draft-ietf-mpls-tp-identifiers-07.txt   rfc6370.txt 
MPLS Working Group M. Bocci Internet Engineering Task Force (IETF) M. Bocci
Internet-Draft Alcatel-Lucent Request for Comments: 6370 Alcatel-Lucent
Intended status: Standards Track G. Swallow Category: Standards Track G. Swallow
Expires: January 22, 2012 Cisco ISSN: 2070-1721 Cisco
E. Gray E. Gray
Ericsson Ericsson
July 21, 2011 September 2011
MPLS-TP Identifiers MPLS Transport Profile (MPLS-TP) Identifiers
draft-ietf-mpls-tp-identifiers-07
Abstract Abstract
This document specifies an initial set of identifiers to be used in This document specifies an initial set of identifiers to be used in
the Transport Profile of Multiprotocol Label Switching (MPLS-TP). the Transport Profile of Multiprotocol Label Switching (MPLS-TP).
The MPLS-TP requirements (RFC 5654) require that the elements and The MPLS-TP requirements (RFC 5654) require that the elements and
objects in an MPLS-TP environment are able to be configured and objects in an MPLS-TP environment are able to be configured and
managed without a control plane. In such an environment many managed without a control plane. In such an environment, many
conventions for defining identifiers are possible. This document conventions for defining identifiers are possible. This document
defines identifiers for MPLS-TP management and OAM functions defines identifiers for MPLS-TP management and Operations,
compatible with IP/MPLS conventions. Administration, and Maintenance (OAM) functions compatible with IP/
MPLS conventions.
This document is a product of a joint Internet Engineering Task Force This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunication Union Telecommunication (IETF) / International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) effort to include an MPLS Transport Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
(PWE3) architectures to support the capabilities and functionalities (PWE3) architectures to support the capabilities and functionalities
of a packet transport network as defined by the ITU-T. 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
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering This is an Internet Standards Track document.
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
This Internet-Draft will expire on January 22, 2012. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6370.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction ....................................................3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology ................................................3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.2. Requirements Language ......................................4
1.3. Notational Conventions . . . . . . . . . . . . . . . . . . 4 1.3. Notational Conventions .....................................4
2. Named Entities . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Named Entities ..................................................5
3. Uniquely Identifying an Operator - the Global_ID . . . . . . . 5 3. Uniquely Identifying an Operator - the Global_ID ................5
4. Node and Interface Identifiers . . . . . . . . . . . . . . . . 6 4. Node and Interface Identifiers ..................................6
5. MPLS-TP Tunnel and LSP Identifiers . . . . . . . . . . . . . . 7 5. MPLS-TP Tunnel and LSP Identifiers ..............................7
5.1. MPLS-TP Point to Point Tunnel Identifiers . . . . . . . . 8 5.1. MPLS-TP Point-to-Point Tunnel Identifiers ..................8
5.2. MPLS-TP LSP Identifiers . . . . . . . . . . . . . . . . . 8 5.2. MPLS-TP LSP Identifiers ....................................9
5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers . . . 9 5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers .....9
5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers . . . 9 5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers ....9
5.3. Mapping to RSVP Signaling . . . . . . . . . . . . . . . . 10 5.3. Mapping to RSVP Signaling .................................10
6. Pseudowire Path Identifiers . . . . . . . . . . . . . . . . . 11 6. Pseudowire Path Identifiers ....................................11
7. Maintenance Identifiers . . . . . . . . . . . . . . . . . . . 12 7. Maintenance Identifiers ........................................13
7.1. Maintenance Entity Group Identifiers . . . . . . . . . . . 13 7.1. Maintenance Entity Group Identifiers ......................13
7.1.1. MPLS-TP Section MEG_IDs . . . . . . . . . . . . . . . 13 7.1.1. MPLS-TP Section MEG_IDs ............................13
7.1.2. MPLS-TP LSP MEG_IDs . . . . . . . . . . . . . . . . . 13 7.1.2. MPLS-TP LSP MEG_IDs ................................13
7.1.3. Pseudowire MEG_IDs . . . . . . . . . . . . . . . . . . 13 7.1.3. Pseudowire MEG_IDs .................................14
7.2. Maintenance Entity Group End Point Identifiers . . . . . . 14 7.2. Maintenance Entity Group End Point Identifiers ............14
7.2.1. MPLS-TP Section MEP_IDs . . . . . . . . . . . . . . . 14 7.2.1. MPLS-TP Section MEP_IDs ............................14
7.2.2. MPLS-TP LSP_MEP_ID . . . . . . . . . . . . . . . . . . 14 7.2.2. MPLS-TP LSP_MEP_ID .................................15
7.2.3. MEP_IDs for Pseudowires . . . . . . . . . . . . . . . 15 7.2.3. MEP_IDs for Pseudowires ............................15
7.3. Maintenance Entity Group Intermediate Point Identifiers . 15 7.3. Maintenance Entity Group Intermediate Point Identifiers ...15
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 8. Security Considerations ........................................15
9. Security Considerations . . . . . . . . . . . . . . . . . . . 15 9. References .....................................................16
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 9.1. Normative References ......................................16
10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 9.2. Informative References ....................................17
10.2. Informative References . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
This document specifies an initial set of identifiers to be used in This document specifies an initial set of identifiers to be used in
the Transport Profile of Multiprotocol Label Switching (MPLS-TP). the Transport Profile of Multiprotocol Label Switching (MPLS-TP).
The MPLS-TP requirements (RFC 5654) [7] require that the elements and The MPLS-TP requirements (RFC 5654 [7]) require that the elements and
objects in an MPLS-TP environment are able to be configured and objects in an MPLS-TP environment are able to be configured and
managed without a control plane. In such an environment many managed without a control plane. In such an environment, many
conventions for defining identifiers are possible. This document conventions for defining identifiers are possible. This document
defines identifiers for MPLS-TP management and OAM functions defines identifiers for MPLS-TP management and OAM functions
compatible with IP/MPLS conventions. That is, the identifiers have compatible with IP/MPLS conventions. That is, the identifiers have
been chosen to be compatible with existing IP, MPLS, GMPLS, and been chosen to be compatible with existing IP, MPLS, GMPLS, and
Pseudowire definitions. Pseudowire definitions.
This document is a product of a joint Internet Engineering Task Force This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunication Union Telecommunication (IETF) / International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) effort to include an MPLS Transport Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
(PWE3) architectures to support the capabilities and functionalities (PWE3) architectures to support the capabilities and functionalities
of a packet transport network as defined by the ITU-T. of a packet transport network as defined by the ITU-T.
1.1. Terminology 1.1. Terminology
AGI: Attachment Group Identifier
AII: Attachment Interface Identifier AII: Attachment Interface Identifier
AS: Autonomous System
ASN: Autonomous System Number ASN: Autonomous System Number
EGP: Exterior Gateway Protocol EGP: Exterior Gateway Protocol
FEC: Forwarding Equivalence Class FEC: Forwarding Equivalence Class
GMPLS: Generalized Multi-Protocol Label Switching GMPLS: Generalized Multiprotocol Label Switching
IGP: Interior Gateway Protocol IGP: Interior Gateway Protocol
LSP: Label Switched Path LSP: Label Switched Path
LSR: Label Switching Router LSR: Label Switching Router
MEG: Maintenance Entity Group MEG: Maintenance Entity Group
MEP: Maintenance Entity Group End Point MEP: Maintenance Entity Group End Point
MIP: Maintenance Entity Group Intermediate Point MIP: Maintenance Entity Group Intermediate Point
MPLS: Multiprotocol Label Switching
MPLS: Multi-Protocol Label Switching
NNI: Network-to-Network Interface NNI: Network-to-Network Interface
OAM: Operations, Administration and Maintenance
P2P: Point to Point OAM: Operations, Administration, and Maintenance
PW: Pseudowire PW: Pseudowire
RSVP: Resource Reservation Protocol RSVP: Resource Reservation Protocol
RSVP-TE: RSVP Traffic Engineering RSVP-TE: RSVP Traffic Engineering
SPME: Sub Path Maintenance Entities SAII: Source AII
S-PE: Switching Provider Edge SPME: Sub-Path Maintenance Entity
T-PE: Terminating Provider Edge T-PE: Terminating Provider Edge
TAII: Target AII
1.2. Requirements Language 1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [1]. document are to be interpreted as described in RFC 2119 [1].
1.3. Notational Conventions 1.3. Notational Conventions
All multiple-word atomic identifiers use underscores (_) between the All multiple-word atomic identifiers use underscores (_) between the
words to join the words. Many of the identifiers are composed of a words to join the words. Many of the identifiers are composed of a
set of other identifiers. These are expressed by listing the latter set of other identifiers. These are expressed by listing the latter
identifiers joined with double-colon, "::", notation. identifiers joined with double-colon "::" notation.
Where the same identifier type is used multiple times in a Where the same identifier type is used multiple times in a
concatenation, they are qualified by a prefix joined to the concatenation, they are qualified by a prefix joined to the
identifier by a dash (-). For example A1-Node_ID is the Node_ID of a identifier by a dash (-). For example, A1-Node_ID is the Node_ID of
node referred to as A1. a node referred to as A1.
The notation defines a preferred ordering of the fields. The notation defines a preferred ordering of the fields.
Specifically the designation A1 is used to indicate the lower sort Specifically, the designation A1 is used to indicate the lower sort
order of a field or set of fields and Z9 is used to indicate the order of a field or set of fields and Z9 is used to indicate the
higher sort order of the same. The sort is either alphanumeric or higher sort order of the same. The sort is either alphanumeric or
numeric depending on the field's definition. Where the sort applies numeric depending on the field's definition. Where the sort applies
to a group of fields, those fields are grouped with {...}. to a group of fields, those fields are grouped with {...}.
Note, however, that the uniqueness of an identifier does not depend Note, however, that the uniqueness of an identifier does not depend
on the ordering, but rather, upon the uniqueness and scoping of the on the ordering, but rather, upon the uniqueness and scoping of the
fields that compose the identifier. Further the preferred ordering fields that compose the identifier. Further, the preferred ordering
is not intended to constrain protocol designs by dictating a is not intended to constrain protocol designs by dictating a
particular field sequence (for example see Section 5.2.1) or even particular field sequence (for example, see Section 5.2.1) or even
what fields appear in which objects (for example see Section 5.3). what fields appear in which objects (for example, see Section 5.3).
2. Named Entities 2. Named Entities
In order to configure, operate and manage a transport network based In order to configure, operate, and manage a transport network based
on the MPLS Transport Profile, a number of entities require on the MPLS Transport Profile, a number of entities require
identification. Identifiers for the following entities are defined identification. Identifiers for the following entities are defined
in this document: in this document:
* Global_ID * Global_ID
* Node * Node
* Interface * Interface
skipping to change at page 5, line 30 skipping to change at page 5, line 33
* LSP * LSP
* PW * PW
* MEG * MEG
* MEP * MEP
* MIP * MIP
Note that we have borrowed the term tunnel from RSVP-TE (RFC 3209) Note that we have borrowed the term "tunnel" from RSVP-TE (RFC 3209
[2] where it is used to describe an entity that provides a logical [2]) where it is used to describe an entity that provides a logical
association between a source and destination LSR. The tunnel in turn association between a source and destination LSR. The tunnel, in
is instantiated by one or more LSPs, where the additional LSPs are turn, is instantiated by one or more LSPs, where the additional LSPs
used for protection or re-grooming of the tunnel. are used for protection or re-grooming of the tunnel.
3. Uniquely Identifying an Operator - the Global_ID 3. Uniquely Identifying an Operator - the Global_ID
The Global_ID is defined to uniquely identify an operator. RFC 5003 The Global_ID is defined to uniquely identify an operator. RFC 5003
[3] defines a globally unique Attachment Interface Identifier (AII). [3] defines a globally unique Attachment Interface Identifier (AII).
That AII is composed of three parts, a Global_ID which uniquely That AII is composed of three parts: a Global_ID that uniquely
identifies an operator, a prefix, and finally, an attachment circuit identifies an operator, a prefix, and, finally, an attachment circuit
identifier. We have chosen to use that Global ID for MPLS-TP. identifier. We have chosen to use that Global ID for MPLS-TP.
Quoting from RFC 5003, section 3.2, "The global ID can contain the Quoting from RFC 5003, Section 3.2:
2-octet or 4-octet value of the operator's Autonomous System Number
(ASN). It is expected that the global ID will be derived from the The global ID can contain the 2-octet or 4-octet value of the
globally unique ASN of the autonomous system hosting the PEs provider's Autonomous System Number (ASN). It is expected that
containing the actual AIIs. The presence of a global ID based on the the global ID will be derived from the globally unique ASN of the
operator's ASN ensures that the AII will be globally unique." autonomous system hosting the PEs containing the actual AIIs. The
presence of a global ID based on the operator's ASN ensures that
the AII will be globally unique.
A Global_ID is an unsigned 32-bit value and MUST be derived from a A Global_ID is an unsigned 32-bit value and MUST be derived from a
4-octet AS number assigned to the operator. Note that 2-octet AS 4-octet AS number assigned to the operator. Note that 2-octet AS
numbers have been incorporated in the 4-octet by placing the 2-octet numbers have been incorporated in the 4-octet by placing the 2-octet
AS number, in the low-order octets and setting the two high-order AS number in the low-order octets and setting the two high-order
octets to zero. octets to zero.
ASN 0 is reserved and cannot be assigned to an operator. An ASN 0 is reserved and cannot be assigned to an operator. An
identifier containing a Global_ID of zero means that no Global_ID is identifier containing a Global_ID of zero means that no Global_ID is
specified. Note that a Global_ID of zero is limited to entities specified. Note that a Global_ID of zero is limited to entities
contained within a single operator and MUST NOT be used across an contained within a single operator and MUST NOT be used across an
NNI. NNI.
The Global_ID is used solely to provide a globally unique context for The Global_ID is used solely to provide a globally unique context for
other MPLS-TP identifiers. While the AS Number used in the Global_ID other MPLS-TP identifiers. While the AS number used in the Global_ID
MUST be one which the operator is entitled to use, the use of the MUST be one that the operator is entitled to use, the use of the
Global_ID is not related to the use of the ASN in protocols such as Global_ID is not related to the use of the ASN in protocols such as
BGP. BGP.
4. Node and Interface Identifiers 4. Node and Interface Identifiers
An LSR requires identification of the node itself and of its An LSR requires identification of the node itself and of its
interfaces. An interface is the attachment point to a server interfaces. An interface is the attachment point to a server
(sub-)layer, e.g., MPLS-TP section or MPLS-TP tunnel. (sub-)layer, e.g., MPLS-TP section or MPLS-TP tunnel.
We call the identifier associated with a node a Node Identifier We call the identifier associated with a node a "Node Identifier"
(Node_ID). The Node_ID is a unique 32-bit value assigned by the (Node_ID). The Node_ID is a unique 32-bit value assigned by the
operator within the scope of a Global_ID. The structure of the operator within the scope of a Global_ID. The structure of the
Node_ID is operator specific and is outside the scope of this Node_ID is operator-specific and is outside the scope of this
document. However, the value zero is reserved and MUST NOT be used. document. However, the value zero is reserved and MUST NOT be used.
Where IPv4 addresses are used, it may be convenient to use the Node's Where IPv4 addresses are used, it may be convenient to use the Node's
IPv4 loopback address as the Node_ID, however the Node_ID does not IPv4 loopback address as the Node_ID; however, the Node_ID does not
need to have any association with the IPv4 address space used in the need to have any association with the IPv4 address space used in the
operator's IGP or EGP. Where IPv6 addresses are used exclusively, a operator's IGP or EGP. Where IPv6 addresses are used exclusively, a
32-bit value unique within the scope of a Global_ID is assigned. 32-bit value unique within the scope of a Global_ID is assigned.
An LSR can support multiple layers (e.g. hierarchical LSPs) and the An LSR can support multiple layers (e.g., hierarchical LSPs) and the
Node_ID belongs to the multiple layer context i.e. it is applicable Node_ID belongs to the multiple-layer context, i.e., it is applicable
to all LSPs or PWs that originate on, have a intermediate point on, to all LSPs or PWs that originate on, have an intermediate point on,
or terminate on the node. or terminate on the node.
In situations where a Node_ID needs to be globally unique, this is In situations where a Node_ID needs to be globally unique, this is
accomplished by prefixing the identifier with the operator's accomplished by prefixing the identifier with the operator's
Global_ID. Global_ID.
The term interface is used for the attachment point to an MPLS-TP The term "interface" is used for the attachment point to an MPLS-TP
section. Within the context of a particular node, we call the section. Within the context of a particular node, we call the
identifier associated with an interface an Interface Number (IF_Num). identifier associated with an interface an "Interface Number"
The IF_Num is a 32-bit unsigned integer assigned by the operator and (IF_Num). The IF_Num is a 32-bit unsigned integer assigned by the
MUST be unique within the scope of a Node_ID. The IF_Num value 0 has operator and MUST be unique within the scope of a Node_ID. The
special meaning (see Section 7.3, MIP Identifiers) and MUST NOT be IF_Num value 0 has special meaning (see Section 7.3, MIP Identifiers)
used to identify an MPLS-TP interface. and MUST NOT be used to identify an MPLS-TP interface.
Note that IF_Num has no relation with the ifNum object defined in RFC Note that IF_Num has no relation with the ifNum object defined in RFC
2863 [8]. Further, no mapping is mandated between IF_Num and ifIndex 2863 [8]. Further, no mapping is mandated between IF_Num and ifIndex
in RFC 2863. in RFC 2863.
An Interface Identifier (IF_ID) identifies an interface uniquely An "Interface Identifier" (IF_ID) identifies an interface uniquely
within the context of a Global_ID. It is formed by concatenating the within the context of a Global_ID. It is formed by concatenating the
Node_ID with the IF_Num. That is, an IF_ID is a 64-bit identifier Node_ID with the IF_Num. That is, an IF_ID is a 64-bit identifier
formed as Node_ID::IF_Num. formed as Node_ID::IF_Num.
This convention was chosen to allow compatibility with GMPLS. The This convention was chosen to allow compatibility with GMPLS. The
GMPLS signaling functional description [4] requires interface GMPLS signaling functional description [4] requires interface
identification. GMPLS allows three formats for the Interface_ID. identification. GMPLS allows three formats for the Interface_ID.
The third format consists of an IPv4 Address plus a 32-bit unsigned The third format consists of an IPv4 address plus a 32-bit unsigned
integer for the specific interface. The format defined for MPLS-TP integer for the specific interface. The format defined for MPLS-TP
is consistent with this format, but uses the Node_ID instead of an is consistent with this format, but uses the Node_ID instead of an
IPv4 Address. IPv4 address.
If an IF_ID needs to be globally unique, this is accomplished by If an IF_ID needs to be globally unique, this is accomplished by
prefixing the identifier with the operator's Global_ID. prefixing the identifier with the operator's Global_ID.
Note that MPLS-TP supports hierarchical sections. The attachment Note that MPLS-TP supports hierarchical sections. The attachment
point to a MPLS-TP Section at any (sub-)layer requires a node-unique point to an MPLS-TP section at any (sub-)layer requires a node-unique
IF_Num. IF_Num.
5. MPLS-TP Tunnel and LSP Identifiers 5. MPLS-TP Tunnel and LSP Identifiers
In MPLS the actual transport of packets is provided by label switched In MPLS, the actual transport of packets is provided by Label
paths (LSPs). A transport service may be composed of multiple LSPs. Switched Paths (LSPs). A transport service may be composed of
Further the LSPs providing a service may change over time due to multiple LSPs. Further, the LSPs providing a service may change over
protection and restoration events. In order to clearly identify the time due to protection and restoration events. In order to clearly
service we use the term "MPLS-TP Tunnel" or simply "tunnel" for a identify the service, we use the term "MPLS-TP Tunnel" or simply
service provided by (for example) a working LSP and protected by a "tunnel" for a service provided by (for example) a working LSP and
protection LSP. The Tunnel Identifier (Tunnel_ID) identifies the protected by a protection LSP. The "Tunnel Identifier" (Tunnel_ID)
transport service and provides a stable binding to the client in the identifies the transport service and provides a stable binding to the
face of changes in the data plane LSPs used to provide the service client in the face of changes in the data-plane LSPs used to provide
due to protection or restoration events. This section defines an the service due to protection or restoration events. This section
MPLS-TP Tunnel_ID to uniquely identify a tunnel, and an MPLS-TP LSP defines an MPLS-TP Tunnel_ID to uniquely identify a tunnel, and an
Identifier (LSP_ID) to uniquely identify an LSP associated with a MPLS-TP LSP Identifier (LSP_ID) to uniquely identify an LSP
tunnel. associated with a tunnel.
For the case where multiple LSPs (for example) are used to support a For the case where multiple LSPs (for example) are used to support a
single service with a common set of end-points, using the Tunnel_ID single service with a common set of end points, using the Tunnel_ID
allows for a trivial mapping between the server and client layers, allows for a trivial mapping between the server and client layers,
providing a common service identifier which may be either defined by, providing a common service identifier that may be either defined by
or used by, the client. or used by the client.
Note that this usage is not intended to constrain protection schemes, Note that this usage is not intended to constrain protection schemes,
and may be used to identify any service (protected or unprotected) and may be used to identify any service (protected or unprotected)
that may appear to the client as a single service attachment point. that may appear to the client as a single service attachment point.
Keeping the Tunnel_ID consistent across working and protection LSPs Keeping the Tunnel_ID consistent across working and protection LSPs
is a useful construct currently employed within GMPLS. However, the is a useful construct currently employed within GMPLS. However, the
Tunnel_ID for a protection LSP MAY differ from that used by its Tunnel_ID for a protection LSP MAY differ from that used by its
corresponding working LSP. corresponding working LSP.
5.1. MPLS-TP Point to Point Tunnel Identifiers 5.1. MPLS-TP Point-to-Point Tunnel Identifiers
At each endpoint a tunnel is uniquely identified by the endpoint's At each end point, a tunnel is uniquely identified by the end point's
Node_ID and a locally assigned tunnel number. Specifically a Tunnel Node_ID and a locally assigned tunnel number. Specifically, a
Number (Tunnel_Num) is a 16-bit unsigned integer unique within the "Tunnel Number" (Tunnel_Num) is a 16-bit unsigned integer unique
context of the Node_ID. The motivation for each endpoint having its within the context of the Node_ID. The motivation for each end point
own tunnel number is to allow a compact form for the MEP_ID. See having its own tunnel number is to allow a compact form for the
Section 7.2.2. MEP_ID. See Section 7.2.2.
Having two tunnel numbers also serves to simplify other signaling Having two tunnel numbers also serves to simplify other signaling
(e.g., setup of associated bidirectional tunnels as described in (e.g., setup of associated bidirectional tunnels as described in
Section 5.3). Section 5.3).
The concatenation of the two endpoint identifiers serves as the full The concatenation of the two end point identifiers serves as the full
identifier. Using the A1/Z9 convention the format of a Tunnel_ID is: identifier. Using the A1/Z9 convention, the format of a Tunnel_ID
is:
A1-{Node_ID::Tunnel_Num}::Z9-{Node_ID::Tunnel_Num} A1-{Node_ID::Tunnel_Num}::Z9-{Node_ID::Tunnel_Num}
Where the Tunnel_ID needs to be globally unique, this is accomplished Where the Tunnel_ID needs to be globally unique, this is accomplished
by using globally unique Node_IDs as defined above. Thus a globally by using globally unique Node_IDs as defined above. Thus, a globally
unique Tunnel_ID becomes: unique Tunnel_ID becomes:
A1-{Global_ID::Node_ID::Tunnel_Num}::Z9-{Global_ID::Node_ID:: A1-{Global_ID::Node_ID::Tunnel_Num}::Z9-{Global_ID::Node_ID::
Tunnel_Num} Tunnel_Num}
When an MPLS-TP Tunnel is configured, it MUST be assigned a unique When an MPLS-TP Tunnel is configured, it MUST be assigned a unique
IF_ID at each endpoint. As usual, the IF_ID is composed of the local IF_ID at each end point. As usual, the IF_ID is composed of the
Node_ID concatenated with a 32-bit IF_Num. local Node_ID concatenated with a 32-bit IF_Num.
5.2. MPLS-TP LSP Identifiers 5.2. MPLS-TP LSP Identifiers
This section defines identifiers for MPLS-TP co-routed bidirectional This section defines identifiers for MPLS-TP co-routed bidirectional
and associated bidirectional LSPs. Note that MPLS-TP Sub Path and associated bidirectional LSPs. Note that MPLS-TP Sub-Path
Maintenance Entities (SPMEs) as defined in RFC 5921 [9] are also LSPs Maintenance Entities (SPMEs), as defined in RFC 5921 [9], are also
and use these same forms of identifiers. LSPs and use these same forms of identifiers.
5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers 5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers
A co-routed bidirectional LSP can be uniquely identified by a single A co-routed bidirectional LSP can be uniquely identified by a single
LSP number within the scope of an MPLS-TP Tunnel_ID. Specifically an LSP number within the scope of an MPLS-TP Tunnel_ID. Specifically,
LSP Number (LSP_Num) is a 16-bit unsigned integer unique within the an LSP Number (LSP_Num) is a 16-bit unsigned integer unique within
Tunnel_ID. Thus the format of an MPLS-TP co-routed bidirectional the Tunnel_ID. Thus, the format of an MPLS-TP co-routed
LSP_ID is: bidirectional LSP_ID is:
A1-{Node_ID::Tunnel_Num}::Z9-{Node_ID::Tunnel_Num}::LSP_Num A1-{Node_ID::Tunnel_Num}::Z9-{Node_ID::Tunnel_Num}::LSP_Num
Note that the uniqueness of identifiers does not depend on the A1/Z9 Note that the uniqueness of identifiers does not depend on the A1/Z9
sort ordering. Thus the identifier sort ordering. Thus, the identifier:
Z9-{Node_ID::Tunnel_Num}::A1-{Node_ID::Tunnel_Num}::LSP_Num Z9-{Node_ID::Tunnel_Num}::A1-{Node_ID::Tunnel_Num}::LSP_Num
is synonymous with the one above. is synonymous with the one above.
At the dataplane level, a co-routed bidirectional LSP is composed of At the data-plane level, a co-routed bidirectional LSP is composed of
two unidirectional LSPs traversing the same links in opposite two unidirectional LSPs traversing the same links in opposite
directions. Since a co-routed bidirectional LSP is provisioned or directions. Since a co-routed bidirectional LSP is provisioned or
signaled as a single entity, a single LSP_Num is used for both signaled as a single entity, a single LSP_Num is used for both
unidirectional LSPs. The unidirectional LSPs can be referenced by unidirectional LSPs. The unidirectional LSPs can be referenced by
the identifiers: the identifiers:
A1-Node_ID::A1-Tunnel_Num::LSP_Num::Z9-Node_ID and A1-Node_ID::A1-Tunnel_Num::LSP_Num::Z9-Node_ID and
Z9-Node_ID::Z9-Tunnel_Num::LSP_Num::A1-Node_ID respectively. Z9-Node_ID::Z9-Tunnel_Num::LSP_Num::A1-Node_ID, respectively.
Where the LSP_ID needs to be globally unique, this is accomplished by Where the LSP_ID needs to be globally unique, this is accomplished by
using globally unique Node_IDs as defined above. Thus a globally using globally unique Node_IDs as defined above. Thus, a globally
unique LSP_ID becomes: unique LSP_ID becomes:
A1-{Global_ID::Node_ID::Tunnel_Num}::Z9-{Global_ID:: A1-{Global_ID::Node_ID::Tunnel_Num}::Z9-{Global_ID::
Node_ID::Tunnel_Num}::LSP_Num Node_ID::Tunnel_Num}::LSP_Num
5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers 5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers
For an associated bidirectional LSP each of the unidirectional LSPs For an associated bidirectional LSP, each of the unidirectional LSPs
from A1 to Z9 and Z9 to A1 require LSP_Nums. Each unidirectional LSP from A1 to Z9 and Z9 to A1 require LSP_Nums. Each unidirectional LSP
is uniquely identified by a single LSP number within the scope of the is uniquely identified by a single LSP number within the scope of the
ingress's Tunnel_Num. Specifically an LSP Number (LSP_Num) is a 16- ingress's Tunnel_Num. Specifically, an "LSP Number" (LSP_Num) is a
bit unsigned integer unique within the scope of the ingress's 16-bit unsigned integer unique within the scope of the ingress's
Tunnel_Num. Thus the format of an MPLS-TP associated bidirectional Tunnel_Num. Thus, the format of an MPLS-TP associated bidirectional
LSP_ID is: LSP_ID is:
A1-{Node_ID::Tunnel_Num::LSP_Num}:: A1-{Node_ID::Tunnel_Num::LSP_Num}::
Z9-{Node_ID::Tunnel_Num::LSP_Num} Z9-{Node_ID::Tunnel_Num::LSP_Num}
At the dataplane level, an associated bidirectional LSP is composed At the data-plane level, an associated bidirectional LSP is composed
of two unidirectional LSPs between two nodes in opposite directions. of two unidirectional LSPs between two nodes in opposite directions.
The unidirectional LSPs may be referenced by the identifiers: The unidirectional LSPs may be referenced by the identifiers:
A1-Node_ID::A1-Tunnel_Num::A1-LSP_Num::Z9-Node_ID and A1-Node_ID::A1-Tunnel_Num::A1-LSP_Num::Z9-Node_ID and
Z9-Node_ID::Z9-Tunnel_Num::Z9-LSP_Num::A1-Node_ID respectively. Z9-Node_ID::Z9-Tunnel_Num::Z9-LSP_Num::A1-Node_ID, respectively.
Where the LSP_ID needs to be globally unique, this is accomplished by Where the LSP_ID needs to be globally unique, this is accomplished by
using globally unique Node_IDs as defined above. Thus a globally using globally unique Node_IDs as defined above. Thus, a globally
unique LSP_ID becomes: unique LSP_ID becomes:
A1-{Global_ID::Node_ID::Tunnel_Num::LSP_Num}:: A1-{Global_ID::Node_ID::Tunnel_Num::LSP_Num}::
Z9-{Global_ID::Node_ID::Tunnel_Num::LSP_Num} Z9-{Global_ID::Node_ID::Tunnel_Num::LSP_Num}
5.3. Mapping to RSVP Signaling 5.3. Mapping to RSVP Signaling
This section is informative and exists to help understand the This section is informative and exists to help understand the
structure of the LSP IDs. structure of the LSP IDs.
GMPLS [5] is based on RSVP-TE [2]. This section defines the mapping GMPLS [5] is based on RSVP-TE [2]. This section defines the mapping
from an MPLS-TP LSP_ID to RSVP-TE. At this time, RSVP-TE has yet to from an MPLS-TP LSP_ID to RSVP-TE. At this time, RSVP-TE has yet to
be extended to accommodate Global_IDs. Thus a mapping is only made be extended to accommodate Global_IDs. Thus, a mapping is only made
for the network unique form of the LSP_ID and assumes that the for the network unique form of the LSP_ID and assumes that the
operator has chosen to derive its Node_IDs from valid IPv4 addresses. operator has chosen to derive its Node_IDs from valid IPv4 addresses.
GMPLS and RSVP-TE signaling use a 5-tuple to uniquely identify an LSP GMPLS and RSVP-TE signaling use a 5-tuple to uniquely identify an LSP
within a operator's network. This tuple is composed of a Tunnel within an operator's network. This tuple is composed of a Tunnel
Endpoint Address, Tunnel_ID, Extended Tunnel ID, and Tunnel Sender End-point Address, Tunnel_ID, Extended Tunnel ID, Tunnel Sender
Address and (RSVP) LSP_ID. RFC 3209 allows some flexibility in how Address, and (RSVP) LSP_ID. RFC 3209 allows some flexibility in how
the Extended Tunnel ID is chosen and a direct mapping is not the Extended Tunnel ID is chosen, and a direct mapping is not
mandated. One convention that is often used, however, is to populate mandated. One convention that is often used, however, is to populate
this field with the same value as the Tunnel Sender Address. The this field with the same value as the Tunnel Sender Address. The
examples below follow that convention. Note that these are only examples below follow that convention. Note that these are only
examples. examples.
For a co-routed bidirectional LSP signaled from A1 to Z9, the mapping For a co-routed bidirectional LSP signaled from A1 to Z9, the mapping
to the GMPLS 5-tuple is as follows: to the GMPLS 5-tuple is as follows:
* Tunnel Endpoint Address = Z9-Node_ID * Tunnel End-point Address = Z9-Node_ID
* Tunnel_ID = A1-Tunnel_Num * Tunnel_ID = A1-Tunnel_Num
* Extended Tunnel_ID = A1-Node_ID * Extended Tunnel_ID = A1-Node_ID
* Tunnel Sender Address = A1-Node_ID * Tunnel Sender Address = A1-Node_ID
* (RSVP) LSP_ID = LSP_Num * (RSVP) LSP_ID = LSP_Num
An associated bidirectional LSP between two nodes A1 and Z9 consists An associated bidirectional LSP between two nodes A1 and Z9 consists
of two unidirectional LSPs, one from A1 to Z9 and one from Z9 to A1. of two unidirectional LSPs, one from A1 to Z9 and one from Z9 to A1.
In situations where a mapping to the RSVP-TE 5-tuples is required, In situations where a mapping to the RSVP-TE 5-tuples is required,
the following mappings are used. For the A1 to Z9 LSP the mapping the following mappings are used. For the A1 to Z9 LSP, the mapping
would be: would be:
* Tunnel Endpoint Address = Z9-Node_ID * Tunnel End-point Address = Z9-Node_ID
* Tunnel_ID = A1-Tunnel_Num * Tunnel_ID = A1-Tunnel_Num
* Extended Tunnel_ID = A1-Node_ID * Extended Tunnel_ID = A1-Node_ID
* Tunnel Sender Address = A1-Node_ID * Tunnel Sender Address = A1-Node_ID
* (RSVP) LSP_ID = A1-LSP_Num * (RSVP) LSP_ID = A1-LSP_Num
Likewise, the Z9 to A1 LSP, the mapping would be: Likewise, the Z9 to A1 LSP, the mapping would be:
* Tunnel Endpoint Address = A1-Node_ID * Tunnel End-point Address = A1-Node_ID
* Tunnel_ID = Z9-Tunnel_Num * Tunnel_ID = Z9-Tunnel_Num
* Extended Tunnel_ID = Z9-Node_ID * Extended Tunnel_ID = Z9-Node_ID
* Tunnel Sender Address = Z9-Node_ID * Tunnel Sender Address = Z9-Node_ID
* (RSVP) LSP_ID = Z9-LSP_Num * (RSVP) LSP_ID = Z9-LSP_Num
6. Pseudowire Path Identifiers 6. Pseudowire Path Identifiers
Pseudowire signaling (RFC 4447 [6]) defines two FECs used to signal Pseudowire signaling (RFC 4447 [6]) defines two FECs used to signal
pseudowires. Of these, FEC Type 129 along with AII Type 2 as defined pseudowires. Of these, the Generalized PWid FEC (type 129) along
in RFC 5003 [3] fits the identification requirements of MPLS-TP. with AII Type 2 as defined in RFC 5003 [3] fits the identification
requirements of MPLS-TP.
In an MPLS-TP environment, a PW is identified by a set of identifiers In an MPLS-TP environment, a PW is identified by a set of identifiers
which can be mapped directly to the elements required by FEC 129 and that can be mapped directly to the elements required by the
AII Type 2. To distinguish this identifier from other Pseudowire Generalized PWid FEC (type 129) and AII Type 2. To distinguish this
Identifiers, we call this a Pseudowire Path Identifier (PW_Path_ID). identifier from other Pseudowire Identifiers, we call this a
Pseudowire Path Identifier (PW_Path_ID).
The AII Type 2 is composed of three fields. These are the Global_ID, The AII Type 2 is composed of three fields. These are the Global_ID,
the Prefix, and the AC_ID. The Global_ID used in this document is the Prefix, and the AC_ID. The Global_ID used in this document is
identical to the Global_ID defined in RFC 5003. The Node_ID is used identical to the Global_ID defined in RFC 5003. The Node_ID is used
as the Prefix. The AC_ID is as defined in RFC 5003. as the Prefix. The AC_ID is as defined in RFC 5003.
To complete the FEC 129, all that is required is an Attachment Group To complete the Generalized PWid FEC (type 129), all that is required
Identifier (AGI). That field is exactly as specified in RFC 4447. A is an Attachment Group Identifier (AGI). That field is exactly as
(bidirectional) pseudowire consists of a pair of unidirectional LSPs, specified in RFC 4447. A (bidirectional) pseudowire consists of a
one in each direction. Thus for signaling, FEC 129 has a notion of pair of unidirectional LSPs, one in each direction. Thus, for
Source AII (SAII) and Target AII (TAII). These terms are used signaling, the Generalized PWid FEC (type 129) has a notion of Source
relative to the direction of the LSP. AII (SAII) and Target AII (TAII). These terms are used relative to
the direction of the LSP, i.e., the SAII is assigned to the end that
allocates the PW label for a given direction, and the TAII to the
other end.
In a purely configured environment when referring to the entire PW, In a purely configured environment, when referring to the entire PW,
this distinction is not critical. That is a FEC 129 of AGIa::AIIb:: this distinction is not critical. That is, a Generalized PWid FEC
AIIc is equivalent to AGIa::AIIc::AIIb. (type 129) of AGIa::AIIb::AIIc is equivalent to AGIa::AIIc::AIIb.
We note that in a signaled environment, the required convention in We note that in a signaled environment, the required convention in
RFC 4447 is that at a particular endpoint, the AII associated with RFC 4447 is that at a particular end point, the AII associated with
that endpoint comes first. The complete PW_Path_ID is: that end point comes first. The complete PW_Path_ID is:
AGI::A1-{Global_ID::Node_ID::AC_ID}:: AGI::A1-{Global_ID::Node_ID::AC_ID}::
Z9-{Global_ID::Node_ID::AC_ID}. Z9-{Global_ID::Node_ID::AC_ID}.
In a signaled environment the LSP from A1 to Z9 would be initiated In a signaled environment the LSP from A1 to Z9 would be initiated
with a label request from A1 to Z9 with the fields of the FEC 129 with a label request from A1 to Z9 with the fields of the Generalized
completed as follows: PWid FEC (type 129) completed as follows:
AGI = AGI AGI = AGI
SAII = A1-{Global_ID::Node_ID::AC_ID} SAII = A1-{Global_ID::Node_ID::AC_ID}
TAII = Z9-{Global_ID::Node_ID::AC_ID} TAII = Z9-{Global_ID::Node_ID::AC_ID}
The LSP from Z9 to A1 would signaled with: The LSP from Z9 to A1 would signaled with:
AGI = AGI AGI = AGI
SAII = Z9-{Global_ID::Node_ID::AC_ID} SAII = Z9-{Global_ID::Node_ID::AC_ID}
TAII = A1-{Global_ID::Node_ID::AC_ID} TAII = A1-{Global_ID::Node_ID::AC_ID}
7. Maintenance Identifiers 7. Maintenance Identifiers
In MPLS-TP a Maintenance Entity Group (MEG) represents an Entity that In MPLS-TP, a Maintenance Entity Group (MEG) represents an entity
requires management and defines a relationship between a set of that requires management and defines a relationship between a set of
maintenance points. A maintenance point is either a Maintenance maintenance points. A maintenance point is either a Maintenance
Entity Group End-point (MEP), a Maintenance Entity Group Intermediate Entity Group End Point (MEP), a Maintenance Entity Group Intermediate
Point (MIP), or a Pseudowire Segment Endpoint. Within the context of Point (MIP), or a Pseudowire Segment End Point. Within the context
a MEG, MEPs and MIPs must be uniquely identified. This section of a MEG, MEPs and MIPs must be uniquely identified. This section
defines a means of uniquely identifying Maintenance Entity Groups, defines a means of uniquely identifying Maintenance Entity Groups and
Maintenance Entities and uniquely defining MEPs and MIPs within the Maintenance Entities. It also uniquely defines MEPs and MIPs within
context of a Maintenance Entity Group. the context of a Maintenance Entity Group.
7.1. Maintenance Entity Group Identifiers 7.1. Maintenance Entity Group Identifiers
Maintenance Entity Group Identifiers (MEG_IDs) are required for Maintenance Entity Group Identifiers (MEG_IDs) are required for
MPLS-TP sections, LSPs and Pseudowires. The formats were chosen to MPLS-TP sections, LSPs, and Pseudowires. The formats were chosen to
follow the IP compatible identifiers defined above. follow the IP-compatible identifiers defined above.
7.1.1. MPLS-TP Section MEG_IDs 7.1.1. MPLS-TP Section MEG_IDs
MPLS-TP allows a hierarchy of sections. See "MPLS-TP Data Plane MPLS-TP allows a hierarchy of sections. See "MPLS-TP Data Plane
Architecture" (RFC 5960)[10]. Sections above layer 0 are MPLS-TP Architecture" (RFC 5960 [10]). Sections above layer 0 are MPLS-TP
LSPs. These use their MPLS-TP LSP MEG IDs defined in Section 7.1.2. LSPs. These use their MPLS-TP LSP MEG IDs defined in Section 7.1.2.
IP compatible MEG_IDs for MPLS-TP sections at layer 0 are formed by IP-compatible MEG_IDs for MPLS-TP sections at layer 0 are formed by
concatenating the two IF_IDs of the corresponding section using the concatenating the two IF_IDs of the corresponding section using the
A1/Z9 ordering. For example: A1/Z9 ordering. For example:
A1-IF_ID::Z9-IF_ID A1-IF_ID::Z9-IF_ID
Where the Section_MEG_ID needs to be globally unique, this is Where the Section_MEG_ID needs to be globally unique, this is
accomplished by using globally unique Node_IDs as defined above. accomplished by using globally unique Node_IDs as defined above.
Thus a globally unique Section_MEG_ID becomes: Thus, a globally unique Section_MEG_ID becomes:
A1-{Global_ID::IF_ID}::Z9-{Global_ID::IF_ID} A1-{Global_ID::IF_ID}::Z9-{Global_ID::IF_ID}
7.1.2. MPLS-TP LSP MEG_IDs 7.1.2. MPLS-TP LSP MEG_IDs
A MEG pertains to a unique MPLS-TP LSP. IP compatible MEG_IDs for A MEG pertains to a unique MPLS-TP LSP. IP compatible MEG_IDs for
MPLS-TP LSPs are simply the corresponding LSP_IDs, however, the A1/Z9 MPLS-TP LSPs are simply the corresponding LSP_IDs; however, the A1/Z9
ordering MUST be used. For bidirectional co-routed LSPs the format ordering MUST be used. For bidirectional co-routed LSPs, the format
of the LSP_ID is found in Section 5.2.1. For associated of the LSP_ID is found in Section 5.2.1. For associated
bidirectional LSPs the format is in Section 5.2.2. bidirectional LSPs, the format is in Section 5.2.2.
We note that while the two identifiers are syntactically identical, We note that while the two identifiers are syntactically identical,
they have different semantics. This semantic difference needs to be they have different semantics. This semantic difference needs to be
made clear. For instance if both a MPLS-TP LSP_ID and MPLS-TP LSP made clear. For instance, if both an MPLS-TP LSP_ID and MPLS-TP LSP
MEG_IDs are to be encoded in TLVs, different types need to be MEG_IDs are to be encoded in TLVs, different types need to be
assigned for these two identifiers. assigned for these two identifiers.
7.1.3. Pseudowire MEG_IDs 7.1.3. Pseudowire MEG_IDs
For Pseudowires a MEG pertains to a single PW. The IP compatible For Pseudowires, a MEG pertains to a single PW. The IP-compatible
MEG_ID for a PW is simply the corresponding PW_Path_ID, however, the MEG_ID for a PW is simply the corresponding PW_Path_ID; however, the
A1/Z9 ordering MUST be used. The PW_Path_ID is described in A1/Z9 ordering MUST be used. The PW_Path_ID is described in
Section 6. We note that while the two identifiers are syntactically Section 6. We note that while the two identifiers are syntactically
identical, they have different semantics. This semantic difference identical, they have different semantics. This semantic difference
needs to be made clear. For instance if both a PW_Path_ID and a needs to be made clear. For instance, if both a PW_Path_ID and a
PW_MEG_ID are to be encoded in TLVs, different types need to be PW_MEG_ID are to be encoded in TLVs, different types need to be
assigned for these two identifiers. assigned for these two identifiers.
7.2. Maintenance Entity Group End Point Identifiers 7.2. Maintenance Entity Group End Point Identifiers
7.2.1. MPLS-TP Section MEP_IDs 7.2.1. MPLS-TP Section MEP_IDs
IP compatible MEP_IDs for MPLS-TP sections above layer 0 are their IP-compatible MEP_IDs for MPLS-TP sections above layer 0 are their
MPLS-TP LSP_MEP_IDs. See Section 7.2.2. MPLS-TP LSP_MEP_IDs. See Section 7.2.2.
IP compatible MEP_IDs for MPLS-TP sections at layer 0 are simply the IP-compatible MEP_IDs for MPLS-TP sections at layer 0 are simply the
IF_IDs of each end of the section. For example, for a section whose IF_IDs of each end of the section. For example, for a section whose
MEG_ID is MEG_ID is:
A1-IF_ID::Z9-IF_ID A1-IF_ID::Z9-IF_ID
the Section MEP_ID at A1 would be the Section MEP_ID at A1 would be:
A1-IF_ID A1-IF_ID
and the Section MEP_ID at Z9 would be and the Section MEP_ID at Z9 would be:
Z9-IF_ID. Z9-IF_ID.
Where the Section MEP_ID needs to be globally unique, this is Where the Section MEP_ID needs to be globally unique, this is
accomplished by using globally unique Node_IDs as defined above. accomplished by using globally unique Node_IDs as defined above.
Thus a globally unique Section MEP_ID becomes Thus, a globally unique Section MEP_ID becomes:
Global_ID::IF_ID. Global_ID::IF_ID.
7.2.2. MPLS-TP LSP_MEP_ID 7.2.2. MPLS-TP LSP_MEP_ID
In order to automatically generate MEP_IDs for MPLS-TP LSPs, we use In order to automatically generate MEP_IDs for MPLS-TP LSPs, we use
the elements of identification that are unique to an endpoint. This the elements of identification that are unique to an end point. This
ensures that MEP_IDs are unique for all LSPs within a operator. When ensures that MEP_IDs are unique for all LSPs within an operator.
Tunnels or LSPs cross operator boundaries, these are made unique by When Tunnels or LSPs cross operator boundaries, these are made unique
pre-pending them with the operator's Global_ID. by pre-pending them with the operator's Global_ID.
The MPLS-TP LSP_MEP_ID is The MPLS-TP LSP_MEP_ID is:
Node_ID::Tunnel_Num::LSP_Num Node_ID::Tunnel_Num::LSP_Num
where the Node_ID is the node in which the MEP is located and where the Node_ID is the node in which the MEP is located and
Tunnel_Num is the tunnel number unique to that node. In the case of Tunnel_Num is the tunnel number unique to that node. In the case of
co-routed bidirectional LSPs, the single LSP_Num is used at both co-routed bidirectional LSPs, the single LSP_Num is used at both
ends. In the case of associated bidirectional LSPs, the LSP_Num is ends. In the case of associated bidirectional LSPs, the LSP_Num is
the one unique to where the MEP resides. the one unique to where the MEP resides.
In situations where global uniqueness is required this becomes: In situations where global uniqueness is required, this becomes:
Global_ID::Node_ID::Tunnel_Num::LSP_Num Global_ID::Node_ID::Tunnel_Num::LSP_Num
7.2.3. MEP_IDs for Pseudowires 7.2.3. MEP_IDs for Pseudowires
Like MPLS-TP LSPs, Pseudowire endpoints (T-PEs) require MEP_IDs. In Like MPLS-TP LSPs, Pseudowire end points (T-PEs) require MEP_IDs. In
order to automatically generate MEP_IDs for PWs, we simply use the order to automatically generate MEP_IDs for PWs, we simply use the
AGI plus the AII associated with that end of the PW. Thus a MEP_ID AGI plus the AII associated with that end of the PW. Thus, a MEP_ID
for a Pseudowire T-PE takes the form for a Pseudowire T-PE takes the form:
AGI::Global_ID::Node_ID::AC_ID AGI::Global_ID::Node_ID::AC_ID
where the Node_ID is the node in which the MEP is located and the where the Node_ID is the node in which the MEP is located and the
AC_ID is the AC_ID of the Pseudowire at that node. AC_ID is the AC_ID of the Pseudowire at that node.
7.3. Maintenance Entity Group Intermediate Point Identifiers 7.3. Maintenance Entity Group Intermediate Point Identifiers
For a MIP which is associated with particular interface, we simply For a MIP that is associated with a particular interface, we simply
use the IF_ID (see Section 4) of the interfaces which are cross- use the IF_ID (see Section 4) of the interfaces that are cross-
connected. This allows, MIPs to be independently identified in one connected. This allows MIPs to be independently identified in one
node where a per-interface MIP model is used. If only a per node MIP node where a per-interface MIP model is used. If only a per-node MIP
model is used then one MIP is configured. In this case the MIP_ID is model is used, then one MIP is configured. In this case, the MIP_ID
formed using the Node_ID and an IF_Num of 0. is formed using the Node_ID and an IF_Num of 0.
8. IANA Considerations
There are no IANA actions resulting from this document.
9. Security Considerations 8. Security Considerations
This document describes an information model and, as such, does not This document describes an information model and, as such, does not
introduce security concerns. Protocol specifications that describe introduce security concerns. Protocol specifications that describe
use of this information model, however, may introduce security risks use of this information model, however, may introduce security risks
and concerns about authentication of participants. For this reason, and concerns about authentication of participants. For this reason,
the writers of protocol specifications for the purpose of describing the writers of protocol specifications for the purpose of describing
implementation of this information model need to describe security implementation of this information model need to describe security
and authentication concerns that may be raised by the particular and authentication concerns that may be raised by the particular
mechanisms defined and how those concerns may be addressed. mechanisms defined and how those concerns may be addressed.
Uniqueness of the identifiers from this document is guaranteed by the Uniqueness of the identifiers from this document is guaranteed by the
assigner (e.g., a Global_ID is unique based on the assignment of ASNs assigner (e.g., a Global_ID is unique based on the assignment of ASNs
from IANA and both a Node_ID and a IF_Num are unique based on the from IANA and both a Node_ID and an IF_Num are unique based on the
assignment by an operator). Failure by an assigner to use unique assignment by an operator). Failure by an assigner to use unique
values within the specified scoping for any of the identifiers values within the specified scoping for any of the identifiers
defined herein could result in operational problems. For example and defined herein could result in operational problems. For example, a
non-unique MEP value could result in failure to detect a mis-merged non-unique MEP value could result in failure to detect a mis-merged
LSP. LSP.
Protocol specifications that utilize the identifiers defined herein Protocol specifications that utilize the identifiers defined herein
need to consider the implications of guessable identifiers and, where need to consider the implications of guessable identifiers and, where
there is a security implication, SHOULD give advice on how to make there is a security implication, SHOULD give advice on how to make
identifiers less guessable. identifiers less guessable.
10. References 9. References
10.1. Normative References 9.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and [2] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and
G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels",
RFC 3209, December 2001. RFC 3209, December 2001.
[3] Metz, C., Martini, L., Balus, F., and J. Sugimoto, "Attachment [3] Metz, C., Martini, L., Balus, F., and J. Sugimoto, "Attachment
Individual Identifier (AII) Types for Aggregation", RFC 5003, Individual Identifier (AII) Types for Aggregation", RFC 5003,
skipping to change at page 16, line 36 skipping to change at page 17, line 5
Signaling Functional Description", RFC 3471, January 2003. Signaling Functional Description", RFC 3471, January 2003.
[5] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) [5] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS)
Signaling Resource ReserVation Protocol-Traffic Engineering Signaling Resource ReserVation Protocol-Traffic Engineering
(RSVP-TE) Extensions", RFC 3473, January 2003. (RSVP-TE) Extensions", RFC 3473, January 2003.
[6] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, [6] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron,
"Pseudowire Setup and Maintenance Using the Label Distribution "Pseudowire Setup and Maintenance Using the Label Distribution
Protocol (LDP)", RFC 4447, April 2006. Protocol (LDP)", RFC 4447, April 2006.
10.2. Informative References 9.2. Informative References
[7] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and [7] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and
S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654, S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654,
September 2009. September 2009.
[8] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB", [8] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB",
RFC 2863, June 2000. RFC 2863, June 2000.
[9] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A [9] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A
Framework for MPLS in Transport Networks", RFC 5921, July 2010. Framework for MPLS in Transport Networks", RFC 5921, July 2010.
skipping to change at page 17, line 13 skipping to change at page 17, line 28
Data Plane Architecture", RFC 5960, August 2010. Data Plane Architecture", RFC 5960, August 2010.
Authors' Addresses Authors' Addresses
Matthew Bocci Matthew Bocci
Alcatel-Lucent Alcatel-Lucent
Voyager Place, Shoppenhangers Road Voyager Place, Shoppenhangers Road
Maidenhead, Berks SL6 2PJ Maidenhead, Berks SL6 2PJ
UK UK
Email: matthew.bocci@alcatel-lucent.com EMail: matthew.bocci@alcatel-lucent.com
George Swallow George Swallow
Cisco Cisco
Email: swallow@cisco.com EMail: swallow@cisco.com
Eric Gray Eric Gray
Ericsson Ericsson
900 Chelmsford Street 900 Chelmsford Street
Lowell, Massachussetts 01851-8100 Lowell, Massachussetts 01851-8100
Email: eric.gray@ericsson.com EMail: eric.gray@ericsson.com
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