Internet DRAFT - draft-brockners-ippm-ioam-vxlan-gpe
draft-brockners-ippm-ioam-vxlan-gpe
ippm F. Brockners, Ed.
Internet-Draft Cisco
Intended status: Informational S. Bhandari
Expires: 2 September 2024 Thoughtspot
V. Govindan
Cisco
C. Pignataro, Ed.
NC State University
H. Gredler
RtBrick Inc.
J. Leddy
S. Youell
JPMC
T. Mizrahi, Ed.
Huawei
A. Kfir
B. Gafni
Nvidia
P. Lapukhov
Facebook
M. Spiegel
Barefoot Networks, an Intel company
1 March 2024
VXLAN-GPE Encapsulation for In Situ OAM (IOAM) Data
draft-brockners-ippm-ioam-vxlan-gpe-05
Abstract
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 VXLAN-GPE.
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/.
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This Internet-Draft will expire on 2 September 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3
3. IOAM Data Field Encapsulation in VXLAN-GPE . . . . . . . . . 3
4. Considerations . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Discussion of the Encapsulation Approach . . . . . . . . 5
4.2. IOAM and the Use of the VXLAN-GPE O-bit . . . . . . . . . 6
4.3. Transit Devices . . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5.1. VXLAN-GPE Next Protocol Value . . . . . . . . . . . . . . 6
5.2. LISP-GPE Next Protocol Value . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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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 being sent within packets specifically dedicated
to OAM. This document defines how IOAM data fields are transported
as part of the VXLAN-GPE [I-D.ietf-nvo3-vxlan-gpe] encapsulation.
The IOAM data fields are defined in [RFC9197]. An implementation of
IOAM which leverages VXLAN-GPE to carry the IOAM data is available
from the FD.io open-source software project [FD.io].
2. Conventions
2.1. Requirements 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:
IOAM:
In Situ Operations, Administration, and Maintenance
OAM:
Operations, Administration, and Maintenance
VXLAN-GPE:
Virtual eXtensible Local Area Network, Generic Protocol Extension
3. IOAM Data Field Encapsulation in VXLAN-GPE
VXLAN-GPE is defined in [I-D.ietf-nvo3-vxlan-gpe]. IOAM data fields
are carried in VXLAN-GPE using a next protocol value of TBD_IOAM. An
IOAM header is added containing the different IOAM data fields
defined in [RFC9197]. In an administrative domain where IOAM is
used, insertion of the IOAM header in VXLAN-GPE is enabled at the
VXLAN-GPE tunnel endpoints, which also serve as IOAM encapsulating/
decapsulating nodes by means of configuration.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer Ethernet Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer IP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer UDP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+
|R|R|Ver|I|P|R|O| Reserved | NP=TBD_IOAM | VXL
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ AN-
| VXLAN Network Identifier (VNI) | Reserved | GPE
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
| IOAM-Type | IOAM Len | Reserved | Next Protocol | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ I
| | O
| | A
~ IOAM Option and Optional Data Space ~ M
| | |
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
| |
| |
| Payload + Padding (L2/L3/ESP/...) |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: IOAM Data Encapsulation in VXLAN-GPE
The VXLAN-GPE header and fields are defined in
[I-D.ietf-nvo3-vxlan-gpe]. The VXLAN-GPE Next Protocol value for
IOAM is TBD_IOAM.
The IOAM related fields in VXLAN-GPE are defined as follows:
IOAM-Type:
8-bit field defining the IOAM Option type, as defined in
Section 7.2 of [RFC9197].
IOAM Len:
8-bit unsigned integer. Length of the IOAM protocol message shim,
expressed in 4-octet units not including the first 4 octets.
Reserved:
8-bit reserved field MUST be set to zero upon transmission and
ignored upon receipt.
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Next Protocol:
8-bit unsigned integer that determines the type of header
following IOAM protocol. The value is from the IANA registry
setup for VXLAN-GPE Next Protocol defined in
[I-D.ietf-nvo3-vxlan-gpe].
IOAM Option and Optional Data Space:
IOAM option header and data is present as specified by the IOAM-
Type field and is defined in Section 4 of [RFC9197].
Multiple IOAM options MAY be included within the VXLAN-GPE
encapsulation. For example, if a VXLAN-GPE encapsulation contains
two IOAM options before a data payload, the Next Protocol field of
the first IOAM option will contain the value of TBD_IOAM, while the
Next Protocol field of the second IOAM option will contain the VXLAN-
GPE "Next Protocol" number indicating the type of the data payload.
4. Considerations
This section summarizes a set of considerations on the overall
approach taken for IOAM data encapsulation in VXLAN-GPE, 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
VXLAN-GPE.
An encapsulation of IOAM data fields in VXLAN-GPE should be friendly
to an implementation in both hardware as well as software forwarders.
Hardware forwarders benefit from an encapsulation that minimizes
iterative lookups of fields within the packet: Any operation which
looks up the value of a field within the packet, based on which
another lookup is performed, consumes additional gates and time in an
implementation - both of which are desired to be kept to a minimum.
This means that flat TLV structures are to be preferred over nested
TLV structures. IOAM data fields are grouped into three option
categories: trace, proof-of-transit, and edge-to-edge. Each of these
three options defines a TLV structure. A hardware-friendly
encapsulation approach avoids grouping these three option categories
into yet another TLV structure and would rather carry the options as
a serial sequence.
Two approaches for encapsulating IOAM data fields in VXLAN-GPE could
be considered:
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1. Use a single GPE protocol type for all IOAM types: IOAM would
receive a single GPE protocol type code point. A "sub-type"
field would then specify what IOAM options type (e.g., trace,
proof-of-transit, and edge-to-edge) is carried.
2. Use one GPE protocol type per IOAM options type: Each IOAM data
field option (e.g., trace, proof-of-transit, and edge-to-edge)
would be specified by its own "next protocol", i.e. each IOAM
options type becomes its own GPE protocol type with a dedicated
code point. This implies that in case additional IOAM option
types would be added in the future, additional GPE protocol type
code points would need to be allocated.
The first option has been chosen here. Multiple back-to-back IOAM
options can be encoded as a succession of IOAM headers, with the same
single GPE protocol type appearing as the next protocol before each
IOAM header, but different sub-types within each IOAM header.
4.2. IOAM and the Use of the VXLAN-GPE O-bit
[I-D.ietf-nvo3-vxlan-gpe] defines an "O bit" for OAM packets. Per
[I-D.ietf-nvo3-vxlan-gpe] the O bit indicates that the packet
contains an OAM 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 header following the VXLAN-GPE header. In
case UDP port numbers are not controlled there might be UDP packets
specifying the same UDP port number that VXLAN-GPE utilizes, i.e.
4790, but with a payload that is not VXLAN-GPE. 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
5.1. VXLAN-GPE Next Protocol Value
IANA is requested to allocate a value in the VXLAN-GPE "Next
Protocol" registry for IOAM, which is defined in
[I-D.ietf-nvo3-vxlan-gpe].
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+---------------+-------------+---------------+
| Next Protocol | Description | Reference |
+---------------+-------------+---------------+
| 0x81 | IOAM | This document |
+---------------+-------------+---------------+
5.2. LISP-GPE Next Protocol Value
IANA is requested to allocate a value in the LISP-GPE "Next Protocol"
registry for IOAM, which is defined in [RFC9305].
+---------------+-------------+---------------+
| Next Protocol | Description | Reference |
+---------------+-------------+---------------+
| 0x81 | IOAM | This document |
+---------------+-------------+---------------+
6. Security Considerations
The security considerations of VXLAN-GPE are discussed in
[I-D.ietf-nvo3-vxlan-gpe], and the security considerations of IOAM in
general are discussed in [RFC9197].
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. References
8.1. Normative References
[I-D.ietf-nvo3-vxlan-gpe]
Maino, F., Kreeger, L., and U. Elzur, "Generic Protocol
Extension for VXLAN (VXLAN-GPE)", Work in Progress,
Internet-Draft, draft-ietf-nvo3-vxlan-gpe-13, 4 November
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
nvo3-vxlan-gpe-13>.
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[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>.
[RFC7605] Touch, J., "Recommendations on Using Assigned Transport
Port Numbers", BCP 165, RFC 7605, DOI 10.17487/RFC7605,
August 2015, <https://www.rfc-editor.org/info/rfc7605>.
[RFC9197] Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi,
Ed., "Data Fields for In Situ Operations, Administration,
and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197,
May 2022, <https://www.rfc-editor.org/info/rfc9197>.
[RFC9305] Maino, F., Ed., Lemon, J., Agarwal, P., Lewis, D., and M.
Smith, "Locator/ID Separation Protocol (LISP) Generic
Protocol Extension", RFC 9305, DOI 10.17487/RFC9305,
October 2022, <https://www.rfc-editor.org/info/rfc9305>.
8.2. Informative References
[FD.io] "Fast Data Project: FD.io", <https://fd.io>.
Authors' Addresses
Frank Brockners (editor)
Cisco Systems, Inc.
Hansaallee 249, 3rd Floor
40549 DUESSELDORF
Germany
Email: fbrockne@cisco.com
Shwetha Bhandari
Thoughtspot
3rd Floor, Indiqube Orion, 24th Main Rd, Garden Layout, HSR Layout
Bangalore, KARNATAKA 560 102
India
Email: shwetha.bhandari@thoughtspot.com
Vengada Prasad Govindan
Cisco Systems, Inc.
Email: venggovi@cisco.com
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Carlos Pignataro (editor)
North Carolina State University
United States of America
Email: cpignata@gmail.com, cmpignat@ncsu.edu
Hannes Gredler
RtBrick Inc.
Email: hannes@rtbrick.com
John Leddy
Email: john@leddy.net
Stephen Youell
JP Morgan Chase
25 Bank Street
London
E14 5JP
United Kingdom
Email: stephen.youell@jpmorgan.com
Tal Mizrahi (editor)
Huawei
8-2 Matam
Haifa 3190501
Israel
Email: tal.mizrahi.phd@gmail.com
Aviv Kfir
Nvidia
350 Oakmead Parkway, Suite 100
Sunnyvale, CA, 94085
United States of America
Email: avivk@nvidia.com
Barak Gafni
Nvidia
350 Oakmead Parkway, Suite 100
Sunnyvale, CA, 94085
United States of America
Email: gbarak@nvidia.com
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Petr Lapukhov
Facebook
1 Hacker Way
Menlo Park, CA, 94025
United States of America
Email: petr@fb.com
Mickey Spiegel
Barefoot Networks, an Intel company
4750 Patrick Henry Drive
Santa Clara, CA, 95054
United States of America
Email: mickey.spiegel@intel.com
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