MPLS Working Group W. Cheng
Internet-Draft China Mobile
Intended status: Standards Track X. Min
Expires: September 11, 2019 ZTE
T. Zhou
Huawei
X. Dong
FiberHome
March 10, 2019
Encapsulation For MPLS Inband Performance Measurement
draft-cheng-mpls-inband-pm-encapsulation-00
Abstract
This document defines the encapsulation for MPLS inband performance
measurement, which performs flow-based packet loss, delay, and jitter
measurements on live traffic, by using the alternate-marking method.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions Used in This Document . . . . . . . . . . . . 2
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3
2. Flow-based Inband PM Encapsulation in MPLS . . . . . . . . . 3
2.1. Examples for Applying Flow-ID and Nested Flow-ID . . . . 4
3. Procedures of Encapsulation, Look-up and Decapsulation . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.1. Normative References . . . . . . . . . . . . . . . . . . 8
7.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
[RFC8321] describes an alternate-marking (coloring) technique, and
generally by which how to achieve hop-by-hop packet loss, delay, and
jitter measurements, specifically, section 5 of [RFC8321] mentions
the alternate-marking method application of MPLS performance
measurement, but it fails to define the encapsulation for MPLS inband
performance measurement using alternate-marking method.
As mentioned in section 5 of [RFC8321], [RFC8372] discusses the
desired capabilities for MPLS flow identification in order to perform
a better MPLS inband performance measurement, and Synonymous Flow
Label (SFL) introduced in [I-D.ietf-mpls-sfl-framework] is identified
as a method of accomplishing MPLS flow identification. This document
employs a method other than SFL to accomplish MPLS flow
identification.
This document defines the encapsulation for MPLS inband performance
measurement, which performs flow-based packet loss, delay, and jitter
measurements on live traffic, by using the alternate-marking method.
1.1. Conventions Used in This Document
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1.1.1. Terminology
LSP: Label Switched Path
MPLS: Multi-Protocol Label Switching
NMS: Network Management System
PM: Performance Measurement
PW: PseudoWire
SFL: Synonymous Flow Label
TC: Traffic Class
TTL: Time to Live
VC: Virtual Channel
VPN: Virtual Private Network
1.1.2. 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.
2. Flow-based Inband PM Encapsulation in MPLS
Flow-based MPLS inband performance measurement encapsulation has the
following format:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inband PM Indicator Label (TBA1) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow-ID |L|D|R|S| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Payload ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Flow-based Inband PM Encapsulation in MPLS
Where Inband PM Indicator Label is defined in this document as value
TBA1, and the other fields related to the encapsulation of Inband PM
are defined as follows:
o Flow-ID - an MPLS label value used as MPLS flow identification
[RFC8372], it should be unique within the administrative domain.
Flow-ID values can be allocated by an external NMS or a controller
based on service object such as LSP and PW, and the specific
method on how to allocate the Flow-ID values is outside the scope
of this draft. Note that Flow-ID can be placed either at the
bottom of the MPLS label stack or not, and the Flow-ID can be
nested, which means more than one Flow-ID can be present within an
MPLS label stack. Section 2.1 of this document provides several
examples to illustrate how to apply Flow-ID and nested Flow-ID.
o L and D - L(oss) bit and D(elay) bit are used for coloring the
packets (called double-marking methodology), which is required by
alternate-marking method defined in [RFC8321].
o R - R bit is reserved for future use and MUST be set to zero.
o Reserved - one octet long field reserved for future use and MUST
be set to zero.
2.1. Examples for Applying Flow-ID and Nested Flow-ID
Several examples of different Flow-ID label (4 octets) layout are
illustrated as follows:
(1) Flow-ID label layout when applied to MPLS LSP.
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+----------------------+
| |
| LSP |
| Label |
+----------------------+
| |
| Inband PM Indicator |
| Label |
+----------------------+
| |
| Flow-ID |
| Label |
+----------------------+
| |
| VPN |
| Label |
+----------------------+ <= Bottom of stack
| |
| Payload |
| |
+----------------------+
Figure 2: Applying Flow-ID to MPLS LSP
(2) Flow-ID label layout when applied to MPLS VPN traffic.
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+----------------------+
| |
| LSP |
| Label |
+----------------------+
| |
| VPN |
| Label |
+----------------------+
| |
| Inband PM Indicator |
| Label |
+----------------------+
| |
| Flow-ID |
| Label |
+----------------------+ <= Bottom of stack
| |
| Payload |
| |
+----------------------+
Figure 3: Applying Flow-ID to MPLS VPN
(3) Flow-ID label layout when applied to both MPLS LSP and MPLS VPN
traffic.
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+----------------------+
| |
| LSP |
| Label |
+----------------------+
| |
| Inband PM Indicator |
| Label |
+----------------------+
| |
| Flow-ID |
| Label |
+----------------------+
| |
| VPN |
| Label |
+----------------------+
| |
| Inband PM Indicator |
| Label |
+----------------------+
| |
| Flow-ID |
| Label |
+----------------------+ <= Bottom of stack
| |
| Payload |
| |
+----------------------+
Figure 4: Applying Flow-ID to both MPLS LSP and MPLS VPN
Note that here VPN label can be MPLS PW label or MPLS IP VPN label,
and it's also called VC label as defined in [RFC4026].
3. Procedures of Encapsulation, Look-up and Decapsulation
The procedures for Flow-ID label encapsulation, look-up and
decapsulation are summarized as follows:
o The ingress node inserts the Inband PM Indicator Label alongside
with the Flow-ID label in the MPLS label stack. At the same time,
the ingress node sets the L bit and D bit as needed by alternate-
marking technique, and sets the Flow-ID value as defined in this
document.
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o The transit nodes look up the Flow-ID label with the help of the
Inband PM Indicator Label, and transmit the collected information
to an external NMS or a controller, which includes the values of
the block counters and the timestamps of the marked packets along
with the value of the Flow-ID, referring to the procedures defined
in [RFC8321].
o The egress node pops the Inband PM Indicator Label alongside with
the Flow-ID label from the MPLS label stack. This document
doesn't introduce any new procedure regarding to the process of
the decapsulated packet.
4. Security Considerations
This document does not introduce additional security requirements and
mechanisms.
5. IANA Considerations
In the Special-Purpose MPLS Label Values registry defined in
[SP-MPLS-Label], a new Special-Purpose MPLS Label Value for Inband PM
Indicator is requested from IANA as follows:
+---------------------+-----------------+---------------+-----------+
| Special-Purpose | Description | Semantics | Reference |
| MPLS Label Value | | Definition | |
+---------------------+-----------------+---------------+-----------+
| TBA1 | Inband PM | Section 2 | This |
| | Indicator Label | | Document |
+---------------------+-----------------+---------------+-----------+
Table 1: New Special-Purpose MPLS Label Value for Inband PM Indicator
6. Acknowledgements
To be added.
7. References
7.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
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[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>.
[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
"Alternate-Marking Method for Passive and Hybrid
Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
January 2018, <https://www.rfc-editor.org/info/rfc8321>.
[SP-MPLS-Label]
"Special-Purpose MPLS Label Values", 2014,
<https://www.iana.org/assignments/mpls-label-values/
mpls-label-values.xml>.
7.2. Informative References
[I-D.ietf-mpls-sfl-framework]
Bryant, S., Chen, M., Li, Z., Swallow, G., Sivabalan, S.,
and G. Mirsky, "Synonymous Flow Label Framework", draft-
ietf-mpls-sfl-framework-04 (work in progress), December
2018.
[RFC4026] Andersson, L. and T. Madsen, "Provider Provisioned Virtual
Private Network (VPN) Terminology", RFC 4026,
DOI 10.17487/RFC4026, March 2005,
<https://www.rfc-editor.org/info/rfc4026>.
[RFC8372] Bryant, S., Pignataro, C., Chen, M., Li, Z., and G.
Mirsky, "MPLS Flow Identification Considerations",
RFC 8372, DOI 10.17487/RFC8372, May 2018,
<https://www.rfc-editor.org/info/rfc8372>.
Authors' Addresses
Weiqiang Cheng
China Mobile
Beijing
China
Email: chengweiqiang@chinamobile.com
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Xiao Min
ZTE
Nanjing
China
Email: xiao.min2@zte.com.cn
Tianran Zhou
Huawei
Beijing
China
Email: zhoutianran@huawei.com
Ximing Dong
FiberHome
China
Email: dxm@fiberhome.com
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