draft-ietf-mpls-tp-oam-analysis-07.txt   draft-ietf-mpls-tp-oam-analysis-08.txt 
Network Working Group N. Sprecher Network Working Group N. Sprecher
Internet-Draft Nokia Siemens Networks Internet-Draft Nokia Siemens Networks
Intended status: Informational L. Fang Intended status: Informational L. Fang
Expires: June 23, 2012 Cisco Expires: September 7, 2012 Cisco
December 21, 2011 March 6, 2012
An Overview of the OAM Tool Set for MPLS based Transport Networks An Overview of the OAM Tool Set for MPLS based Transport Networks
draft-ietf-mpls-tp-oam-analysis-07.txt draft-ietf-mpls-tp-oam-analysis-08.txt
Abstract Abstract
This document provides an overview of the OAM toolset for MPLS based This document provides an overview of the OAM toolset for MPLS based
Transport Networks. The toolset consists of a comprehensive set of Transport Networks. The toolset consists of a comprehensive set of
fault management and performance monitoring capabilities (operating fault management and performance monitoring capabilities (operating
in the data-plane) which are appropriate for transport networks as in the data-plane) which are appropriate for transport networks as
required in RFC 5860 and support the network and services at required in RFC 5860 and support the network and services at
different nested levels. This overview includes a brief recap of different nested levels. This overview includes a brief recap of
MPLS-TP OAM requirements and functions, and of generic mechanisms MPLS-TP OAM requirements and functions, and of generic mechanisms
created in the MPLS data plane to allow the OAM packets run in-band created in the MPLS data plane to allow the OAM packets run in-band
and share their fate with data packets. The protocol definitions for and share their fate with data packets. The protocol definitions for
each of the MPLS-TP OAM tools are defined in separate documents (RFCs each of the MPLS-TP OAM tools are defined in separate documents (RFCs
or Working Group drafts) which are referenced by this document. or Working Group drafts) which are referenced by this document.
This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunications Union Telecommunications
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and PWE3 architectures to support the
capabilities and functionalities of a packet transport network as
defined by the ITU-T.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 23, 2012. This Internet-Draft will expire on September 7, 2012.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Contributing Authors . . . . . . . . . . . . . . . . . . . 5 1.2. Contributing Authors . . . . . . . . . . . . . . . . . . . 5
1.3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . 6
2. Basic OAM Infrastructure Functionality . . . . . . . . . . . . 6 2. Basic OAM Infrastructure Functionality . . . . . . . . . . . . 6
3. MPLS-TP OAM Functions . . . . . . . . . . . . . . . . . . . . 8 3. MPLS-TP OAM Functions . . . . . . . . . . . . . . . . . . . . 8
3.1. Continuity Check and Connectivity Verification . . . . . . 8 3.1. Continuity Check and Connectivity Verification . . . . . . 8
3.1.1. Documents for CC-CV tools . . . . . . . . . . . . . . 9 3.1.1. Documents for CC-CV tools . . . . . . . . . . . . . . 9
3.2. Remote Defect Indication . . . . . . . . . . . . . . . . . 9 3.2. Remote Defect Indication . . . . . . . . . . . . . . . . . 9
3.2.1. Documents for RDI . . . . . . . . . . . . . . . . . . 9 3.2.1. Documents for RDI . . . . . . . . . . . . . . . . . . 9
3.3. Route Tracing . . . . . . . . . . . . . . . . . . . . . . 9 3.3. Route Tracing . . . . . . . . . . . . . . . . . . . . . . 9
3.3.1. Documents for Route Tracing . . . . . . . . . . . . . 9 3.3.1. Documents for Route Tracing . . . . . . . . . . . . . 10
3.4. Alarm Reporting . . . . . . . . . . . . . . . . . . . . . 9 3.4. Alarm Reporting . . . . . . . . . . . . . . . . . . . . . 10
3.4.1. Documents for Alarm Reporting . . . . . . . . . . . . 10 3.4.1. Documents for Alarm Reporting . . . . . . . . . . . . 10
3.5. Lock Instruct . . . . . . . . . . . . . . . . . . . . . . 10 3.5. Lock Instruct . . . . . . . . . . . . . . . . . . . . . . 10
3.5.1. Documents for Lock Instruct . . . . . . . . . . . . . 10 3.5.1. Documents for Lock Instruct . . . . . . . . . . . . . 10
3.6. Lock Reporting . . . . . . . . . . . . . . . . . . . . . . 10 3.6. Lock Reporting . . . . . . . . . . . . . . . . . . . . . . 10
3.6.1. Documents for Lock Reporting . . . . . . . . . . . . . 10 3.6.1. Documents for Lock Reporting . . . . . . . . . . . . . 10
3.7. Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . 10 3.7. Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . 11
3.7.1. Documents for Diagnostic Testing . . . . . . . . . . . 11 3.7.1. Documents for Diagnostic Testing . . . . . . . . . . . 11
3.8. Packet Loss Measurement . . . . . . . . . . . . . . . . . 11 3.8. Packet Loss Measurement . . . . . . . . . . . . . . . . . 11
3.8.1. Documents for Packet Loss Measurement . . . . . . . . 11 3.8.1. Documents for Packet Loss Measurement . . . . . . . . 11
3.9. Packet Delay Measurement . . . . . . . . . . . . . . . . . 11 3.9. Packet Delay Measurement . . . . . . . . . . . . . . . . . 12
3.9.1. Documents for Delay Measurement . . . . . . . . . . . 12 3.9.1. Documents for Delay Measurement . . . . . . . . . . . 12
4. MPLS-TP OAM documents guide . . . . . . . . . . . . . . . . . 12 4. MPLS-TP OAM documents guide . . . . . . . . . . . . . . . . . 12
5. OAM Toolset Applicability and Utilization . . . . . . . . . . 14 5. OAM Toolset Applicability and Utilization . . . . . . . . . . 14
5.1. Connectivity Check and Connectivity Verification . . . . . 14 5.1. Connectivity Check and Connectivity Verification . . . . . 14
5.2. Diagnostic Tests and Lock Instruct . . . . . . . . . . . . 15 5.2. Diagnostic Tests and Lock Instruct . . . . . . . . . . . . 15
5.3. Lock Reporting . . . . . . . . . . . . . . . . . . . . . . 15 5.3. Lock Reporting . . . . . . . . . . . . . . . . . . . . . . 16
5.4. Alarm Reporting and Link Down Indication . . . . . . . . . 16 5.4. Alarm Reporting and Link Down Indication . . . . . . . . . 16
5.5. Remote Defect Indication . . . . . . . . . . . . . . . . . 17 5.5. Remote Defect Indication . . . . . . . . . . . . . . . . . 17
5.6. Packet Loss and Delay Measurement . . . . . . . . . . . . 17 5.6. Packet Loss and Delay Measurement . . . . . . . . . . . . 17
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 7. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.1. Normative References . . . . . . . . . . . . . . . . . . . 19 9.1. Normative References . . . . . . . . . . . . . . . . . . . 19
9.2. Informative References . . . . . . . . . . . . . . . . . . 21 9.2. Informative References . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 21
skipping to change at page 7, line 35 skipping to change at page 7, line 35
particular MPLS-TP OAM functions to point-to-point associated particular MPLS-TP OAM functions to point-to-point associated
bidirectional LSPs, point-to-point unidirectional LSPs, and point- bidirectional LSPs, point-to-point unidirectional LSPs, and point-
to-multipoint LSPs, is described in ([RFC 5860], section 2.2)). to-multipoint LSPs, is described in ([RFC 5860], section 2.2)).
In addition, MPLS-TP OAM supports these LSPs and PWs when they In addition, MPLS-TP OAM supports these LSPs and PWs when they
span either a single or multiple domains ([RFC 5860], section span either a single or multiple domains ([RFC 5860], section
2.1.1). 2.1.1).
o OAM packets may be directed to an intermediate point of a LSP/PW o OAM packets may be directed to an intermediate point of a LSP/PW
([RFC 5860], sections 2.2.3, 2.2.4 and 2.2.5). ([RFC 5860], sections 2.2.3, 2.2.4 and 2.2.5).
It is recommended that any protocol solution, meeting one or more [RFC 5860] recommends that any protocol solution, meeting one or more
functional requirement(s), be the same for PWs, LSPs, and Sections. functional requirement(s), be the same for PWs, LSPs, and Sections
(section 2.2).
The following document-set addresses the basic requirements listed The following document-set addresses the basic requirements listed
above: above:
o The [RFC 6371] document describes the architectural framework for o The [RFC 6371] document describes the architectural framework for
conformance to the basic requirements listed above. It also conformance to the basic requirements listed above. It also
defines the basic relationships between the MPLS structures, e.g. defines the basic relationships between the MPLS structures, e.g.
LSP, PW, and the structures necessary for OAM functionality, i.e. LSP, PW, and the structures necessary for OAM functionality, i.e.
the Managed Entity Group, its End-points, and Intermediate Points. the Managed Entity Group, its End-points, and Intermediate Points.
skipping to change at page 8, line 11 skipping to change at page 8, line 12
Pseudowire (PW) Associated Channel Header (ACH) to MPLS LSPs and Pseudowire (PW) Associated Channel Header (ACH) to MPLS LSPs and
Sections, by defining a Generic Associated Channel (G-ACh). The Sections, by defining a Generic Associated Channel (G-ACh). The
G-ACh allows control packets to be multiplexed transparently over G-ACh allows control packets to be multiplexed transparently over
LSPs and sections, similar to that of PW VCCV [RFC 5085]. The LSPs and sections, similar to that of PW VCCV [RFC 5085]. The
Generic Association Label (GAL) is defined by assigning a reserved Generic Association Label (GAL) is defined by assigning a reserved
MPLS label value and is used to identify the OAM control packets. MPLS label value and is used to identify the OAM control packets.
The value of the ACH Channel Type field indicates the specific The value of the ACH Channel Type field indicates the specific
protocol carried on the associated control channel. Each MPLS-TP protocol carried on the associated control channel. Each MPLS-TP
OAM protocol has an IANA assigned channel type allocated to it. OAM protocol has an IANA assigned channel type allocated to it.
o The creation of G-ACh and GAL provided the necessary mechanisms to [RFC 5085] defines an Associated Channel Header (ACH) which
allow OAM packets run in-band and share their fate with data provides a PW associated control channel between a PW's endpoints,
packets. It is expected that all of the OAM protocols will be over which OAM and other control messages can be exchanged. [RFC
used in conjunction with this Generic Associated Channel. 5586] generalizes MPLS-TP generalized the PW Associated Channel
Header (ACH) to provide common in-band control channels also at
the LSP and MPLS-TP link levels. The G-ACh allows control packets
to be multiplexed transparently over the same LSP or MPLS-TP link
as in PW VCCV. Multiple control channels can exist between end
points.
[RFC 5085] also defines a label-based exception mechanism that
helps an LSR to identify the control packets and direct them to
the appropriate entity for processing. The use of G-ACh and GAL
provides the necessary mechanisms to allow OAM packets run in-band
and share their fate with data packets. It is expected that all
of the OAM protocols will be used in conjunction with this Generic
Associated Channel.
o The [RFC 6370] document provides an IP-based identifier set for o The [RFC 6370] document provides an IP-based identifier set for
MPLS-TP that can be used to identify the transport entities in the MPLS-TP that can be used to identify the transport entities in the
network and referenced by the different OAM protocols. [RFC 6375] network and referenced by the different OAM protocols. [RFC 6375]
augments that set of identifiers to include identifier information augments that set of identifiers to include identifier information
in a format used by the ITU-T. Other identifier sets may be in a format used by the ITU-T. Other identifier sets may be
defined as well. defined as well.
3. MPLS-TP OAM Functions 3. MPLS-TP OAM Functions
skipping to change at page 12, line 33 skipping to change at page 12, line 48
4. MPLS-TP OAM documents guide 4. MPLS-TP OAM documents guide
The complete MPLS-TP OAM protocol suite is covered by a small set of The complete MPLS-TP OAM protocol suite is covered by a small set of
existing IETF documents. This set of documents may be expanded in existing IETF documents. This set of documents may be expanded in
the future to cover additional OAM functionality. In order to allow the future to cover additional OAM functionality. In order to allow
the reader to understand this set of documents, a cross-reference of the reader to understand this set of documents, a cross-reference of
the existing documents (IETF RFCs or Internet drafts while this the existing documents (IETF RFCs or Internet drafts while this
document is work in progress) for the initial phase of the document is work in progress) for the initial phase of the
specification of MPLS based transport networks is provided below. specification of MPLS based transport networks is provided below.
Editor's note:
Only RFCs will be referenced in the final version of the document.
[RFC 5586] provides a specification of the basic structure of [RFC 5586] provides a specification of the basic structure of
protocol messages for in-band data plane OAM in an MPLS environment. protocol messages for in-band data plane OAM in an MPLS environment.
[RFC 6370] provides definitions of different formats that may be used [RFC 6370] provides definitions of different formats that may be used
within OAM protocol messages to identify the network elements of a within OAM protocol messages to identify the network elements of a
MPLS based transport network. MPLS based transport network.
The following table (Table 1) provides the summary of proactive The following table (Table 1) provides the summary of proactive
MPLS-TP OAM Fault Management toolset functions, associated tool/ MPLS-TP OAM Fault Management toolset functions, associated tool/
protocol, and the corresponding IETF RFCs or Internet drafts where protocol, and the corresponding IETF RFCs where they are defined.
they are defined.
+------------------------+----------------------------+-------------+ +--------------------------+-------------------------------+--------+
| OAM Functions | OAM Tools/Protocols | RFCs / | | OAM Functions | OAM Tools/Protocols | RFCs |
| | | Internet | +--------------------------+-------------------------------+--------+
| | | Drafts | | Continuity Check and | Bidirectional Forwarding | [RFC |
+------------------------+----------------------------+-------------+ | Connectivity | Detection (BFD) | 6428] |
| Continuity Check and | Bidirectional Forwarding | [RFC 6428] | | Verification | | |
| Connectivity | Detection (BFD) | | +--------------------------+-------------------------------+--------+
| Verification | | | | Remote Defect Indication | Flag in Bidirectional | [RFC |
+------------------------+----------------------------+-------------+ | (RDI) | Forwarding Detection (BFD) | 6428] |
| Remote Defect | Flag in Bidirectional | [RFC 6428] | | | message | |
| Indication (RDI) | Forwarding Detection (BFD) | | +--------------------------+-------------------------------+--------+
| | message | | | Alarm Indication Signal | G-ACh bases AIS message | [RFC |
+------------------------+----------------------------+-------------+ | (AIS) | | 6427] |
| Alarm Indication | G-ACh bases AIS message | [RFC 6427] | +--------------------------+-------------------------------+--------+
| Signal (AIS) | | | | Link Down Indication | Flag in AIS message | [RFC |
+------------------------+----------------------------+-------------+ | (LDI) | | 6427] |
| Link Down Indication | Flag in AIS message | [RFC 6427] | +--------------------------+-------------------------------+--------+
| (LDI) | | | | Lock Reporting (LKR) | G-ACh bases LKR message | [RFC |
+------------------------+----------------------------+-------------+ | | | 6427] |
| Lock Reporting (LKR) | G-ACh bases LKR message | [RFC 6427] | +--------------------------+-------------------------------+--------+
+------------------------+----------------------------+-------------+
Proactive Fault Management OAM Toolset Proactive Fault Management OAM Toolset
Table 1 Table 1
The following table (Table 2) provides an overview of the on-demand The following table (Table 2) provides an overview of the on-demand
MPLS-TP OAM Fault Management toolset functions, associated tool/ MPLS-TP OAM Fault Management toolset functions, associated tool/
protocol, and the corresponding IETF RFCs or Internet drafts where protocol, and the corresponding IETF RFCs or Internet drafts where
they are defined. they are defined.
+----------------------+-----------------------------+--------------+ +------------------------+---------------------------------+--------+
| OAM Functions | OAM Tools/Protocols | RFCs / | | OAM Functions | OAM Tools/Protocols | RFCs |
| | | Internet | +------------------------+---------------------------------+--------+
| | | Drafts | | Connectivity | LSP Ping | [RFC |
+----------------------+-----------------------------+--------------+ | Verification | | 6426] |
| Connectivity | LSP Ping | [RFC 6426] | +------------------------+---------------------------------+--------+
| Verification | | | | Diagnostic: Loopback | (1) G-ACh based Loopback and | [RFC |
+----------------------+-----------------------------+--------------+ | and Lock Instruct | Lock Instruct, (2) LSP Ping | 6435] |
| Diagnostic: Loopback | (1) G-ACh based Loopback | [RFC 6435] | +------------------------+---------------------------------+--------+
| and Lock Instruct | and Lock Instruct, (2) LSP | | +------------------------+---------------------------------+--------+
| | Ping | | | Lock Instruct(LI) | Flag in AIS message | [RFC |
+----------------------+-----------------------------+--------------+ | | | 6427] |
| Lock Instruct(LI) | Flag in AIS message | [RFC 6427] | +------------------------+---------------------------------+--------+
+----------------------+-----------------------------+--------------+
On Demand Fault Management OAM Toolset On Demand Fault Management OAM Toolset
Table 2 Table 2
The following table (Table 3) provides the Performance Monitoring The following table (Table 3) provides the Performance Monitoring
Fuctions, asscociated tool/protocol definitions, and corresponding Fuctions, asscociated tool/protocol definitions, and corresponding
RFCs or Internet Drafts. RFCs or Internet Drafts.
+---------------------+--------------------------+------------------+ +----------------------+--------------------------+-----------------+
| OAM Functions | OAM Tools/Protocols | RFCs / Internet | | OAM Functions | OAM Tools/Protocols | RFCs |
| | | Drafts | +----------------------+--------------------------+-----------------+
+---------------------+--------------------------+------------------+ | Packet Loss | G-ACh based LM & DM | [RFC 6374] [RFC |
| Packet Loss | G-ACh based LM & DM | [RFC 6374] [RFC | | Measurement (LM) | query messages | 6375] |
| Measurement (LM) | query messages | 6375] | +----------------------+--------------------------+-----------------+
+---------------------+--------------------------+------------------+ | Packet Delay | G-ACh based LM & DM | [RFC 6374] [RFC |
| Packet Delay | G-ACh based LM & DM | [RFC 6374] [RFC | | Measurement (DM) | query messages | 6375] |
| Measurement (DM) | query messages | 6375] | +----------------------+--------------------------+-----------------+
+---------------------+--------------------------+------------------+ | Throughput | derived from Loss | [RFC 6374] [RFC |
| Throughput | derived from Loss | [RFC 6374] [RFC | | Measurement | Measurement | 6375] |
| Measurement | Measurement | 6375] | +----------------------+--------------------------+-----------------+
+---------------------+--------------------------+------------------+ | Delay Variation | derived from Delay | [RFC 6374] [RFC |
| Delay Variation | derived from Delay | [RFC 6374] [RFC | | Measurement | Measurement | 6375] |
| Measurement | Measurement | 6375] | +----------------------+--------------------------+-----------------+
+---------------------+--------------------------+------------------+
Performance Monitoring OAM Toolset Performance Monitoring OAM Toolset
Table 3 Table 3
5. OAM Toolset Applicability and Utilization 5. OAM Toolset Applicability and Utilization
The following subsections present the MPLS-TP OAM toolset from the The following subsections present the MPLS-TP OAM toolset from the
perspective of the specified protocols and identifies which of the perspective of the specified protocols and identifies which of the
required functionality is supported by the particular protocol. required functionality is supported by the particular protocol.
skipping to change at page 16, line 37 skipping to change at page 16, line 42
with AIS message. The AIS message is forwarded to downstream sink with AIS message. The AIS message is forwarded to downstream sink
MEP in the client layer. This would enable the client layer to MEP in the client layer. This would enable the client layer to
suppress the generation of secondary alarms. suppress the generation of secondary alarms.
A Link Down Indication (LDI) flag is defined in the AIS message. The A Link Down Indication (LDI) flag is defined in the AIS message. The
LDI flag is set in the AIS message in response to detecting a fatal LDI flag is set in the AIS message in response to detecting a fatal
failure in the server layer. Receipt of an AIS message with this failure in the server layer. Receipt of an AIS message with this
flag set may be interpreted by a MEP as an indication of signal fail flag set may be interpreted by a MEP as an indication of signal fail
at the client layer. at the client layer.
The protocols for Alarm Indication Signal (AIS) and A Link Down The protocols for Alarm Indication Signal (AIS) and Link Down
Indication (LDI) are defined in [RFC 6427]. Indication (LDI) are defined in [RFC 6427].
Fault OAM messages are generated by intermediate nodes where an LSP Fault OAM messages are generated by intermediate nodes where an LSP
is switched, and propagated to the end points (MEPs). is switched, and propagated to the end points (MEPs).
From a practical point of view, when both proactive Continuity Check From a practical point of view, when both proactive Continuity Check
functions and LDI are used, one may consider running the proactive functions and LDI are used, one may consider running the proactive
Continuity Check functions at a slower rate (e.g. longer BFD hello Continuity Check functions at a slower rate (e.g. longer BFD hello
intervals), and reply on LDI to trigger fast protection switch over intervals), and reply on LDI to trigger fast protection switch over
upon failure detection in a given LSP. upon failure detection in a given LSP.
5.5. Remote Defect Indication 5.5. Remote Defect Indication
Remote Defect Indication (RDI) function enables an End Point to Remote Defect Indication (RDI) function enables an End Point to
report to the other End Point that a fault or defect condition is report to the other End Point that a fault or defect condition is
detected on the PW, LSP, or Section for which they are the End detected on the PW, LSP, or Section for which they are the End
Points. Points.
The RDI OAM function is supported by the use of Bidirectional The RDI OAM function is supported by the use of Bidirectional
Forwarding Detection (BFD) Control Packets [RFC 6428???]. RDI is Forwarding Detection (BFD) Control Packets [RFC 6428]. RDI is only
only used for bidirectional connections and is associated with used for bidirectional connections and is associated with proactive
proactive CC-CV activation. CC-CV activation.
When an end point (MEP) detects a signal failure condition, it sets When an end point (MEP) detects a signal failure condition, it sets
the flag up by setting the diagnostic field of the BFD control packet the flag up by setting the diagnostic field of the BFD control packet
to a particular value to indicate the failure condition on the to a particular value to indicate the failure condition on the
associated PW, LSP, or Section, and transmitting the BFD control associated PW, LSP, or Section, and transmitting the BFD control
packet with the failure flag up to the other end point (its peer packet with the failure flag up to the other end point (its peer
MEP). MEP).
The RDI function can be used to facilitate protection switching by The RDI function can be used to facilitate protection switching by
synchronizing the two end points when unidirectional failure occurs synchronizing the two end points when unidirectional failure occurs
skipping to change at page 18, line 41 skipping to change at page 18, line 41
The OAM tools and functions defined under G-ACh use IANA assigned The OAM tools and functions defined under G-ACh use IANA assigned
code points. the codes are defined in the corresponding IETF RFCs code points. the codes are defined in the corresponding IETF RFCs
Note to RFC Editor: Note to RFC Editor:
this section may be removed on publication as an RFC. this section may be removed on publication as an RFC.
7. Security Considerations 7. Security Considerations
This document does not by itself raise any particular security This document as an overview of MPLS OAM tools does not by itself
considerations. Security considerations for each function in the OAM raise any particular security considerations.
toolset need to be documented in the document that specifies the
particular functionality.
The general security considerations are provided in [RFC 6920] and The general security considerations are provided in [RFC 6920] and
[MPLS-TP Security Frwk]. [MPLS-TP Security Frwk]. Security considerations for each function
in the OAM toolset have been documented in each document that
specifies the particular functionality.
OAM in general is always an area where the security risk is high,
e.g. confidential information may be intercepted for attackers to
again access to the networks, therefore authentication,
authorization, and encryption need to be enforced for prevent
security breach.
In addition to implement security protocol, tools, and mechanisms,
following strict operation security procedures is very important,
especially MPSL-TP static provisioning processes involve operator
direct interactions with NMS and devices, its critical to prevent
human errors and malicious attacks.
Since MPLS-TP OAM uses G-ACh, the security risks and mitigation
described in [RFC 5085] apply here. In short, the G-ACh could be
intercepted, or false G-ACh packets could be inserted. DoS attack
could happen by flooding G-ACh messages to peer devices. To mitigate
this type of attacks, throttling mechanisms can be used. For more
details, please see [RFC 5085].
8. Acknowledgements 8. Acknowledgements
The discussion on the needed OAM toolset took place, mainly, in the The discussion on the needed OAM toolset took place, mainly, in the
MPLS Interoperability Design Team (the MEAD). A toolset was agreed MPLS Interoperability Design Team (the MEAD). A toolset was agreed
upon and was reported to the MPLS working group in Stockholm (July upon and was reported to the MPLS working group in Stockholm (July
2009) during the IETF (#75) meetings. This was also judged to be the 2009) during the IETF (#75) meetings. This was also judged to be the
working group consensus. working group consensus.
The editors wish to thank the MPLS-TP Design Team members, from both The authors would like to thank the MPLS-TP experts from both the
the IETF and ITU-T leadership teams, in formulating the IETF and ITU-T for their helpful comments. In particular, we would
recommendations documented here. In particular, we would like to like to thank Loa Andersson, Huub van Helvoort, and the Area
thank Loa Andersson, Huub van Helvoort, and the Area Directors for Directors for their suggestions and enhancements to the text.
their suggestions and enhancements to the text.
Thanks to Tom Petch for useful comments and discussions. Thanks to Tom Petch for useful comments and discussions.
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC 4379] [RFC 4379]
Kompella, K. and G. Swallow, "Detecting Multi-Protocol Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379, Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006. February 2006.
[RFC 4385]
Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for
Use over an MPLS PSN", RFC 4385, February 2006.
[RFC 5085] [RFC 5085]
Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit
Connectivity Verification (VCCV): A Control Channel for Connectivity Verification (VCCV): A Control Channel for
Pseudowires", RFC 5085, December 2007. Pseudowires", RFC 5085, December 2007.
[RFC 5586] [RFC 5586]
Bocci, M., Bryant, S., and M. Vigoureux, "MPLS Generic Bocci, M., Bryant, S., and M. Vigoureux, "MPLS Generic
Associated Channel", RFC 5586, June 2009. Associated Channel", RFC 5586, June 2009.
[RFC 5654] [RFC 5654]
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