Internet DRAFT - draft-gafni-ippm-ioam-ipv4-options
draft-gafni-ippm-ioam-ipv4-options
ippm B. Gafni
Internet-Draft A. Kfir
Intended status: Standards Track Mellanox Technologies, Inc.
Expires: September 10, 2019 S. Bhandari
F. Brockners
R. Sivakolundu
Cisco
T. Mizrahi
Huawei Network.IO Innovation Lab
March 09, 2019
In-situ OAM IPv4 Options
draft-gafni-ippm-ioam-ipv4-options-00
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 IPv4.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3
3. In-situ OAM Metadata Transport in IPv4 . . . . . . . . . . . 3
3.1. Considerations for in-situ OAM in IPv4 options . . . . . 4
3.1.1. Alignment . . . . . . . . . . . . . . . . . . . . . . 4
3.1.2. Total available length . . . . . . . . . . . . . . . 5
3.1.3. Pre-allocation vs. Incremental trace types . . . . . 5
3.1.4. Checksum considerations . . . . . . . . . . . . . . . 5
3.1.4.1. IP checksum . . . . . . . . . . . . . . . . . . . 5
3.1.4.2. TCP checksum . . . . . . . . . . . . . . . . . . 6
3.1.4.3. UDP checksum . . . . . . . . . . . . . . . . . . 6
3.1.5. Fragmentation . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . 7
6.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
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 the IPv4 [RFC0791].
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.
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2.2. Abbreviations
Abbreviations used in this document:
E2E: Edge-to-Edge
IOAM: In-situ Operations, Administration, and Maintenance
OAM: Operations, Administration, and Maintenance
3. In-situ OAM Metadata Transport in IPv4
An IPv4 option is defined corresponding to each of the IOAM data
fields defined in [I-D.ietf-ippm-ioam-data]. These mechanisms of in-
situ OAM in IPv4 are used to enhance diagnostics of IPv4 networks.
IOAM is carried in IPv4 packets as a new single option, with an
option type identifier TBD_IOAM that will be defined by IANA, and
according to the options definition in [RFC0791]. While specifying a
new option to carry IOAM data, one may see this as an extension to
the already defined "record route" and "internet timestamp" options
in [RFC0791], which allows a packet to record its route and collect
timestamps throughout the network. The various IOAM data fields
defined in [I-D.ietf-ippm-ioam-data] are added as TLVs within the new
IPv4 option. In an administrative domain where IOAM is used,
insertion of the IOAM header in IPv4 is enabled at the IOAM domain
edge, which serve as IOAM encapsulating/decapsulating nodes by means
of configuration.
An IPv4 option format for carrying in-situ OAM data fields:
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option Type | Option Length | Reserved | IOAM-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
. . |
. Option Data . I
. . O
. . A
. . M
. . -
. . O
. . P
. . T
. . I
. . O
. . N
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
Option Type: 8-bit identifier of the type of option, consist of: 1
bit - copied flag, 2 bits - option class, 5 bits - option number.
For more details see [RFC0791].
Option Length: 8-bit unsigned integer. Length of the option
including the Option Type octet, the Option Length octet, the
Reserved octet, the IOAM Type octet, and option-data octets.
Reserved: 8-bits field, reserved for future use. MUST be zero on
transmission and ignored on receipt.
IOAM Type: 8-bit field defining the IOAM Option type, as defined in
Section 7.2 of [I-D.ietf-ippm-ioam-data].
Option Data: Variable-length field, including the IOAM data as
defined in [I-D.ietf-ippm-ioam-data], in particular see section 4.
3.1. Considerations for in-situ OAM in IPv4 options
In the scope of IPv4 header and its options in [RFC0791], there are
unique considerations for embedding in-situ OAM in the IPv4 options.
3.1.1. Alignment
Within an IPv4 options stack there is no requirement for alignment
outside the octet granularity, which doesn't limit the granularity of
the in-situ OAM, since it is already 4-octects aligned.
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3.1.2. Total available length
There are three fields that may affect the total available length for
in-situ OAM data to be incorporated in the IPv4 options:
1. The IPv4 header's IHL, as described in [RFC0791] in section 3.1:
This 4-bit field can reach up to 15 times 4 octets, including the
IPv4 header, which is 20 octets. This leaves a maximum actual
length of 40 octets to the options. Reducing 4 octets for the
use of the option's header, it leaves 36 octets for the use of
the in-situ OAM data. In the context of the trace type, which
has an 8 octets header, this leaves 28 bytes for actual data to
be collected during the packet's traverse through the network.
2. The option's length, as described here above in section 3: This
8-bit field can reach up to 255 octets. Doesn't further restrict
the in-situ OAM length, because of the above restrictions that
are already applied.
3. Datagram's Total length, as described in [RFC0791] in section
3.1: Doesn't further restrict the in-situ OAM length, because of
the above restrictions that are already applied.
3.1.3. Pre-allocation vs. Incremental trace types
Considering the IPv4 architecture, and specifically the "record
route" and "internet timestamp" options definitions, the RFC calls
for "The size of the option does not change due to adding
addresses...", and similarly for the timestamp option. Hence, while
incorporating In-situ OAM trace type header, an implementation SHOULD
use one of these two techniques:
1. Immediate Export mode, controlled by the I-bit as part of the
trace flags.
2. Pre-allocated trace type as described in section 4.1.1 of
[I-D.ietf-ippm-ioam-data].
3.1.4. Checksum considerations
3.1.4.1. IP checksum
IPv4 Header Checksum, as described in [RFC0791] MUST be recalculated
by a device that is updating the In-situ OAM IPv4 option.
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3.1.4.2. TCP checksum
TCP's pseudo header, as described in [RFC0793], doesn't include
neither the IPv4 options nor the IHL, hence doesn't need to be
recalculated by a device that is adding, removing or updating the in-
situ OAM IPv4 option.
3.1.4.3. UDP checksum
UDP's pseudo header, as described in [RFC0768], doesn't include
neither the IPv4 options nor the IHL, hence doesn't need to be
recalculated by a device that is adding, removing or updating the in-
situ OAM IPv4 option.
3.1.5. Fragmentation
Considering the IPv4 architecture, and specifically the "record
route" and "internet timestamp" options definitions, [RFC0791] is
calling for setting the option's copy to zero, hence "Not copied on
fragmentation, goes in first fragment only". It seems reasonable to
the authors to keep this idea to prevent duplication of route data
and maintain similar behavior for the operator, hence an implementer
SHOULD follow this method.
4. Security Considerations
This document describes the encapsulation of IOAM data fields in
IPv4. Security considerations of the specific IOAM data fields for
each case (i.e., Trace, Proof of Transit, and E2E) are described in
defined in [I-D.ietf-ippm-ioam-data].
As this document describes a new option for IPv4, that is similar in
their behavior to an already existing options, the security
considerations are similar as well to those of [RFC0791].
5. IANA Considerations
This draft requests the following IPv4 Option Type assignments from
sub-registry of Internet Protocol Version 4 (IPv4) Parameters:
TBD
6. References
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6.1. 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", draft-ietf-ippm-ioam-data-01 (work in
progress), October 2017.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
6.2. Informative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/info/rfc768>.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, DOI 10.17487/RFC0793, September 1981,
<https://www.rfc-editor.org/info/rfc793>.
Authors' Addresses
Barak Gafni
Mellanox Technologies, Inc.
350 Oakmead Parkway, Suite 100
Sunnyvale, CA 94085
U.S.A.
Email: gbarak@mellanox.com
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Aviv Kfir
Mellanox Technologies, Inc.
350 Oakmead Parkway, Suite 100
Sunnyvale, CA 94085
U.S.A.
Email: avivk@mellanox.com
Shwetha Bhandari
Cisco Systems, Inc.
Cessna Business Park, Sarjapura Marathalli Outer Ring Road
Bangalore, KARNATAKA 560 087
India
Email: shwethab@cisco.com
Frank Brockners
Cisco Systems, Inc.
Hansaallee 249, 3rd Floor
DUESSELDORF, NORDRHEIN-WESTFALEN 40549
Germany
Email: fbrockne@cisco.com
Ramesh Sivakolundu
Cisco Systems, Inc.
170 West Tasman Dr.
SAN JOSE, CA 95134
U.S.A.
Email: sramesh@cisco.com
Tal Mizrahi
Huawei Network.IO Innovation Lab
Israel
Email: tal.mizrahi.phd@gmail.com
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