ippm F. Brockners
Internet-Draft S. Bhandari
Intended status: Standards Track V. Govindan
Expires: September 4, 2018 C. Pignataro
H. Gredler
RtBrick Inc.
J. Leddy
S. Youell
T. Mizrahi
P. Lapukhov
B. Gafni
A. Kfir
Mellanox Technologies, Inc.
M. Spiegel
Barefoot Networks
March 3, 2018

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.

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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.

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. and d. daniel.bernier@bell.ca, "Data Fields for In-situ OAM", Internet-Draft draft-ietf-ippm-ioam-data-01, October 2017.
[I-D.ietf-nvo3-geneve] Gross, J., Ganga, I. and T. Sridhar, "Geneve: Generic Network Virtualization Encapsulation", Internet-Draft draft-ietf-nvo3-geneve-05, September 2017.
[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.

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 Marvell 6 Hamada St. Yokneam, 20692 Israel EMail: talmi@marvell.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