ippm F. Brockners
Internet-Draft S. Bhandari
Intended status: Standards Track V. Govindan
Expires: May 7, 2020 C. Pignataro
Cisco
H. Gredler
RtBrick Inc.
J. Leddy
S. Youell
JMPC
T. Mizrahi
Huawei Network.IO Innovation Lab
A. Kfir
B. Gafni
Mellanox Technologies, Inc.
P. Lapukhov
Facebook
M. Spiegel
Barefoot Networks
November 4, 2019
VXLAN-GPE Encapsulation for In-situ OAM Data
draft-brockners-ippm-ioam-vxlan-gpe-03
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.
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This Internet-Draft will expire on May 7, 2020.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirement 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 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 . . . . . . . . . . . . . . . . . . . . . . . 9
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 [I-D.ietf-ippm-ioam-data]. An
implementation of IOAM which leverages VXLAN-GPE to carry the IOAM
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data is available from the FD.io open source software project
[FD.io].
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:
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 [I-D.ietf-ippm-ioam-data]. 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 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ GPE
| Virtual Network Identifier (VNI) | Reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
| IOAM-Type | IOAM HDR len | Reserved | Next Protocol | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ I
! | O
! | A
~ IOAM Option and 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 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 [I-D.ietf-ippm-ioam-data].
IOAM HDR len: 8-bit unsigned integer. Length of the IOAM HDR in
4-octet units not including the first 4 octects.
Reserved: 8-bit reserved field MUST be set to zero upon transmission
and ignored upon receipt.
Next Protocol: 8-bit unsigned integer that determines the type of
header following IOAM protocol. The value is from the IANA
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registry setup for VXLAN GPE Next Protocol defined in
[I-D.ietf-nvo3-vxlan-gpe].
IOAM Option and Data Space: IOAM option header and data is present
as specified by the IOAM-Type field, and is defined in Section 4
of [I-D.ietf-ippm-ioam-data].
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
"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 look-ups 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, but would rather carry the options as
a serial sequence.
Two approaches for encapsulating IOAM data fields in VXLAN-GPE could
be considered:
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 (trace, proof-of-
transit, edge-to-edge) is carried.
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2. Use one GPE protocol type per IOAM options type: Each IOAM data
field option (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 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 [I-D.ietf-lisp-gpe].
+---------------+-------------+---------------+
| 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 [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. References
8.1. Normative References
[ETYPES] "IANA Ethernet Numbers",
<https://www.iana.org/assignments/ethernet-numbers/
ethernet-numbers.xhtml>.
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[I-D.ietf-ippm-ioam-data]
Brockners, F., Bhandari, S., Pignataro, C., Gredler, H.,
Leddy, J., Youell, S., Mizrahi, T., Mozes, D., Lapukhov,
P., remy@barefootnetworks.com, r., daniel.bernier@bell.ca,
d., and J. Lemon, "Data Fields for In-situ OAM", draft-
ietf-ippm-ioam-data-08 (work in progress), October 2019.
[I-D.ietf-lisp-gpe]
Maino, F., Lemon, J., Agarwal, P., Lewis, D., and M.
Smith, "LISP Generic Protocol Extension", draft-ietf-lisp-
gpe-09 (work in progress), October 2019.
[I-D.ietf-nvo3-vxlan-gpe]
Maino, F., Kreeger, L., and U. Elzur, "Generic Protocol
Extension for VXLAN", draft-ietf-nvo3-vxlan-gpe-08 (work
in progress), October 2019.
[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>.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
DOI 10.17487/RFC2784, March 2000,
<https://www.rfc-editor.org/info/rfc2784>.
[RFC3232] Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced
by an On-line Database", RFC 3232, DOI 10.17487/RFC3232,
January 2002, <https://www.rfc-editor.org/info/rfc3232>.
[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>.
8.2. Informative References
[FD.io] "Fast Data Project: FD.io", <https://fd.io/>.
[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>.
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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
Email: john@leddy.net
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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
Aviv Kfir
Mellanox Technologies, Inc.
350 Oakmead Parkway, Suite 100
Sunnyvale, CA 94085
U.S.A.
Email: avivk@mellanox.com
Barak Gafni
Mellanox Technologies, Inc.
350 Oakmead Parkway, Suite 100
Sunnyvale, CA 94085
U.S.A.
Email: gbarak@mellanox.com
Petr Lapukhov
Facebook
1 Hacker Way
Menlo Park, CA 94025
US
Email: petr@fb.com
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Mickey Spiegel
Barefoot Networks
2185 Park Boulevard
Palo Alto, CA 94306
US
Email: mspiegel@barefootnetworks.com
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