SPRING Working Group R. Gandhi, Ed.
Internet-Draft Z. Ali
Intended status: Standards Track C. Filsfils
Expires: April 26, 2019 F. Brockners
Cisco Systems, Inc.
B. Wen
V. Kozak
Comcast
October 23, 2018
Segment Routing with MPLS Data Plane encapsulation
for In-situ OAM Data
draft-gandhi-spring-ioam-sr-mpls-00
Abstract
In-situ Operations, Administration, and Maintenance (IOAM) records
operational and telemetry information in the data packet while the
packet traverses a path between two points in the network. This
document defines how IOAM data fields are transported with the
Segment Routing with MPLS data plane (SR-MPLS) encapsulation.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1. Requirement Language . . . . . . . . . . . . . . . . . . . 2
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3
3. IOAM Data Field Encapsulation in SR-MPLS Header . . . . . . . 3
4. Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
8. Normative References . . . . . . . . . . . . . . . . . . . . . 6
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
In-situ Operations, Administration, and Maintenance (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 probe packets specifically dedicated to OAM.
This document defines how IOAM data fields are transported with the
Segment Routing with MPLS data plane
[I-D.ietf-spring-segment-routing-mpls] encapsulation.
The IOAM data fields carried are defined in
[I-D.ietf-ippm-ioam-data], and can be used for various use-cases
including Performance Measurement (PM).
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
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document are to be interpreted as described in [RFC2119] [RFC8174]
when, and only when, they appear in all capitals, as shown here.
2.2. Abbreviations
Abbreviations used in this document:
IOAM In-situ Operations, Administration, and Maintenance
OAM Operations, Administration, and Maintenance
PM Performance Measurement
PoT Proof-of-Transit
SR Segment Routing
SR-MPLS Segment Routing with MPLS Data plane
3. IOAM Data Field Encapsulation in SR-MPLS Header
SR-MPLS encapsulation is defined in
[I-D.ietf-spring-segment-routing-mpls]. IOAM data fields are carried
in the SR-MPLS header, as an IOAM data fields. The different IOAM
data fields defined in [I-D.ietf-ippm-ioam-data] are added as TLVs.
More than one TLV can be present in the IOAM data fields. The IOAM
Indicator Label (value TBA1) is added at the bottom of the MPLS label
stack to indicate the presence of the IOAM data fields in the header.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IOAM Indicator Label (TBA1) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
| IOAM-Type | IOAM HDR LEN | RESERVED | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ I
! | O
! | A
~ IOAM Option and Data Space ~ M
| | |
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
| |
| |
| Payload + Padding (L2/L3/ESP/...) |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: IOAM data encapsulation in SR-MPLS Header
IOAM Indicator Label is defined in this document as value TBA1.
The fields related to the encapsulation of IOAM data fields in the
SR-MPLS header 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.
RESERVED: 8-bit reserved field MUST be set to zero upon
transmission and ignored upon receipt.
IOAM Option and Data Space: IOAM option header and data is present
as defined by the IOAM-Type field, and is defined in Section 4 of
[I-D.ietf-ippm-ioam-data].
4. Procedure
This section summarizes the procedure for IOAM data encapsulation in
SR-MPLS.
o The ingress node inserts the IOAM Indicator Label and IOAM TLV in
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the MPLS header.
o On the ultimate node where the last MPLS label is popped from the
header, the node "forwards and punts the timestamped copy" of the
data packet with IOAM TLV when the node recognizes the IOAM
Indicator Label.
o The ultimate node also pops the IOAM Indicator Label and the IOAM
data fields from the MPLS header.
5. IANA Considerations
IANA maintains the "Special-Purpose Multiprotocol Label Switching
(MPLS) Label Values" registry (see
<https://www.iana.org/assignments/mpls-label-values/mpls-label-
values.xml>). IANA is requested to allocate IOAM Indicator Label
value from the "Special-Purpose MPLS Label Values" registry:
+---------------+-------------------------+---------------+
| Value | Description | Reference |
+---------------+-------------------------+---------------+
| TBA1 | IOAM Indicator Label | This document |
+---------------+-------------------------+---------------+
6. Security Considerations
The security considerations of SR-MPLS are discussed in
[I-D.ietf-spring-segment-routing-mpls], 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 Shwetha Bhandari and Vengada Prasad
Govindan for the discussions on IOAM.
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8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", RFC 8174, May 2017.
[I-D.ietf-spring-segment-routing-mpls] Bashandy, A., Filsfils, C.,
Previdi, S., Decraene, B., Litkowski, S., and R. Shakir,
"Segment Routing with MPLS data plane",
draft-ietf-spring-segment-routing-mpls, work in progress.
[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 Bernier, D., "Data
Fields for In-situ OAM", draft-ietf-ippm-ioam-data, work
in progress.
Contributors
Sagar Soni
Cisco Systems, Inc.
Email: sagsoni@cisco.com
Patrick Khordoc
Cisco Systems, Inc.
Email: pkhordoc@cisco.com
Authors' Addresses
Rakesh Gandhi (editor)
Cisco Systems, Inc.
Canada
Email: rgandhi@cisco.com
Zafar Ali
Cisco Systems, Inc.
Email: zali@cisco.com
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Clarence Filsfils
Cisco Systems, Inc.
Belgium
Email: cf@cisco.com
Frank Brockners
Cisco Systems, Inc.
Hansaallee 249, 3rd Floor
DUESSELDORF, NORDRHEIN-WESTFALEN 40549
Germany
Email: fbrockne@cisco.com
Bin Wen
Comcast
Email: Bin_Wen@cable.comcast.com
Voitek Kozak
Comcast
Email: Voitek_Kozak@comcast.com
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