ippm F. Brockners
Internet-Draft S. Bhandari
Intended status: Standards Track V. Govindan
Expires: September 12, 2019 C. Pignataro
H. Gredler
RtBrick Inc.
J. Leddy
S. Youell
T. Mizrahi
Huawei Network.IO Innovation Lab
P. Lapukhov
B. Gafni
A. Kfir
Mellanox Technologies, Inc.
M. Spiegel
Barefoot Networks
March 11, 2019

Geneve encapsulation for In-situ OAM Data


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 outlines how IOAM data fields are encapsulated in Geneve.

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 September 12, 2019.

Copyright Notice

Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

Table of Contents

1. Introduction

In-situ OAM (IOAM) records OAM information within the packet while the packet traverses a particular network domain. The term "in-situ" refers to the fact that the IOAM data fields are added to the data packets rather than is being sent within packets specifically dedicated to OAM. This document defines how IOAM data fields are transported as part of the Geneve [I-D.ietf-nvo3-geneve] encapsulation. The IOAM data fields are defined in [I-D.ietf-ippm-ioam-data].

2. Conventions

2.1. Requirement Language

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].

2.2. Abbreviations

Abbreviations used in this document:

In-situ Operations, Administration, and Maintenance
Operations, Administration, and Maintenance
Generic Network Virtualization Encapsulation

3. IOAM Data Field Encapsulation in Geneve

Geneve is defined in [I-D.ietf-nvo3-geneve]. IOAM data fields are carried in the Geneve header as a tunnel option, using a single Geneve Option Class TBD_IOAM. The different IOAM data fields defined in [I-D.ietf-ippm-ioam-data] are added as TLVs using that Geneve Option Class. In an administrative domain where IOAM is used, insertion of the IOAM header in Geneve is enabled at the Geneve tunnel endpoints, which also serve as IOAM encapsulating/decapsulating nodes by means of configuration.

 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
|Ver|  Opt Len  |O|C|    Rsvd.  |          Protocol Type        |  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Hdr
|        Virtual Network Identifier (VNI)       |    Reserved   |  |
|  Option Class  =  TBD_IOAM    |     Type      |R|R|R| Length  |  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  I
!                                                               |  O
!                                                               |  A
~                 IOAM Option and Data Space                    ~  M
|                                                               |  |
|                                                               |  |
|                                                               |
|                                                               |
|                 Payload + Padding (L2/L3/ESP/...)             |
|                                                               |
|                                                               |
|                                                               |

Figure 1: IOAM data encapsulation in Geneve

The Geneve header and fields are defined in [I-D.ietf-nvo3-geneve]. The Geneve Option Class value for use with IOAM is TBD_IOAM.

The fields related to the encapsulation of IOAM data fields in Geneve are defined as follows:

Option Class:
16-bit unsigned integer that determines the IOAM option class. The value is from the IANA registry setup for Geneve option classes as defined in [I-D.ietf-nvo3-geneve].
8-bit field defining the IOAM Option type, as defined in Section 7.2 of [I-D.ietf-ippm-ioam-data].
R (3 bits):
Option control flags reserved for future use. MUST be zero on transmission and ignored on receipt.
5-bit unsigned integer. Length of the IOAM HDR in 4-octet units.
IOAM Option and Data Space:
IOAM option header and data is present as defined by the Type field, and is defined in Section 4 of [I-D.ietf-ippm-ioam-data].

Multiple IOAM options MAY be included within the Geneve encapsulation. For example, if a Geneve encapsulation contains two IOAM options before a data payload, there would be two fields with TBD_IOAM Option Class each, differentiated by the Type field which specifies the type of the IOAM data included.

4. Considerations

This section summarizes a set of considerations on the overall approach taken for IOAM data encapsulation in Geneve, as well as deployment considerations.

4.1. Discussion of the encapsulation approach

This section is to support the working group discussion in selecting the most appropriate approach for encapsulating IOAM data fields in Geneve.

An encapsulation of IOAM data fields in Geneve should be friendly to an implementation in both hardware as well as software forwarders and support a wide range of deployment cases, including large networks that desire to leverage multiple IOAM data fields at the same time.

Concerns with the current encapsulation approach:

4.2. IOAM and the use of the Geneve O-bit

[I-D.ietf-nvo3-geneve] defines an "O bit" for OAM packets. Per [I-D.ietf-nvo3-geneve] the O bit indicates that the packet contains a control message instead of data payload. Packets that carry IOAM data fields in addition to regular data payload / customer traffic must not set the O bit. Packets that carry only IOAM data fields without any payload must set the O bit.

4.3. Transit devices

If IOAM is deployed in domains where UDP port numbers are not controlled and do not have a domain-wide meaning, such as on the global Internet, transit devices MUST NOT attempt to modify the IOAM data contained in the IOAM option class. In case UDP port numbers are not controlled there might be UDP packets, which leverage the UDP port number that Geneve utilizes, i.e. 6081, but the payload of these packets isn't Geneve. The scenario and associated reasoning is discussed in [RFC7605] which states that "it is important to recognize that any interpretation of port numbers -- except at the endpoints -- may be incorrect, because port numbers are meaningful only at the endpoints."

5. IANA Considerations

IANA is requested to allocate a Geneve "option class" numbers for IOAM:

              | Option Class  | Description | Reference     |
              | x             | TBD_IOAM    | This document |

6. Security Considerations

The security considerations of Geneve are discussed in [I-D.ietf-nvo3-geneve], and the security considerations of IOAM in general are discussed in [I-D.ietf-ippm-ioam-data].

IOAM is considered a "per domain" feature, where one or several operators decide on leveraging and configuring IOAM according to their needs. Still, operators need to properly secure the IOAM domain to avoid malicious configuration and use, which could include injecting malicious IOAM packets into a domain.

7. Acknowledgements

The authors would like to thank Eric Vyncke, Nalini Elkins, Srihari Raghavan, Ranganathan T S, Karthik Babu Harichandra Babu, Akshaya Nadahalli, Stefano Previdi, Hemant Singh, Erik Nordmark, LJ Wobker, and Andrew Yourtchenko for the comments and advice.

8. Normative References

[I-D.ietf-ippm-ioam-data] Brockners, F., Bhandari, S., Pignataro, C., Gredler, H., Leddy, J., Youell, S., Mizrahi, T., Mozes, D., Lapukhov, P., Chang, R., daniel.bernier@bell.ca, d. and J. Lemon, "Data Fields for In-situ OAM", Internet-Draft draft-ietf-ippm-ioam-data-04, October 2018.
[I-D.ietf-nvo3-geneve] Gross, J., Ganga, I. and T. Sridhar, "Geneve: Generic Network Virtualization Encapsulation", Internet-Draft draft-ietf-nvo3-geneve-09, February 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D. and P. Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, DOI 10.17487/RFC2784, March 2000.
[RFC3232] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by an On-line Database", RFC 3232, DOI 10.17487/RFC3232, January 2002.
[RFC7605] Touch, J., "Recommendations on Using Assigned Transport Port Numbers", BCP 165, RFC 7605, DOI 10.17487/RFC7605, August 2015.

Authors' Addresses

Frank Brockners Cisco Systems, Inc. Hansaallee 249, 3rd Floor DUESSELDORF, NORDRHEIN-WESTFALEN 40549 Germany EMail: fbrockne@cisco.com
Shwetha Bhandari Cisco Systems, Inc. Cessna Business Park, Sarjapura Marathalli Outer Ring Road Bangalore, KARNATAKA 560 087, India EMail: shwethab@cisco.com
Vengada Prasad Govindan Cisco Systems, Inc. EMail: venggovi@cisco.com
Carlos Pignataro Cisco Systems, Inc. 7200-11 Kit Creek Road Research Triangle Park, NC 27709 United States EMail: cpignata@cisco.com
Hannes Gredler RtBrick Inc. EMail: hannes@rtbrick.com
John Leddy Comcast EMail: John_Leddy@cable.comcast.com
Stephen Youell JP Morgan Chase 25 Bank Street London, E14 5JP United Kingdom EMail: stephen.youell@jpmorgan.com
Tal Mizrahi Huawei Network.IO Innovation Lab Israel EMail: tal.mizrahi.phd@gmail.com
Petr Lapukhov Facebook 1 Hacker Way Menlo Park, CA, 94025 US EMail: petr@fb.com
Barak Gafni Mellanox Technologies, Inc. 350 Oakmead Parkway, Suite 100 Sunnyvale, CA, 94085 U.S.A. EMail: gbarak@mellanox.com
Aviv Kfir Mellanox Technologies, Inc. 350 Oakmead Parkway, Suite 100 Sunnyvale, CA, 94085 U.S.A. EMail: avivk@mellanox.com
Mickey Spiegel Barefoot Networks 2185 Park Boulevard Palo Alto, CA, 94306 US EMail: mspiegel@barefootnetworks.com