draft-ietf-mpls-tp-identifiers-01.txt   draft-ietf-mpls-tp-identifiers-02.txt 
MPLS Working Group M. Bocci MPLS Working Group M. Bocci
Internet-Draft Alcatel-Lucent Internet-Draft Alcatel-Lucent
Intended status: Standards Track G. Swallow Intended status: Standards Track G. Swallow
Expires: September 9, 2010 Cisco Expires: January 13, 2011 Cisco
March 8, 2010 July 12, 2010
MPLS-TP Identifiers MPLS-TP Identifiers
draft-ietf-mpls-tp-identifiers-01 draft-ietf-mpls-tp-identifiers-02
Abstract Abstract
This document specifies identifiers for MPLS-TP objects. Included This document specifies identifiers for MPLS-TP objects. Included
are identifiers conformant to existing ITU conventions and are identifiers conformant to existing ITU conventions and
identifiers which are compatible with existing IP, MPLS, GMPLS, and identifiers which are compatible with existing IP, MPLS, GMPLS, and
Pseudowire definitions. Pseudowire definitions.
Status of this Memo Status of this Memo
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Named Entities . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Named Entities . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Uniquely Identifying an Operator . . . . . . . . . . . . . . . 5 3. Uniquely Identifying an Operator . . . . . . . . . . . . . . . 5
3.1. The Global ID . . . . . . . . . . . . . . . . . . . . . . 5 3.1. The Global ID . . . . . . . . . . . . . . . . . . . . . . 5
3.2. ITU Carrier Code . . . . . . . . . . . . . . . . . . . . . 5 3.2. ITU Carrier Code . . . . . . . . . . . . . . . . . . . . . 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 Tunnel Identifiers . . . . . . . . . . . . . . . . 7 5.1. MPLS-TP Point to Point Tunnel Identifiers . . . . . . . . 7
5.2. MPLS-TP LSP Identifiers . . . . . . . . . . . . . . . . . 7 5.2. MPLS-TP LSP Identifiers . . . . . . . . . . . . . . . . . 8
5.3. Mapping to GMPLS Signalling . . . . . . . . . . . . . . . 8 5.3. Mapping to GMPLS Signalling . . . . . . . . . . . . . . . 8
6. Pseudowire Path Identifiers . . . . . . . . . . . . . . . . . 8 6. Pseudowire Path Identifiers . . . . . . . . . . . . . . . . . 9
7. Maintenance Identifiers . . . . . . . . . . . . . . . . . . . 9 7. Maintenance Identifiers . . . . . . . . . . . . . . . . . . . 9
7.1. Maintenance Entity Group Identifiers . . . . . . . . . . . 9 7.1. Maintenance Entity Group Identifiers . . . . . . . . . . . 10
7.1.1. ICC based MEG_IDs . . . . . . . . . . . . . . . . . . 9 7.1.1. ICC based MEG_IDs . . . . . . . . . . . . . . . . . . 10
7.1.2. IP Compatible MEG_IDs . . . . . . . . . . . . . . . . 10 7.1.2. IP Compatible MEG_IDs . . . . . . . . . . . . . . . . 10
7.1.2.1. MPLS-TP Tunnel MEG_IDs . . . . . . . . . . . . . . 10 7.1.2.1. MPLS-TP LSP MEG_IDs . . . . . . . . . . . . . . . 10
7.1.2.2. MPLS-TP LSP MEG_IDs . . . . . . . . . . . . . . . 10 7.1.2.2. Pseudowire MEG_IDs . . . . . . . . . . . . . . . . 10
7.1.2.3. Pseudowire MEG_IDs . . . . . . . . . . . . . . . . 10
7.2. MEP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 11 7.2. MEP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2.1. ICC based MEP_IDs . . . . . . . . . . . . . . . . . . 11 7.2.1. ICC based MEP_IDs . . . . . . . . . . . . . . . . . . 11
7.2.2. IP based MEP_IDs . . . . . . . . . . . . . . . . . . . 11 7.2.2. IP based MEP_IDs . . . . . . . . . . . . . . . . . . . 11
7.2.2.1. MEP_IDs for MPLS-TP LSPs and Tunnels . . . . . . . 11 7.2.2.1. MPLS-TP LSP_MEP_ID . . . . . . . . . . . . . . . . 11
7.2.2.2. MEP_IDs for Pseudowires . . . . . . . . . . . . . 12 7.2.2.2. MEP_IDs for Pseudowires . . . . . . . . . . . . . 11
7.2.2.3. MEP_IDs for Pseudowire Segments . . . . . . . . . 12 7.2.2.3. Endpoint IDs for Pseudowire Segments . . . . . . . 12
7.3. MIP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 13 7.3. MIP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 12
8. Open issues . . . . . . . . . . . . . . . . . . . . . . . . . 13 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . . 14 10.1. Normative References . . . . . . . . . . . . . . . . . . . 13
10.2. Informative References . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
This document specifies identifiers to be used in within the This document specifies identifiers to be used in within the
Transport Profile of Multiprotocol Label Switching (MPLS-TP). The Transport Profile of Multiprotocol Label Switching (MPLS-TP). The
MPLS-TP requirements [12] require that the elements and objects in an MPLS-TP requirements [12] require that the elements and objects in an
MPLS-TP environment are able to be configured and managed without a MPLS-TP environment are able to be configured and managed without a
control plane. In such an environment many conventions for defining control plane. In such an environment many conventions for defining
identifiers are possible. This document defines identifiers for identifiers are possible. This document defines identifiers for
MPLS-TP management and OAM functions suitable to ITU conventions and MPLS-TP management and OAM functions suitable to ITU conventions and
to IP/MPLS conventions. Applicability of the different identifier to IP/MPLS conventions. Applicability of the different identifier
schemas to different applications are outside the scope of this schemas to different applications are outside the scope of this
document. document.
1.1. Terminology 1.1. Terminology
AII: Attachment Interface Identifier AII: Attachment Interface Identifier
AP: Attachment Point
ASN: Autonomous System Number ASN: Autonomous System Number
FEC: Forwarding Equivalence Class FEC: Forwarding Equivalence Class
GMPLS: Generalized Multi-Protocol Label Switching GMPLS: Generalized Multi-Protocol Label Switching
ICC: ITU Carrier Code ICC: ITU Carrier Code
LSP: Label Switched Path LSP: Label Switched Path
skipping to change at page 3, line 50 skipping to change at page 3, line 52
MIP: Maintenance Entity Group Intermediate Point MIP: Maintenance Entity Group Intermediate Point
MPLS: Multi-Protocol Label Switching MPLS: Multi-Protocol Label Switching
OAM: Operations, Administration and Maintenance OAM: Operations, Administration and Maintenance
P2MP: Point to Multi-Point P2MP: Point to Multi-Point
P2P: Point to Point P2P: Point to Point
PSC: Protection State Coordination
PW: Pseudowire PW: Pseudowire
RSVP: Resource Reservation Protocol RSVP: Resource Reservation Protocol
RSVP-TE: RSVP Traffic Engineering RSVP-TE: RSVP Traffic Engineering
S-PE: Switching Provider Edge S-PE: Switching Provider Edge
T-PE: Terminating Provider Edge T-PE: Terminating Provider Edge
Requirements Language 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].
Notational Conventions in Backus-Naur Form
All multiple-word atomic identifiers use underscores (_) between the
words to join the words. Many of the identifiers are composed of a
concatenation of other identifiers, these are expressed using Backus-
Naur Form. Where the same identifier is used multiple times in a
concatenation, they are qualified by a prefix joining it to the
identifier by a dash (-). For example Src-Node_ID is the Node_ID of
a node referred to as Src (short for source).
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 follow entities are defined in identification. Identifiers for the follow entities are defined in
this document: this document:
o Operator o Operator
* ICC
* Global_ID * Global_ID
* ICC
o LSR o LSR
o LSP o LSP
o PW o PW
o Interface o Interface
o MEG o MEG
o MEP o MEP
o MIP o MIP
o Tunnel o Tunnel
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 an LSP [2] where it is used to describe an entity that provides a connection
connection between a source and destination LSR which in turn is between a source and destination LSR. The tunnel in turn is
instantiated by one or more LSPs, where the additional LSPs are used instantiated by one or more LSPs, where the additional LSPs are used
for protection or re-grooming of the tunnel. for protection or re-grooming of the tunnel.
3. Uniquely Identifying an Operator 3. Uniquely Identifying an Operator
Two forms of identification are defined, one that is compatible with Two forms of identification are defined, one that is compatible with
IP operational practice called a Global_ID and one compatible with IP operational practice called a Global_ID and one compatible with
ITU practice, the ICC. An Operator MAY be identified either by its ITU practice, the ICC. An Operator MAY be identified either by its
Global_ID or by its ICC. Global_ID or by its ICC.
3.1. The Global ID 3.1. The Global ID
RFC 5003 [3] defines a globally unique Attachment Interface RFC 5003 [3] defines a globally unique Attachment Interface
Identifier (AII). That AII is composed of three parts, a Global ID Identifier (AII). That AII is composed of three parts, a Global_ID
which uniquely identifies a operator, a prefix, and finally and which uniquely identifies a operator, a prefix, and finally and
attachment circuit identifier. We have chosen to use that Global ID attachment circuit identifier. We have chosen to use that Global ID
for MPLS-TP. Quoting from RFC 5003, section 3.2, "The global ID can for MPLS-TP. Quoting from RFC 5003, section 3.2, "The global ID can
contain the 2-octet or 4-octet value of the operator's Autonomous contain the 2-octet or 4-octet value of the operator's Autonomous
System Number (ASN). It is expected that the global ID will be System Number (ASN). It is expected that the global ID will be
derived from the globally unique ASN of the autonomous system hosting derived from the globally unique ASN of the autonomous system hosting
the PEs containing the actual AIIs. The presence of a global ID 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 based on the operator's ASN ensures that the AII will be globally
unique." unique."
skipping to change at page 6, line 8 skipping to change at page 6, line 17
kinds. kinds.
The ICC is a string of one to six characters, each character being The ICC is a string of one to six characters, each character being
either alphabetic (i.e. A-Z) or numeric (i.e. 0-9) characters. either alphabetic (i.e. A-Z) or numeric (i.e. 0-9) characters.
Alphabetic characters in the ICC SHOULD be represented with upper Alphabetic characters in the ICC SHOULD be represented with upper
case letters. case letters.
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. We call the identifier associated with a node a Node interfaces. An interface is the Access Point (AP) to a server layer
Identifier (Node_ID). Within the context of a particular node, we MPLS-TP section or MPLS-TP tunnel.
call the identifier associated with an interface an Logical Interface
Handle or LIH. The combination of Node_ID::LIH we call an Network
Interface ID or IF_ID.
In existing MPLS deployments Node_IDs are IPv4 addresses. Therefore We call the identifier associated with a node a Node Identifier
we have chosen the Node_ID to be a 32-bit value assigned by the (Node_ID). The Node_ID is a unique 32-bit unsigned integer assigned
operator. Where IPv4 addresses are in use the Node_ID can be by the operator within the scope of the Global_ID. The value 0 (or
0.0.0.0 in dotted decimal notation) is reserved MUST NOT be used.
The Node_ID is not an IPv4 address. However, it was chosen to be 32-
bits to allow compatibility with existing MPLS deployments. In
existing MPLS deployments LSRs are generally identified by an IPv4
loopback address. Where IPv4 addresses are in use the Node_ID MAY be
automatically mapped to the LSR's /32 IPv4 loopback address. Note automatically mapped to the LSR's /32 IPv4 loopback address. Note
that, when IP reachability is not needed, the 32-bit Node_ID is not that, when IP reachability is not needed, the 32-bit Node_ID is not
required to have any association with the IPv4 address space used in required to have any association with the IPv4 address space used in
the operator's IGP or BGP, other that that they be uniquely chosen the operator's IGP or BGP.
within the scope of that operator.
GMPLS signaling [4] requires interface identification. We have In situations where a Node_ID needs to be globally unique, this is
chosen to adopt the conventions of that RFC. GMPLS allows three accomplished by prefixing the identifier with the operator's
formats for the Interface_ID. For IP numbered links, it is simply Global_ID. The combination of Global_ID::Node_ID we call an Global
the IPv4 or IPv6 address associated with the interface. The third Node ID or Global_Node_ID.
format consists of an IPv4 Address plus a 32-bit unsigned integer for
the specific interface.
For MPLS-TP, we have adopted a format consistent with the third Within the context of a particular node, we call the identifier
format above. In MPLS-TP, each interface is assigned a 32-bit associated with an interface an Interface Number or IF_Num. The
identifier which we call a Logical Interface Handle (LIH). The LIH IF_Num is a 32-bit unsigned integer assigned by the operator and MUST
MUST be unique within the context of the Node_ID. We map the Node_ID be unique within the scope of a Node_ID. The IF_Num value 0 has
to the field the field which carries the IP address. That is, an special meaning (see section Section 7.3 and must not be used as the
IF_ID is a 64-bit identifier consisting of the Node_ID followed by IF_Num in an MPLS-TP IF_ID.
the LIH. The LIH in turn is a 32-bit unsigned integer unique to the
node. The LIH value 0 has special meaning (see section Section 7.3
and must not be used as the LIH in an MPLS-TP IF_ID.
In situations where a Node_ID or an IF_ID needs to be globally An Interface Identifier or IF_ID identifies an interface uniquely
unique, this is accomplished by prefixing the identifier with the within the context of a Global_ID. It is formed by concatenating the
operator's Global_ID. The combination of Global_ID::Node_ID we call Node_ID with the IF_Num. That is an IF_ID is a 64-bit identifier
an Global Node ID or Global_Node_ID. Likewise, the combination of formed as Node_ID::IF_Num.
Global_ID::Node_ID::LIH we call an Global Interface ID or
Global_IF_ID.
MPLS-TP Tunnels (see section Section 5.1) also need interface This convention was chosen to allow compatibility with GMPLS. GMPLS
identifiers. A procedure for automatically generating these is signaling [4] requires interface identification. GMPLS allows three
contained in that section. formats for the Interface_ID. The third format consists of an IPv4
Address plus a 32-bit unsigned integer for the specific interface.
The format defined for MPLS-TP is consistent with this format, but
uses the Node_ID instead of an IPv4 Address.
An IF_ID needs to be globally unique, this is accomplished by
prefixing the identifier with the operator's Global_ID. The
combination of Global_ID::Node_ID::IF_Num we call an Global Interface
ID or Global_IF_ID.
The attachment point to an MPLS-TP Tunnel (see section Section 5.1
also needs an interface identifier. A procedure for automatically
generating these is contained in that section.
5. MPLS-TP Tunnel and LSP Identifiers 5. MPLS-TP Tunnel and LSP Identifiers
A important construct within MPLS_TP is a connection which is A important construct within MPLS_TP is a connection which is
provided across a working and a protection LSP. Within this document provided across a working and a protection LSP. Within this document
we will use the term MPLS-TP Tunnel or simply tunnel for the we will use the term MPLS-TP Tunnel or simply tunnel for the
connection provided by the working and protect LSPs. This section connection provided by the working and protect LSPs. This section
defines an MPLS-TP Tunnel_ID to uniquely identify a tunnel and defines an MPLS-TP Tunnel_ID to uniquely identify a tunnel and
MPLS-TP LSP_IDs within the context of a tunnel. MPLS-TP LSP_IDs within the context of a tunnel.
5.1. MPLS-TP Tunnel Identifiers 5.1. MPLS-TP Point to Point Tunnel Identifiers
At each endpoint a tunnel is uniquely identified by the Source At each endpoint a tunnel is uniquely identified by the endpoint's
Node_ID and a locally assigned tunnel number. Specifically a Node_ID and a locally assigned tunnel number. Specifically a
Tunnel_Num is a 16-bit unsigned integer unique to the node. The Tunnel_Num is a 16-bit unsigned integer unique within the context of
concatenation of the two endpoint identifier servers as the full the node. The motivation for each endpoint having its own tunnel
identifier. Thus the format of a Tunnel_ID is: number is to allow a compact form for the MEP-ID. See section
Section 7.1.2.1.
Having two tunnel-ids also serves to simplify other signaling. For
instance an associated bi-directional tunnel could be setup using two
unidirectional tunnels signaled via RSVP.
The concatenation of the two endpoint identifier servers as the full
identifier. In a signaled situation, the node originating the
signaling exchange is called the source and the target node is called
the destination. In a configured environment the endpoints could
equally be called East and West. Using the signaled convention and
abbreviating the endpoint qualifiers to Src and Dst respectively, the
format of the format of a Tunnel_ID is:
Src-Node_ID::Src-Tunnel_Num::Dst-Node_ID::Dst-Tunnel_Num Src-Node_ID::Src-Tunnel_Num::Dst-Node_ID::Dst-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:
Src-Global_ID::Src-Node_ID::Src-Tunnel_Num:: Dst-Global_ID::Dst- Src-Global_Node_ID::Src-Tunnel_Num::Dst-Global_Node_ID::
Node_ID::Dst-Tunnel_Num Dst-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 both the source and destination endpoints. As usual, the IF_ID at both the source and destination endpoints. As usual, the
IF_ID is composed of the local NODE_ID concatenated with a 32-bit IF_ID is composed of the local NODE_ID concatenated with a 32-bit
LIH. It is RECOMMENDED that the LIH be auto-generated by adding 2^31 IF_Num. It is RECOMMENDED that the IF_Num be auto-generated by adding
to the local Tunnel_Num. 2^31 to the local Tunnel_Num.
5.2. MPLS-TP LSP Identifiers 5.2. MPLS-TP LSP Identifiers
Within the scope of an MPLS-TP Tunnel_ID an LSP can be uniquely Within the scope of an MPLS-TP Tunnel_ID an LSP can be uniquely
identified by a single LSP number. Specifically an LSP_Num is a 16- identified by a single LSP number. Specifically an LSP_Num is a 16-
bit unsigned integer unique within the Tunnel_ID. Thus the format of bit unsigned integer unique within the Tunnel_ID. Thus the format of
a Tunnel_ID is: a LSP_ID is:
Src-Node_ID::Src-Tunnel_Num::Dst-Node_ID::Dst-Tunnel_Num:: LSP_Num Src-Node_ID::Src-Tunnel_Num::Dst-Node_ID::Dst-Tunnel_Num::LSP_Num
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 Tunnel_ID becomes: unique Tunnel_ID becomes:
Src-Global_ID::Src-Node_ID::Src-Tunnel_Num:: Dst-Global_ID::Dst- Src-Global_Node_ID::Src-Tunnel_Num::Dst-Global_Node_ID::
Node_ID::Dst-Tunnel_Num::LSP_Num Dst-Tunnel_Num::LSP_Num
5.3. Mapping to GMPLS Signalling 5.3. Mapping to GMPLS Signalling
This section defines the mapping from an MPLS-TP LSP_ID to GMPLS. At This section defines the mapping from an MPLS-TP LSP_ID to GMPLS. At
this time, GMPLS has yet to be extended to accommodate Global_IDs. this time, GMPLS has yet to be extended to accommodate Global_IDs.
Thus a mapping is only made for the network unique form of the Thus a mapping is only made for the network unique form of the
LSP_ID. LSP_ID.
GMPLS signaling [5] uses a 5-tuple to uniquely identify an LSP within GMPLS signaling [5] uses a 5-tuple to uniquely identify an LSP within
a operator's network. This tuple is composed of a Tunnel Endpoint a operator's network. This tuple is composed of a Tunnel Endpoint
skipping to change at page 9, line 9 skipping to change at page 9, line 37
Identifier (AGI). That field is exactly as specified in RFC 4447. Identifier (AGI). That field is exactly as specified in RFC 4447.
FEC 129 has a notion of Source AII (SAII) and Target AII (TAII). FEC 129 has a notion of Source AII (SAII) and Target AII (TAII).
These terms are used relative to the direction of the signaling. In These terms are used relative to the direction of the signaling. In
a purely configured environment when referring to the entire PW, this a purely configured environment when referring to the entire PW, this
distinction is not critical. That is a FEC 129 of AGIa::AIIb::AIIc distinction is not critical. That is a FEC 129 of AGIa::AIIb::AIIc
is equivalent to AGIa::AIIc::AIIb. We note that in a signaled is equivalent to AGIa::AIIc::AIIb. We note that in a signaled
environment, the required convention in RFC 4447 is that at a environment, the required convention in RFC 4447 is that at a
particular endpoint, the AII associated with that endpoint comes particular endpoint, the AII associated with that endpoint comes
first. The complete PW_Path_Id is: first. The complete PW_Path_Id is:
AGI:Src-Global_ID::Src-Node_ID::Src-AC_ID:: Dst-Global_ID::Dst- AGI:Src-Global_ID::Src-Node_ID::Src-AC_ID::Dst-Global_ID::
Node_ID::Dst-AC_ID. Dst-Node_ID::Dst-AC_ID.
7. Maintenance Identifiers 7. Maintenance Identifiers
[Note this section needs to reconciled with the MPLS-TP OAM
Framework]
In MPLS-TP a Maintenance Entity Group (MEG) represents an Entity that In MPLS-TP a Maintenance Entity Group (MEG) represents an Entity that
requires management and defines a relationship between a set of requires management and defines a relationship between a set of
maintenance points. A maintenance point is either Maintenance Entity maintenance points. A maintenance point is either Maintenance Entity
Group End-point (MEP) or a Maintenance Entity Group Intermediate Group End-point (MEP) or a Maintenance Entity Group Intermediate
Point (MIP). Maintenance points are uniquely associated with a MEG. Point (MIP). Maintenance points are uniquely associated with a MEG.
Within the context of a MEG, MEPs and MIPs must be uniquely Within the context of a MEG, MEPs and MIPs must be uniquely
identified. This section defines a means of uniquely identifying identified. This section defines a means of uniquely identifying
Maintenance Entity Groups, Maintenance Entities and uniquely defining Maintenance Entity Groups, Maintenance Entities and uniquely defining
MEPs and MIPs within the context of a Maintenance Entity Group. MEPs and MIPs within the context of a Maintenance Entity Group.
Note that depending on the requirements of a particular OAM Note that depending on the requirements of a particular OAM
interaction, the MPLS-TP maintenance entity context may be provided interaction, the MPLS-TP maintenance entity context may be provided
either explicitly using the MEG_IDs described above or implicitly by either explicitly using the MEG_IDs described above or implicitly by
the label of the received OAM message. the label of the received OAM message.
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 Paths and Pseudowires. Two classes of MEG_IDs are defined, MPLS-TP LSPs and Pseudowires. Two classes of MEG_IDs are defined,
one that follows the IP compatible identifier defined above as well one that follows the IP compatible identifier defined above as well
as the ICC-format. as the ICC-format.
7.1.1. ICC based MEG_IDs 7.1.1. ICC based MEG_IDs
MEG_ID for MPLS-TP LSPs and Pseudowires MAY use the globally unique MEG_ID for MPLS-TP LSPs and Pseudowires MAY use the globally unique
ICC-based format. ICC-based format.
In this case, the MEG_ID is a string of up to thirteen characters, In this case, the MEG_ID is a string of up to thirteen characters,
each character being either alphabetic (i.e. A-Z) or numeric (i.e. each character being either alphabetic (i.e. A-Z) or numeric (i.e.
0-9) characters. It consists of two subfields: the ICC (as defined 0-9) characters. It consists of two subfields: the ICC (as defined
in section 3) followed by a unique MEG code (UMC). in section 3) followed by a unique MEG code (UMC). The UMC MUST be
unique within the organization identified by the ICC.
The UMC MUST be unique within the organization identified by the ICC.
The ICC MEG_ID may be applied equally to MPLS-TP tunnels, a single
MPLS-TP LSP, groups of MPLS-TP LSPs, Pseudowires, and groups of
Pseudowires.
Note that when encoded in a protocol such as in a TLV, a different The ICC MEG_ID may be applied equally to a single MPLS-TP LSP or
type needs to be defined for LSP and PWs as the OAM capabilities may Pseudowires. Note that when encoded in a protocol such as in a TLV,
be different. a different type needs to be defined for LSP and PWs as the OAM
capabilities may be different.
7.1.2. IP Compatible MEG_IDs 7.1.2. IP Compatible MEG_IDs
7.1.2.1. MPLS-TP Tunnel MEG_IDs 7.1.2.1. MPLS-TP LSP MEG_IDs
Since a MEG pertains to a single MPLS-TP Tunnel, IP compatible
MEG_IDs for MPLS-TP Tunnels are simply the corresponding Tunnel_IDs.
We note that while the two identifiers are syntactically identical,
they have different semantics. This semantic difference needs to be
made clear. For instance if both a MPLS-TP Tunnel_ID and MPLS-TP
Tunnel MEG_IDs are to be encoded in TLVs different types need to be
assigned for these two identifiers.
7.1.2.2. MPLS-TP LSP MEG_IDs
MEG_IDs for MPLS-TP LSPs may pertain to one or more LSPs. Therefore
the direct mapping used for tunnels is not possible. However an
indirect mapping which keeps the formats aligned is possible. This
is done by replacing the LSP_Num with a LSP_MEG_Num. Thus the format
of a MPLS-TP LSP MEG_ID is:
Src-Global_ID::Src-Node_ID::Src-Tunnel_Num:: Dst-Global_ID::Dst-
Node_ID::Dst-Tunnel_Num::LSP_MEG_Num
When a MEG_ID is assigned to a single MPLS-TP LSP it is RECOMMENDED Since a MEG pertains to a single MPLS-TP LSP, IP compatible MEG_IDs
that the LSP_MEG_Num be assigned equal to the LSP_Num. When a MEG_ID for MPLS-TP LSPs are simply the corresponding LSP_IDs. We note that
is assigned to a group of MPLS-TP LSPs within a single MPLS-TP while the two identifiers are syntactically identical, they have
Tunnel, it is recommended that the MEG_ID be assigned equal to the different semantics. This semantic difference needs to be made
LSP_Num of one member of the group of MPLS-TP LSPs. In this clear. For instance if both a MPLS-TP LSP_ID and MPLS-TP LSP MEG_IDs
situation if the chosen LSP is later deconfigured it is RECOMMENDED are to be encoded in TLVs different types need to be assigned for
that this LSP_Num not be reused unless the new LSP in question will these two identifiers.
become a member of the same MEG.
7.1.2.3. Pseudowire MEG_IDs 7.1.2.2. 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. We note that MEG_ID for a PW is simply the corresponding PW_Path_ID. We note that
while the two identifiers are syntactically identical, they have while the two identifiers are syntactically identical, they have
different semantics. This semantic difference needs to be made different semantics. This semantic difference needs to be made
clear. For instance if both a PW_Path_ID and a PW_MEG_ID is to be clear. For instance if both a PW_Path_ID and a PW_MEG_ID is to be
encoded in TLVs different types need to be assigned for these two encoded in TLVs different types need to be assigned for these two
identifiers. identifiers.
7.2. MEP_IDs 7.2. MEP_IDs
7.2.1. ICC based MEP_IDs 7.2.1. ICC based MEP_IDs
ICC-based MEP_IDs for MPLS-TP LSPs and Pseudowires MAY be formed by ICC-based MEP_IDs for MPLS-TP LSPs and Pseudowires are formed by
appending a unique number to the MEG_ID defined in section appending a unique number to the MEG_ID defined in section
Section 7.1.1 above. Within the context of a particular MEG, we call Section 7.1.1 above. Within the context of a particular MEG, we call
the identifier associated with a MEP the MEP Index (MEP_Index). The the identifier associated with a MEP the MEP Index (MEP_Index). The
MEP_Index is administratively assigned and is encoded as a 16-bit MEP_Index is administratively assigned. It is encoded as a 16-bit
unsigned integer. An ICC-based MEP_ID is: unsigned integer and MUST be unique within the MEG. An ICC-based
MEP_ID is:
MEG_ID::MEP_Index MEG_ID::MEP_Index
An ICC-based MEP ID is globally unique by construction given the ICC- An ICC-based MEP ID is globally unique by construction given the ICC-
based MEG_ID global uniqueness. based MEG_ID global uniqueness.
7.2.2. IP based MEP_IDs 7.2.2. IP based MEP_IDs
7.2.2.1. MEP_IDs for MPLS-TP LSPs and Tunnels 7.2.2.1. MPLS-TP LSP_MEP_ID
In order to automatically generate MEP_IDs for MPLS-TP Tunnels and
LSPs, we use the elements of identification that are unique to an
endpoint. This ensures that MEP_IDs are unique for all Tunnels and
LSPs within a operator. When Tunnels or LSPs cross operator
boundaries, these are made unique by pre-pending them with the
operator's Global_ID.
7.2.2.1.1. MPLS-TP Tunnel_MEP_ID
A MPLS-TP Tunnel_MEP_ID is:
Src-Node_ID::Src-Tunnel_Num
In situations where global uniqueness is required this becomes:
Src-Global_ID::Src-Node_ID::Src-Tunnel_Num In order to automatically generate MEP_IDs for MPLS-TP LSPs, we use
the elements of identification that are unique to an endpoint. This
ensures that MEP_IDs are unique for all LSPs within a operator. When
Tunnels or LSPs cross operator boundaries, these are made unique by
pre-pending them with the operator's Global_ID.
7.2.2.1.2. MPLS-TP LSP_MEP_ID The MPLS-TP LSP_MEP_ID is
A MPLS-TP LSP_MEP_ID is: Node_ID::Tunnel_Num::LSP_Num,
Src-Node_ID::Src-Tunnel_Num::LSP_Num 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 situations where global uniqueness is required this becomes: In situations where global uniqueness is required this becomes:
Src-Global_ID::Src-Node_ID::Src-Tunnel_Num::LSP_Num Src-Global_ID::Src-Node_ID::Src-Tunnel_Num::LSP_Num
7.2.2.2. MEP_IDs for Pseudowires 7.2.2.2. MEP_IDs for Pseudowires
Like MPLS-TP LSPs, Pseudowire endpoints (T-PEs) require MEP_IDs. In Like MPLS-TP LSPs, Pseudowire endpoints (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
used in end-to-end for an Pseudowire T-PE takes the form: used in end-to-end for an Pseudowire T-PE takes the form
AGI:Src-Global_ID::Src-Node_ID::Src-AC_ID,
AGI:Src-Global_ID::Src-Node_ID::Src-AC_ID where the Node_ID is the node in which the MEP is located and
Tunnel_Num is the tunnel number unique to that node.
7.2.2.3. MEP_IDs for Pseudowire Segments 7.2.2.3. Endpoint IDs for Pseudowire Segments
In some OAM communications, messages are originated at one end of a In some OAM communications, messages are originated by the node at
PW segment and relayed to the other end by setting the TTL of the PW one end of a PW segment and relayed to the other end by setting the
label to one. TTL of the PW label to one.
The MEP_ID Is Formed by a combination of a PW MEP_ID and the The MEP_ID Is Formed by a combination of a PW MEP_ID and the
identification of the local node. At an S-PE, there are two PW identification of the local node. At an S-PE, there are two PW
segments. We distinguish the segments by using the MEP_ID which is segments. We distinguish the segments by using the MEP_ID which is
upstream of the PW segment in question. To complete the upstream of the PW segment in question. To complete the
identification we suffix this with the identification of the local identification we suffix this with the identification of the local
node. node.
+-------+ +-------+ +-------+ +-------+ +-------+ +-------+ +-------+ +-------+
| | | | | | | | | | | | | | | |
skipping to change at page 12, line 50 skipping to change at page 12, line 43
The identification for the Pseudowire is: The identification for the Pseudowire is:
AGI = AGI1 AGI = AGI1
Src-Global_ID = GID1 Src-Global_ID = GID1
Src-Node_ID = T-PE1 Src-Node_ID = T-PE1
Src-AC_ID = AII1 Src-AC_ID = AII1
Dst-Global_ID = GID1 Dst-Global_ID = GID1
Dst-Node_ID = T-PE1 Dst-Node_ID = T-PE1
Dst-AC_ID = AII4 Dst-AC_ID = AII4
The MEP_ID at point A would be AGI1::GID1:T-PE1::AII1. The MP_ID at The PW segment endpoint at point A would be AGI1::GID1:T-PE1::AII1.
point C would be AGI1::GID1:T-PE1::AII1::GID1:S-PE2. The MP_ID at point C would be AGI1::GID1:T-PE1::AII1::GID1:S-PE2.
For interaction where the T-PE is acting as the segment endpoint, it
too may use the Pseudowire Segment MEP_ID.
7.3. MIP_IDs 7.3. MIP_IDs
At a cross connect point, in order to automatically generate MIP_IDs At a cross connect point, in order to automatically generate MIP_IDs
for MPLS-TP, we simply use the IF_IDs of the two interfaces which are for MPLS-TP, we simply use the IF_IDs of the two interfaces which are
cross connected via the label bindings of the MPLS-TP LSP. If only cross connected via the label bindings of the MPLS-TP LSP. If only
one MIP is configured, then the MIP_ID is formed using the Node_ID one MIP is configured, then the MIP_ID is formed using the Node_ID
and an LIH of 0. In some contexts, such as LSP Ping[13], the Node_ID and an IF_Num of 0. In some contexts, such as LSP Ping[13], the
alone may be used as the MEP_ID. Node_ID alone may be used as the MIP_ID.
8. Open issues
1. MEPs and MIPs need to be aligned with MPLS-TP OAM Framework. 8. IANA Considerations
2. Identifiers for P2MP entities. 9. Security Considerations
9. References 10. References
9.1. Normative References 10.1. 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 14, line 25 skipping to change at page 14, line 14
[10] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD [10] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD
For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in progress), For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in progress),
June 2008. June 2008.
[11] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding [11] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Detection (BFD) for the Pseudowire Virtual Circuit Connectivity
Verification (VCCV)", draft-ietf-pwe3-vccv-bfd-07 (work in Verification (VCCV)", draft-ietf-pwe3-vccv-bfd-07 (work in
progress), July 2009. progress), July 2009.
9.2. Informative References 10.2. Informative References
[12] Vigoureux, M. and D. Ward, "Requirements for OAM in MPLS [12] Vigoureux, M. and D. Ward, "Requirements for OAM in MPLS
Transport Networks", draft-ietf-mpls-tp-oam-requirements-06 Transport Networks", draft-ietf-mpls-tp-oam-requirements-06
(work in progress), March 2010. (work in progress), March 2010.
[13] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label [13] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label
Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. Switched (MPLS) Data Plane Failures", RFC 4379, February 2006.
[14] Ohta, H., "Assignment of the 'OAM Alert Label' for [14] Ohta, H., "Assignment of the 'OAM Alert Label' for
Multiprotocol Label Switching Architecture (MPLS) Operation and Multiprotocol Label Switching Architecture (MPLS) Operation and
Maintenance (OAM) Functions", RFC 3429, November 2002. Maintenance (OAM) Functions", RFC 3429, November 2002.
[15] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and [15] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and
S. Ueno, "MPLS-TP Requirements", S. Ueno, "MPLS-TP Requirements",
draft-ietf-mpls-tp-requirements-10 (work in progress), draft-ietf-mpls-tp-requirements-10 (work in progress),
August 2009. August 2009.
[16] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A [16] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A
Framework for MPLS in Transport Networks", Framework for MPLS in Transport Networks",
draft-ietf-mpls-tp-framework-10 (work in progress), draft-ietf-mpls-tp-framework-12 (work in progress), May 2010.
February 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
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