Internet-Draft Ping Enabled IOAM Capabilities July 2021
Min, et al. Expires 26 January 2022 [Page]
Workgroup:
IPPM Working Group
Internet-Draft:
draft-ietf-ippm-ioam-conf-state-00
Published:
Intended Status:
Standards Track
Expires:
Authors:
X. Min
ZTE Corp.
G. Mirsky
ZTE Corp.
L. Bo
China Telecom

Echo Request/Reply for Enabled In-situ OAM Capabilities

Abstract

This document describes an extension to the echo request/reply mechanisms used in IPv6, MPLS, SFC and BIER 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 26 January 2022.

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 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.

  • 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.
  • 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, SFC and BIER 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, SFC and BIER environments:

  • [RFC4443] ("Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification"), [RFC4884] ("Extended ICMP to Support Multi-Part Messages") and [RFC8335] ("PROBE: A Utility for Probing Interfaces")
  • [RFC8029] ("Detecting Multiprotocol Label Switched (MPLS) Data-Plane Failures")
  • [I-D.ietf-sfc-multi-layer-oam] ("Active OAM for Service Function Chains in Networks")
  • [I-D.ietf-bier-ping] ("BIER Ping and Trace")

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

BIER: Bit Index Explicit Replication

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

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.

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.

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 pre-allocated 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.

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 incremental 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.

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.

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.

  • 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.

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.

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 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:

  • IOAM SoR Capability
  • 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

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].

  • 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.
  • 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.

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", Work in Progress, Internet-Draft, draft-ietf-ippm-ioam-data-14, , <https://www.ietf.org/archive/id/draft-ietf-ippm-ioam-data-14.txt>.
[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", Work in Progress, Internet-Draft, draft-ietf-ippm-ioam-direct-export-05, , <https://www.ietf.org/archive/id/draft-ietf-ippm-ioam-direct-export-05.txt>.
[IEEE1588v2]
IEEE, "IEEE Std 1588-2008 - IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", IEEE Std 1588-2008, , <http://standards.ieee.org/findstds/standard/1588-2008.html>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <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, , <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, , <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.

8.2. Informative References

[I-D.ietf-bier-ping]
Kumar, N., Pignataro, C., Akiya, N., Zheng, L., Chen, M., and G. Mirsky, "BIER Ping and Trace", Work in Progress, Internet-Draft, draft-ietf-bier-ping-07, , <https://www.ietf.org/archive/id/draft-ietf-bier-ping-07.txt>.
[I-D.ietf-sfc-multi-layer-oam]
Mirsky, G., Meng, W., Khasnabish, B., and C. Wang, "Active OAM for Service Function Chaining", Work in Progress, Internet-Draft, draft-ietf-sfc-multi-layer-oam-13, , <https://www.ietf.org/archive/id/draft-ietf-sfc-multi-layer-oam-13.txt>.
[RFC4302]
Kent, S., "IP Authentication Header", RFC 4302, DOI 10.17487/RFC4302, , <https://www.rfc-editor.org/info/rfc4302>.
[RFC4303]
Kent, S., "IP Encapsulating Security Payload (ESP)", RFC 4303, DOI 10.17487/RFC4303, , <https://www.rfc-editor.org/info/rfc4303>.
[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, , <https://www.rfc-editor.org/info/rfc4443>.
[RFC4884]
Bonica, R., Gan, D., Tappan, D., and C. Pignataro, "Extended ICMP to Support Multi-Part Messages", RFC 4884, DOI 10.17487/RFC4884, , <https://www.rfc-editor.org/info/rfc4884>.
[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, , <https://www.rfc-editor.org/info/rfc8029>.
[RFC8335]
Bonica, R., Thomas, R., Linkova, J., Lenart, C., and M. Boucadair, "PROBE: A Utility for Probing Interfaces", RFC 8335, DOI 10.17487/RFC8335, , <https://www.rfc-editor.org/info/rfc8335>.

Authors' Addresses

Xiao Min
ZTE Corp.
Nanjing
China
Greg Mirsky
ZTE Corp.
United States of America
Lei Bo
China Telecom
Beijing
China