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Versions: (draft-swallow-mpls-tp-identifiers)
00 01 02 03 04 05 06 07 RFC 6370
MPLS Working Group M. Bocci
Internet-Draft Alcatel-Lucent
Intended status: Standards Track G. Swallow
Expires: September 4, 2011 Cisco
E. Gray
Ericsson
March 3, 2011
MPLS-TP Identifiers
draft-ietf-mpls-tp-identifiers-04
Abstract
This document specifies identifiers for MPLS-TP objects. Included
are identifiers conformant to existing ITU conventions and
identifiers which are compatible with existing IP, MPLS, GMPLS, and
Pseudowire definitions.
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
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
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 4, 2011.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4
1.3. Notational Conventions in Backus-Naur Form . . . . . . . . 4
2. Named Entities . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Uniquely Identifying an Operator . . . . . . . . . . . . . . . 5
3.1. The Global ID . . . . . . . . . . . . . . . . . . . . . . 5
3.2. ITU Carrier Code . . . . . . . . . . . . . . . . . . . . . 6
4. Node and Interface Identifiers . . . . . . . . . . . . . . . . 6
5. MPLS-TP Tunnel and LSP Identifiers . . . . . . . . . . . . . . 7
5.1. MPLS-TP Point to Point Tunnel Identifiers . . . . . . . . 8
5.2. MPLS-TP LSP Identifiers . . . . . . . . . . . . . . . . . 8
5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers . . . 8
5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers . . . 9
5.3. Mapping to GMPLS and RSVP-TE Signalling . . . . . . . . . 9
6. Pseudowire Path Identifiers . . . . . . . . . . . . . . . . . 10
7. Maintenance Identifiers . . . . . . . . . . . . . . . . . . . 11
7.1. Maintenance Entity Group Identifiers . . . . . . . . . . . 11
7.1.1. ICC-based MEG Identifiers . . . . . . . . . . . . . . 12
7.1.2. IP Compatible MEG_IDs . . . . . . . . . . . . . . . . 12
7.1.2.1. MPLS-TP LSP MEG_IDs . . . . . . . . . . . . . . . 12
7.1.2.2. Pseudowire MEG_IDs . . . . . . . . . . . . . . . . 12
7.2. MEP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.2.1. ICC-based MEP Identifiers . . . . . . . . . . . . . . 12
7.2.2. IP based MEP_IDs . . . . . . . . . . . . . . . . . . . 13
7.2.2.1. MPLS-TP LSP_MEP_ID . . . . . . . . . . . . . . . . 13
7.2.2.2. MEP_IDs for Pseudowires . . . . . . . . . . . . . 13
7.2.2.3. Pseudowire Segments Endpoint IDs . . . . . . . . . 13
7.3. MIP Identifiers . . . . . . . . . . . . . . . . . . . . . 14
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
9. Security Considerations . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
This document specifies identifiers to be used in within the
Transport Profile of Multiprotocol Label Switching (MPLS-TP). The
MPLS-TP requirements (RFC 5654) [7] require that the elements and
objects in an MPLS-TP environment are able to be configured and
managed without a control plane. In such an environment many
conventions for defining identifiers are possible. This document
defines identifiers for MPLS-TP management and OAM functions suitable
to ITU conventions and to IP/MPLS conventions. Applicability of the
different identifier schemas to different applications is outside the
scope of this document.
1.1. Terminology
AII: Attachment Interface Identifier
ASN: Autonomous System Number
FEC: Forwarding Equivalence Class
GMPLS: Generalized Multi-Protocol Label Switching
ICC: ITU Carrier Code
LSP: Label Switched Path
LSR: Label Switching Router
ME: Maintenance Entity
MEG: Maintenance Entity Group
MEP: Maintenance Entity Group End Point
MIP: Maintenance Entity Group Intermediate Point
MPLS: Multi-Protocol Label Switching
NNI: Network-to-Network Interface
OAM: Operations, Administration and Maintenance
P2MP: Point to Multi-Point
P2P: Point to Point
PW: Pseudowire
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RSVP: Resource Reservation Protocol
RSVP-TE: RSVP Traffic Engineering
S-PE: Switching Provider Edge
T-PE: Terminating Provider Edge
1.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [1].
1.3. 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 (using double-colon - "::" - notation).
Where the same identifier type is used multiple times in a
concatenation, they are qualified by a prefix joined to the
identifier by a dash (-). For example East-Node_ID is the Node_ID of
a node referred to as East.
2. Named Entities
In order to configure, operate and manage a transport network based
on the MPLS Transport Profile, a number of entities require
identification. Identifiers for the follow entities are defined in
this document:
o Operator
* Global_ID
* ICC
o LSR
o LSP
o PW
o Interface
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o MEG
o MEP
o MIP
o Tunnel
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
association between a source and destination LSR. The tunnel in turn
is instantiated by one or more LSPs, where the additional LSPs are
used for protection or re-grooming of the tunnel.
3. Uniquely Identifying an Operator
An operator is uniquely identified by an Operator Identifier
(Opr_ID). Two formats are defined, one that is compatible with IP
operational practice called a Global_ID and or one compatible with
ITU practice, the ICC. An The Opr_ID MAY use either the Global_ID or
ICC format.
3.1. The Global ID
RFC 5003 [3] defines a globally unique Attachment Interface
Identifier (AII). That AII is composed of three parts, a Global_ID
which uniquely identifies a operator, a prefix, and finally and
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
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
derived from the globally unique ASN of the 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."
When the Global_ID is derived from a 2-octet AS number, the two high-
order octets of this 4-octet identifier MUST be set to zero. Further
ASN 0 is reserved. A Global_ID of zero means that no Global_ID is
present. Note that a Global_ID of zero is limited to entities
contained within a single operator and MUST NOT be used across an
NNI. A non-zero Global_ID MUST be derived from an ASN owned by the
operator.
Note that this Global_ID is used solely to provide a globally unique
context for other MPLS-TP identifiers. It has nothing to do with the
use of the ASN in protocols such as BGP.
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3.2. ITU Carrier Code
M.1400 defines the ITU Carrier Code (ICC) assigned to a network
operator/service provider and maintained by the ITU-T
Telecommunication Standardization Bureau (TSB): www.itu.int/ITU-T/
inr/icc/index.html.
ICCs can be assigned both to ITU-T and non-ITU-T members and the
referenced local ICC website may contain ICCs of operators of both
kinds.
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.
Alphabetic characters in the ICC SHOULD be represented with upper
case letters.
4. Node and Interface Identifiers
An LSR requires identification of the node itself and of its
interfaces. An interface is the attachment point to a server layer
MPLS-TP section or MPLS-TP tunnel.
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
operator within the scope of the Global_ID. The structure of the
Node_ID is operator specific and is outside the scope of this
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
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
operator's IGP or BGP. Where IPv6 addresses are used exclusively, a
32-bit value unique within the scope of the Global_ID is assigned.
A LSR can support multiple layers (e.g. hierarchical LSPs) and the
Node_ID belongs to the multiple layer context i.e. it is applicable
to all LSPs or PWs that originate on, have a midpoint on, or
terminate on the node.
In situations where a Node_ID needs to be globally unique, this is
accomplished by prefixing the identifier with the operator's Opr_ID.
The particular combination of Global_ID::Node_ID we call a Global
Node ID or Global_Node_ID.
Within the context of a particular node, we call the identifier
associated with an interface an Interface Number or IF_Num. The
IF_Num is a 32-bit unsigned integer assigned by the operator and MUST
be unique within the scope of a Node_ID. The IF_Num value 0 has
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special meaning (see section , MIP Identifiers) (Section 7.3) and
MUST NOT be used to identify an MPLS-TP interface.
An Interface Identifier or IF_ID identifies an interface uniquely
within the context of an Opr_ID. It is formed by concatenating the
Node_ID with the IF_Num. That is an IF_ID is a 64-bit identifier
formed as Node_ID::IF_Num.
This convention was chosen to allow compatibility with GMPLS. GMPLS
signaling [4] requires interface identification. GMPLS allows three
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.
If an IF_ID needs to be globally unique, this is accomplished by
prefixing the identifier with the operator's Opr_ID.
The attachment point to an MPLS-TP Tunnel (see section Section 5.1
also needs an interface identifier. Note that MPLS-TP supports
hierarchical tunnels. The attachment point to a MPLS-TP Tunnel at
any sub layer requires a unique IF_ID.
5. MPLS-TP Tunnel and LSP Identifiers
In MPLS the actual transport of packets is provided by label switched
paths (LSPs). A transport service may be composed of multiple LSPs.
Further the LSPs providing a service may change over time due to
protection and restoration events. In order to clearly identify the
service we use the term "MPLS-TP Tunnel" or simply "tunnel" for a
service provided by (for example) a working LSP and protected by a
protection LSP. The Tunnel_ID identifies the transport service and
provides a stable binding to the client in the face of changes in the
the data plane LSPs used to provide the service due to protection and
restoration events. This section defines an MPLS-TP Tunnel_ID to
uniquely identify a tunnel and MPLS-TP LSP_IDs within the context of
that tunnel.
For the case where multiple LSPs (for example) are used to support a
single service with a common set of end-points, using this identifier
allows for a trivial mapping between the server and client layers to
a common service identifier which may be either defined by, or used
by, the client.
Note that this usage is not intended to constrain protection schemes,
and may be used to identify any service (protected or un-protected)
that may appear to the client as a single service attachment point.
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Keeping the tunnel number consistent across working and protection
LSPs is a useful construct currently employed within GMPLS. However
there is no requirement that a protection LSP use the same tunnel
number as the working LSP.
5.1. MPLS-TP Point to Point Tunnel Identifiers
At each endpoint a tunnel is uniquely identified by the endpoint's
Node_ID and a locally assigned tunnel number. Specifically a
Tunnel_Num is a 16-bit unsigned integer unique within the context of
the Node_ID. The motivation for each endpoint having its own tunnel
number is to allow a compact form for the MEP-ID. See section
Section 7.1.2.1.
Having two tunnel numbers also serves to simplify other signaling
(e.g., setup of associated bi-directional tunnels as described in
section Section 5.3.)
The concatenation of the two endpoint identifiers serves as the full
identifier. In a configured environment the endpoints are often
called East and West. Using this convention the format of the format
of a Tunnel_ID is:
East-Node_ID::East-Tunnel_Num::West-Node_ID::West-Tunnel_Num
Where the Tunnel_ID needs to be globally unique, this is accomplished
by using globally unique Node_IDs as defined above. Thus a globally
unique Tunnel_ID becomes:
East-Global_Node_ID::East-Tunnel_Num::West-Global_Node_ID::
West-Tunnel_Num
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 is composed of the local NODE_ID concatenated with a 32-bit
IF_Num.
5.2. MPLS-TP LSP Identifiers
5.2.1. MPLS-TP Co-Routed Bidirectional LSP Identifiers
For 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_Num is a 16-bit unsigned integer unique within
the Tunnel_ID. Thus the format of a LSP_ID is:
East-Node_ID::East-Tunnel_Num::West-Node_ID::West-
Tunnel_Num::LSP_Num
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Where the LSP_ID needs to be globally unique, this is accomplished by
using globally unique Node_IDs as defined above. Thus a globally
unique LSP_ID becomes:
East-Global_Node_ID::East-Tunnel_Num::West-Global_Node_ID::
West-Tunnel_Num::LSP_Num
The corresponding ICC-based version of this identifier would be:
East-ICC::East-Node_ID::East-Tunnel_Num::West-ICC::West-Node_ID::
West-Tunnel_Num::LSP_Num
5.2.2. MPLS-TP Associated Bidirectional LSP Identifiers
For an associated bidirectional LSP each of the unidirectional LSPs
from East to West and West to East require LSP IDs. The each LSP can
be uniquely identified by a single LSP number within the scope of the
senders Tunnel_Num. Specifically an LSP_Num is a 16-bit unsigned
integer unique within the Tunnel_Num. Thus the format of a LSP_ID is:
East-Node_ID::East-Tunnel_Num::East-LSP_Num::
West-Node_ID::West-Tunnel_Num::West-LSP_Num
Where the LSP_ID needs to be globally unique, this is accomplished by
using globally unique Node_IDs as defined above. Thus a globally
unique LSP_ID becomes:
East-Global_Node_ID::East-Tunnel_Num::East-LSP_Num::
West-Global_Node_ID::West-Tunnel_Num::West-LSP_Num
The corresponding ICC-based version of this identifier would be:
East-ICC::East-Node_ID::East-Tunnel_Num::East-LSP_Num::
West-ICC::West-Node_ID::West-Tunnel_Num::West-LSP_Num
5.3. Mapping to GMPLS and RSVP-TE Signalling
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.
Thus a mapping is only made for the network unique form of the
LSP_ID.
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
Address, Tunnel_ID, Extended Tunnel ID, and Tunnel Sender Address and
(GMPLS) LSP_ID.
In situations where a mapping to the GMPLS 5-tuple is required, the
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following mapping is used.
o Tunnel Endpoint Address = West-Node_ID
o Tunnel_ID = East-Tunnel_Num
o Extended Tunnel_ID = East-Node_ID
o Tunnel Sender Address = East-Node_ID
o LSP_ID = East-LSP_Num
An associated bi-directional LSP between two nodes East and West
consists of two uni-directional LSPs, one from East to West and one
from West to East. RSVP-TE is capable of signaling such LSPs.
In situations where a mapping to the RSVP 5-tuples is required, the
following mappings are used. For the East to West LSP the mapping
would be:
o Tunnel Endpoint Address = West-Node_ID
o Tunnel_ID = East-Tunnel_Num
o Extended Tunnel_ID = East-Node_ID
o Tunnel Sender Address = East-Node_ID
o LSP_ID = East-LSP_Num
Likewise, the East to West LSP the mapping would be:
o Tunnel Endpoint Address = East-Node_ID
o Tunnel_ID = West-Tunnel_Num
o Extended Tunnel_ID = West-Node_ID
o Tunnel Sender Address = West-Node_ID
o LSP_ID = West-LSP_Num
6. Pseudowire Path Identifiers
Pseudowire signaling (RFC 4447 [6]) defines two FECs used to signal
pseudowires. Of these, FEC Type 129 along with AII Type 2 as defined
in RFC 5003 [3] fits the identification requirements of MPLS-TP.
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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
AII Type 2. To distinguish this identifier from other Pseudowire
Identifiers, we call this a Pseudowire Path Identifier or PW_Path_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
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.
To complete the FEC 129, all that is required is a Attachment Group
Identifier (AGI). That field is exactly as specified in RFC 4447.
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
a purely configured environment when referring to the entire PW, this
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
environment, the required convention in RFC 4447 is that at a
particular endpoint, the AII associated with that endpoint comes
first. The complete PW_Path_Id is:
AGI::East-Global_Node_ID::East-AC_ID::West-Global_Node_ID::
West-AC_ID.
The corresponding ICC-based version for this identifier would be:
AGI::East-ICC::East-Node_ID::East-AC_ID::West-ICC::West-Node_ID::
West-AC_ID
7. Maintenance Identifiers
In MPLS-TP a Maintenance Entity Group (MEG) represents an Entity that
requires management and defines a relationship between a set of
maintenance points. A maintenance point is either Maintenance Entity
Group End-point (MEP) or a Maintenance Entity Group Intermediate
Point (MIP). Maintenance points are uniquely associated with a MEG.
Within the context of a MEG, MEPs and MIPs must be uniquely
identified. This section defines a means of uniquely identifying
Maintenance Entity Groups, Maintenance Entities and uniquely defining
MEPs and MIPs within the context of a Maintenance Entity Group.
7.1. Maintenance Entity Group Identifiers
Maintenance Entity Group Identifiers (MEG_IDs) are required for
MPLS-TP LSPs and Pseudowires. Two classes of MEG_IDs are defined,
one that follows the IP compatible identifier defined above as well
as the ICC-format.
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7.1.1. ICC-based MEG Identifiers
MEG_ID for MPLS-TP LSPs and Pseudowires MAY use the globally unique
ICC-based format.
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.
0-9) characters. It consists of two subfields: the ICC (as defined
in section 3) followed by a unique MEG code (UMC). The UMC MUST be
unique within the organization identified by the ICC.
The ICC MEG_ID may be applied equally to a single MPLS-TP LSP or
Pseudowires. Note that when encoded in a protocol such as in a TLV,
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
7.1.2.1. MPLS-TP LSP MEG_IDs
Since a MEG pertains to a single MPLS-TP LSP, IP compatible MEG_IDs
for MPLS-TP LSPs are simply the corresponding LSP_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 LSP_ID and MPLS-TP LSP MEG_IDs
are to be encoded in TLVs different types need to be assigned for
these two identifiers.
7.1.2.2. Pseudowire MEG_IDs
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
while the two identifiers are syntactically identical, they have
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
encoded in TLVs different types need to be assigned for these two
identifiers.
7.2. MEP_IDs
7.2.1. ICC-based MEP Identifiers
ICC-based MEP_IDs for MPLS-TP LSPs and Pseudowires are formed by
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
the identifier associated with a MEP the MEP Index (MEP_Index). The
MEP_Index is administratively assigned. It is encoded as a 16-bit
unsigned integer and MUST be unique within the MEG. An ICC-based
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MEP_ID is:
MEG_ID::MEP_Index
An ICC-based MEP ID is globally unique by construction given the ICC-
based MEG_ID global uniqueness.
7.2.2. IP based MEP_IDs
7.2.2.1. MPLS-TP LSP_MEP_ID
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.
The MPLS-TP LSP_MEP_ID is
Node_ID::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 the case of
Associated Bi-directional LSPs, the LSP_Num unique to where the MEP
resides.
In situations where global uniqueness is required this becomes:
Global_ID::Node_ID::Tunnel_Num::LSP_Num
7.2.2.2. MEP_IDs for Pseudowires
Like MPLS-TP LSPs, Pseudowire endpoints (T-PEs) require MEP_IDs. In
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
used in end-to-end for an Pseudowire T-PE takes the form
AGI:Global_ID::Node_ID::AC_ID,
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.
7.2.2.3. Pseudowire Segments Endpoint IDs
In some OAM communications, messages are originated by the node at
one end of a PW segment and relayed to the other end of that same
segment by setting the TTL of the PW label to one (1). For a multi-
segment pseudowire, TTL could be set to any value that would cause
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OAM messages to reach the target segment end-point (up to and
including 255). In such communications an identifier for the
pseudowire segment endpoint. We call this a Pseudowire Segments
Endpoint ID or PW_SE_ID.
The PW_SE_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
segments. We distinguish the segments by using the MEP_ID which is
upstream of the PW segment in question. To complete the
identification we suffix this with the identification of the local
node.
+-------+ +-------+ +-------+ +-------+
| | | | | | | |
| A|---------|B C|---------|D E|---------|F |
| | | | | | | |
+-------+ +-------+ +-------+ +-------+
(T)PE1 (S)PE2 (S)PE3 (T)PE4
Pseudowire Maintenance Points
For example, suppose that in the above figure all of the nodes have
Global_ID GID1; the node are represented as named in the figure; and
The identification for the Pseudowire is:
AGI = AGI1
East-Global_ID = GID1
East-Node_ID = PE1
East-AC_ID = AII1
West-Global_ID = GID1
West-Node_ID = PE4
West-AC_ID = AII4
The MEP_ID at point A would be -
AGI1::GID1::PE1::AII1
The PW_SE_ID at point C would be -
AGI1::GID1::PE1::AII1::GID1::PE2
7.3. MIP Identifiers
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
cross-connected via the label bindings of the MPLS-TP LSP. This
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Internet-Draft MPLS-TP Identifiers March 2011
allows, two MIPs to be independently identified in one 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 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
This document describes an information model and, as such, does not
introduce security concerns. Protocol specifications that describe
use of this information model - however - may introduce security
risks and concerns about authentication of participants. For this
reason, the writers of protocol specifications for the purpose of
describing implementation of this information model need to describe
security and authentication concerns that may be raised by the
particular mechanisms defined and how those concerns may be
addressed.
10. References
10.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G.
Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels",
RFC 3209, December 2001.
[3] Metz, C., Martini, L., Balus, F., and J. Sugimoto, "Attachment
Individual Identifier (AII) Types for Aggregation", RFC 5003,
September 2007.
[4] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS)
Signaling Functional Description", RFC 3471, January 2003.
[5] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS)
Signaling Resource ReserVation Protocol-Traffic Engineering
(RSVP-TE) Extensions", RFC 3473, January 2003.
[6] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron,
"Pseudowire Setup and Maintenance Using the Label Distribution
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Internet-Draft MPLS-TP Identifiers March 2011
Protocol (LDP)", RFC 4447, April 2006.
10.2. Informative References
[7] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and S.
Ueno, "Requirements of an MPLS Transport Profile", RFC 5654,
September 2009.
Authors' Addresses
Matthew Bocci
Alcatel-Lucent
Voyager Place, Shoppenhangers Road
Maidenhead, Berks SL6 2PJ
UK
Email: matthew.bocci@alcatel-lucent.com
George Swallow
Cisco
Email: swallow@cisco.com
Eric Gray
Ericsson
900 Chelmsford Street
Lowell, Massachussetts 01851-8100
Email: eric.gray@ericsson.com
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