if_id (short format) in the node data. Bit 2 When set, indicates presence of timestamp seconds in the node data. Bit 3 When set, indicates presence of timestamp subseconds in the node data. Bit 4 When set, indicates presence of transit delay in the node data. Bit 5 When set, indicates presence of IOAM-Namespace specific data (short format) in the node data. Bit 6 When set, indicates presence of queue depth in the node data. Bit 7 When set, indicates presence of the Checksum Complement node data. Bit 8 When set, indicates presence of Hop_Lim and node_id in wide format in the node data. Bit 9 When set, indicates presence of ingress_if_id and egress_if_id in wide format in the node data. Bit 10 When set, indicates presence of IOAM-Namespace specific data in wide format in the node data. Bit 11 When set, indicates presence of buffer occupancy in the node data. Bit 12-21 Undefined. An IOAM encapsulating node MUST set the value of each of these bits to 0. If an IOAM transit node receives a packet with one or more of these bits set to 1, it MUST either: 1. Add corresponding node data filled with the reserved value 0xFFFFFFFF, after the node data fields for the IOAM-Trace-Type bits defined above, such that theBrockners, et al. Expires August 25, 2021 [Page 16]
Internet-Draft In-situ OAM Data Fields February 2021 total node data added by this node in units of 4-octets is equal to NodeLen, or 2. Not add any node data fields to the packet, even for the IOAM-Trace-Type bits defined above. Bit 22 When set, indicates presence of variable length Opaque State Snapshot field. Bit 23 Reserved: MUST be set to zero upon transmission and ignored upon receipt.Section 5.4.2 describes the IOAM-Data-Types and their formats. Within an IOAM-Domain possible combinations of these bits making the IOAM-Trace-Type can be restricted by configuration knobs. Reserved: 8-bits. An IOAM encapsulating node MUST set the value to zero upon transmission. IOAM transit nodes MUST ignore the received value. Node data List [n]: Variable-length field. This is a list of node data elements where the content of each node data element is determined by the IOAM-Trace-Type. The order of packing the data fields in each node data element follows the bit order of the IOAM-Trace-Type field. Each node MUST prepend its node data element in front of the node data elements that it received, such that the transmitted node data list begins with this node's data element as the first populated element in the list. The last node data element in this list is the node data of the first IOAM capable node in the path. Populating the node data list in this way ensures that the order of node data list is the same for incremental and pre-allocated trace options. In the pre-allocated trace option, the index contained in RemainingLen identifies the offset for current active node data to be populated.5.4.2. IOAM node data fields and associated formats All the IOAM-Data-Fields MUST be 4-octet aligned. If a node which is supposed to update an IOAM-Data-Field is not capable of populating the value of a field set in the IOAM-Trace-Type, the field value MUST be set to 0xFFFFFFFF for 4-octet fields or 0xFFFFFFFFFFFFFFFF for 8-octet fields, indicating that the value is not populated, except when explicitly specified in the field description below. Some IOAM-Data-Fields defined below, such as interface identifiers or IOAM-Namespace specific data, are defined in both "short format" as well as "wide format". Their use is not exclusive. A deployment could choose to leverage both. For example, ingress_if_id_(shortBrockners, et al. Expires August 25, 2021 [Page 17]
Internet-Draft In-situ OAM Data Fields February 2021 format) could be an identifier for the physical interface, whereas ingress_if_id_(wide format) could be an identifier for a logical sub- interface of that physical interface. Data fields and associated data types for each of the IOAM-Data- Fields are specified in the following sections.5.4.2.1. Hop_Lim and node_id short format The "Hop_Lim and node_id short format" field is a 4-octet field that is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Hop_Lim: 1-octet unsigned integer. It is set to the Hop Limit value in the packet at the node that records this data. Hop Limit information is used to identify the location of the node in the communication path. This is copied from the lower layer, e.g., TTL value in IPv4 header or hop limit field from IPv6 header of the packet when the packet is ready for transmission. The semantics of the Hop_Lim field depend on the lower layer protocol that IOAM is encapsulated into, and therefore its specific semantics are outside the scope of this memo. The value of this field MUST be set to 0xff when the lower level does not have a TTL/Hop limit equivalent field. node_id: 3-octet unsigned integer. Node identifier field to uniquely identify a node within the IOAM-Namespace and associated IOAM-Domain. The procedure to allocate, manage and map the node_ids is beyond the scope of this document.5.4.2.2. ingress_if_id and egress_if_id The "ingress_if_id and egress_if_id" field is a 4-octet field that is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ingress_if_id | egress_if_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ingress_if_id: 2-octet unsigned integer. Interface identifier to record the ingress interface the packet was received on.Brockners, et al. Expires August 25, 2021 [Page 18]
Internet-Draft In-situ OAM Data Fields February 2021 egress_if_id: 2-octet unsigned integer. Interface identifier to record the egress interface the packet is forwarded out of. Note that due to the fact that IOAM uses its own IOAM-Namespaces for IOAM-Data-Fields, data fields like interface identifiers can be used in a flexible way to represent system resources that are associated with ingressing or egressing packets, i.e. ingress_if_id could represent a physical interface, a virtual or logical interface, or even a queue.5.4.2.3. timestamp seconds The "timestamp seconds" field is a 4-octet unsigned integer field. Absolute timestamp in seconds that specifies the time at which the packet was received by the node. This field has three possible formats; based on either PTP [IEEE1588v2], NTP [RFC5905], or POSIX [POSIX]. The three timestamp formats are specified inSection 6. In all three cases, the Timestamp Seconds field contains the 32 most significant bits of the timestamp format that is specified inSection 6. If a node is not capable of populating this field, it assigns the value 0xFFFFFFFF. Note that this is a legitimate value that is valid for 1 second in approximately 136 years; the analyzer has to correlate several packets or compare the timestamp value to its own time-of-day in order to detect the error indication.5.4.2.4. timestamp subseconds The "timestamp subseconds" field is a 4-octet unsigned integer field. Absolute timestamp in subseconds that specifies the time at which the packet was received by the node. This field has three possible formats; based on either PTP [IEEE1588v2], NTP [RFC5905], or POSIX [POSIX]. The three timestamp formats are specified inSection 6. In all three cases, the Timestamp Subseconds field contains the 32 least significant bits of the timestamp format that is specified inSection 6. If a node is not capable of populating this field, it assigns the value 0xFFFFFFFF. Note that this is a legitimate value in the NTP format, valid for approximately 233 picoseconds in every second. If the NTP format is used the analyzer has to correlate several packets in order to detect the error indication.5.4.2.5. transit delay The "transit delay" field is a 4-octet unsigned integer in the range 0 to 2^31-1. It is the time in nanoseconds the packet spent in the transit node. This can serve as an indication of the queuing delay at the node. If the transit delay exceeds 2^31-1 nanoseconds then the top bit 'O' is set to indicate overflow and value set to 0x80000000. When this field is part of the data field but a nodeBrockners, et al. Expires August 25, 2021 [Page 19]
Internet-Draft In-situ OAM Data Fields February 2021 populating the field is not able to fill it, the field position in the field MUST be filled with value 0xFFFFFFFF to mean not populated. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |O| transit delay | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+5.4.2.6. namespace specific data The "namespace specific data" field is a 4-octet field which can be used by the node to add IOAM-Namespace specific data. This represents a "free-format" 4-octet bit field with its semantics defined in the context of a specific IOAM-Namespace. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | namespace specific data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+5.4.2.7. queue depth The "queue depth" field is a 4-octet unsigned integer field. This field indicates the current length of the egress interface queue of the interface from where the packet is forwarded out. The queue depth is expressed as the current amount of memory buffers used by the queue (a packet could consume one or more memory buffers, depending on its size). 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | queue depth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+5.4.2.8. Checksum Complement The "Checksum Complement" field is a 4-octet node data which contains a 4-octet Checksum Complement field. The Checksum Complement is useful when IOAM is transported over encapsulations that make use of a UDP transport, such as VXLAN-GPE or Geneve. Without the Checksum Complement, nodes adding IOAM node data update the UDP Checksum field following the recommendation of the encapsulation protocols. When the Checksum Complement is present, an IOAM encapsulating node or IOAM transit node adding node data MUST carry out one of the following two alternatives in order to maintain the correctness of the UDP Checksum value: 1. Recompute the UDP Checksum field.Brockners, et al. Expires August 25, 2021 [Page 20]
Internet-Draft In-situ OAM Data Fields February 2021 2. Use the Checksum Complement to make a checksum-neutral update in the UDP payload; the Checksum Complement is assigned a value that complements the rest of the node data fields that were added by the current node, causing the existing UDP Checksum field to remain correct. IOAM decapsulating nodes MUST recompute the UDP Checksum field, since they do not know whether previous hops modified the UDP Checksum field or the Checksum Complement field. Checksum Complement fields are used in a similar manner in [RFC7820] and [RFC7821]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Checksum Complement | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+5.4.2.9. Hop_Lim and node_id wide The "Hop_Lim and node_id wide" field is an 8-octet field defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ node_id (contd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Hop_Lim: 1-octet unsigned integer. It is set to the Hop Limit value in the packet at the node that records this data. Hop Limit information is used to identify the location of the node in the communication path. This is copied from the lower layer for e.g. TTL value in IPv4 header or hop limit field from IPv6 header of the packet. The semantics of the Hop_Lim field depend on the lower layer protocol that IOAM is encapsulated into, and therefore its specific semantics are outside the scope of this memo. The value of this field MUST be set to 0xff when the lower level does not have a TTL/Hop limit equivalent field. node_id: 7-octet unsigned integer. Node identifier field to uniquely identify a node within the IOAM-Namespace and associated IOAM-Domain. The procedure to allocate, manage and map the node_ids is beyond the scope of this document.Brockners, et al. Expires August 25, 2021 [Page 21]
Internet-Draft In-situ OAM Data Fields February 20215.4.2.10. ingress_if_id and egress_if_id wide The "ingress_if_id and egress_if_id wide" field is an 8-octet field which is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ingress_if_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | egress_if_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ingress_if_id: 4-octet unsigned integer. Interface identifier to record the ingress interface the packet was received on. egress_if_id: 4-octet unsigned integer. Interface identifier to record the egress interface the packet is forwarded out of.5.4.2.11. namespace specific data wide The "namespace specific data wide" field is an 8-octet field which can be used by the node to add IOAM-Namespace specific data. This represents a "free-format" 8-octet bit field with its semantics defined in the context of a specific IOAM-Namespace. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | namespace specific data ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ namespace specific data (contd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+5.4.2.12. buffer occupancy The "buffer occupancy" field is a 4-octet unsigned integer field. This field indicates the current status of the occupancy of the common buffer pool used by a set of queues. The units of this field are implementation specific. Hence, the units are interpreted within the context of an IOAM-Namespace and/or node-id if used. The authors acknowledge that in some operational cases there is a need for the units to be consistent across a packet path through the network, hence it is RECOMMENDED for implementations to use standard units such as Bytes. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | buffer occupancy | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+Brockners, et al. Expires August 25, 2021 [Page 22]
Internet-Draft In-situ OAM Data Fields February 20215.4.2.13. Opaque State Snapshot The "Opaque State Snapshot" is a variable length field and follows the fixed length IOAM-Data-Fields defined above. It allows the network element to store an arbitrary state in the node data field, without a pre-defined schema. The schema is to be defined within the context of an IOAM-Namespace. The schema needs to be made known to the analyzer by some out-of-band mechanism. The specification of this mechanism is beyond the scope of this document. A 24-bit "Schema Id" field, interpreted within the context of an IOAM- Namespace, indicates which particular schema is used, and has to be configured on the network element by the operator. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length | Schema ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Opaque data | ~ ~ . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Length: 1-octet unsigned integer. It is the length in multiples of 4-octets of the Opaque data field that follows Schema Id. Schema ID: 3-octet unsigned integer identifying the schema of Opaque data. Opaque data: Variable length field. This field is interpreted as specified by the schema identified by the Schema ID. When this field is part of the data field but a node populating the field has no opaque state data to report, the Length MUST be set to 0 and the Schema ID MUST be set to 0xFFFFFF to mean no schema.5.4.3. Examples of IOAM node data An entry in the "node data list" array can have different formats, following the needs of the deployment. Some deployments might only be interested in recording the node identifiers, whereas others might be interested in recording node identifier and timestamp. The section provides example entries of the "node data list".Brockners, et al. Expires August 25, 2021 [Page 23]
Internet-Draft In-situ OAM Data Fields February 2021 0xD40000: IOAM-Trace-Type is 0xD40000 (0b110101000000000000000000) then the format of node data is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ingress_if_id | egress_if_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | timestamp subseconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | namespace specific data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0xC00000: IOAM-Trace-Type is 0xC00000 (0b110000000000000000000000) then the format is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ingress_if_id | egress_if_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0x900000: IOAM-Trace-Type is 0x900000 (0b100100000000000000000000) then the format is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | timestamp subseconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0x840000: IOAM-Trace-Type is 0x840000 (0b100001000000000000000000) then the format is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | namespace specific data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+Brockners, et al. Expires August 25, 2021 [Page 24]
Internet-Draft In-situ OAM Data Fields February 2021 0x940000: IOAM-Trace-Type is 0x940000 (0b100101000000000000000000) then the format is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | timestamp subseconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | namespace specific data | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0x308002: IOAM-Trace-Type is 0x308002 (0b001100001000000000000010) then the format is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | timestamp seconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | timestamp subseconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Hop_Lim | node_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | node_id(contd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length | Schema Id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Opaque data | ~ ~ . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+5.5. IOAM Proof of Transit Option-Type IOAM Proof of Transit Option-Type is to support path or service function chain [RFC7665] verification use cases. Proof-of-transit leverages mechanisms like Shamir's Secret Sharing Schema (SSSS) [SSS]. For further information on Proof-of-transit, please refer to [I-D.ietf-sfc-proof-of-transit]. While details on how the IOAM data for the Proof-of-transit option is processed at IOAM encapsulating, decapsulating and transit nodes are outside the scope of the document, all of these approaches share the need to uniquely identify a packet as well as iteratively operate on a set of information thatBrockners, et al. Expires August 25, 2021 [Page 25]
Internet-Draft In-situ OAM Data Fields February 2021 is handed from node to node. Correspondingly, two pieces of information are added as IOAM-Data-Fields to the packet: o Random: Unique identifier for the packet (e.g., 64-bits allow for the unique identification of 2^64 packets). o Cumulative: Information which is handed from node to node and updated by every node according to a verification algorithm. The IOAM Proof-of-Transit Option-Type consist of a fixed size "IOAM proof of transit option header" and "IOAM proof of transit option data fields": IOAM proof of transit option header: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID |IOAM POT Type | IOAM POT flags| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IOAM proof of transit Option-Type IOAM-Data-Fields MUST be 4-octet aligned: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | POT Option data field determined by IOAM-POT-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Namespace-ID: 16-bit identifier of an IOAM-Namespace. The Namespace-ID value of 0x0000 is defined as the "Default-Namespace- ID" (seeSection 5.3) and MUST be known to all the nodes implementing IOAM. For any other Namespace-ID value that does not match any Namespace-ID the node is configured to operate on, the node MUST NOT change the contents of the IOAM-Data-Fields. IOAM POT Type: 8-bit identifier of a particular POT variant that specifies the POT data that is included. This document defines POT Type 0: 0: POT data is a 16 Octet field as described below. If a node receives an IOAM POT Type value that it does not understand, the node MUST NOT change the contents of the IOAM- Data-Fields.Brockners, et al. Expires August 25, 2021 [Page 26]
Internet-Draft In-situ OAM Data Fields February 2021 IOAM POT flags: 8-bit. Following flags are defined: Bit 0 "Profile-to-use" (P-bit) (most significant bit). For IOAM POT types that use a maximum of two profiles to drive computation, indicates which POT-profile is used. The two profiles are numbered 0, 1. Bit 1-7 Reserved: MUST be set to zero upon transmission and ignored upon receipt. POT Option data: Variable-length field. The type of which is determined by the IOAM-POT-Type.5.5.1. IOAM Proof of Transit Type 0 IOAM proof of transit option of IOAM POT Type 0: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID |IOAM POT Type=0|P|R R R R R R R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ | Random | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ P | Random(contd) | O +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ T | Cumulative | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Cumulative (contd) | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ Namespace-ID: 16-bit identifier of an IOAM-Namespace. The Namespace-ID value of 0x0000 is defined as the "Default-Namespace- ID" (seeSection 5.3) and MUST be known to all the nodes implementing IOAM. For any other Namespace-ID value that does not match any Namespace-ID the node is configured to operate on, the node MUST NOT change the contents of the IOAM-Data-Fields. IOAM POT Type: 8-bit identifier of a particular POT variant that specifies the POT data that is included. This section defines the POT data when the IOAM POT Type is set to the value 0. P bit: 1-bit. "Profile-to-use" (P-bit) (most significant bit). Indicates which POT-profile is used to generate the Cumulative. Any node participating in POT will have a maximum of 2 profiles configured that drive the computation of cumulative. The twoBrockners, et al. Expires August 25, 2021 [Page 27]
Internet-Draft In-situ OAM Data Fields February 2021 profiles are numbered 0, 1. This bit conveys whether profile 0 or profile 1 is used to compute the Cumulative. R (7 bits): 7-bit IOAM POT flags for future use. MUST be set to zero upon transmission and ignored upon receipt. Random: 64-bit Per packet Random number. Cumulative: 64-bit Cumulative that is updated at specific nodes by processing per packet Random number field and configured parameters. Note: Larger or smaller sizes of "Random" and "Cumulative" data are feasible and could be required for certain deployments (e.g. in case of space constraints in the encapsulation protocols used). Future documents could introduce different sizes of data for "proof of transit".5.6. IOAM Edge-to-Edge Option-Type The IOAM Edge-to-Edge Option-Type is to carry data that is added by the IOAM encapsulating node and interpreted by IOAM decapsulating node. The IOAM transit nodes MAY process the data but MUST NOT modify it. The IOAM Edge-to-Edge Option-Type consist of a fixed size "IOAM Edge- to-Edge Option-Type header" and "IOAM Edge-to-Edge Option-Type data fields": IOAM Edge-to-Edge Option-Type header: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | IOAM-E2E-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IOAM Edge-to-Edge Option-Type IOAM-Data-Fields MUST be 4-octet aligned: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | E2E Option data field determined by IOAM-E2E-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+Brockners, et al. Expires August 25, 2021 [Page 28]
Internet-Draft In-situ OAM Data Fields February 2021 Namespace-ID: 16-bit identifier of an IOAM-Namespace. The Namespace-ID value of 0x0000 is defined as the "Default-Namespace- ID" (seeSection 5.3) and MUST be known to all the nodes implementing IOAM. For any other Namespace-ID value that does not match any Namespace-ID the node is configured to operate on, then the node MUST NOT change the contents of the IOAM-Data-Fields. IOAM-E2E-Type: A 16-bit identifier which specifies which data types are used in the E2E option data. The IOAM-E2E-Type value is a bit field. The order of packing the E2E option data field elements follows the bit order of the IOAM-E2E-Type field, as follows: Bit 0 (Most significant bit) When set indicates presence of a 64-bit sequence number added to a specific "packet group" which is used to detect packet loss, packet reordering, or packet duplication within the group. The "packet group" is deployment dependent and defined at the IOAM encapsulating node e.g. by n-tuple based classification of packets. Bit 1 When set indicates presence of a 32-bit sequence number added to a specific "packet group" which is used to detect packet loss, packet reordering, or packet duplication within that group. The "packet group" is deployment dependent and defined at the IOAM encapsulating node e.g. by n-tuple based classification of packets. Bit 2 When set indicates presence of timestamp seconds, representing the time at which the packet entered the IOAM domain. Within the IOAM encapsulating node, the time that the timestamp is retrieved can depend on the implementation. Some possibilities are: 1) the time at which the packet was received by the node, 2) the time at which the packet was transmitted by the node, 3) when a tunnel encapsulation is used, the point at which the packet is encapsulated into the tunnel. Each implementation has to document when the E2E timestamp that is going to be put in the packet is retrieved. This 4-octet field has three possible formats; based on either PTP [IEEE1588v2], NTP [RFC5905], or POSIX [POSIX]. The three timestamp formats are specified inSection 6. In all three cases, the Timestamp Seconds field contains the 32 most significant bits of the timestamp format that is specified inSection 6. If a node is not capable of populating this field, it assigns the value 0xFFFFFFFF. Note that this is a legitimate value that is valid for 1 second in approximately 136 years; the analyzer has toBrockners, et al. Expires August 25, 2021 [Page 29]
Internet-Draft In-situ OAM Data Fields February 2021 correlate several packets or compare the timestamp value to its own time-of-day in order to detect the error indication. Bit 3 When set indicates presence of timestamp subseconds, representing the time at which the packet entered the IOAM domain. This 4-octet field has three possible formats; based on either PTP [IEEE1588v2], NTP [RFC5905], or POSIX [POSIX]. The three timestamp formats are specified inSection 6. In all three cases, the Timestamp Subseconds field contains the 32 least significant bits of the timestamp format that is specified inSection 6. If a node is not capable of populating this field, it assigns the value 0xFFFFFFFF. Note that this is a legitimate value in the NTP format, valid for approximately 233 picoseconds in every second. If the NTP format is used the analyzer has to correlate several packets in order to detect the error indication. Bit 4-15 Undefined. An IOAM encapsulating node MUST set the value of these bits to zero upon transmission and ignore upon receipt. E2E Option data: Variable-length field. The type of which is determined by the IOAM-E2E-Type.6. Timestamp Formats The IOAM-Data-Fields include a timestamp field which is represented in one of three possible timestamp formats. It is assumed that the management plane is responsible for determining which timestamp format is used.6.1. PTP Truncated Timestamp Format The Precision Time Protocol (PTP) [IEEE1588v2] uses an 80-bit timestamp format. The truncated timestamp format is a 64-bit field, which is the 64 least significant bits of the 80-bit PTP timestamp. The PTP truncated format is specified inSection 4.3 of [RFC8877], and the details are presented below for the sake of completeness.Brockners, et al. Expires August 25, 2021 [Page 30]
Internet-Draft In-situ OAM Data Fields February 2021 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Seconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nanoseconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: PTP [IEEE1588v2] Truncated Timestamp Format Timestamp field format: Seconds: specifies the integer portion of the number of seconds since the epoch. + Size: 32 bits. + Units: seconds. Nanoseconds: specifies the fractional portion of the number of seconds since the epoch. + Size: 32 bits. + Units: nanoseconds. The value of this field is in the range 0 to (10^9)-1. Epoch: The PTP [IEEE1588v2] epoch is 1 January 1970 00:00:00 TAI, which is 31 December 1969 23:59:51.999918 UTC. Resolution: The resolution is 1 nanosecond. Wraparound: This time format wraps around every 2^32 seconds, which is roughly 136 years. The next wraparound will occur in the year 2106. Synchronization Aspects: It is assumed that nodes that run this protocol are synchronized among themselves. Nodes MAY be synchronized to a global reference time. Note that if PTP [IEEE1588v2] is used for synchronization, the timestamp MAY be derived from the PTP-synchronized clock,Brockners, et al. Expires August 25, 2021 [Page 31]
Internet-Draft In-situ OAM Data Fields February 2021 allowing the timestamp to be measured with respect to the clock of an PTP Grandmaster clock. The PTP truncated timestamp format is not affected by leap seconds.6.2. NTP 64-bit Timestamp Format The Network Time Protocol (NTP) [RFC5905] timestamp format is 64 bits long. This format is specified inSection 4.2.1 of [RFC8877], and the details are presented below for the sake of completeness. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Seconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Fraction | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: NTP [RFC5905] 64-bit Timestamp Format Timestamp field format: Seconds: specifies the integer portion of the number of seconds since the epoch. + Size: 32 bits. + Units: seconds. Fraction: specifies the fractional portion of the number of seconds since the epoch. + Size: 32 bits. + Units: the unit is 2^(-32) seconds, which is roughly equal to 233 picoseconds. Epoch: The epoch is 1 January 1900 at 00:00 UTC. Resolution: The resolution is 2^(-32) seconds.Brockners, et al. Expires August 25, 2021 [Page 32]
Internet-Draft In-situ OAM Data Fields February 2021 Wraparound: This time format wraps around every 2^32 seconds, which is roughly 136 years. The next wraparound will occur in the year 2036. Synchronization Aspects: Nodes that use this timestamp format will typically be synchronized to UTC using NTP [RFC5905]. Thus, the timestamp MAY be derived from the NTP-synchronized clock, allowing the timestamp to be measured with respect to the clock of an NTP server. The NTP timestamp format is affected by leap seconds; it represents the number of seconds since the epoch minus the number of leap seconds that have occurred since the epoch. The value of a timestamp during or slightly after a leap second could be temporarily inaccurate.6.3. POSIX-based Timestamp Format This timestamp format is based on the POSIX time format [POSIX]. The detailed specification of the timestamp format used in this document is presented below. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Seconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Microseconds | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: POSIX-based Timestamp Format Timestamp field format: Seconds: specifies the integer portion of the number of seconds since the epoch. + Size: 32 bits. + Units: seconds. Microseconds: specifies the fractional portion of the number of seconds since the epoch. + Size: 32 bits.Brockners, et al. Expires August 25, 2021 [Page 33]
Internet-Draft In-situ OAM Data Fields February 2021 + Units: the unit is microseconds. The value of this field is in the range 0 to (10^6)-1. Epoch: The epoch is 1 January 1970 00:00:00 TAI, which is 31 December 1969 23:59:51.999918 UTC. Resolution: The resolution is 1 microsecond. Wraparound: This time format wraps around every 2^32 seconds, which is roughly 136 years. The next wraparound will occur in the year 2106. Synchronization Aspects: It is assumed that nodes that use this timestamp format run the Linux operating system, and hence use the POSIX time. In some cases nodes MAY be synchronized to UTC using a synchronization mechanism that is outside the scope of this document, such as NTP [RFC5905]. Thus, the timestamp MAY be derived from the NTP- synchronized clock, allowing the timestamp to be measured with respect to the clock of an NTP server. The POSIX-based timestamp format is affected by leap seconds; it represents the number of seconds since the epoch minus the number of leap seconds that have occurred since the epoch. The value of a timestamp during or slightly after a leap second could be temporarily inaccurate.7. IOAM Data Export IOAM nodes collect information for packets traversing a domain that supports IOAM. IOAM decapsulating nodes as well as IOAM transit nodes can choose to retrieve IOAM information from the packet, process the information further and export the information using e.g., IPFIX. The mechanisms and associated data formats for exporting IOAM data is outside the scope of this document. Raw data export of IOAM data using IPFIX is discussed in [I-D.spiegel-ippm-ioam-rawexport].Brockners, et al. Expires August 25, 2021 [Page 34]
Internet-Draft In-situ OAM Data Fields February 20218. IANA Considerations This document requests the following IANA Actions. IANA is requested to define a registry group named "In-Situ OAM (IOAM) Protocol Parameters". This group will include the following registries: IOAM Option-Type IOAM Trace-Type IOAM Trace-Flags IOAM POT-Type IOAM POT-Flags IOAM E2E-Type IOAM Namespace-ID New registries in this group can be created via RFC Required process as per [RFC8126]. The subsequent sub-sections detail the registries herein contained.8.1. IOAM Option-Type Registry This registry defines 128 code points for the IOAM Option-Type field for identifying IOAM Option-Types as explained inSection 5. The following code points are defined in this draft: 0 IOAM Pre-allocated Trace Option-Type 1 IOAM Incremental Trace Option-Type 2 IOAM POT Option-Type 3 IOAM E2E Option-Type 4 - 127 are available for assignment via RFC Required process as per [RFC8126].Brockners, et al. Expires August 25, 2021 [Page 35]
Internet-Draft In-situ OAM Data Fields February 20218.2. IOAM Trace-Type Registry This registry defines code point for each bit in the 24-bit IOAM- Trace-Type field for Pre-allocated trace option and Incremental trace option defined inSection 5.4. The meaning of Bits 0 - 11 for trace type are defined in this document in Paragraph 5 ofSection 5.4.1: Bit 0 hop_Lim and node_id in short format Bit 1 ingress_if_id and egress_if_id in short format Bit 2 timestamp seconds Bit 3 timestamp subseconds Bit 4 transit delay Bit 5 namespace specific data in short format Bit 6 queue depth Bit 7 checksum complement Bit 8 hop_Lim and node_id in wide format Bit 9 ingress_if_id and egress_if_id in wide format Bit 10 namespace specific data in wide format Bit 11 buffer occupancy Bit 22 variable length Opaque State Snapshot Bit 23 reserved The meaning for Bits 12 - 21 are available for assignment via RFC Required process as per [RFC8126].8.3. IOAM Trace-Flags Registry This registry defines code points for each bit in the 4 bit flags for the Pre-allocated trace option and for the Incremental trace option defined inSection 5.4. The meaning of Bit 0 (the most significant bit) for trace flags is defined in this document in Paragraph 3 ofSection 5.4.1: Bit 0 "Overflow" (O-bit)Brockners, et al. Expires August 25, 2021 [Page 36]
Internet-Draft In-situ OAM Data Fields February 2021 Bit 1 - 3 are available for assignment via RFC Required process as per [RFC8126].8.4. IOAM POT-Type Registry This registry defines 256 code points to define IOAM POT Type for IOAM proof of transit optionSection 5.5. The code point value 0 is defined in this document: 0: 16 Octet POT data 1 - 255 are available for assignment via RFC Required process as per [RFC8126].8.5. IOAM POT-Flags Registry This registry defines code points for each bit in the 8 bit flags for IOAM POT option defined inSection 5.5. The meaning of Bit 0 for IOAM POT flags is defined in this document inSection 5.5: Bit 0 "Profile-to-use" (P-bit) The meaning for Bits 1 - 7 are available for assignment via RFC Required process as per [RFC8126].8.6. IOAM E2E-Type Registry This registry defines code points for each bit in the 16 bit IOAM- E2E-Type field for IOAM E2E optionSection 5.6. The meaning of Bit 0 - 3 are defined in this document: Bit 0 64-bit sequence number Bit 1 32-bit sequence number Bit 2 timestamp seconds Bit 3 timestamp subseconds The meaning of Bits 4 - 15 are available for assignment via RFC Required process as per [RFC8126].8.7. IOAM Namespace-ID Registry IANA is requested to set up an "IOAM Namespace-ID Registry", containing 16-bit values. The meaning of Bit 0 is defined in this document. IANA is requested to reserve the values 0x0001 to 0x7FFF for private use (managed by operators), as specified inSection 5.3Brockners, et al. Expires August 25, 2021 [Page 37]
Internet-Draft In-situ OAM Data Fields February 2021 of the current document. Registry entries for the values 0x8000 to 0xFFFF are to be assigned via the "Expert Review" policy defined in [RFC8126]. Upon a new allocation request, the responsible AD will appoint a designated expert, who will review the allocation request. The expert will post the request on the mailing list of the IPPM working group in the IETF (ippm@ietf.org), and possibly on other relevant mailing lists, to allow for community feedback. Based on the review, the expert will either approve or deny the request. The intention is that any allocation will be accompanied by a published RFC. But in order to allow for the allocation of values prior to the RFC being approved for publication, the designated expert can approve allocations once it seems clear that an RFC will be published. 0: default namespace (known to all IOAM nodes) 0x0001 - 0x7FFF: reserved for private use 0x8000 - 0xFFFF: unassigned9. Management and Deployment Considerations This document defines the structure and use of IOAM data fields. This document does not define the encapsulation of IOAM data fields into different protocols. Management and deployment aspects for IOAM have to be considered within the context of the protocol IOAM data fields are encapsulated into and as such, are out of scope for this document. For a discussion of IOAM deployment, please also refer to [I-D.brockners-opsawg-ioam-deployment], which outlines a framework for IOAM deployment and provides best current practices.10. Security Considerations As discussed in [RFC7276], a successful attack on an OAM protocol in general, and specifically on IOAM, can prevent the detection of failures or anomalies, or create a false illusion of nonexistent ones. In particular, these threats are applicable by compromising the integrity of IOAM data, either by maliciously modifying IOAM options in transit, or by injecting packets with maliciously generated IOAM options The Proof of Transit Option-Type (SectionSection 5.5) is used for verifying the path of data packets. The security considerations of POT are further discussed in [I-D.ietf-sfc-proof-of-transit]. From a confidentiality perspective, although IOAM options do not contain user data, they can be used for network reconnaissance, allowing attackers to collect information about network paths, performance, queue states, buffer occupancy and other information.Brockners, et al. Expires August 25, 2021 [Page 38]
Internet-Draft In-situ OAM Data Fields February 2021 Moreover, if IOAM data leaks from the IOAM domain it could enable reconnaissance beyond the scope of the IOAM domain. Note that in case IOAM is used in "Direct Exporting" mode [I-D.ioamteam-ippm-ioam-direct-export], the IOAM related trace information would not be available in the customer data packets, but would trigger export of packet related IOAM information at every node, thus restricting the potential threat to the management plane and mitigating the leakage threat. IOAM data exporting and the way it is secured is outside the scope of this document. IOAM can be used as a means for implementing Denial of Service (DoS) attacks, or for amplifying them. For example, a malicious attacker can add an IOAM header to packets in order to consume the resources of network devices that take part in IOAM or entities that receive, collect or analyze the IOAM data. Another example is a packet length attack, in which an attacker pushes headers associated with IOAM Option-Types into data packets, causing these packets to be increased beyond the MTU size, resulting in fragmentation or in packet drops. Since IOAM options can include timestamps, if network devices use synchronization protocols then any attack on the time protocol [RFC7384] can compromise the integrity of the timestamp-related data fields. At the management plane, attacks can be set up by misconfiguring or by maliciously configuring IOAM-enabled nodes in a way that enables other attacks. Thus, IOAM configuration has to be secured in a way that authenticates authorized users and verifies the integrity of configuration procedures. Solutions to ensure the integrity of IOAM data fields are outside the scope of this document. [I-D.brockners-ippm-ioam-data-integrity] discusses several methods to ensure the integrity of IOAM data fields for those deployments that have a need to protect the integrity of IOAM data fields. The current document does not define a specific IOAM encapsulation. It has to be noted that some IOAM encapsulation types can introduce specific security considerations. A specification that defines an IOAM encapsulation is expected to address the respective encapsulation-specific security considerations. Notably, in most cases IOAM is expected to be deployed in specific network domains, thus confining the potential attack vectors to within the network domain. A limited administrative domain provides the operator with the means to select, monitor, and control the access of all the network devices, making these devices trusted by the operator. Indeed, in order to limit the scope of threatsBrockners, et al. Expires August 25, 2021 [Page 39]
Internet-Draft In-situ OAM Data Fields February 2021 mentioned above to within the current network domain the network operator is expected to enforce policies that prevent IOAM traffic from leaking outside of the IOAM domain, and prevent IOAM data from outside the domain to be processed and used within the domain. The security considerations of a system that deploys IOAM, much like any system, has to be reviewed on a per-deployment-scenario basis, based on a systems-specific threat analysis, which can lead to specific security solutions that are beyond the scope of the current document. Specifically, in an IOAM deployment that is not confined to a single LAN, but spans multiple inter-connected sites (for example, using an overlay network), the inter-site links can be secured (e.g., by IPsec) in order to avoid external threats. IOAM deployment considerations, including approaches to mitigate the above discussed threads and potential attacks are outside the scope of this document. IOAM deployment considerations are discussed in [I-D.brockners-opsawg-ioam-deployment].11. Acknowledgements The authors would like to thank Eric Vyncke, Nalini Elkins, Srihari Raghavan, Ranganathan T S, Karthik Babu Harichandra Babu, Akshaya Nadahalli, LJ Wobker, Erik Nordmark, Vengada Prasad Govindan, Andrew Yourtchenko, Aviv Kfir, Tianran Zhou, Zhenbin (Robin) and Greg Mirsky for the comments and advice. This document leverages and builds on top of several concepts described in [I-D.kitamura-ipv6-record-route]. The authors would like to acknowledge the work done by the author Hiroshi Kitamura and people involved in writing it. The authors would like to gracefully acknowledge useful review and insightful comments received from Joe Clarke, Al Morton, Tom Herbert, Haoyu Song, Mickey Spiegel and Barak Gafni.12. References12.1. Normative References [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, <http://standards.ieee.org/findstds/standard/1588-2008.html>.Brockners, et al. Expires August 25, 2021 [Page 40]
Internet-Draft In-situ OAM Data Fields February 2021 [POSIX] Institute of Electrical and Electronics Engineers, "IEEE Std 1003.1-2008 (Revision of IEEE Std 1003.1-2004) - IEEE Standard for Information Technology - Portable Operating System Interface (POSIX(R))", IEEE Std 1003.1-2008, 2008, <https://standards.ieee.org/findstds/standard/1003.1-2008.html>. [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>. [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, <https://www.rfc-editor.org/info/rfc5905>. [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, <https://www.rfc-editor.org/info/rfc8126>.12.2. Informative References [I-D.brockners-ippm-ioam-data-integrity] Brockners, F., Bhandari, S., and T. Mizrahi, "Integrity of In-situ OAM Data Fields",draft-brockners-ippm-ioam-data-integrity-00 (work in progress), January 2021. [I-D.brockners-opsawg-ioam-deployment] Brockners, F., Bhandari, S., and d. daniel.bernier@bell.ca, "In-situ OAM Deployment",draft-brockners-opsawg-ioam-deployment-02 (work in progress), September 2020. [I-D.ietf-nvo3-geneve] Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic Network Virtualization Encapsulation",draft-ietf-nvo3-geneve-16 (work in progress), March 2020. [I-D.ietf-nvo3-vxlan-gpe] Maino, F., Kreeger, L., and U. Elzur, "Generic Protocol Extension for VXLAN (VXLAN-GPE)",draft-ietf-nvo3-vxlan-gpe-10 (work in progress), July 2020.Brockners, et al. Expires August 25, 2021 [Page 41]
Internet-Draft In-situ OAM Data Fields February 2021 [I-D.ietf-sfc-proof-of-transit] Brockners, F., Bhandari, S., Mizrahi, T., Dara, S., and S. Youell, "Proof of Transit",draft-ietf-sfc-proof-of-transit-08 (work in progress), November 2020. [I-D.ioamteam-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-ioamteam-ippm-ioam-direct-export-00 (work in progress), October 2019. [I-D.kitamura-ipv6-record-route] Kitamura, H., "Record Route for IPv6 (PR6) Hop-by-Hop Option Extension",draft-kitamura-ipv6-record-route-00 (work in progress), November 2000. [I-D.spiegel-ippm-ioam-rawexport] Spiegel, M., Brockners, F., Bhandari, S., and R. Sivakolundu, "In-situ OAM raw data export with IPFIX",draft-spiegel-ippm-ioam-rawexport-04 (work in progress), November 2020. [RFC7276] Mizrahi, T., Sprecher, N., Bellagamba, E., and Y. Weingarten, "An Overview of Operations, Administration, and Maintenance (OAM) Tools",RFC 7276, DOI 10.17487/RFC7276, June 2014, <https://www.rfc-editor.org/info/rfc7276>. [RFC7384] Mizrahi, T., "Security Requirements of Time Protocols in Packet Switched Networks",RFC 7384, DOI 10.17487/RFC7384, October 2014, <https://www.rfc-editor.org/info/rfc7384>. [RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function Chaining (SFC) Architecture",RFC 7665, DOI 10.17487/RFC7665, October 2015, <https://www.rfc-editor.org/info/rfc7665>. [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>. [RFC7820] Mizrahi, T., "UDP Checksum Complement in the One-Way Active Measurement Protocol (OWAMP) and Two-Way Active Measurement Protocol (TWAMP)",RFC 7820, DOI 10.17487/RFC7820, March 2016, <https://www.rfc-editor.org/info/rfc7820>.Brockners, et al. Expires August 25, 2021 [Page 42]
Internet-Draft In-situ OAM Data Fields February 2021 [RFC7821] Mizrahi, T., "UDP Checksum Complement in the Network Time Protocol (NTP)",RFC 7821, DOI 10.17487/RFC7821, March 2016, <https://www.rfc-editor.org/info/rfc7821>. [RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed., "Network Service Header (NSH)",RFC 8300, DOI 10.17487/RFC8300, January 2018, <https://www.rfc-editor.org/info/rfc8300>. [RFC8877] Mizrahi, T., Fabini, J., and A. Morton, "Guidelines for Defining Packet Timestamps",RFC 8877, DOI 10.17487/RFC8877, September 2020, <https://www.rfc-editor.org/info/rfc8877>. [SSS] "Shamir's Secret Sharing", <https://en.wikipedia.org/wiki/Shamir%27s_Secret_Sharing>.Contributors' Addresses Carlos Pignataro Cisco Systems, Inc. 7200-11 Kit Creek Road Research Triangle Park, NC 27709 United States Email: cpignata@cisco.com Mickey Spiegel Barefoot Networks, an Intel company 4750 Patrick Henry Drive Santa Clara, CA 95054 US Email: mickey.spiegel@intel.com Barak Gafni Nvidia 350 Oakmead Parkway, Suite 100 Sunnyvale, CA 94085 U.S.A. Email: gbarak@nvidia.com Jennifer Lemon BroadcomBrockners, et al. Expires August 25, 2021 [Page 43]
Internet-Draft In-situ OAM Data Fields February 2021 270 Innovation Drive San Jose, CA 95134 US Email: jennifer.lemon@broadcom.com Hannes Gredler RtBrick Inc. Email: hannes@rtbrick.com John Leddy United States Email: john@leddy.net Stephen Youell JP Morgan Chase 25 Bank Street London E14 5JP United Kingdom Email: stephen.youell@jpmorgan.com David Mozes Email: mosesster@gmail.com Petr Lapukhov Facebook 1 Hacker Way Menlo Park, CA 94025 US Email: petr@fb.com Remy Chang Barefoot Networks 4750 Patrick Henry Drive Santa Clara, CA 95054 USBrockners, et al. Expires August 25, 2021 [Page 44]
Internet-Draft In-situ OAM Data Fields February 2021 Email: remy@barefootnetworks.com Daniel Bernier Bell Canada Canada Email: daniel.bernier@bell.caAuthors' Addresses Frank Brockners (editor) Cisco Systems, Inc. Hansaallee 249, 3rd Floor DUESSELDORF, NORDRHEIN-WESTFALEN 40549 Germany Email: fbrockne@cisco.com Shwetha Bhandari (editor) Thoughtspot 3rd Floor, Indiqube Orion, 24th Main Rd, Garden Layout, HSR Layout Bangalore, KARNATAKA 560 102 India Email: shwetha.bhandari@thoughtspot.com Tal Mizrahi (editor) Huawei 8-2 Matam Haifa 3190501 Israel Email: tal.mizrahi.phd@gmail.comBrockners, et al. Expires August 25, 2021 [Page 45]Datatracker
draft-ietf-ippm-ioam-data-12
This is an older version of an Internet-Draft that was ultimately published asRFC 9197.
| Document | Document type | This is an older version of an Internet-Draft that was ultimately published asRFC 9197. | |
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| Authors | Frank Brockners,Shwetha Bhandari,Tal Mizrahi | ||
| Replaces | draft-brockners-inband-oam-data draft-ippm-ioam-data | ||
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| Additional resources | Mailing list discussion |